KR20160025218A - Manufacturing method of water repellent starch - Google Patents

Abstract

The present invention relates to a process for preparing an extrudate by extruding a mixture comprising starch and siliconate to form an extrudate, wherein the content of the silonate in the mixture is from 2.5 to 50 parts by weight per 100 parts by weight of starch A method for producing water-repellent starch is provided. The production method of the present invention is suitable for mass production of water-repellent starch on an industrial scale, and the water-repellent starch produced by the production method of the present invention is used as an excipient for baby powder, a coating agent for wallpaper, a filling material for foam mat, Powder and the like.

Description

Technical Field [0001] The present invention relates to a water repellent starch,

The present invention relates to a method for producing a water-repellent starch, and more particularly, to a method for producing a water-repellent starch using a simple process.

Starch is a form of carbohydrate present in natural plants, abundant in grains, seeds, roots, and tubers, and has diverse functionality due to its structural characteristics. Specifically, the starch is a glucose polymer composed of? -D-glycosidic bond, wherein the glucose chain is composed of a straight-line amylase and a branching amylopectin And the size and structure of these chains are different depending on the plant from which the starch is derived. In addition, starch derivatives (commonly referred to as "modified starches") prepared by physical modification methods such as physical, chemical and biological treatments have been used for various purposes in food and industrial fields.

Particularly, as hydrophobically modified starches, hydrophobic starches having hydrophobicity increased by esterifying the hydroxyl group of the starch chain structure with alkenyl succinic anhydride are known. As the anhydrous alkenylsuccinic acid, octenyl succinic anhydride and anhydrous dodecenylsuccinic anhydride are mainly used. In the hydrophobic starch, hydroxy group, which is hydrophilic in chemical structure, is exposed to water and suspended in water to have high water repellency However, there is a problem in that sensory feeling is lowered due to the phenomenon that the particle size of each of the starches is fine, but the starch particles are bundled together.

Since it is unsatisfactory to improve the water repellency and sensory touch of the starch by only the hydrophobic group substitution reaction described above, a method of cross-linking a metal ion with a hydrophobic group substitution has been developed. Among them, aluminum starch octenylsuccinate (aluminum starch octenylsuccinate) prepared by replacing the hydroxy group of starch with hydrophobic octenyl succinic anhydride and crosslinking it with a metal ion such as aluminum ion has flowability, water repellency, And is widely used in various industries such as cosmetics, medicines, insecticides, paper and the like as an excipient, a filler, a diluent, a lubricant, an aggregation inhibitor and a flow improver.

In the prior art related to the method for producing the water-repellent starch, Korean Patent Registration No. 10-1108881 discloses a method for producing a water-repellent starch, which comprises (a) adding an acid at a concentration of 0.1 to 1% by weight to a starch slurry in water and performing a hydrolysis reaction at 40 to 60 ° C Wherein the starch separated from the reaction mixture by hydrolysis is added to water at a concentration of 6% (w / w), the starch is heated to 95 ° C to be gelatinized, and then cooled to 50 ° C to have a viscosity of 400 cP Or less; (b) adding C ₁₀ -C ₃₂ alkenylsuccinic anhydride to the reaction mixture obtained in step (a) to form a hydrophobic starch; And (c1) separating the hydrophobic starch and mixing it with water to form a slurry, then adding a metal salt to induce metal-bridging of the hydrophobic starch, or (c2) adding a metal salt to the reaction mixture obtained in step (b) A process for producing a hydrophobic starch by a wet process comprising introducing metal-crosslinking of starch is disclosed. However, the prior art requires that expensive raw materials such as dodecenylsuccinic anhydride be used, the reaction time is long, complicated processes such as filtration, washing and drying are required after completion of the reaction, . Korean Patent Registration No. 10-1409210 discloses a method for preparing starch powder comprising the steps of: adding a polyvalent metal hydroxide powder such as calcium hydroxide to starch powder in an amount of 1.0 to 20 wt% based on the dry weight of the starch and uniformly mixing them to form a first mixture; Adding anhydrous organic acid such as anhydrous octenylsuccinic acid to the first mixture in an amount of 1.5 to 10 wt% based on the weight of the starch dry weight and uniformly mixing to form a second mixture; And an aging step of inducing an esterification reaction between the starch and the anhydrous organic acid contained in the second mixture and a cross-linking reaction between the esterified starch and the polyvalent metal hydroxide, and a process for producing the water-repellent starch by a dry process . However, the above prior art requires the use of an expensive raw material such as octenyl succinic anhydride, and a long aging time of 12 hours or more is required to obtain reliable water repellency. In addition, US Patent No. 7,799,909 discloses a method of adding sodium methylsiliconate to a corn starch slurry, adjusting the pH to 5 to 9 with hydrochloric acid, stirring for 30 minutes, filtering and drying A method for producing a water-repellent starch by a wet process is disclosed. However, in the prior art, since the process is complicated and a wet process, predetermined wastewater is generated, and the physical properties such as water repellency, flowability, sensory touch, etc. of the final starch are affected by the polyhydroxylated metal hydroxide and the water- There is a problem. In addition, U.S. Patent No. 8,703,933 discloses a dry process in which a mixture of starch and sodium methyl silicate solution is uniformly mixed for a predetermined time to prepare a mixture having a water content of 30% or less and dried A method for producing water-repellent starch according to the present invention is disclosed. However, the prior art has a problem that physical properties such as water repellency, flowability, and sensory touch of the final starch are inferior to those of the water-repellent starch prepared using the polyvalent metal hydroxide and anhydrous organic acid.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and it is an object of the present invention to provide a process for producing a polyurethane foam which is suitable for mass production owing to simplification of a process, minimization of a production facility and shortening of a production time, And to provide a method for producing good water repellent starch.

The inventors of the present invention have found that the use of an extruder in place of a conventional wet process or a dry process using a high-speed rotary mixer can simplify the manufacturing process when producing water-repellent starch with a siliconate such as sodium methylsiliconate, , Water repellency, sensory touch, and the like can be produced economically. Thus, the present invention has been completed.

In order to solve the above-mentioned object, the present invention provides a process for producing an extrudate, which comprises extruding a mixture containing starch and a silicone to form an extrudate, wherein the content of the silonate in the mixture is in the range of 2.5 - Wherein the water-soluble starch is 50 parts by weight. In addition, the method for producing a water-repellent starch according to the present invention may further include the step of adding an acid to the extrudate, mixing and neutralizing the extrudate.

The method for producing a water-repellent starch according to the present invention uses an extruder, so that the process is simple, the production time is shortened, the loss of reaction products is little, It is eco-friendly because no wastewater is generated, and a separate wastewater treatment facility is not required, which can drastically reduce manufacturing costs. In addition, the method for producing a water-repellent starch according to the present invention has better physical properties such as water repellency, flowability and sensory touch of the final starch as compared with the conventional manufacturing method using a dry process. Therefore, the production method of the present invention is suitable for mass production of water-repellent starch on an industrial scale, and the water-repellent starch produced by the production method of the present invention is useful as an excipient for baby powder, a coating agent for wallpaper surface, It can be used as a material for preventing abrasion.

Fig. 1 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Production Example 4 of the present invention, and Fig. 2 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Production Example 1 of the present invention.
Fig. 3 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 1 of the present invention, Fig. 4 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 2 of the present invention, Fig. 5 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 3 of the present invention, and Fig. 6 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 4 of the present invention.

Before describing the present invention specifically, the terms used in the present invention will be described first. The term "starch" as used in the present invention is a concept including not only natural starch but also starch obtained by decomposing natural starch into an acid or an enzyme to the extent that water repellency is maintained by the production method of the present invention. The term "Siliconate" used in the present invention means a compound in which at least one of the four hydroxyl groups present in the silicic acid is substituted with an alkyl group, an aryl group, a halogen element, or the like, Metal salt.

Hereinafter, the present invention will be described in detail. The present invention relates to a method for producing a water-repellent starch, and a method for producing a water-repellent starch according to the present invention includes a step of extruding a mixture containing starch and a silicoate to form an extrudate. In addition, the method for producing a water-repellent starch according to the present invention may further include the step of adding an acid to the extrudate, mixing and neutralizing the extrudate.

Hereinafter, the reaction materials using the method for producing water-repellent starch according to the present invention will be described.

Starch

The starch used in the method for producing a water-repellent starch according to the present invention is preferably in the form of powder, considering uniform mixing with other reactants. Further, the moisture content of the starch is 20 wt% or less, more preferably 15 wt% or less, and even more preferably 10 wt% or less. The type of starch used in the present invention is not particularly limited and includes, for example, corn starch, corn starch, potato starch, sweet potato starch, wheat starch, rice starch, tapioca starch, sago starch, sorghum starch, and high amylose starch (for example, starch having an amylose content of at least 40% by weight or more), and the like, but are not limited thereto. The starch used in the present invention may also be an oxidized starch obtained by treating with an oxidizing agent such as sodium hypochlorite; Thin boiling starch obtained by decomposition with acids, heat or enzymes; Esterified starches such as Monostarch Phosphate, Starch Acetate; Etherified starches such as hydroxypropyl starch; Crosslinked starches such as Distarch Phosphate; An esterified crosslinked starch such as Acetylated Distarch Adipate, Acetylated Distarch Phosphate, Phosphated Distarch Phosphate; Modified starches such as etherified crosslinked starches such as Hydroxypropyl Distarch Phosphate, and the like, but are not limited thereto.

Siliconate

The silicones used in the method for producing water-repellent starches according to the present invention are preferably organosiliconates wherein at least one of the four hydroxyl groups present in the silicic acid is substituted with an alkyl group or an aryl group, More preferably, it is a metal salt of organosiliconates. Examples of the metal for forming the metal salt of the organic silicate include an alkali metal or an alkaline earth metal. One preferred form of the alkali metal organosiliconates used in the present invention may be a compound represented by the following general formula (1).

[Chemical Formula 1]

In the above formula (1), R is an alkyl group or an aryl group, and X is an alkali metal. In Formula 1, R is preferably an alkyl group having 1 to 5 carbon atoms or a phenyl group. In Formula 1, X is preferably sodium or potassium. Specific examples of the compound represented by Formula 1 include sodium methylsiliconate, sodium ethylsiliconate, sodium propylsiliconate, sodium phenylsiliconate, Potassium ethylsiliconate, potassium propylsiliconate, and potassium phenylsiliconate, and the silonates used in the present invention are not limited thereto. And may be composed of at least one selected.

The acid

In the present invention, an acid is used to neutralize the extrudate. The acid to be used in the present invention is not limited to a wide range of inorganic acids and organic acids, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and acetic acid, among which hydrochloric acid is preferable.

Hereinafter, the method for producing the water-repellent starch according to the present invention will be described step by step.

The extrudate  Forming step

In the present invention, the step of forming an extrudate comprises extruding a mixture containing starch and siliconate using a predetermined extruder. Siliconate is chemically or physically bound to starch by a predetermined heat and pressure in the extrusion process, and a coating may be formed by a polymerization reaction between silicates.

In this regard, the content of the silicate in the mixture is preferably 2.5 to 50 parts by weight, more preferably 4 to 50 parts by weight, based on 100 parts by weight of the starch, from the viewpoint of ensuring water repellency, flowability, And most preferably 5.5 to 20 parts by weight. If the content of the siliconate in the mixture is less than 2.5 parts by weight based on 100 parts by weight of the starch, there is a possibility that the water repellency of the final starch is insufficient. If it exceeds 50 parts by weight, the extrudate may come close to the liquid phase. The weight of the starch is based on dry starches except moisture, and the weight of the silicate is based on the silicones contained therein rather than the entire solution.

The extrusion temperature is preferably 30 to 90 ° C, more preferably 40 to 85 ° C, and most preferably 45 to 80 ° C, from the viewpoint of ensuring water repellency, flowability and sensory touch of the water-repellent starch . If the extrusion temperature during extrusion is less than 30 ° C or exceeds 90 ° C, the water repellency of the final starch may be insufficient.

The extrusion pressure during extrusion is preferably 5 to 80 kgf / cm2, more preferably 5 to 40 kgf / cm2, and most preferably 5 to 20 kgf / cm2 on the basis of gauge pressure.

The extrudate  Steps to neutralize

The extrudates in the present invention exhibit alkalinity in the addition of the siliconate. When the extrudate is used as an excipient, a filler, a diluent, a lubricant, an aggregation inhibitor, a flow improver, etc. in various industries such as cosmetics, medicines, insecticides, paper and the like, the alkalinity of the extrudate does not matter most, Considering the reliability of the product, it is desirable to neutralize the alkalinity of the extrudate.

In the present invention, the step of neutralizing the extrudate comprises adding and mixing an acid to the extrudate. In this case, the amount of the acid added is preferably such that 20 g of ethanol and 140 ml of distilled water are added to 40 g of the water-repellent starch, and the mixture has a pH of 6-8.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are merely illustrative of the technical features of the present invention and do not limit the scope of protection of the present invention.

1. Preparation of water-repellent starch using an extruder

The sodium methylsiliconate solution at a concentration of 30 wt% and the corn starch were added to a mixer so that the addition amount of sodium methylsiliconate was 2 to 10% (w / w) based on the dry weight of the corn starch, To prepare a mixture. Thereafter, the mixture was poured into an extruder feeder and extruded through an extrusion die to obtain a final modified starch. The extruder is composed of a driving part, a feeder, a screw for feeding the supplied raw material to the extruder die, a barrel for controlling the extrusion temperature, and an extrusion die . The barrel temperature in the preparation of the water-repellent starch was adjusted in the range of 40 to 80 ° C, and the extrusion pressure was 12 ± 4 kgf / cm 2 based on the gauge pressure.

Table 1 shows the amounts of corn starch and sodium methylsilonate used and the extruder barrel temperature according to the preparation examples.

Manufacturing Example Corn starch consumption (parts by weight) Sodium methylsiliconate usage (parts by weight) Barrel temperature (캜) Production Example 1 100 2 60 Production Example 2 100 4 60 Production Example 3 100 5 60 Production Example 4 100 6 60 Production Example 5 100 8 60 Production Example 6 100 10 60 Production Example 7 100 6 40 Production Example 8 100 6 50 Production Example 9 100 6 70 Production Example 10 100 6 80

2. Preparation of Water-repellent Starch Using Conventional Process

(1) Use of sodium methylsiliconate

Comparative Production Example 1: Wet process

38 kg of corn starch and 62 kg of water were added to a thermostatic reactor and mixed to prepare a starch slurry. Thereafter, a sodium methylsiliconate solution having a concentration of 30 wt% was added to the reactor so that the addition amount of sodium methylsilonate was gradually increased to 6.0% (w / w) based on the dry weight of corn starch to form a reaction mixture, The mixture was reacted while stirring at 45 캜 for 12 hours. After the reaction was completed, the pH of the reaction product was adjusted to 6.0 using a 15 wt% aqueous solution of hydrochloric acid, and the resulting solid was washed with water and dried to obtain a final modified starch.

Comparative Production Example 2: Dry process

671 g of corn starch powder was put into a blender (trade name: Lodige mixer M5R type; supplier: Gebruder Lodige Maschinenbau GmbH, Germany), and a sodium methylsiliconate solution with a concentration of 30 wt% was added to the corn starch dry weight (W / w), and the mixture was uniformly mixed for about 30 minutes at a stirring speed of 300 rpm to form a mixture. Thereafter, the mixture was dried at about 40 캜 for 12 hours to obtain a final modified starch.

(2) Use of anhydrous organic acids and metal compounds

Comparative Preparation Example 3: Wet process

38 kg of starch and 62 kg of water were added to a constant temperature reactor maintained at 50 캜 and mixed to prepare a starch slurry. Then, a hydrochloric acid aqueous solution of 7w% concentration was added to the reactor so that the amount of hydrochloric acid added was 0.6% (w / w) based on the weight of the starch dry weight, and the mixture was stirred for 3 hours. Thereafter, the temperature of the starch slurry was lowered to 40 占 폚, and anhydrous octenylsuccinic acid was slowly added to the starch to a dry weight of 2.5% (w / w) to form a reaction mixture. Using a sodium hydroxide aqueous solution having a concentration of 4% The reaction mixture was stirred for 4 hours while maintaining the pH of the reaction mixture at about 8.5. After completion of the reaction, the pH of the reaction product was adjusted to 6.0 using a hydrochloric acid aqueous solution having a concentration of 15 w%, and the resulting solid was washed with water and dried to obtain a hydrophobic starch. Thereafter, 38 kg of the hydrophobic starch obtained above and 62 kg of water were added to a thermostatic reactor maintained at 35 캜 and mixed to prepare a starch slurry. Then, an aluminum sulfate solution having a concentration of 20% by weight was added to the reactor so that the amount of aluminum sulfate added was 2% (w / w) based on the dry weight of the hydrophobic starch, and the mixture was reacted for 2 hours with stirring. After the reaction was completed, the pH of the reaction product was adjusted to about 6.0 using a hydrochloric acid aqueous solution having a concentration of 15 w%, and the resulting solid was washed with water and dried to obtain an aluminum crosslinked hydrophobic modified starch.

Comparative Production Example 4: Dry process

671 g of starch powder was added to a mixer (product name: Lodige mixer M5R type; supplied by Gebruder Lodige Maschinenbau GmbH, Germany), calcium hydroxide powder was added thereto so as to be 2% (w / w) At a rate of about 30 minutes to form a first mixture. Thereafter, the stirring speed was lowered, and anhydrous octenylsuccinic acid was gradually added to the blender so as to be 2.5% (w / w) based on the weight of the starch dry weight, and then mixed homogeneously at a stirring speed of 300 rpm for 30 minutes to form a second mixture. Thereafter, the temperature of the second mixture was adjusted to 40 캜 and aged for about 12 hours to obtain a calcium crosslinked hydrophobic modified starch having a water content of 15% by weight or less.

3. Physical properties test of water-repellent starch

(1) Property test items and test methods

The water repellency, sieving rate, angle of repose and flowability, and sensory tactile properties of the modified starches obtained in Production Examples 1 to 10 and Comparative Production Examples 1 to 4 were evaluated. Specific test methods for each evaluation item are as follows.

* Water repellency test

200 ml of distilled water was added to the beaker, 2 g of the starch sample was added thereto, and after 30 minutes passed, the degree of the starch sample being loosened or settled in water was visually observed to evaluate the water repellency of the starch sample. The water-repellency evaluation criteria through visual observation are as follows.

○: After 30 minutes, the starch completely floated without being dissolved in water; △: After 30 minutes, a part of the starch floats in the water, and a part of the starch sinks to the water; X: Most or all of the starch was released into water after 30 minutes passed.

* Sieve rate

A starch sample was placed on a sieve having a mesh size of about 45 탆 (ASTM Standard No. 325) and the sieve was vibrated for 20 minutes. Then, the weight of the starch sample remaining on the sieve was measured. Then, the body passing rate was calculated in the following manner.

* Repose angle and flow

The angle of response of the starch samples was measured with a BT-200 Tester with Funnel 5 mm, and the flowability of the starch samples was evaluated based on the angle of repose angle. The angle of repose refers to the maximum inclination angle at which an undecomposed powder can be deposited without falling down when deposited on a slope. Generally, a small angle of repose means that the flowability of the powder is good. The principle of measurement is to measure the angle of repose of the cone obtained by passing a certain volume of powder or granular sample through a special funnel fixed at a constant height on a perfectly flat reference plate. Specifically, after mounting the funnel on the reference plate, the 5 mm powder outlet at the bottom of the funnel was fully opened. Thereafter, the starch samples were slowly fed, and conical starch samples were piled up. When the starch samples were overflowed, the supply of the starch samples was stopped, and then the angle of repose was measured. The evaluation criteria of flow through the angle of repose are as follows.

?: Angle of repose of 30 占 or less; DELTA: Repose angle of more than 30 DEG to 50 DEG or less; ×: Repose angle exceeded 50 °

* Sensory touch

The sensory touch properties of starch samples were evaluated by scoring 5 points on the skin adhesion of starch samples and soft touch feeling when skin rubs were applied to 20 panelists.

At this time, the scale of 5 points scale is as follows.

5 points: It is soft, moist and long lasting.

4 points: Soft.

3 points: It is normal.

2 points: It is not smooth and less oil.

1 point: It is very rough.

(2) Test results of water-repellent starch

Table 2 shows the results of physical property tests of the modified starches obtained in Production Examples 1 to 10 and Comparative Production Examples 1 to 4. The water repellency evaluation test results of the modified starches prepared in Production Example 1, Production Example 4 and Comparative Production Examples 1 to 4 are shown in Figs. 1 to 5. Fig. 1 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Production Example 4 of the present invention, and Fig. 2 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Production Example 1 of the present invention. Fig. 3 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 1 of the present invention, Fig. 4 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 2 of the present invention, Fig. 5 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 3 of the present invention, and Fig. 6 is a photograph showing the water repellency evaluation test result of the modified starch prepared in Comparative Preparation Example 4 of the present invention.

division Evaluation items Water repellency 45 탆 Mesh Size Sieve Percentage (%) Angle of repose (°) Flowability Sensory touch Starch sample Production Example 1 × 62 56 × 2 Production Example 2 △ 79 44 △ 3 Production Example 3 △ 81 41 △ 3 Production Example 4 ○ 98 29 ○ 5 Production Example 5 ○ 98 29 ○ 5 Production Example 6 ○ 98 28 ○ 5 Production Example 7 △ 81 38 △ 3 Production Example 8 ○ 98 29 ○ 5 Production Example 9 ○ 98 29 ○ 5 Production Example 10 ○ 98 28 ○ 5 Comparative Preparation Example 1 △ 62 41 △ 3 Comparative Production Example 2 △ 57 48 △ 3 Comparative Production Example 3 ○ 98 29 ○ 4 Comparative Production Example 4 ○ 98 28 ○ 5

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the scope of protection of the present invention is not limited to the specific embodiments but should be construed as including all embodiments belonging to the claims attached to the present invention.

Claims (6)

Comprising extruding a mixture comprising starch and a silicoate to form an extrudate,
Wherein the content of the silonate in the mixture is 2.5 to 50 parts by weight based on 100 parts by weight of the starch.
The method for producing a water-repellent starch according to claim 1, wherein the silicate is a compound represented by the following formula (1).
[Chemical Formula 1]

In the above formula (1), R is an alkyl group or an aryl group, and X is an alkali metal.
The method of claim 2, wherein the silonate is selected from the group consisting of sodium methylsiliconate, sodium ethylsiliconate, sodium propylsiliconate, sodium phenylsiliconate, Wherein the water repellent starch is at least one selected from the group consisting of potassium methylsiliconate, potassium ethylsiliconate, potassium propylsiliconate, and potassium phenylsiliconate. ≪ / RTI >
The method for producing a water-repellent starch according to claim 1, wherein the extrusion temperature during extrusion is 30 to 90 ° C.
The method for producing a water-repellent starch according to claim 1, wherein the extrusion pressure during extrusion is 5 to 80 kgf / cm 2 based on a gauge pressure.
6. The method for producing a water-repellent starch according to any one of claims 1 to 5, further comprising adding an acid to the extrudate and neutralizing the mixture by mixing.

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