JP2000072801A - Composition containing esterified crosslinked derivative of carboxylic alkyl etherified starch and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a starch obtained by further adding an additional value to former carboxymethylated starch. SOLUTION: This composition contains a starch derivative obtained by carboxyalkyl-etherifying of starch and wherein a part of the carboxylic alkyl ester group of the starch derivative forms a crosslinking by forming an ester bond with a hydroxyl group derived from raw material starch. This starch derivative is produced by mixing a carboxylic acid expressed by the formula: X-(CH2)n-COOH X is a halogen atom and (n) is an integer of 1-20} or its salt with an alkali, adjusting the moisture content of the mixture to <5% and subjecting the resultant mixture to a heating reaction at >=90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition containing an ester-crosslinked derivative of a carboxyalkyl etherified starch typified by carboxymethyl etherified starch (carboxymethyl starch) and a method for producing the same.

[0002]

2. Description of the Related Art Carboxymethyl etherified starch is used as warp sizing agent, printing sizing agent, mining mud admixture, concrete dispersant, adhesive, cosmetics, food, feed, anti-aging agent, detergent, pharmaceutical tablet, paper. It is used in a wide range of fields such as force enhancers. As a method for producing carboxymethyl etherified starch, starch is monochloroacetic acid or monochloroacetate,
And a method of adding an alkali to carry out carboxymethylation has been widely known for a long time.

[0003] For example, carboxymethyl ether is produced by a solvent reaction method in which starch, monochloroacetic acid, and sodium hydroxide are reacted while heating in an alcohol solvent such as methanol.
Tellurized starch is obtained (Japanese Patent Publication No. 27-5295). Also, a method called dry etherification in which a reaction is performed without using a solvent is disclosed (Japanese Patent No. 2729651).
No.), since the reaction is performed in a state where the mixture of starch and the reagent has a water content of 5 to 40%, the reaction cannot be performed at a very high temperature.

In the above-mentioned solvent reaction method, there is a limit to the reaction temperature depending on the solvent used, purification of the solvent and removal of the solvent from the reaction product are relatively easy. Can only react up to about ℃. Further, in the solvent reaction method and the dry etherification method, only the carboxymethyl etherification reaction of starch occurs, and the carboxymethyl group does not further cause an ester crosslinking reaction with the hydroxyl group of starch. Such conventional carboxymethyl etherated starch has a marked decrease in viscosity when the paste liquid is acidic, and its application range is limited.

[0005]

As a result of various studies conducted by the present inventors, an object of the present invention is to provide a starch derivative obtained by adding a value to a conventional carboxymethyl etherified starch.

[0006]

The present invention includes the following inventions. (1) A composition comprising a starch derivative obtained by subjecting starch to carboxyalkyl etherification, wherein a part of the carboxyalkyl group is ester-bonded to a hydroxyl group derived from the raw starch to form a crosslink. (2) The starch derivative forming a cross-link is formed by the ester bond between the carboxyalkyl group and the hydroxyl group of the carboxyalkyl etherified starch, and is represented by the following formula:

[0007]

Embedded image -O- (CH _{2) n} -COO- composition according to the is obtained by forming a bridge represented (wherein, n represents. An integer of 1 to 20) (1).

(3) The composition according to the above (1) or (2), wherein the degree of substitution of the carboxyalkyl group in the whole composition is 0.005 to 0.05. (4) Starch and the following formula (I):

[0009]

A carboxylic acid or a salt thereof represented by X- (CH ₂ ) _n -COOH (wherein X represents a halogen atom and n represents an integer of 1 to 20) is mixed with an alkali. After reducing the water content of the mixture to less than 5%,
A method for producing a starch derivative, wherein a heating reaction is performed at 90 ° C. or higher.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The composition of the present invention is a starch derivative obtained by subjecting starch to carboxyalkyl etherification, and a part of the carboxyalkyl group is ester-bonded to a hydroxyl group derived from raw starch to form a crosslink. A composition containing a starch derivative (hereinafter, referred to as “ester crosslinked derivative”) that is formed, in which the carboxyalkyl group of the carboxyalkyl etherified starch forms an ester bond with a hydroxyl group. Therefore, the degree of substitution of the carboxyalkyl group in the whole composition is usually 0.1.
001-0.05, preferably 0.005-0.05,
It is more preferably 0.01 to 0.05, which is lower than the degree of substitution of the carboxyalkyl group in the conventional carboxymethyl etherated starch (usually 0.1 to 1.5).

Further, in the composition of the present invention, the degree of substitution of the ester crosslinking group in the whole composition is usually 0.001.
To 0.12, preferably 0.005 to 0.08, and more preferably 0.01 to 0.08. The composition of the present invention can be produced, for example, by a dry roasting method in which a mixture of starch and a reaction reagent is subjected to a heat reaction at low moisture.

The dry roasting method referred to in the present invention is described in
No. 20512, which is a known method, specifically, impregnating starch with a mixed solution of a reaction reagent and water, impregnating starch with a high-concentration solution of a reaction reagent, or using starch. After spraying the mixed solution or the high-concentration solution, the mixture is stirred until it becomes uniform, and the mixture is heated and reacted using a stirring dryer, a stationary dryer, or the like. The composition of the present invention preferably comprises starch and the following formula (I):

[0013]

Embedded image A carboxylic acid or a salt thereof represented by X— (CH ₂ ) _n —COOH (wherein X represents a halogen atom and n represents an integer of 1 to 20) is mixed with an alkali. After reducing the water content of the mixture to less than 5%,
It can be produced by heating and reacting at 90 ° C or more, preferably 90 to 160 ° C. In the formula (I), examples of the halogen atom represented by X include a fluorine atom, a chlorine atom and a bromine atom, preferably a chlorine atom and a bromine atom.

Examples of the carboxylic acid represented by the formula (I) include monochloroacetic acid, monobromoacetic acid, monochloropropionic acid, monobromopropionic acid, monochlorobutyric acid, monobromobutyric acid, monochlorovaleric acid, monobromovaleric acid, monochlorolauric acid, Monobromolauric acid, monochlorostearic acid, monobromostearic acid. Examples of the salt of the carboxylic acid represented by the formula (I) include alkali metal salts such as sodium salt, potassium salt and lithium salt, alkaline earth metal salts such as calcium salt and barium salt, and inorganic or organic ammonium salts. Can be The amount of the carboxylic acid or a salt thereof represented by the formula (I) is usually 0.1 to 100 parts by weight of the raw starch.
15 parts by weight, preferably 0.5 to 10 parts by weight.

Examples of the alkali include metal hydroxides such as alkali metal hydroxides and alkaline earth metal hydroxides (eg, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide, barium hydroxide). ), Carbonates such as alkali metal carbonates and alkaline earth metal carbonates (eg, sodium carbonate and potassium carbonate), phosphates such as alkali metal phosphates and alkaline earth metal phosphates (eg, phosphoric acid) Inorganic bases such as sodium) and ammonia; and organic bases such as methylamine, dimethylamine, trimethylamine, hexamethylenediamine, pyridine, and dimethylaminopyridine. Preferably, sodium hydroxide is used. The amount of the alkali used is preferably 1.0 to 3.0 molar equivalents for the carboxylic acid represented by the above formula (I) such as monochloroacetic acid, and preferably 0 to 3.0 for the carboxylic acid salt. 0.5 to 1.5 molar equivalents.

The starch used includes, for example, corn starch (corn starch), potato starch, wheat starch, sweet potato starch, rice starch, tapioca starch, and modified starches based on these. A preferred method for producing the composition of the present invention using the above-mentioned raw starch is described below.

First, when a raw starch which has not been specially modified is used, 0.5 to 10 parts by weight of monochloroacetic acid, 0.5 to 10 parts by weight of sodium hydroxide are added to 100 parts by weight of the raw starch. 20 to 30 parts by weight of water, preferably 25 to 30% by weight of the mixture is mixed.
At this time, the pH of the 10% slurry of the reagent and the starch mixture was 9
The amount of alkali is adjusted so as to be as described above. The mixture of this reagent and starch is dried with a hot air drier so that the water content is less than 5%. The dried mixture is heated and roasted at 90 to 160 ° C. using a hot air heater or a jacket heater. At this time, when the roasting temperature is lower than 90 ° C., the behavior of ester cross-linking of a carboxymethyl group, which is one feature of the present invention, is not observed. On the other hand, at a roasting temperature of 90 ° C. or higher, a behavior is observed in which the esterification of the carboxymethyl group is caused to occur along with the reaction time. That is, ester crosslinking can be controlled by the roasting temperature. The degree of ester cross-linking increases as the reaction temperature increases and the reaction time increases.

Further, as the raw material starch, a low-viscosity one may be used.
Low-viscosity product, for example, 20% by weight size liquid B at 50 ° C.
A product having a mold viscosity of 1000 mPa · s or less can be obtained. The low-viscosity starch used here can be produced, for example, as follows. That is, ordinary starch 100
0.2 to 2 parts by weight of an acid catalyst and 20 to 3 parts of water with respect to parts by weight.
0 parts by weight, preferably water is added and mixed so that the water content of the mixture becomes 25 to 30%.
%. This is heated and roasted at 70 ° C. to 180 ° C. with a hot air heater or a jacket heater to obtain a raw starch having a desired viscosity. As the acid catalyst used here, any of inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid and organic acids such as formic acid, acetic acid, oxalic acid, maleic acid and adipic acid may be used. There is also a method using a low-viscosity starch obtained by heating and roasting starch at 150 to 180 ° C. without using an acid catalyst. The heating and roasting in the absence of a catalyst is a method of obtaining a desired viscosity by heating and roasting at a temperature that does not cause dextrin formation.

Even when the raw starch having a reduced viscosity is used, the composition containing carboxyalkyl etherified and ester-crosslinked derivatives thereof is similarly used when the raw starch which is not specially modified is used. Can be manufactured. The composition obtained by the dry roasting method is washed with water, or a mixture of water and alcohol to remove salts contained in the reaction product. Is clearly better visually.

The composition of the present invention can be used in the same manner as a conventional carboxymethyl etherified starch, such as a warp paste, a printing paste, a mining admixture, a concrete dispersant, an adhesive, cosmetics, food, feed, aging It can be used in a wide range of fields such as inhibitors, detergents, pharmaceutical tablets, and paper strength agents. Conventional carboxymethyl etherified starch is a polymer high electrolyte, so its stability is very poor when the paste liquid is in an acidic state, and the viscosity decreases sharply by shearing. In the composition of the present invention, the size liquid has a pH of 3 to 7.
The degree of viscosity decrease is small even in acidic conditions, and the range of application is wide.

[0021]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples. In the following, all parts and percentages are by weight unless otherwise indicated. The methods for measuring the B-type viscosity, the degree of substitution of the carboxymethyl group, the degree of substitution of the ester crosslinking group, and the presence or absence of crosslinking are described below.

<Type B Viscosity> A BM type viscometer manufactured by Tokyo Keiki Co., Ltd. was used. The starch was 2% or 20% concentration at 50 ° C. and 60 rpm.
m. <Degree of substitution of carboxymethyl group> Starch was mixed with 2N hydrochloric acid / methanol (2N hydrochloric acid: methanol = 60: 40).
For 1 hour and filtered. The filter residue Cl ^- was washed with 60% methanol until no, and the residue is washed and dried 3 hours at 105 ° C. dryer. Water was added to the dried starch to form a slurry of about 1%, and gelatinized at 95 ° C. for 30 minutes. The size liquid was cooled to room temperature, and the cooled size liquid was subjected to neutralization titration with a sodium hydroxide solution using phenolphthalein as an indicator (pH 8.8 was defined as a neutralization point). The degree of substitution of the carboxymethyl group was calculated from the titration amount of the aqueous sodium hydroxide solution. The calculation formula is as follows. In addition,
The blank titer is the titer when non-carboxymethylated starch is used.

[0023]

(Equation 1)

<Degree of Substitution of Ester Crosslinking Group> Starch was mixed with 2N hydrochloric acid / methanol mixture (2N hydrochloric acid: methanol = 6).
0:40) for 1 hour and filtered. The filter residue is washed with 60% methanol until Cl ^- is eliminated,
The washing residue was dried in a dryer at 105 ° C. for 3 hours. Water is added to 1.5 g of the dried starch to form a slurry of about 5%,
3.0 ml of a 1.0 N aqueous sodium hydroxide solution was added thereto.
In addition, gelatinization was performed at 95 ° C. for 30 minutes (this operation hydrolyzes the ester cross-linked portion to form a carboxymethyl group). The size liquid was cooled to room temperature, about 150 ml of water was added, and the solution was back titrated with 0.05 N hydrochloric acid (pH 8.8 was taken as the neutralization point). From the titration of hydrochloric acid, the degree of carboxymethyl group substitution (total carboxymethyl groups present after hydrolysis)
Was calculated. The calculation formula is as follows. In addition, the blank titer is a titer when a starch that is not carboxymethylated is used.

[0025]

(Equation 2)

<Presence / absence of cross-linking> RVA (Rapid Visco Analy
ser) -3D (Newport Scientific, Australia) was used. With this RVA viscosity measuring device, the temperature program is changed from 25 ° C to (temperature rise at 1.5 ° C / min)
→ The temperature was kept at 95 ° C. (holding for 20 minutes), and the RVA viscosity pattern of 1% of the sample washed with water was measured (measured at 4% because only the viscosity of Examples 7 and 8 was reduced). When the viscosity increased and decreased (appearance of a peak) before reaching 95 ° C., it was determined that ester crosslinking had not occurred. Also,
When the peak did not appear until the temperature reached 95 ° C., and no change in viscosity was observed during the 95 ° C. hold, or when the viscosity increased, the ester was crosslinked.

Comparative Example 1 Commercially available corn starch 10
An aqueous solution of 6 parts of monochloroacetic acid and 5 parts of sodium hydroxide was mixed with 0 parts to obtain a homogeneous mixture containing 30% of water. After the mixture was dried at 70 ° C. until the water content became 4% or less, a heating reaction was performed at 70 ° C. for 60 minutes using a hot air circulation type heater. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of this carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking.
Shown in

Comparative Example 2 Carboxymethyl etheration was carried out in the same manner as in Comparative Example 1, except that a mixture of corn starch and a reagent was heated and reacted at 70 ° C. for 1440 minutes (24 hours). Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of this carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking.
Shown in

Comparative Example 3 The carboxymethyl etherified starch derivative obtained in Comparative Example 2 was washed with water to remove excess salts. Table 1 shows the results of the B-type viscosity at 50 ° C at a concentration of 2% of the obtained carboxymethyl etherated starch derivative.

Comparative Example 4 Carboxymethyl etheration was carried out in the same manner as in Comparative Example 1 except that a mixture of corn starch and a reagent was heated and reacted at 80 ° C. for 60 minutes. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of the carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking. Show.

Example 1 Carboxymethyl etheration was carried out in the same manner as in Comparative Example 1 except that a mixture of corn starch and a reagent was heated and reacted at 90 ° C. for 60 minutes. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of the carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking. Show.

Example 2 The same operation as in Comparative Example 1 was carried out except that a mixture of 100 parts of corn starch and 1 part of monochloroacetic acid and 0.85 part of sodium hydroxide was heated and reacted at 120 ° C. for 60 minutes. Carboxymethyl etherification was performed. Degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative and 50 ° C. at 2% concentration of this carboxymethyl etherated starch derivative
Table 1 shows the results of the B-type viscosity and the presence or absence of ester crosslinking.

Example 3 The same operation as in Comparative Example 1 was carried out except that a mixture of 3 parts of monochloroacetic acid and 2.5 parts of sodium hydroxide in 100 parts of corn starch was heated and reacted at 120 ° C. for 60 minutes. Carboxymethyl etherification was performed. The degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative and 50 ° C. B at 2% concentration of this carboxymethyl etherated starch derivative
Table 1 shows the results of the mold viscosity and the presence or absence of ester cross-linking.
Table 3 shows the B-type viscosity depending on the difference in H.

Example 4 The carboxymethyl etherified starch derivative obtained in Example 3 was washed with water to remove excess salts. Table 1 shows the results of the B-type viscosity of the obtained carboxymethyl etherated starch derivative at a concentration of 2% at 50 ° C, and Table 3 shows the B-type viscosity depending on the pH of the paste liquid.

Example 5 Carboxymethyl etheration was carried out in the same manner as in Comparative Example 1 except that a mixture of corn starch and a reagent was heated and reacted at 120 ° C. for 60 minutes. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of the carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking. Table 2 shows the B-type viscosity at 50 ° C. and 20% concentration.

Example 6 Carboxymethyl etheration was carried out in the same manner as in Comparative Example 1 except that a mixture of corn starch and a reagent was heated and reacted at 150 ° C. for 60 minutes. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of the carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking. Show.

Example 7 A commercially available corn starch was dried until the water content became 4% or less, and heated and roasted at 160 ° C. for 90 minutes using a hot air circulation type heater. An aqueous solution of 6 parts of monochloroacetic acid and 5 parts of sodium hydroxide was mixed with 100 parts of the roasted corn starch,
A homogeneous mixture containing 30% water was obtained. This mixture is
After drying at 4 ° C. until the water content became 4% or less, a heating reaction was performed at 120 ° C. for 60 minutes by a hot air circulation type heater. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 2% concentration of this carboxymethyl etherated starch derivative at 50 ° C, and the presence or absence of ester crosslinking. Table 2 shows the B-type viscosity at 50 ° C. and 20% concentration.

Example 8 Commercially available corn starch 10
An aqueous solution of 0.1 part of phosphoric acid was mixed with 0 part of the mixture, the mixture was dried until the water content became 4% or less, and the mixture was heated and roasted at 130 ° C. for 30 minutes by a hot air circulation type heater. An aqueous solution of 6 parts of monochloroacetic acid and 5 parts of sodium hydroxide was mixed with 100 parts of corn starch heated and roasted using this acid catalyst to obtain a homogeneous mixture containing 30% of water.
After drying this mixture at 70 ° C. until the water content became 4% or less, a heating reaction was performed at 120 ° C. for 60 minutes by a hot air circulation type heater. The degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative and 50% at 2% concentration of the carboxymethyl etherated starch derivative
Table 1 shows the results of the B type viscosity and the presence or absence of ester crosslinking in Table 1.
Table 2 shows the B-type viscosity at 50% at 0% concentration.

Comparative Example 5 A commercially available corn starch dry solid (100 g) was placed in a flask, and 150 ml of ethanol was added. 6 g of monochloroacetic acid and 5 g of sodium hydroxide were dissolved in 15 g of water, this solution was also added to the flask, and the mixture was refluxed for 1440 minutes (24 hours) to perform a reaction. After completion of the reaction, the resultant was washed with methanol: water = 60: 40 and dried. Table 1 shows the degree of carboxymethyl group substitution of the obtained carboxymethyl etherated starch derivative, the B-type viscosity at 50 ° C. at 2% concentration of this carboxymethyl etherated starch derivative, and the presence or absence of ester crosslinking.
Table 2 shows the B-type viscosity at 50 ° C at a concentration of 20%, and Table 3 shows the B-type viscosity depending on the pH of the size liquid.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

According to the present invention, there is provided a starch derivative which has a high stability and a small degree of viscosity decrease even when the size liquid is in an acidic state, and which has added value to the conventional carboxymethyl starch. be able to.

Continued on the front page F term (reference) 4C090 AA03 AA08 BA15 BA16 BB72 BB82 BB97 BD35 CA04 CA07 CA33 CA36 CA38 DA09 DA21 DA23 DA26 DA27

Claims (4)

[Claims] A composition comprising a starch derivative obtained by subjecting starch to carboxyalkyl etherification, wherein a part of the carboxyalkyl group is ester-bonded to a hydroxyl group derived from a raw starch to form a cross-link. object. 2. A starch derivative having a cross-link is formed by an ester bond between a carboxyalkyl group and a hydroxyl group of a carboxyalkyl etherified starch, and is represented by the following formula: -O- (CH ₂ ) _n -COO The composition according to claim 1, wherein the composition forms a crosslink represented by the formula (wherein, n represents an integer of 1 to 20). 3. The composition according to claim 1, wherein the degree of substitution of the carboxyalkyl group in the whole composition is 0.005 to 0.05. 4. Starch and the following formula (I): X- (CH ₂ ) _n -COOH (wherein X represents a halogen atom and n represents an integer of 1 to 20). After mixing the carboxylic acid or a salt thereof shown with an alkali to make the water content of the mixture less than 5%,
A method for producing a starch derivative, wherein a heating reaction is performed at 90 ° C. or higher.