JPH10182876A - Water-soluble film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-soluble film excellent in tensile strength, uniformity and excellent antifogging properties. SOLUTION: This film is chiefly made from a carboxylmethyl cellulose sodium having a viscosity of 10-1,000mPa.s as measured in a 1% (in terms of the dry product) aqueous solution, a degree of etherification of 0.5-0.9, a purity of 98% or above and a content of water insolubles of 0.2% or below and has excellent tensile strength, uniformly film firming properties and antifogging properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble film containing sodium carboxymethylcellulose (hereinafter referred to as "CMC") as a main component, and more particularly to a small bag containing soluble coffee, tea, soup, sugar, etc., fat and soft. The present invention relates to an edible water-soluble film suitable for packaging candy and confectionery.

[0002]

2. Description of the Related Art A water-soluble film can be produced by applying an aqueous solution of a water-soluble polymer onto a polyethylene terephthalate (PET) film or the like and then evaporating and drying the film. As water-soluble polymers, pectate, gelatin, gelatin metal salts, starch, alginate, casein, xanthan gum, methylcellulose, CMC and the like are used. Among them, CMC has great advantages, such as stable quality, strong cohesion, high elongation of the film, and improvement in fragility, as compared with other natural water-soluble polymers.

Japanese Patent Publication No. 3-54704 proposes a method for modifying a sodium carboxymethyl cellulose film or film by adding glycerin monoacetomono fatty acid ester or the like to an aqueous solution of sodium carboxymethyl cellulose. However, in this method, it is necessary to add and stir acetyltin fat to the CMC aqueous solution, and there is a disadvantage that the operation becomes complicated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems and provides an edible water-soluble film having excellent tensile strength, uniform film-forming properties and excellent anti-fog properties. As an issue.

[0005]

Means for Solving the Problems That is, the following (A) to
This is a water-soluble film containing sodium carboxymethylcellulose having the feature of (D) as a main component. (A) 1% aqueous solution viscosity of 10 to 1000 m in terms of anhydride
Pa · s (B) Degree of etherification is 0.5 to 0.9 (C) Pure content is 98% or more (D) Water insoluble matter is 0.2% or less

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention requires that the viscosity of a 1% aqueous solution of CMC be in the range of 10 to 1000 mPa · s. If the viscosity of the 1% aqueous solution is 10 mPa · s or less, a film having a high strength cannot be obtained due to insufficient adhesion. Also, 10
If the pressure is more than 00 mPa · s, a film having adhesive strength and strong strength can be formed. However, since the film is a high-viscosity aqueous solution, there is a problem in uniform application, and the film has uneven surfaces. Preferably 50 to 500 mPa · s. Range. % In the present invention means% by weight unless otherwise specified, for example, 50% v / v, 65% RH.

In the present invention, the degree of etherification of CMC is 0.5
０．９0.9. If the degree of etherification is 0.5 or less, insufficient water-solubility of cellulose causes insufficient adhesion. In addition, a film having a smooth surface cannot be formed due to an insoluble substance or a swollen gel-like substance.
If the ratio is 0.9 or more, a beautiful film having a smooth surface can be formed, but the film strength is reduced. Preferably 0.
It is in the range of 6 to 0.7.

The present invention requires that the pure content of CMC be 98% or more. Impurities include salts produced as by-products such as sodium chloride, sodium glycolate, unreacted cellulose, and undissolved gel. When the purity is 98% or less, the film becomes cloudy, the transparency becomes poor, and the uniform film forming property is obtained. Only low films can be obtained. Preferably it is 99% or more.

In the present invention, the water-insoluble matter of CMC is 0.2%
You need to: Impurities such as salt,
They are classified into water-soluble substances such as sodium glycolate and water-insoluble substances such as unreacted cellulose and undissolved gel. Water-insoluble substances of CMC include lint-like substances and undissolved gel substances caused by unreacted cellulose. If a small amount of unreacted cellulose is mixed, it is formed as it is. When the undissolved gel-like substance is mixed, the surface becomes uneven or fogged, so that the film cannot be uniformly formed, the transparency is reduced, and a non-uniform film is formed. 0% water insolubles.
If it is 2% or more, unevenness or fogging occurs on the surface, and uniform film forming property cannot be maintained. Preferably it is 0.1% or less.

[0010] In order to increase the added value of the film as long as the effects of the present invention are not impaired, flavors, pigments, sweeteners and the like can be added.

[0011]

【Example】

Examples 1 to 7 and Comparative Examples 1 to 12 The methods of analyzing the viscosity of 1% aqueous solution of CMC, the degree of etherification, the pure content, and the insoluble matter in water are shown in 1-4. The film preparation method is shown in 5, and the film evaluation methods such as tensile strength, moisture absorption, film fogging, film smoothness, and uniform film forming property are shown in 6. 1.1% aqueous solution viscosity (1) Preparation of solution In a 300 ml stoppered Erlenmeyer flask, a sample is precisely weighed at about 4.7 g for a 2% aqueous solution and 2.3 g for a 1% aqueous solution. (Weighing 500 g), add 200 g of distilled water, immediately stopper, shake vigorously, disperse in small chunks, and allow to stand. Separately, measure the water content of the same sample. After standing overnight (about 18 to 20 hours), the insufficient water is supplemented with a burette according to the following formula based on the measured moisture value.

[0012]

(Equation 1)

After the correction is completed, a small rotor is placed in the flask,
The mixture is stirred with a magnetic stirrer for 5 minutes to completely disperse and dissolve the swollen liquid. (2) Measurement Transfer the solution to a 250-ml container with a lid (50 m / m in diameter, 140 m / m in height), cover, leave in a thermostat at 25 ± 0.2 ° C for 30 minutes, and gently measure with a thermometer. The temperature is checked while stirring, and when the temperature reaches 25 ° C., the rotor and guard of the B-type viscometer are attached, the rotation of the rotor is started, and the scale is read after 3 minutes. The viscosity is obtained by multiplying the coefficient by the rotor used and the number of revolutions. 2. Degree of etherification (Ashing method) 0.5 to 0.7 g of a sample anhydride is precisely weighed, wrapped in filter paper, and incinerated in a porcelain crucible. 500cc after cooling
Transfer the crucible to a beaker, add about 250 cc of water,
Further, 35 cc of N / 10H ₂ SO ₄ is added by a pipette, and the mixture is boiled for 30 minutes. This is cooled and excess acid is back titrated with N / 10 KOH using phenolphthalein as an indicator. Separately, the alkalinity or acidity of the sample is measured, and the degree of etherification is determined from the following equation.

[0014]

(Equation 2)

(Note) Alkalinity 1 g of the sample in terms of anhydride is precisely weighed, and about 200 cc of water is added to dissolve it. This exactly added N / 10H ₂ SO ₄ 5cc, boiled for 10 minutes and titrated with N / 10 KOH using phenolphthalein After cooling as an indicator.

[0016]

(Equation 3)

3. Pure (copper salt precipitation method) Reagent Methyl alcohol 50% v / v aqueous solution Hydrochloric acid 1% aqueous solution of copper sulfate 5% aqueous solution of 3% aqueous ammonia Methyl red indicator Nitric acid Equipment and tools Magnetic stirrer, glass electrode pH meter, glass filter (No3G-3) Magnetic crucible, spectrophotometer Operation method (1) Formation of copper salt Approximately 0.3 g of CMC (anhydride) is precisely weighed in a 100 ml Erlenmeyer flask.

After wetting with methyl alcohol, water 40m
Add 1 and dissolve completely. To this, methyl red indicator 2
Add dropwise and add hydrochloric acid until it shows red. (Usually 1
Turn red with drops, add one more drop. Separately, 100 ml of a copper sulfate solution and 20 ml of methyl alcohol are placed in a 300 ml beaker, and acidified by adding 2 drops of hydrochloric acid.

PH corrected at two points, pH 4 and pH 7
Using a meter, add the sample solution little by little while stirring well with a stirrer. Fill the flask with a small amount of water
Wash three times, and adjust the washing solution to the beaker. Usually p at this time
H is about 2. Next, stir well and add 3
% Ammonia water is added dropwise to adjust the pH to 4.0 to 4.1. If the pH is 4.1 or more, copper hydroxide is generated.
Once H4.1 or higher, hydrochloric acid must be added once to pH 2.0 to bring the pH back to 4.0-4.1.

(2) Filtration and washing The supernatant is filtered with a clean glass filter which has been weighed in advance. The precipitate is washed with 50 ml of a 50% v / v aqueous solution of methyl alcohol while stirring well with a glass rod. The washing is repeated twice more, followed by washing twice with methyl alcohol, and then drying at 105 ± 2 ° C. until the temperature becomes constant. (Cu
-CMC weight) (3) Determination of copper The above Cu-CM was added to a pre-weighed magnetic crucible.
Transfer most of C and weigh it. Next, this is burnt incinerated, then cooled, put into a 100 ml beaker together with the crucible, 1 ml of nitric acid and 5 ml of water are added, and heated on a hot water bath to completely dissolve the residue.

The crucible is removed by washing with water, and this solution is filtered and transferred to a 100 ml volumetric flask using filter paper.
% Ammonia water up to the marked line, shake well, and use a spectrophotometer to compare 6% ammonia water with 5% ammonia water.
Measure the absorbance at 20 mμ. The amount of copper is calculated from a calibration curve prepared with a standard copper solution.

[0022]

(Equation 4)

(4) Calculation

[0024]

(Equation 5)

4. Water insoluble material Equipment and tools 5 l stainless beaker Three one motor, stirring blade (90 mmφ 3 blades,
Shaft 3mmφ50mm) Separate holder (inner diameter 70mm Example: ADVANT
EC KGS-90) Vacuum filtration device (see Fig. 1) Filter cloth (250 mesh made of polyester) Operation (1) Dissolution Put 3 l of pure water in a 5 l stainless beaker, set it on a three one motor, and put a vinyl lid on to prevent foreign matter from entering. And prepare for dissolution.

30 g of the precisely weighed sample is added little by little while stirring to dissolve mamako and dissolve. (600
~ 700 rpm) 3
Stir and dissolve for hours and leave overnight. The next day again 2
Stir for hours to completely dissolve. (2) Measurement of filter cloth weight The filter cloth previously cut to 105 mmφ is dried on an aluminum foil for 30 minutes using a constant-temperature electric drier before filtering.

The dried filter cloth is transferred to a desiccator and cooled for one hour. The empty weight is measured with the filter cloth placed on an aluminum foil. The value 60 seconds after placing on the balance is 0.0001.
Read to g. (3) Filtration The pressure in the vacuum filter is adjusted to 200 mmHg. Set the separate holder in the vacuum filtration device. A filter cloth is set, and the solution is completely filtered.

About 1 liter of pure water is used to wash off the adherence to the wall of the beaker, and the whole is filtered. The upper part of the filter cloth is washed away with about 1 liter of pure water. Water insolubles in the CMC remain on the filter cloth. The filter cloth is taken out and put into a constant temperature electric dryer and dried for 3 hours. (4) Measurement of insoluble matter Take out the dried filter cloth, put it in a desiccator, and cool it for 1 hour. The residual weight is measured with the filter cloth placed on an aluminum foil. The value 60 seconds after placing on the balance is 0.0001.
Read to g.

(5) Calculation

[0030]

(Equation 6)

5. Film Preparation Method A 5% by weight CMC aqueous solution is prepared. During the operation of removing air bubbles on the PET film, coating is performed while air bubbles are not mixed. Dry at 40 ° C for about 20-30 hours to make a film. Confirm that the thickness is 0.15 mm. If the thickness is insufficient, further coat with an aqueous solution to 0.15mm
So that After drying, peel off the PET film to obtain a CMC film. 6. Evaluation of film (1) A test piece having a tensile strength of 100 × 5 mm was prepared, and a temperature of 20 ° C.6
After wetting at 5% RH, the tensile strength is measured with a Shopper type tensile tester. (Kg / mm ² ) The larger the value, the stronger the strength.

(2) Moisture Absorption Rate Five test pieces of 100 × 5 mm were dried at 100 ° C. for 1 hour, and the weight gain after 24 hours at 20 ° C. and 65% RH was measured. It is preferable that the moisture absorption is small because the strength tends to decrease when the moisture absorption is large. (3) Film fogging The obtained film was placed on white paper with 15 parallel lines drawn in black at 1 mm width and 1 mm interval, the lines were discriminated, and the fogging was observed.

×: No black line can be recognized at all △: Somehow visible lines ○: A state where lines can be recognized ◎: Good condition that film cannot be felt on the film (4) Smoothness of film, Uniform film-forming property The obtained film was observed with naked eyes.

×: There are many lint-like and rough feelings in the film. Δ: Lint-like and rough feeling is slightly felt in the film. …: The film has a lint-like shape and some roughness. …: There is almost no lint-like or rough feeling in the film. The characteristics of each CMC were measured by measuring methods 1-4, and 5
A film was produced by the film production method described above, and the film was evaluated by each method of 6. Table 1 shows the results.

[0035]

[Table 1]

[0036]

By using the CMC according to the present invention in the water-soluble film obtained by the CMC, it is possible to obtain a film having excellent tensile strength, uniform film-forming properties and excellent anti-fog properties.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a reduced pressure filtration device used in Examples of the present application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separate holder 2 Decompression adjusting cock 3 Vacuum line 4 Decompression gauge 5 Filtration receiving tank 6 Drain line

Claims (1)

[Claims] 1. A water-soluble film comprising sodium carboxymethylcellulose having the following features (A) to (D) as main components: (A) 1% aqueous solution viscosity of 10 to 1000 m in terms of anhydride
Pa · s (B) Degree of etherification is 0.5 to 0.9 (C) Pure content is 98% or more (D) Water insoluble matter is 0.2% or less