JPH10251980A - Coloring of half-split chopstick - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for tinging chopsticks with various colors such as red, blue or green while ensuring the safety of the chopsticks for human bodies. SOLUTION: Chopsticks are immersed in a coloring solution prepared by dissolving an edible dye in an aqueous medium or coated with the coloring solution. For example, New Coccine, Acid Red, Tartrazine, Sunset Yellow, Fast Green and Brilliant Blue are used alone or in a mixture of two or more thereof as the edible dye. The concentration of the edible dye in the coloring solution is preferably 0.01-5wt.%, especially preferably 0.05-1wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coloring chopsticks, and more particularly, to a method for coloring chopsticks in various colors such as red, blue and green while ensuring the safety of the chopsticks on the human body. About.

[0002]

2. Description of the Related Art Disposable chopsticks are made from various plant materials such as cedar, cypress, willow, Ezomatsu, aspen and bamboo, but only the colors of the materials are used as they are. I can't find it.

[0003]

However, the demands of users for disposable chopsticks also tend to be diversified. For example, at wedding receptions, disposable chopsticks colored in red and white are considered to be useful for raising the atmosphere.

[0004] In addition, it is conceivable to color disposable chopsticks used for in-flight meals of airplanes in their respective corporate colors, and in various theme parks, colored disposable chopsticks are considered to be particularly pleasing to children.

However, disposable chopsticks are used for pinching food, so that they need not only have good appearance but also have to be safe for the human body.

Accordingly, it is an object of the present invention to provide a method of coloring chopsticks while ensuring the safety of the chopsticks on the human body.

[0007]

The present inventor has conducted various studies to solve the above-mentioned problems. As a result, the disposable chopsticks were immersed in a coloring liquid obtained by dissolving an edible dye in an aqueous medium, or the disposable chopsticks were added to the disposable chopsticks. When applying the coloring liquid, it has been found that the chopsticks can be colored in various colors such as red, blue, and green while securing the safety of the chopsticks to the human body, and the present invention has been completed. .

As described above, in the present invention, since disposable chopsticks are colored with food dyes, there is no problem with respect to safety to the human body.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The food dyes used in the present invention are those permitted by the Food Sanitation Act, and specific examples thereof include, for example, Amaranth (edible red No. 2),
Erythrosin (edible red No. 3), Alla Red AC (edible red No. 40), New coccin (edible red 102)
No.), Phloxine (edible red No. 104), Rose Bengal (edible red No. 105), Acid Red (edible red 1)
No.06), tartrazine (edible yellow No.4), sunset yellow (edible yellow No.5), fast green (edible green No.3), brilliant blue (edible blue No.1), indigo carmine (edible blue No.2), etc. These can be used alone or in combination of two or more. Further, by mixing two or more of them, a color different from the original color can be obtained.

A coloring liquid is prepared by dissolving the food dye in an aqueous medium. The concentration of the food dye in the coloring liquid is 0.01 to 5% by weight, particularly 0.1 to 5% by weight.
It is preferably from 0.5 to 1% by weight. When the concentration of the food dye in the coloring liquid is lower than 0.01% by weight, the disposable chopsticks may not be sufficiently colored, and the concentration of the food dye in the coloring liquid may be higher than 5% by weight. However, there is almost no increase in the effect, and the use of expensive food dyes in large amounts leads to an increase in cost.

The aqueous medium used in the preparation of the coloring liquid may be water alone, or may contain a solvent such as ethyl alcohol which can ensure safety for the human body. In addition, the coloring liquid may be basically one in which the edible dye is simply dissolved in an aqueous medium, but within a range where safety to the human body can be ensured, for example, to promote the penetration of the coloring liquid into the disposable chopsticks. And an additive such as a penetrant.

Although the coloring of the chopsticks can be carried out at room temperature, it is preferable to heat the coloring liquid in order to carry out the production with good productivity. The heating temperature is not particularly limited, but is preferably about 40 to 80 ° C., particularly preferably about 40 to 60 ° C. Further, when pressurized, the penetration of the coloring liquid into the disposable chopsticks is promoted, and the productivity is further improved. be able to.

When the chopsticks are immersed in the coloring liquid, the immersion time is preferably about 1 to 240 minutes, although it depends on whether or not heating or pressurization is adopted and the number of disposable chopsticks to be treated.

When it is necessary to enhance the fixability of the food dye colored on the disposable chopsticks, it is preferable to perform a fixing treatment with a water-soluble resin such as a water-soluble polyamide resin or a water-soluble polyurethane resin. The fixing process using the water-soluble resin may be performed by applying the water-soluble resin as clear paint to the disposable chopsticks after the coloring process, or
It can also be carried out by including a water-soluble resin in the coloring liquid.
However, although these water-soluble resins are water-soluble at the time of use, they can be made high molecular weight by reaction or heating to become water-insoluble, and can prevent leaching of edible dyes from disposable chopsticks. is required.

After immersion in the coloring liquid or application of the coloring liquid, the disposable chopsticks are dried and the aqueous medium in the coloring liquid is evaporated to obtain colored disposable chopsticks.

The chopsticks may be made of any plant material such as cedar, cypress, willow, white birch, Ezomatsu, aspen and bamboo. Also, the shape of the disposable chopsticks may be round or square. You may have it.

[0017]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples below,% indicating the concentration of the edible dye in the coloring liquid is% by weight.

Example 1 A coloring liquid was prepared by dissolving the food dyes shown in Table 1 in water. The concentration of each of the food dyes was 0.1%.

[0019]

[Table 1]

As disposable chopsticks to be colored, cedar cut chopsticks are used, and 100 sets of the above cedar cut chopsticks are immersed in 10 liters of each of the coloring liquids shown in Table 1 at 60 ° C. for 60 minutes.
After pulling up the cedar chopsticks from the coloring liquid, they were blown and dried at 35 ° C. to obtain cedar stake chopsticks colored in a color based on each food dye.

The colored chopsticks after coloring are used as test specimens, and the color is measured at two locations on each test specimen.
Cold resistance, acid resistance, and alcohol resistance tests were performed. Also,
An uncolored cedar straight cut chopsticks was used as a test specimen for comparison, and the same test as above was performed.

After the test, the color change of the test specimen was visually observed, and the color was measured again at the same position on the test specimen to check the color change by the test. Color is color difference meter (Z-1 made by Nippon Denshoku Industries)
001DP), L ^* , a ^* , b before and after the test
The degree of color change was evaluated by the color difference ΔE ^* calculated by squaring each difference of ^* and halving the sum of them. For each test, colored cedar straight cut chopsticks were used for each three specimens, and an average value of six measured values was calculated. The respective test methods and test results are as shown below.

A Test Method A—Lightfastness: Each test specimen was irradiated with a mercury lamp (Toshiba H400-F) for 20 hours using a fade meter, and the lightfastness was evaluated based on the color change before and after the irradiation. It is said that irradiation for 20 hours by the mercury lamp causes a color change similar to that when left in a bright room for one year.

A-Heat resistance: Each test specimen was left in a dryer at 100 ° C. for 24 hours, and the heat resistance was evaluated based on the resulting color change.

A-Cold Resistance: Each test specimen was left in a freezer at −20 ° C. for 24 hours, and the cold resistance was evaluated based on the resulting color change.

A- Acid Resistance: In the acid resistance test, first, each test specimen was left in running water at 15 ° C. for 6 hours to impregnate the test specimen with cold water, then blow dried at 35 ° C. Was measured.

Next, the test specimen was immersed in a 5% aqueous acetic acid solution at pH 2 for 2 hours, and the acid resistance was evaluated based on the resulting color change. The color measurement is performed in a wet state immediately after the end of immersion.
E ^* was calculated by comparison with that after impregnation with cold water. 5 as test solution
The acetic acid aqueous solution was selected in consideration of the fact that edible vinegar contains about 4% acetic acid.

A-Alcohol resistance: As in the case of the acid resistance test, first, the test specimen was impregnated with cold water, and then dried by blowing at 35 ° C., and the color was measured in advance.

Next, the test piece was immersed in 60% ethyl alcohol for 2 hours, and the resulting color change was evaluated for alcohol resistance. The color was measured in a wet state immediately after the completion of the immersion, and ΔE ^* was calculated by comparison with that after the impregnation with cold water. The reason that 60% ethyl alcohol was selected as the test liquid was because the alcohol concentration of the distilled liquor was taken into consideration.

B Test Results and Discussion B- The light-fast, uncolored cedar straight cut chopsticks were slightly yellow in color and had a ΔE ^* of 6.5. In addition, in the chopsticks cut with cedar, colored by Newkokushin, Tartrazine, Sunset Yellow,
ΔE ^* was 5.6, 5.6, and 5.2, respectively, and although the color changed, the value was small and inconspicuous. On the other hand, cedar straight cut chopsticks colored with Acid Red, First Green, and Brilliant Blue have considerably large ΔE ^* of 15.0, 10.7, and 17.1, respectively. Sex was inferior to the others.

In most cases, the use of disposable chopsticks is used only once. Therefore, it is considered that the low light resistance under the severe test conditions as described above does not cause a serious problem in practical use. In selling disposable chopsticks colored with low food dyes, it is considered preferable to adopt a selling method that is not directly exposed to light.

B- ΔE when left in a dryer at 100 ° C. for 24 hours
^* Is 4 or less in any of the test pieces, no color change is observed with the naked eye, and there is no problem with heat resistance.

B—Cooling resistance ΔE when left in a freezer at −20 ° C. for 24 hours
^{* Indicates} that all the test specimens were as small as 2 or less, no color change was observed with the naked eye, and there was no problem with respect to cold resistance.

B- When immersed in an acid -resistant 5% acetic acid aqueous solution for 2 hours,
^* Was a large value of 5 to 15, but as far as the naked eye observed, any of the specimens was caused by the leaching of the food dye, the cause of which was that the color became lighter, and the food dye itself deteriorated. It is thought that there is no.

It is considered that disposable chopsticks are rarely used in the state of being immersed in water for two hours. However, even in the above test, the food dye itself is not deteriorated.
It is considered preferable to physically prevent leaching of the food dye by, for example, injecting the water-soluble resin at the same time as the surface protection of the water-soluble resin with clear paint as described above or the food dye at the same time.

B—Alcohol Resistance When immersed in 60% ethyl alcohol for 2 hours, ΔE ^* became a large value of 5 to 15 in any case. It is considered that the color was lightened due to the leaching of the food dye, and the food dye itself was not deteriorated.

In view of the usage of the disposable chopsticks, it is considered that there is no practical problem. However, it is preferable to take measures to prevent the edible dye from leaching as necessary.

The above test results are symbolized and shown in Table 2 below.

[0039]

[Table 2]

Example 2 Tartrazine and brilliant blue were mixed at a weight ratio of 3: 2 to adjust the color of green, and this was dissolved in water to prepare a coloring liquid having a food dye concentration of 0.1%.

The disposable chopsticks to be colored are described in Example 1.
In the same manner as above, using 100% cut cedar chopsticks in 10 liters of the above-mentioned coloring liquid, immerse 100 sets of Japanese cedar chopsticks at 60 ° C for 60 minutes,
It was blow-dried at 35 ° C to obtain green colored chopsticks.

The colored chopsticks were used as test specimens, and the color was measured in the same manner as in Example 1. After that, light resistance, heat resistance, cold resistance, acid resistance, and alcohol resistance tests were performed.

As a result of the light resistance test, ΔE ^* was 11.2
, And showed an intermediate value between tartrazine and brilliant blue, and slight discoloration was observed with the naked eye.

In a heat resistance test left for 24 hours in a drier at 100 ° C., ΔE ^* was 4 or less.
In a cold resistance test left in a freezer for 24 hours, ΔE ^*
Was as small as 2 or less, and there was no particular problem with respect to heat resistance and cold resistance.

In an acid resistance test immersed in a 5% acetic acid aqueous solution for 2 hours and an alcohol resistance test immersed in 60% ethyl alcohol for 2 hours, ΔE ^* was 10.5.
And 11.0 showed a considerably large value, which is considered to be due to leaching of the food dye as in the case of Example 1.

As described above, green chopped cedar straight cut chopsticks have no particular problem with respect to heat resistance and cold resistance, and have some problems with light resistance, acid resistance and alcohol resistance.
By adopting a sales system that is not exposed directly to light when selling, problems with light resistance can be solved.Also, acid resistance and alcohol resistance have been adopted under severe test conditions, and edible It is thought that the cause is leaching, not the deterioration of the dye. Therefore, it is considered that there is no practical problem in view of the usage of disposable chopsticks. However, if it is expected that the food dye will be immersed in water for a long time, take measures to prevent the food dye from leaching by using a water-soluble resin to prevent leaching of the food dye after coloring. It is thought that it is desirable to keep

In the above embodiment, the chopsticks of cedar masu are colored.
Instead, Yanagimaru chopsticks, Aspen round chopsticks, Aspen Genroku chopsticks, etc. were colored in the same manner as in Examples 1 and 2 above, but all were able to be colored to desired colors.

[0048]

As described above, according to the present invention, the chopsticks can be colored in various colors while securing the safety of the chopsticks to the human body.

Claims (2)

[Claims] 1. A method for coloring disposable chopsticks, comprising immersing disposable chopsticks in a coloring liquid obtained by dissolving a food dye in an aqueous medium, or applying the coloring liquid to disposable chopsticks to color the disposable chopsticks. 2. The concentration of the edible dye in the coloring liquid is 0.05 to 0.05.
The method for coloring disposable chopsticks according to claim 1, which is 5% by weight.