Film and method of preparing the same
A film and a method of preparing the same. The film includes cellulose ether and sodium chloride, wherein an amount of the sodium chloride is from about 0.25 wt % to about 0.6 wt % based on a total weight of the film, and the film has a light-transmission reduction ratio of about 15% or less.
1. A film comprising cellulose ether and sodium chloride, wherein an amount of the sodium chloride is from about 0.25 wt % to about 0.6 wt % based on a total weight of the film, and the film has a light-transmission reduction ratio of about 15% or less.
2. The film of claim 1 , wherein the film has a light-transmission reduction ratio of about 2% or less.
3. The film of claim 1 , wherein the film is a transparent film.
4. The film of claim 3 , wherein the film has a light-transmission of about 80% or greater.
5. The film of claim 1 , wherein the film is a colored film.
6. The film of claim 1 , wherein the film has a water vapor transmission rate (WVTR) of about 160 g/m 2 /day or less.
7. The film of claim 1 , wherein the film is used for hard capsules, food films, medical films, or industrial films.
8. A method of preparing the film of claim 1 , the method comprising: dissolving cellulose ether in a solvent to obtain an untreated cellulose ether solution; ultrasonicating the untreated cellulose ether solution to obtain a treated cellulose ether solution; coating the treated cellulose ether solution on a substrate; and drying the coated cellulose ether solution.
9. The method of claim 8 , wherein the cellulose ether comprises sodium chloride, wherein an amount of the sodium chloride is greater than about 0.3 wt % and equal to or less than 0.6 wt % based on the total weight of the cellulose ether.
10. The method of claim 8 , wherein the cellulose ether is water-soluble, and the solvent is an aqueous solvent.
11. The method of claim 8 , wherein the cellulose ether comprises at least one selected from the group consisting of methyl cellulose, hydroxypropylmethyl cellulose, and hydroxyethylmethyl cellulose.
12. The method of claim 8 , wherein the untreated cellulose ether solution has a cellulose ether concentration of from about 5 wt % to about 25 wt %.
13. The method of claim 8 , wherein the ultrasonication comprises irradiating ultrasonic waves having a frequency of from about 10 kHz to about 30 kHz onto the untreated cellulose ether solution at an energy of from about 80 kJ/L (per volume of the untreated cellulose ether solution) to about 300 kJ/L (per volume of the untreated cellulose ether solution) .
14. The method of claim 8 , further comprising adding a plasticizer into the untreated cellulose ether solution.
15. The method of claim 14 , wherein the plasticizer comprises at least one selected from the group consisting of glycerol, sorbitol, propylene glycol, and polyethylene glycol.
16. The method of claim 14 , wherein an amount of the plasticizer is from 1 part by weight to 10 parts by weight based on 100 parts by weight of the cellulose ether.