Abstract:On the basis of previous research, the gel-type carbon dioxide indicator label was studied. The indicator label consists of carbon dioxide indicator solution and gelling solvent. The mass concentration of the indicator solution was 5% and the indicator was composed of 3/5 methyl red and 2/5 bromothymol blue. Methyl cellulose and glycerol were the primary materials to make the gel. The goodness-of-fit during the color changing process of the gel and the indicating liquid were studied. Then the optimum formulation for the indicator film was studied by using the gel. Results show that: the gel made by appropriate concentration of methyl cellulose had a high goodness-of-fit with color change of indicator solution. As it had no effect on color change of indicator solution, so it could be used as the main film forming material to develop the indicator label. Considering overall indexes of viscosity, response time of color change, the hanging wall percentage and casting performance, the optimum additive mass fraction of methylcellulose was got as being 1.6%~1.8% to make the indicator gel. During the process of making the indicator film by using the gel which contained 1.6~1.8 g/100 g methylcellulose, it was found that appropriate additive amount of glycerol could make the membrane smooth and flat, while it was good for keeping moisture. Finally the optimum condition of making the label was got: the adding mass fraction of methyl cellulose was 1.8% and the adding volume fraction of glycerol was 4%.