Study On Color Food Packing Paper Using Edible Stain As Dyeing Agent

In recent years, the problem of food safety has caused wild public concern. The food safety was not only relevant to the food itself, but also the safety of the food package. The advantages of the paper for the food package were obvious, such as its rich source, convenient processing, high performance, low price, environmental protection and so on. And the food package paper was playing an important role in the package industry. To meet the requirement of safety, the demand of the outward appearance of the food packing was increasingly higher than before. It’s meaningful to study the safety color food packing paper for its widely market demands.In this paper, nature pigment and edible stain as the dye stuff were used to dye pulp and paper by the way of surface sizing and pulp dyeing. The factors which had effects on dyeing were discussed, such as temperature, reactive time, pH, color fixation solution and so on. Besides, the waterproof of the food package paperand color matching were also studied in the paper.The results showed that surface sizing coloring was better than pulp dyeing. Under laboratory conditions, The optimum process of dyeing with Sorghum Red was found to be:dyeing temperature:40℃,the reactive time:45min, pH of dyeing liquid:5, the degree of the refining:45°SR, the dosage of Sorghum Red:1%; the dosage of Al2(SO4)3:1%. The optimum process of dyeing with tartrazine was found to be:the DS of cationic starch:0.5, the dosage of chitosan:0.4%, the dosage of cationic starch:1.5%, the pretreatment temperature:30℃, the pretreatment time:20min, pH of dyeing liquid:5. At the condition of5%dosage of tartrazine, b*was56.78, the dyeing process was closed to saturation.Brilliant Blue was studied for the requirement of dyeing food package paper by the surface sizing. Under the concentration of Brilliant Blue at0.75g/L, the optimum process of dyeing by single-factor tests was obtained as:dyeing temperature:60℃, the dosage of waterproof agent:1.8%, the dosage of A12(SO4)3:0.02%, solid content of the sizing liquid:10%. Contrast to the coloring in the pulp, dyeing paper by the surface sizing was more effective to improve the coloring effort. After the surface sizing, a better result of water-proof was obtained and the Cobb value of paper was reduced to32-36g/m2.