Research On Apparent Processing Of Molded Pulp Packaging Products

In recent years, in response to the "green" philosophy, The community and the industryhave been attaching great importance to the environmental protection packaging materials. Asa new type of environmentally friendly materials, molded pulp has become the third largestconsumption industry of waster paper, fields of application become more and more widely.Because of the wide source of raw materials, recyclable and readily biodegradable, moldedpulp is the most popular material instead of plastic. However, the color and surfacesmoothness of the product is poor because of the influence of raw materials, which limits theapplication of molded pulp. Improving the appearance performance of molded pulp,increasing their added value in the package has become one of the research hotspot.On the basis of domestic and international research, combined with the specificcircumstance of the laboratory, the paper improved the appearance color, surface smoothnessand linting situation of molded pulp which is made from OCC paper fiber with surfacetreatment technologies such as bleaching, dyeing and coating. Studied the variation ofbursting and ring crush strength of molded pulp before and after treatment. Specifically, themain contents include:(1) According to the composition of raw material-OCC pulp and pulp properties, fromthe perspective of the chemical mechanism, analysed the interaction of chemicals and fibersin pulp bleaching, dyeing and surface sizing process, determined the choice of chemicalreagents and evaluation index of the follow-up experiments.(2) The microwave heating has been used in a period of hydrogen peroxide bleachingOCC pulp. Pulp brightness and residual liquid chemical oxygen demand as the evaluationindexs, the optimum process parameters have been determined by orthogonal experiment:alkali ratio0.2, H2O2dosage of2%, the microwave power300w, microwave time150s. Inorder to obtain higher pulp brightness, using H2O2/FAS/NaBH4three-stage bleaching, theeffect of the bleaching sequence of three-stage bleaching on pulp brightness has been studied.The test results showed that: after NaBH4/FAS/H2O2three-stage bleaching, pulp brightnesshas reached73.41, compared with one-stage bleaching, pulp brightness increased by11.8%;while COD values are similar to one-stage bleaching, wastewater treatment burden has notincreased significantly after three-stage bleaching.(3) Dyeing of pulp which has been bleached by microwave-H2O2. Dye uptake and colorfastness as the main indicators, the pulp brightness as the supplementary indicator, studied theoptimum conditions of dyeing with direct Turquoise Blue GL through L16(45) orthogonalexperiment: dye dosage1.6%, NaCl dosage10%, PH value of the pulp4, dyeing temperature60℃, dyeing time30min. The pulp dye uptake reached about98.5%, direct Fast TurquoiseBlue GL dyeing fibers generally have a higher color fastness. (4) Influence of four kinds of surface sizing agent (PS-255surface sizing starch, KR-002surface dry strength agent, KR-230cationic surface sizing and B-1surface enhancer) onimproving surface smoothness and linting of molded pulp products has been studied.Compound experiments have been conducted on this basis, the results showed that: PS-255sizing starch has the best effect on improving the surface smoothness of molded pulp products,KR-002surface dry strength agents has a general effect on improving the surface smoothness,but has the best effect on decreasing linting, and sample surface is beautiful after thermalplastic. The PS-255and KR-002are compounded, the optimum formula has been determined:m (PS-255): m (KR-002) is10:2, sizing substance concentration20%, film thickness400μm.(5) Studied the effects of physical properties (bursting and ring crush strength) of moldedpulp plate after bleaching, dyeing and surface sizing; the physical properties of articles havelittle change after bleaching and dyeing, surface sizing can improve their physical propertiesin some extent.Research results indicate that the apparent performance of molded pulp products whichis made from OCC pulp can be effectively improved after bleaching, dyeing and surfacesizing treatment. The color, surface smoothness and linting of products have reached a higherlevel, providing a possibility of wide range applications in the high-grade packaging. Theresearch results provide a theoretical and experimental basis on further studies of the apparentprocessing technologies of molded pulp products, which have a high reference value.