Research Of Kelp Coated Packaging Paper And Its Enhancement Mechanism

Development of green packaging products has currently become an important issue tothe packaging industry, even to the whole economic construction. As a typical greenpackaging materials, paper packaging creates an interest of researchers. In our countrya large number of waste paper was used to pulp recycle, and straw pulp recently wasused to repeat papermaking, as a result cause the strength loss of paper. Although therehave been many types of strength additives applied to the improvement of paperstrength, few of their have been applied on a large scale in industry taking thelimitations of their defects and application cost. So research of new strengthening agentsfor paper has been a realistic and pressing issue.This study aims to study kelp coated paper, and determine the mechanicalproperties change of coated paper. Through the scanning electron microscope,microscopic structure of the coated paper was observed and influence of coatingsolution on paper fiber was discussed from micro level. In order to improveperformance of kelp solution, PVA was combined with it to study the influence of thecomposite coating for paper. Because during storage changes were happened, sostability of kelp solution was studied. This study has achieved a great significance bothto research of new enhancer and expansive application of kelp.1.The article chose dry kelp as material, after pulping, kelp solution was coated oncorrugated core paper. Physical and mechanical properties were tested in the research.The study showed that performance of paper was greatly improved. Thickness of papersheets of sample1was between0.181~0.183mm and basic weight was114.6g/m~2,which was increased by3.2%；thickness of paper sheets2was between0.178~0.182mmand basic weight was113.2g/m~2, which was increased by3.0%. The article also testedthe effects of coating weight on packaging paper. It was found that greater basis weightgave greater tensile strength. Tensile strength of sample1was increased by2%~19%,while to sample2, it was increased by5%~18%. Under the condition of certain coating weight and method, coating times often effected the performance of coated papers.Coating weight was chosen as5g/m~2in this study. It revealed that to sample1, whencoating time was1, tensile strength increased by2%, as coating times increased to5,tensile strength was increased to12%; while to sample2, when coating time was1,tensile strength increased by5.6%, as coating times increased to5, tensile strength wasincreased to8%. Different concentration of kelp coating solutions were chosen ascoating solution. Through the test, it was found that when viscosity of kelp solution waswithin34.8~35.1Pa, tensile properties of sample1coated paper increased by morethan13%, while sample2increased more than15%. Taken all conditions intoconsideration,38℃,3h was an optimum drying condition. Under the situation abovekelp coated paper got a smooth appearance and good tensile performance.2.The article studied the combined sizing effect of kelp/PVA, based on the highstrength characteristic of kelp, in order to further improve mechanical strength ofcorrugated core paper, reduce its basic weight, and enhance its mechanical property.The best parameters to sample1were: kelp density1%, PVA concentration10%, kelpand PVA volume ratio3:1, sizing weight5.0g/m~2, and double sizing along paper fiberdirection. It was found that while the best parameters were chosen, results were asfollows: tensile strength increased by5.0%, elongation increased by5.4%; surfacefrictional coefficient was obviously reduced and, and static friction coefficient reducedby20%. After thermal aging treatment, tensile strength of sizing corrugated core paperreduced by1.6%, less than4.6%of that compared paper.3.In the article, through the scanning electron microscopy (SEM) observation ofsurface and cross-section coated paper, interspace between paper fiber and tightness ofpaper fiber layers was compared and analyst between original and coated paper indifferent magnification change. Results showed the coating particles had a good mutualbonding performance, coating layer and original paper was strongly cohered, and kelp、PVA、PVA/kelp coating layers all could form compact membrane structure. Kelpsolution, kelp/PVA combined sizing both improved physical properties of corrugatedcore paper. After coating, gap between paper fibers was significantly shrank, layers ofpaper fibers became compact. TG was used to analyst the thermal stability of coatinglayer. Two main stages was existed in the thermogravimetric changes. In stageⅡ,decomposition of cellulose and hemicellulose was happed. Compared with originalpaper, weight loss of original paper reached70%, while coated paper60%. Rate of weight loss was reduce by10%which illustrated thermal stability of paper wasenhanced.4.The article studied the stability of the kelp solution. By adding PVA solution,carrageenan, CMC, sodium alginate, xanthan gum, stability of kelp solution had acertain degree of enhancement. It revealed that at room temperature, PVA was the beststabilizer, then was xanthan gum,and stability effect of CMC and carrageenan waspoorer. After adding PVA, precipitation rate reduced to2.17%compared to7.65%ofcontrol group; layers separation time increased from10h to32h. Effect order of fivekinds of stabilizer on product stability was: PVA solution> sodium alginate CMC>xanthan gum> carrageenan.In the process of coated paper, kelp solution was easy to induce microorganismbreeding as a result cause solution decay because of rich nutrition of kelp. Decay ofsolution affected bonding and flow performance of the coating material, such as colorchange. Quality deterioration of coating material finally cause strength decrease ofcoated paper surface and surface produces blotch. To solve the problem right amount ofcoating preservative adding was necessary. Salt and vinegar were chosen as additives inthe article. It was found that both of them could extend the preservation time of kelpsolution. When used together storage time extend more than7d. In order to get rid ofkelp smell and protect the seaweed liquid color, acid and alkali were used and heatprocessing was studied. Acid and alkali test showed that after processing, color stabilityof kelp was enhanced, at the same time smell was effectively removed of.