Application of modified wheat starch glues to increase the physical and mechanical parameters of paper and cardboard production processes

Abstract

The waste paper is mainly used as a fibrous semi-finished product for technological production processes of paper and paperboard products. The use of waste paper in the production of paper and paperboard products makes it possible to reduce the use of natural resources and the load of pollutant emissions on the environment significantly. But together with the positive aspects there are a number of problems in the production process stipulated by lower waste paper quality compared with cellulose. The fiber retention on the wire of a paper or paperboard machine deteriorates, and, accordingly, this leads to contamination of pit water, increasing the raw materials losses with pit water. Repeated use of retained fiber as a sediment degrades the quality of the finished product, because the content of fine fibers in the composition of the finished product increases. Due to such phenomena, in order to increase the percentage of fine fiber on the wire of the paper-paperboard machine and the physical and mechanical properties of the finished product, modified starch glues are used in the paper and paperboard production [1,2].Analysis of literature sources [1,2] and additional studies of paper and paperboard production systems made it possible to determine the field of experimental research, as well as factors that have a decisive influence on the production state. In order to carry out the researches at the laboratory, a plan (matrix) of the experiment is developed. The synthesis of experimental research plans is carried out using criteria that provide maximum informativeness of the conducted experiments [3]. Such approach to the experiment ensures the researcher the maximum possible amount of useful information about the behavior of the object to be studied. It should be noted that with a fairly significant number of factors included to the experiment and the change of factors at least at 4 levels the number of experiments is fixed at a certain reasonable level. However, the researcher has no, i.e. in advance indeterminate, information about the structure of the dependence between the optimization parameters, as well as factors that are included to the process of research and modeling. The next step in the research implementation is to create adequate mathematical models that will be suitable for the purposes of situations modeling that occur by paper and paperboard production. The development of mathematical models is carried out with using the method of self-organization MSUA [4,5].The purpose of this article is to study the effect of starch glue from wheat grains and the degree of its substitution on the paper web quality, provided the glue addition at the stage of waste paper grinding.Based on the results of literature research and previous laboratory studies, a set of factors is determined that, according to the experimenter, will have an influence on the physical and mechanical properties of finished products.Taking into account the fact that the dependencies will be clearly nonlinear, the factors are planned to change, if possible, at 4 levels [3].The following parameters were chosen as optimization parameters, according to which the indices of finished products will be evaluated, namely:- flat compression resistance, H, (Ŷ1);- absolute bursting strength, kPa, (Ŷ2);- specific tearing strength in the machine direction, kN \ m, (Ŷ3);- end compression resistance, kN \ m, (Ŷ4);- surface water absorption, g, Cobb30, (Ŷ5).Experimental studies were carried out at the laboratory of the Department of E and TRP in accordance with the developed matrix of experimental studies.In accordance with the volume of the experimental data and using the necessary methodology [4-5] the mathematical models for optimization parameters were created, which were determined during the process of the research problem setting.Using mathematical models, a study was carried out and was found that the optimal value of the degree of waste paper grinding by glue addition at the stage of grinding for waste paper brand MS-5B by indices: flat compression resistance and absolute bursting strength is within 55° SHR. According to the indices of specific tensile strength and end compression resistance, the optimal value of the grinding degree can be considered to be 60° SHR, at which the maximum strength value is achieved.The next step of the study is to verify in real production conditions the results obtained on the basis of adequate mathematical models.