Optical properties of new types of paper packaging

Abstract

Background. Environmental paper materials are gaining worldwide popularity in recent years. At the same time, the most problematic issue is the development of paper with an optimal ratio of optical indicators (opacity, whiteness) and strength at minimum mass and thickness.
Different methods, approaches and technological solutions are used in each particular case to ensure the required level of a particular indicator of the quality of the packaging paper. Therefore, the problem of simultaneous increase of opacity and whiteness of paper with the preservation of its strength is not resolved.
The aim of the work is to improve the optical properties of the packaging paper with preserving its strength.
Material and methods. Materials of scientific works were used. The objects of the study were packaging paper, sulfate whitened pulp from coniferous and hardwood, as well as kaolin filler. The methods of complex analysis and synthesis were applied. The research of quality indices of packaging paper was carried out according to standardized methods [12–14] adopted in pulp and paper industry.
Results. Amethod for producing food packaging paper was invented according to the results of the research. It is a microporous fiber material, made of a paper mass comprising pulverized fibers of bleached cellulose from coniferous and deciduous wood, mineral filler, binder and gumming agents, and characterized in that the paper mass contains a mixture of fibers of cellulose from coniferous wood, grinding to a degree 42–44°ShR, and cellulose from deciduous wood, grinding to a degree 24–26°ShR, and getting of a fraction cellulose fibers from coniferous and deciduous wood mixed before molding (outpouring) of paper with the ratio of the masses: cellulose from coniferous wood – 85–90 %, cellulose from deciduous wood – 10–15 %.
Kaolin with a mass fraction of 2–3 microns 92–94 % and whiteness (reflection coefficient) of 87 % is used as mineral filler. The mass fraction of the filler in the paper is 8–9 % of absolutely dry fiber.
Conclusion. A method of producing food packaging paper is proposed according to the results of the research. This method is an original composition of a microporous fibrous material made from a paper mass comprising a mixture of fibers from pulp of coniferous and deciduous wood, ground to a different degree of fraction, a mineral filler of kaolin and sizing agents. This method allows providing a high degree of paper opacity at low content of the filler with the preservation of a sufficiently high whiteness and mechanical strength compared to counterparts.