# Evaluation of Recycled Paperboard Properties and Characteristics  
[PERSON]  
1 Department of Printing Technology, St. Petersburg State University of Industrial Technologies and Design, 18 Bolshaya Morskaya Street, 191186 St. Petersburg, Russia; [EMAIL_ADDRESS] (E.T. ); [EMAIL_ADDRESS] (D.A.) [PERSON]  
1 Department of Printing Technology, St. Petersburg State University of Industrial Technologies and Design, 18 Bolshaya Morskaya Street, 191186 St. Petersburg, Russia; [EMAIL_ADDRESS] (E.T. ); [EMAIL_ADDRESS] (D.A.) [PERSON]  
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organizing the life cycle of materials in a manner that minimizes waste and optimizes the use of natural resources, promoting efficiency throughout the process of the recycling of paper products. This is accomplished by establishing a system where waste fiber-based products serve as the primary raw material for the new production cycle. Recycling paper, carton, fiberboard, and paperboard can significantly reduce the amount of raw wood used in papermaking, potentially up to 100% depending on the paper type. As a result, this process considerably reduces energy consumption, water use, air pollution, and water and soil contamination, in contrast to the traditional paper production process [7]. Packaging materials are among the most demanded applications of paper products. Despite the decline of traditional printed products (books, newspapers, magazines, documentation) due to digitalization, the production of packaging, such as cartons, cardboard, and paperboard, is consistently increasing [8]. Paperboard, a robust and relatively thick type of paper, finds versatile applications in crafting various packaging materials, carriers, folding cartons, and set-up boxes [9]. In addition to virgin cellulosic fibers, the paperboard composition can be supplemented with recovered fibers obtained by the recycling of wastepaper (recycled paperboard). Recycled paperboard typically contains approximately 80-100% recovered fibers in the composition; it can have a craft, gray, or white reverse side. Paperboard usually consists of several plies: the top ply determines the whiteness and smoothness of the surface, while the middle ply (or plies) is responsible for the bulk density and firmness. The coating can significantly enhance print quality by improving image resolution. The coated surface of the cardboard becomes smoother, absorbs printing inks, and exhibits increased whiteness [10]. Paperboard is the ideal choice for the packaging of a wide range of goods due to its beneficial functional properties (protection from contamination and damage) and printability (has an advertising function, increasing the attractiveness of the goods). Among the main characteristics of paperboard are firmness, tensile strength, resistance to abrasion and plucking, barrier properties, absorbency, smoothness, whiteness, brightness, gloss, etc. The listed properties must correspond to both the printing method and the nature of the product. Despite the fact that recycled paperboard is a promising alternative to traditional virgin fibers, offering both environmental and economic benefits, the industry is distrustful of this material and prefers to use it in the simplest types of packaging. There are numerous publications regarding the properties of recycled boards. Paperboard with the addition of recovered fibers generally has lower performance than one with corresponding mass produced from virgin fibers, e.g., it has higher strength, but the density is lower. [PERSON] et al. compared the relative strengths of virgin and recycled paperboards. The results showed that both materials exceeded industry specifications at standard conditions; however, they severely degraded at extreme conditions, with the recycled material showing the greatest degradation [11]. Other disadvantages of recycled paperboard include high absorbency, which affects the quality of printing, and the presence of impurities--such materials cannot be used for packaging in direct contact with food.