Internet of things for smart printing production

Natural paper aging as the base material for printed editions results in changes to the chemical composition of plant fibers, accompanied by the loss of corresponding physical, mechanical, and optical properties. Consequently, there is a need for a complex of conservation and restoration measures to stop deteriorative processes and strengthen the material basis of printed documents. To counteract chemical degradation affecting paper properties, restore its appearance, and ensure maximal authenticity preservation, several factors influencing the restoration and stabilization processes must be considered. It is established that during the initial stages of restoration work, immersion washing method not only facilitates mechanical cleaning but also reduces paper acidity and enhances its strength. The immersion into a methylcellulose solution additionally strengthens the paper base and smoothens sheets along their surfaces, as evidenced by increased paper smoothness. It is established that in the case of aged book and journal paper, its strength increases by 1.17 times in the machine direction and by 1.19 times in the transverse direction. Similarly, for old newspaper paper, strength increases by 1.23 times in the machine direction and by 1.08 times in the transverse direction. Optimal methylcellulose concentration for paper strengthening via its water immersion is determined to be 1% while higher concentrations lead to paper deformation due to residual internal stresses after drying. Restoration of surface evenness of the washed paper is indicated by the surface gloss measurements, showing 4.6 GU for washed and 5.3 GU for immersed paper samples. Stopping natural aging processes prolongs the lifespan of printed documents, rare books of historical value, and national cultural heritage.

Keywords: paper aging, restoration of printed editions, neutralization of paper acidity, buffer solutions, paper strength.

doi: 10.32403/0554-4866-2024-1-87-140-147