Preparation and Application of Polyurethane Coating Material Based on Epoxycyclohexane-Epoxychloropropane Protective for Paper

Abstract

Paper historic relics are of great value to research and preserve. However, with the change of environment, paper cultural relics are constantly aging and damaged. Therefore, the reinforcement and conservation of the paper is an important topic in the field of cultural relics protection; thus, it is a crucial and arduous task to discover high-performance protective materials. The coating reinforcement method is a kind of commonsense method to strengthen the paper. Additionally, it is key to select appropriate reinforcing resins. Polyurethane has influence on the improvement of paper strength, stability, and appearance. The epoxycyclohexane-epoxychloropropane polyether polyol was prepared with epoxycyclohexane and epoxychloropropane as materials, glycerol as the initiator, boron trifluoride diethyl etherate as the catalyst, and dichloromethane as the solvent. Infrared (IR) spectroscopy as well as proton nuclear magnetic resonance (1HNMR) spectroscopy were adopted to characterize the structure of the synthetic copolyether. Then, polyurethane based on epoxycyclohexane-epoxychloropropane was prepared by the synthetic copolyether reacting with hexamethylene diisocyanate (HDI) trimer. The effect of the mass concentration of polyurethane on the tensile strength, elongation, folding endurance, and the tearing strength of paper samples were tested. When 10% polyurethane solution was applied to paper, not only were the mechanical properties greatly improved, but the gloss and brightness also changed slightly, which conformed to the principle of “repair as old”. The above results indicate that the synthetic polyurethane combines the advantages of epoxycyclohexane-poxychloropropane polyether polyol along with polyurethane, presenting excellent properties in paper reinforcement or conservation.

Preparation and Application of Polyurethane Coating Material Based on Epoxycyclohexane-Tetrahydrofuran in Paper Conservation

“…At each mass concentration, the tearing strength of paper in homopolyetheryl-based polyurethane coating was lower than that in copolyether-based polyurethane coating. In addition, the gloss and brightness were affected little by the synthetic polyurethane [19,25]. Generally, copolyether-based polyurethane performing in similarity is preferable in the influences of polyurethane solution upon the paper.…”

“…Subsequently, Xuan paper (cut into 210 mm × 297 mm) was steeped into different concentrations of polyurethane liquid for 2-5 min. In the end, the treated Xuan paper was dried at room temperature [18,24,25]. Coating process is illustrated in Figure 1.…”