Study on manufacturing hot water-resistant PVOH coated paper by gas grafting palmitoyl chloride (II)–Control of palmitoyl chloride penetration by inorganic pigments coating

Abstract

Abstract In this experiment, we explored how to control the penetration of palmitoyl chloride in the gas grafting of PVOH-coated paper. When calcium carbonate was pre-coated, the gas grafting reaction of the PVOH-coated paper tended to be inhibited. It is believed that palmitoyl chloride is additionally consumed by moisture generated when calcium carbonate neutralizes hydrochloric acid gas, a by-product of the graft reaction, thereby inhibiting the graft reaction and reducing the hydrophobization efficiency by generating unreacted residual free fatty acids. Unlike calcium carbonate, the clay coating layer blocks the penetration of vaporized palmitoyl chloride and improves the gas grafting density of PVOH without moisture generation. The PVOH coating layer, where vaporized palmitoyl chloride penetrates, is thinly processed to avoid unnecessary graft reactions in the thickness direction, and the propagation of palmitoyl chloride in the gas phase is blocked by the clay-coating layer. In previous studies, an excess of 1400 mg/m2 of palmitoyl chloride was required to secure strong hydrophobicity of less than 10 g/m2 of Cobb hot water absorption. However, by pre-coating the clay, only 650 mg/m2 of palmitoyl chloride, which was about a 53% reduction compared to previous studies, was sufficient to perform a strong hydrophobic treatment.