親水性ポリウレタン樹脂のガラス転移温度と水膨潤率および水蒸気透過率との関係

Abstract

In this study, hydrophilic polyurethane (PU) resins with glass transition temperatures (Tg) between 0 and 5 ℃ were synthesized using polyethylene glycol and polycarbonate diol with isosorbide. The PUs were then made into films, and their moisture transfer properties and water swelling rates were measured at different temperatures. The practicality of using these PUs as waterproof and moisturepermeable fabrics was also investigated. The results confirmed that the water vapor transmission coefficient of the hydrophilic PU film changes between 30 and 40 ℃, which is approximately 30 ℃ above Tg. Therefore, when this film is used as a moisture-permeable waterproof fabric, its moisture permeability may change depending on the temperature inside the garment during wear. Furthermore, when worn inside a garment at temperatures between 0-20 ℃, hydrophilic PU films used in garments with limited fluorinated water repellents swell significantly due to rainwater infiltration from the outside. Test results showed that the PU film in this study had a low Tg (0-5 ℃), meaning it remained almost in a glassy state at 0-20 ℃. The water swelling rate was constant in this temperature range, suggesting the possibility of improving the film’s water swelling properties.