| 摘要 |
PURPOSE:To obtain a hydrogel useful as an adhesive free of organic solvent, by adding a specific water-soluble polymer to a high-molecular weight copolymer of an acidic group-containing unsaturated monomer, etc., adding an alkaline substance and water to the mixture, and incverting the phase from W/O-type to O/W-type. CONSTITUTION:100pts.wt. of a copolymer having a weight-average molecular weight of 10<4>-10<6> and composed of an unsaturated monomer having acidic group (e.g. n-butyl acrylate) and 99.5-80wt% other unsaturated monomer copolymerizable therewith (e.g. styrene) is added with 0.01-20pts.wt. of a water- soluble polymer such as a nonionic water-soluble polymer having alkylene oxide group, a water-soluble polyurethane resin, etc. The objective hydrosol containing the copolymer dispersed in water in the form of particles having an average particle diameter of 0.01-10mum can be produced by adding an alkaline substance and water to the above mixture, thereby neutralizing at least a part of the acidic grooup in the copolymer molecule and at the same time inverting the phase of the emulsion from W/O-type to O/W-type. |
