Porous layer constituent and production method therefor

A porous layer structure, comprising:

• a base material;
• and
• a polyurethane porous layer formed on the base material, the polyurethane porous layer being formed by a polyurethane resin aqueous dispersion, the polyurethane porous layer having a continuous air bubble wherein air bubbles generated by foaming in the polyurethane porous layer on the base material are partially united with each other to share holes, the holes having diameters smaller than a diameter of the air bubbles, thereby forming the continuous air bubble,
• wherein a moisture permeability A of the porous layer structure measured by JIS L1099 A-1 is 2,000 to 10,000 g/(m2·24 h),
• a moisture permeability loss rate is 75% or less, the moisture permeability loss rate being obtained by formula:
• moisture permeability loss rate (%)=(1−(moisture permeability A/moisture permeability B))×100,
• wherein the moisture permeability B is a moisture permeability of the base material alone measured by JIS L1099A-1,
• wherein a peel strength at a bonding surface between the base material and the polyurethane porous layer is 0.7 kgf/inch or more, and
• wherein the polyurethane porous layer comprises a polyurethane containing a polyol component, an isocyanate component, and a hydrophilic alkylene oxide component having one or more active hydrogen groups and having an alkylene oxide.