Spunbonded plastic films

Since wind barriers are located at the cold side of the thermal insulation (in cold climates) they should combine a sufficient air and water tightness with a high vapour permeance. Materials which combine these properties and are often recommended as wind barriers are the spunbonded plastic films (also called house-wraps). These films are composed of rolled synthetic filaments (typically polypropylene or polyethylene fibres) that are welded together to form a continuous porous fabric. Measuring procedures and results of vapour transfer properties of spunbonded plastic films are reported in detail by Janssens and Hens [36]. The diffusion thicknesses of the films are a few centimetres and of the same order of magnitude as an air boundary layer. 

Plastic paper (synthetic paper) n. Paper-like products in which the skeletal structure is composed of synthetic resin. Three main types are spunbonded sheet, film paper, and synthetic pump (synpulp). Film papers are similar to thin films of oriented polystyrene or polyolefins but they are treated to obtain opacity and ink receptivity. Syn-pulps are papermaking pumps made usually from polyolefins by processes that produce fibrous pulps without the use of conventional spinning methods. 

---