g cotton kapok and milkweed leaf fibres e g sisal abaca pineapple new zealand hemp and bast fibres e g flax hemp ramie jute kenaf varying fibre lengths can be used and with a foam forming technique longer fibres than those which are possible with conventional wet laying of fibre webs can be used long fibres circa 18 30 mm are advantageous for hydroentangling since they increase the strength of the material in both wet as well as dry conditions an additional advantage with foam forming is that it is possible to produce material with lower surface weight than that which is the case with wet laying as a replacement for pulp fibres plant fibres with short fibre length can be used such as esparto grass phalaris arundinacea and straw from crop seed with certain types of fibres a binder may be desirable in order to give additional strength to the material suitable binders include starch based binders polyvinyl alcohol latex etc which are used in order to increase the strength of nonwoven materials a run was made on a fourdrinier machine having a machine speed of 20 m min with use of a fibre mixture consisting of 50 pulp fibres of bleached conifer sulphate and 50 polypropylene fibres 1 4 dtex 18 mm a fibre dispersion having a fibre concentration of 0 34 weight was.