Blood filter material

A filter material for filtering leucocytes from a fraction of or whole blood, comprising:

• a shape-sustaining laid textile web having a thickness of at least about 1 millimeter and a bulk density of between about 0.05 and 0.4 g/cm.sup.3, said web having:
• (i) a plurality of interlocked, textile fibers with average deniers between about 0.05 and 0.75 and average lengths between about 3 millimeters and 15 millimeters, said textile fibers being substantially uniformly distributed in said web so as to form a matrix of the textile fibers with spaces between adjacent interstices of interlocked fibers;
• (ii) a plurality of fibrillated particles of polymeric material having a surface area of at least about 5 square meters per gram substantially disposed within said spaces of the matrix, wherein the weight ratio of the fibrillated particles to the textile fibers is between about 1:99 and 40:60;
• (iii) a plurality of glass fibers having an average diameter of between about 0.1 and 5 microns, the amount of glass fibers being about 2% to 85% by weight of said web and the glass fibers forming a part of the matrix;
• and
• (iv) a thermoplastic binder disposed at least at cross-over positions of said textile fibers and glass fibers, the amount of the binder being about 0.1% to 10% by weight of the web.