Stemmed webs, such as hook and loop fasteners, have been in use for a number of years. These webs typically include stems that are secured to the web. The stems are commonly formed into hooks configured to interlock with a loop material. In this description, small protrusions capable of engaging small loops or mesh of, for example, fabric or polymer will be referred to as hooks whether they are actually in the shape of hooks or other shapes. A common form of hook is mushroom-shaped and can also be used as a mechanical fastener to engage other hooks.
U.S. Pat. Nos. 4,056,593, 4,959,265, and 5,077,870 disclose methods of forming polymeric stemmed webs. In these patents, a thermoplastic resin is extruded into a tool having an array of cavities. Upon separation from the tool, the thermoplastic resin forms an array of stems. The stems are subsequently calendered to produce a broader head at the top of the stems. The shape, dimensions, and angularity of the heads and the stem density determine the ease of capture and tenacity of hold of the loop. Similarly, U.S. Pat. No. 5,393,475 discloses a method of making a stemmed web with stems on both sides of the web. This patent discloses extruding two different materials to form two base portions and forming hooks by allowing the material to fill cavities on two rollers between which the materials pass.
Although these patents disclose acceptable stemmed webs, they may not be readily adapted to meet different applications and purposes.