The present invention relates three-dimensional sheet materials which resist nesting of superimposed layers into one another. More particularly, the present invention provides a three-dimensional, nesting-resistant sheet material having a first side and a second side. The first side comprises at least...http://www.google.com.tw/patents/US6254965?utm_source=gb-gplus-share專利 US6254965 - Three-dimensional nesting-resistant sheet materials and method and apparatus for making
