Patent ID: 7943010

Claim:
A method of making paper or board, comprising: surface-sizing a fibrous web; and increasing drying stresses in the fibrous web by limiting drying shrinkage in a treatment process following surface-sizing of the fibrous web so as to obtain a measured change of flexural strength of between about 45% and about 95% less than a calculated change of flexural strength for a selected fibrous web thickness, and such that the fibrous web increases between about 0.5% and about 10% in thickness with respect to a non-surface-sized fibrous web, and wherein: the treatment process is performed with a spreader roll, including engagement elements configured to engage edges of the fibrous web and to guide the edges so as to expand the fibrous web; and the engagement elements comprise separately bearing-mounted roll end pieces defining vacuum holes, said end pieces being configured to engage the edges of the fibrous web via said vacuum holes, and said roll end pieces being installed in an angular position for guiding the edges of the fibrous web outward.