Process for manufacturing multi-layer substrates comprising sandwich layers and polyethylene

A multi-layer substrate comprising a top surface layer in which fibers thereof comprise at least 95% pulp fibers, a bottom surface layer in which fibers thereof comprise at least 95% pulp fibers, and a thermoplastic material that comprises polyethylene or has a tan delta value of from 0.2 to 0.4 within the temperature range of 100° F. to 350° F. wherein the multi-layer substrate is formed by the following process:

• (a) providing the top surface layer;
• (b) providing the bottom surface layer;
• (c) providing the thermoplastic material;
• (d) sandwiching the thermoplastic material between the top and bottom surface layers, creating a 3 or more layer sandwich structure, and applying a calendaring process to the 3 or more layer sandwich structure by heating the 3 or more layer sandwich structure to a temperature at which the thermoplastic material softens, while applying pressure during such heating, so as to bond the thermoplastic material to pulp fibers in the top and bottom surface layers that are in contact with the thermoplastic material as it softens, such that no chemical adhesives are used to adhere the top and bottom surface layers to the thermoplastic material;
• (e) wherein after calendaring, the thermoplastic material includes open pores through the thermoplastic material, providing a fluid pathway therethrough such that any liquid loaded into the top surface layer is able to pass through the fluid pathway, into the bottom surface layer, and
• (f) wherein a cleaning composition is loaded into the multi-layer substrate, wherein the fluid pathway through the thermoplastic material allows the cleaning composition to travel between the top surface layer and the bottom surface layer.