Problem Summary

Low slide angle or COF (coefficient of friction) of paperboard can cause problems during the converting process.  These problems range from telescoping of reels and rewound rolls to slippery end products such as corrugated containers that are difficult to handle and stack.  Corrugated containers made from low COF paperboard also present a safety hazard to workers in the immediate area since stacked boxes may slide and/or fall.

Paperboard made from recycled fiber tends to have lower COF due to organic contaminants present in the recycled fiber furnishes.   Lower COF can also result in paperboard made with certain sizing agents.

Papermakers usually address low COF by adding colloidal silica to the sheet surface applied at either the calendar box or via spray application just before the reel.  The silica increases the measured COF or slide angle of the sheet.  However, the net benefit realized from this application decreases during the converting process as some of the silica is removed from the sheet by handling and processing.

Recommended Solution

Prequel® Liquid Reactive Size (LRS) Technology combines chemistry, equipment, and application expertise to deliver a reliable sizing program that gives faster on-machine sizing development and an increase in COF.

Key benefits from Prequel® LRS Technology include:

Increased paperboard slide angle and COF
Reduction or elimination of silica application for COF enhancement
Elimination of silica equipment maintenance problems e.g. no more      plugged spray nozzles or silica pump problems
Increased on-machine sizing development
Improved convertibility of paperboard
Improved safety at converting plants and warehouses where corrugated containers are stacked
Sizing capability over a wider range of wet end operating conditions.