Paper mills are increasingly using recycle furnish and practicing some degree of water system closure.  Consequently, problems related to pitch and stickies deposition are more common today than in the past.  Further compounding the problem, modern day deposits are more robust and generally harder to remove. 

Solvents such hexane, toluene, and d-limonene are typically used to remove deposits from paper machine clothing and surfaces.  However, these and most other solvents pose serious environmental, health, and safety issues and, therefore, are regulated.  Until now, attempts to develop safer solvents have resulted in higher cost and lower performance technologies. 

Technology Overview

Ashland’s new biosolvent technology comprises a family of patented products used for felt conditioning, general cleaning, and roll treatments.  The products, which are marketed as Presstige® biosolvents, are extremely effective at removing pitch and stickies deposits (see Figure 1).  The properties of the biosolvent products mirror those of methylene chloride, an extremely effective solvent; however, unlike conventional solvents, the biosolvent products contain low VOCs, feature excellent HMIS ratings, have high flash points, and emit mild odors.

A Natural Approach

Presstige® biosolvent products are based on natural agri-based oils (i.e., oil produced from agricultural produce) that are readily available and naturally occurring.  All raw materials used in production are purchased from North American sources.  The products, which are biodegradable and environmentally friendly, reflect the great strides that Hercules has made toward addressing the environmental, health, and safety issues of traditional solvents. 

Features

The major features of Presstige® biosolvent technology are as follows:

Easy-to-pump liquid products
< 10% VOCs per EPA Method 24
No APEs/NPEs or SARA 313 Components
High flash point (> 425°F)
Low odor
FDA-approved products for dry, fatty, and aqueous food contact
per 21 CFR 176.170
One-year shelf life

Benefits

The following benefits were recorded from practical applications of Presstige® biosolvent technology.  Not all benefits are realized for all applications.

Improved removal of pitch and stickies deposits
Improved sheet quality
Extended felt and fabric life
Decreased downtime for cleaning
Improved worker/workplace safety