Here’s how modifying Canadian fibres can make them competitive with other market pulps

canadian fibre modificationCanadian market pulps are being challenged by competition from Scandinavia, Russia, the United States, South Asia and South America, in the two largest tissue markets: China and the United States. To maintain and improve the market share of Canadian pulps in current applications, as well as promote their further integration into new applications and markets, FPInnovations has been conducting research to identify the unique features and advantages of Canadian market pulps, giving them a competitive edge to facilitate their expansion into the tissue markets.

Changes in the market pulp industry

Market pulp is a major part the Canadian pulp and paper industry and a valuable export product.

The continuously growing demand for market pulp has been shifting from North America and Europe to Asia, and the applications of market pulp have been shifting from printing and writing papers to tissue.

Due to its superior strength, Canadian Northern bleached Softwood Kraft (NBSK) pulp has a global reputation as a reinforcement pulp for printing and writing paper applications. However, the requirements for tissue application are going beyond just strength. For pulp to be suitable for tissue manufacturing, its bulk, softness, absorbency as well as its strength are all important characteristics to consider.

As for Canadian Northern Hardwood Kraft (NBHK) pulp including aspen, birch, and maple, it faces strong competition from the South American bleached eucalyptus kraft (BEK) pulp due the high bulk and softness offered by BEK.

In order to provide a competitive edge for the Canadian fibres, it became crucial to explore fibre modification beyond the simple, low consistency refining that was being traditionally applied.

Need to maximize potential of Canadian pulps

Pulp furnish represents 60-70% of the overall costs to tissue manufacturers. In many tissue mills, the pulp furnish must undergo some fibre modification (usually low consistency refining). This type of modification enhances tensile strength, but at the expense of a reduction in drainage and loss of tissue properties such as bulk, absorption, and softness.

Canadian market pulps (both softwood and hardwood) have unique fibre morphologies allowing them to meet tissue property requirements. However, new and more cost-effective fibre modification methods were necessary to enhance the performance and/or reduce the cost of tissue products, thus maximizing Canadian market pulps’ potential and give them clear differential and competitive advantage in the global market.

Important discoveries

The consumer products and pulp process research teams at FPInnovations wanted to identify cost-effective ways of improving tissue or towel properties through alternate refining technology. They also wanted to evaluate the impact of incorporating or increasing the content of bleached chemi-thermomechanical pulp (BCTMP).

To do so, FPInnovations conducted pilot tissue trials to benchmark tissue making potential of softwood kraft pulp (including various NBSK and Southern Bleached Softwood Kraft (SBSK)). This exercise allowed the research team to identify key fibre attributes that are important for improving tissue performance.

The pilot tissue trials also benchmarked NBHK against BEK for tissue applications. These trials proved that NBHK can in fact provide many tissue properties that are similar to those of BEK.

In fact, the trials allowed the research team to identify a unique advantage of NBHK over BEK, namely, a much lower tendency in linting, which is an important consumer concern when it comes to high softness tissue.

FPInnovations also evaluated the possibility of blending NBHK with BEK in tissue application, where we’ve found synergy in many tissue properties. This synergy could lead to an increased use of NBHK while improving tissue performance.

What’s next?

We are continuing our efforts in evaluating how different refining technologies could help develop NBHK fibres to maximize its potential in tissue making.

We’re also working on reducing extractives content to help NBHK meet the runnability requirements of new high-speed tissue machines.

We’re also identifying opportunities to incorporate or increase the content of NBHK and high-yield pulps (BCTMP and thermomechanical pulp (TMP)) in tissue application. One of the options we’re testing is blending NBHK with BEK as well as non-wood fibres such as bamboo fibres which are growing significantly in China.

For more information on this project, you may contact Theodore Radiotis, Senior Scientist – Fibre Production, Smart Manufacturing, or Daniel Ricard, Scientist, Innovative Pilot Tools Group.

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