Treated grades of fluff pulp are debonded with specialty surfactants which disrupt interfiber hydrogen bonds. This results in an increase in the overall bulk of the fiber matrix and creates pockets for fluid accumulation. Typically, our fluff pulp debonders are fatty-based quaternary ammonium compounds, so they will also soften and lubricate the fibers. This lubricating effect reduces degradation of individual fibers and decreases the amount of fines produced during defibration of the pulp. Additionally debonded pulp requires lower energy consumption and affords reduced knot formation during hammermill defibration.
Although the majority of treated fluff pulp is consumed in diapers and personal hygiene products, a significant portion of it is used in products such as pads and meat tray liners in contact with food. For these applications, all of the debonder components must be FDA sanctioned for food contact. Often, it is more convenient for the fluff producer to inventory and use only a FDA sanctioned debonder to treat all pulps. Therefore, these formulations must balance debonding performance, absorbency maintenance and regulatory compliance.
The debonder formulations for fluff pulp must rapidly and completely exhaust onto the fibers to ensure cost effective performance. They should effectively reduce tensile strength (often measured as Mullen Burst strength) at add-on rates of 0.5 to 3 kg/metric ton of fiber.
Since treated fluff pulp is often used in applications where indirect food contact is possible, compliance of debonder formulations with statutory regulations, such as FDA-regulations, is one of the most important prerequisites. For diaper and personal hygiene applications, the debonder formulations must be mild and non-sensitizing due to skin contact.
The trade-off between debonding effectiveness and absorbency must be optimized through the proper selection of quaternary compounds and their careful formulation. The final formulation must not contribute to foam generation nor to significant VOC levels.
Since the debonders are based on quaternary ammonium compounds, they also exhibit antistatic properties which are of particular benefit in the defibration operation or when treated pulp is conveyed and processed in air-laid operations.
REQUIREMENTS FOR FLUFF PULP DEBONDERS
- Effective debonding
- Highly substantive
- Rapid pickup by fibers
- Effective at low concentrations
- Easy to handle liquid formulation
- Antistatic effect
- Easily dispersible
- Low foaming
- FDA sanctioned for food service applications under 21 CFR 176.170 and 176.180
- Reduced or zero VOC-content
- Cost effective performance
Our softener/debonders should be introduced into the furnish at the point in the wet end which maximizes contact time with the fibers, thus allowing complete and uniform exhaustion.
Typical application dosages are 0.5 - 3 kg/ton of fiber, but this is highly dependent on the quality and compostion of the furnish as well as the desired product attributes.
To prevent overdosing with a concentrate, formulated debonders can be easily predispersed prior to contact with the furnish. Dispersions of 1- 6 % solids levels are prepared by adding the debonder concentrate to water that is 20 °C or warmer with adequate mixing. Care should be taken when water is added to the softener formulation, as undesired gellation may occur. For continuous, in-line mixing the softener/debonder concentrate can be pumped into the water circuit. An in-line mixer is recommended to facilitate complete dispersion.
The following test methods are used in our Technical Centers in Hopewell, Virginia and Steinau, Germany for evaluation of debonder performance on fluff pulp specimens:
- TAPPI test method T 205 (test sheet preparation)
- TAPPI test method T 402 (conditioning)
- TAPPI test method T 403 (Mullen Burst tensile strength)
- Absorption rate and capacity
- Vertical wicking
When appropriate, contract testing is undertaken to independently confirm the laboratory results.
Our fluff pulp debonders are proven to provide high debonding efficiency in a broad range of fluff pulp applications. This will be shown below for our AROSURF® PA-777 fluff pulp debonder which conforms to 21 CFR 176.170 for food contact. Comparative data are reported for a competitive product which is known to afford a treated pulp with high absorbency. Note that Competitive Product A has no sanction for food contact and contains VOCs. A southern U.S. softwood Kraft market pulp was used in these evaluations.