1. Non-fibrous Additives
PPT 110

2. Non-fibrous Additives
Impart/Enhance Properties
Other Purposes (like defoamers/drainage etc)

3. Additives Additive Application Acids and Bases Controls pH
Alum Controls pH; Fix Additives onto Fibers; Improves Retention
Sizing agents Controls Penetration of Liquids (eg. rosin)
Dry-Strength Adhesives Improves Burst and Tensile (eg. starches, gums) Adds Stiffness and Pick Resistance
Wet Strength Resins Adds Wet Strength to Such Grades as Toweling and Wrapping

4. Additives cont’d Additive Application
Fillers Improves optical and (eg. clay, talc, TiO2) Surface Properties
Coloring Materials Imparts Desired Color (dyes and pigments)
Retention Aids Improves Retention of Fines and Fillers
Fiber Flocculants Improves Sheet Formation
Defoamers Improves Drainage and Sheet Formation

5. Additives cont’d Additive Application
Drainage Aids Increases Water Removal on Wire
Optical Brighteners Improves Apparent Brightness
Pitch Control Chemicals Prevents Deposits/ Accumulation of Pitch
Slimicides Controls Slime Growth and Other Microorganisms
Specialty Chemicals Corrosion Inhibitors, Flame Proofing, Anti-tarnish Chemicals, and etc.

6. * Used Mainly for Wet Strength Retention
Strength Adhesives
1. Natural Polymers
Starches - Natural of Unmodified (Pearl and Powdered) Chemically Modified (Cationic Starches, Anionic Starches, Oxidized Starches, and Dextrin)
Gums - Natural
- Chemically Modified
Cellulose Derivatives
Carboxymethyl Cellulose
Methyl Cellulose
Hemicellulose
Synthetic Polymers
Phenolics
Latices
Polyamines
Polyacrylamides
Urea-Formaldehyde
Melamine-Formaldehyde
Polyamids*
* Used Mainly for Wet Strength Retention

8. Retention
Overall = amount retained in sheet/ amount added in stock (whitewater overflow)
Single Pass = amount retained in sheet/ amount from headbox (two sidedness)
Fines consume chemicals (cruddy system)
Flocculation
Fibers carry negative charge

9. Internal Sizing Resist penetration of fluids Rosin ASA AKD
Trend toward pH>7
More stable
Less corrosive

10. Internal Strength Starches/gums/cellulose based/synthetic
Increase fiber strength
Reduce linting

11. Wet Strength Resins Reinforce fiber bonds –cure
Maintains > 15% of tensile when wet
Hard to Repulp

12. Fillers Clay – cheap but dusty CaCO3 – high brightness/good opacity
TiO2 – costly – best brightness/opacity
Talc - soft, dusty, control pitch

13. Chemical Dyes Absorption by pulp fibers Types
Acid–helped to absorb/no mottle/soluble
Direct-more readily absorbed/expensive
Basic-least expensive/high brilliance/ poor color fastness

14. Control of Pitch Okay if stable and remains in sheet
Ways to shock it out
Free calcium or magnesium ions
Fluctuations in pH and temperature
Poor washing efficiency
Cationic fixative
Talc
Watch for reagglomeration

15. Stock Prep: Pulper, Refining, and Additive Addition