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New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood Containing Furnishes Ulf Stenbacka, Christopher Lewis & Marco.

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Presentation on theme: "New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood Containing Furnishes Ulf Stenbacka, Christopher Lewis & Marco."— Presentation transcript:

1 New Micropolymer Technologies for Increased Drainage and Retention for both Wood and Non Wood Containing Furnishes Ulf Stenbacka, Christopher Lewis & Marco Polverari Kemira Oyj

2 Outline Brief Review of Retention Mechanisms Characterization of New Micropolymer Dispersion Technology A.Structure B.Synergies C.Retention Mechanisms Pilot Studies A.Alkaline Fine Paper Case Studies A.Alkaline Fine Paper – Strength B.Alkaline Fine Paper – Dusting C.Alkaline Fine Paper – Production Conclusions

3 Retention Mechanisms Narrow balance exists to achieve optimal retention and formation Runnability vs. Quality Dispersed colloids deposit onto fines and fibre to form flocs Retained by filtration Adsorption of small particles becomes more challenging as furnish exposed to greater hydrodynamic shear stress Increasing machine speed Increased complexity with the presence of ash and elevated ash load

4 Traditional Retention Chemistries Poly-acrylamides (PAMs) are efficient for gross retention High molar mass long chain polymers Generally linear some structured versions Development of large flocs via bridging mechanism to achieve sufficient retention of fillers and fines Sheet structure = hard flocced or macro flocculated PAMs can agglomerate filler particles Effectively increase average particle size Optical efficiency can be compromised PAM created floc can contain a substantial level of bound water Former drainage improved but pressing efficiency decreased

5 Traditional Retention Chemistries High charged low molar mass polymers allow for fixation or patch retention Fillers, fines, detrimental substances Can improve drainage via soluble charge control Retention limited due to lack of floc structure Necessary application rate for reactivity can overly decrease cationic demand Inhibit retention of other process additives

6 Next Generation Micropolymers Creates floc and subsequent sheet structure that maximizes former drainage without compromising pressing efficiency Very effective for retention of ash Calcium carbonates (precipitated and ground) Kaolin Calcium Silicate Unique structure and composition enables them to be reactive in low and high ash environments and in wood and non wood containing furnishes SC News LWC Printing and Writing Unbleached/Bleached Board Unique synergies when applied in conjunction with traditional inorganic microparticle technologies Colloidal SilicaColloidal Silica Swellable Minerals (Bentonite)Swellable Minerals (Bentonite)

7 A Dual System in a Single Application A controlled molecular weight cationic or anionic polyacrylamide polymerized within a coagulant matrix. The coagulant matrix is either: Inorganic coagulant (Sulfate salt) Organic coagulant (e.g. polyamine) In order to distinguish these new products from conventional water-in-oil emulsions the name water-in-water dispersion has been chosen The coagulant matrices of these products is responsible for the fixation of anionic trash, and the high-molecular species for the retention of fibres and fillers Inclusion of hydrophobic associative monomers Cationic and anionic versions Forms hydrogel polymer Strongly hydrogen bonding Advanced Micropolymer Technology

8 Fennosil ® Micropolymers Cationic Micropolymers Anionic Micropolymers

9 Product Characteristics Schematic Illustration Micropolymer Series Micropolymer Drop (~ 3 μm) Water Coagulant Lower MW PAM Higher MW Water

10 Product: Technology Hydrophobic groups incorporated to HMW/LCD polyelectrolyte Hydrophobic groups lead to inter and/or intra molecular interactions Formation of micelles Higher solution viscosity Higher elasticity More structure

11 Properties

12 Micropolymer Retention/Drainage Mechanism Micropolymer unique charge and structural properties allows (cationic) polymer to control anionic trash while retaining fibres and fillers Floc structure advantageous for both retention and drainage Increased dewatering in former Increased dewatering in press Fines and filler flocculated along the long fibres as small discrete flocs Minimize level of bound water Reduction of blocking of inter-fibre pores Conventional System Micropolymer System

13 Effect of Fennosil E on Ash Retention and Distribution Electro-micrograph of filler distribution after Fennosil E-325 conversion. Electro-micrograph of filler distribution prior to Fennosil E-325 conversion.

14 Pilot Study A: Strength and Structure Enhancement Pilot machine study conducted using alkaline fine paper Primary objective of the study was to increase sheet ash to 20% while reducing use of starch Applied cationic potato starch pre-shear at 2 kg/T (1/3 regular dosage) Applied cationic PAM pre-shear at ½ regular dosage Applied silica and anionic dispersion micropolymer post shear simultaneously Relate gains to the resulting sheet structure Fibre and Process Characteristics ASA size Precipitated calcium carbonate (PCC) used for filler Cationic potato starch OBA added at both size press and wet-end Sheet ash 16-18% maximum

15 Pilot Study A: Scott Bond and TEA Dosage of PCC = 6.0 kg/t Ash in sheet = 28% FS-515 dosage = 0.7 kg/t (active) Increasing ASMP has a significant positive effect on internal bond strength 35% improvement Increasing ASMP has a significant positive effect on tensile strength 30% improvement

16 Pilot Study A: Breaking Length and Specific Formation Ash in sheet = 28% Colloidal Silica dosage = 0.7 kg/t (active) Increasing ASMP has a significant positive effect on tensile strength 25% improvement Increasing dosage of anionic micropolymer improved formation. The lower the number the better the formation. 40% improvement

17 Case A: Uncoated Free Sheet Machine Type:Top Former Objective:Improve ash retention and strength to potentially increase sheet ash target Grades: Offset, Xerographic Sheet Ash: 15% - 18% Incumbent Program:Silica (0.60 – 0.75 kg/t) and Cationic Potato Starch (4 – 5 kg/t) Other Wet End Chemistry:Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium Carbonate, Alum Proposed Chemistry:Anionic Dispersion Micropolymer Chemistry + Colloidal Silica Application:Anionic Dispersion Micropolymer (0.15 – 0.4 kg/t) applied post shear with existing silica (0.25 – 0.35 kg/t)

18 Case A: Retention Anionic Dispersion MP applied post screen (shear) applied with colloidal silica Applied with Cationic Starch Significant increase in ash retention across all the grades Improved additive efficiency: OBA & Size This achieved with 40%+ reduction in application rate of colloidal silica Ability to evaluate lower cost starch Some loss in efficiency Improved retention over incumbent program with potato

19 Case A: Strength (Tear) Anionic Dispersion MP applied post screen (shear) applied with colloidal silica Applied with Cationic Starch Significant increase in both MD and CD tear

20 Case A: Strength (Tensile/Burst) Anionic Dispersion MP applied post screen (shear) applied with colloidal silica Applied with Cationic Starch Significant increase in tensile strength CD and MD Burst With increased strength potential to increase sheet ash target by 3% (20% total) Achieved in trials Done with both corn and potato starch & without significantly increasing retention chemistry Potential for significant savings in fibre cost

21 Case Study B: Uncoated Free Sheet Machine Type:Top Wire Former Objective:Increase sheet ash by 1% - 2% without negatively impacting sheet strength or increasing dusting propensity. Grades:Xerographic Basis Weights:80 – 90g/m 2 Sheet Ash:22% Machine Speed (Range): m/min Furnish Components:Bleached Hardwood 50%, Softwood 50% Broke 20% - 30+% Incumbent Program:Silicated PAC + Anionic PAM Other Wet End Chemistry:Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium Carbonate, Starch, Alum Proposed Program:Anionic Dispersion Micropolymer applied with existing Anionic PAM (A-Pam) and silicated PAC system

22 Case Study B: Retention/Dosage (On-Line) Anionic Dispersion Micropolymer introduced in addition to existing A-PAM and silicated PAC chemistry Co-Mixed with A-PAM Immediate decrease in headbox ash 2.9 g/L to 2.2 g/L Immediate decrease in white water solids g/L to.137 g/L

23 Case Study B: Retention (Lab) Increase in First Pass Ash Retention better than 10+ points Achieved both at equal and with sheet ash levels at 1% and 2% greater

24 Case Study B: Dusting Decreased dusting level at equal ash Dusting propensity did not increase with higher sheet ash load Sheet ash increment of 2% (24%) at equal dust level as 22% sheet

25 Case Study B: Defects ULMA Defects 01 – 02 reduced by 45+% Lowest defect level achieved at highest ash loading Function of transition 22% data included start- up Cleaning-Up of wet end

26 Mill Case C: Uncoated Free Sheet Machine Type:Fourdrinier Objective:Replace existing retention program to improve formation and increase production Grades: Lt. Wt. Opaque, Offset, Text Sheet Ash: 12% - 16% Incumbent Program:Bentonite, Linear C-Pam, Cationic Potato Starch Other Wet End Chemistry:Alkenyl Succinic Anhydride (ASA) Sizing, Precipitated Calcium Carbonate Proposed Chemistry:Anionic Dispersion Micropolymer Chemistry, A-Pam, and poly- aluminium chloride (PAC) Application:Anionic Dispersion Micropolymer (0.6 – 1.0 kg/t) applied post shear with A-Pam (0.2 – 0.5 kg/t) applied pre shear, and PAC (1 – 2 kg/t) applied pre A-Pam

27 Mill Case C: Production Anionic Dispersion MP applied post screen (shear) A-Pam applied pre-screen (shear) PAC applied at fan pump (pre A-Pam) Significant increase in production across majority of grades As much as 15+%As much as 15+% This achieved despite that pre- size press moisture was reduced as much as 0.7% Bentonite program pre size press moisture average approximately 1.6%

28 Mill Case C: Formation Higher formation values are better Anionic Dispersion MP applied post screen (shear) A-Pam applied pre-screen (shear) PAC applied at fan pump (pre A-Pam) Formation improved across majority of the grades At least equal Grades with largest improvement in formation also saw an average of ½ point increase in opacity 50#, 55# book 40# Offset Grades where equal, generally greatest increase in production

29 Mill Case C: Additive Efficiency Anionic Dispersion MP applied post screen (shear) A-Pam applied pre-screen (shear) PAC applied at fan pump (pre A-Pam) Significant starch reduction across all the grades 1.5 – 3.0 kg/t No loss in retention FPAR as high as 80% on some grades Quality not compromised Sizing response equal or better at equivalent or lower ASA application rate

30 Conclusions A new generation of cationic and anionic micropolymer dispersions has been developed Unique synergies exist with co-application of the micropolymer dispersions with traditional inorganic microparticle technologies Chemistries are robust enough to be applied in a wide range of furnishes Unique composition and structure allow them to increase sheet dewatering while significantly increasing retention in both low and high ash environments Chemistry shows ash selectivity, particularly with presence of (precipitated) calcium carbonate Significant increase in retention quality exhibiting lower propensities for dusting Sheets formed with this technology impart greater strength (wood free) – significant increases of both tear and tensile have been observed Appreciable increases in drainage have been observed

31 Thank you


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