Environmentally Friendly Wet-End Paper Reinforcement Agents
EiEnvironmenta llfidllly friendly wet-end paper reinforcement agents
Asif Hasan , Chen Gong, Biljana Bujanovic*, Tom Amidon Department of Paper and Bioprocess Engineering SUNY ESF, Syracuse, New York-13210
PaperCon 2011 Page 1679 SMART, ENVIRONMENTALLY FRIENDLY PAPER
• Today’s motto “ more for less” Increase in profit margin by -Reduction of basis weight -Replacement of fiber by cheaper materials such as fillers
• Industry of future needs to design its paper without compromising -strength -bulk
PaperCon 2011 Page 1680 REPLACE FIBER? •• Disadvantage of adding fillers
•• How to compensate for the strength loss? --Additives?Additives?
PaperCon 2011 Page 1681 • Society and Government are looking for an industry :
1. More sustainable 2. Based on renewables 3. Environmentally benign 4. PdProduces net posi iitive energy 5. Green
Consistent with that is the concept of Biorefinery….
PaperCon 2011 Page 1682 Pulping within biorefinery: hot water extraction (HWE) of chips before pulping, ESPRI SUNY ESF process
PaperCon 2011 Page 1683 Hot water Extraction (HWE) is Performed to produce fermentable feedstock by dissolution of hemicelluloses HW Extracted chips for pulp/paper production HilllHemicelluloses are wor th3t45tith 3 to 4.5 times as Ethanol than energy in kraft pulping (Restina, Pykannen, 2007)
PaperCon 2011 Page 1684 BENEFICIAL EFFECTS OF EXTRACTION
Hemicelluloses as fermentable feedstock Lower HH--factorfactor reqpquirement to make the same kapppa number of pulp as with un-un-extractedextracted wood - Open substrate structure, penetration of chemicals and diffusion of deggpraded products become easier Lower alkali consumption - Due to lower hemicellulose content (lower acetyl content) Hig her bu lk -- Resulting in high porosity, high scattering coefficient / good opacity, greater caliper , high stiffness Higher refining energy -- Due to higher fiber rigidity, lower response to beating
PaperCon 2011 Page 1685 Lower tensile strength
--ThereThere is a need to strengthen paper based on pulp from extracted woodchips to retain the bulk advantage and have compatible strengt h to unextracted pu lp
PaperCon 2011 Page 1686 Conventional Environmentally Additives Fr ien dly Additives PAE( Polyamide – Starch: Epichlorohydrin) resins Compatible with any pulping Compat ible w it h a lka line pu lps, system Gives wet strength Gives only dry strength - produce chlorine compounds hydrophillic Biodegradable Renewable Urea-formaldehyde resins Polylactic Acid (polylactide): Melamine-fpormaldehyde Compatible with any pulp system resins Gives wet strength Used in acid conditions, in the Helps dry strength presence of Alum Compostable Gives wet strength Product of Renewable feedstock Both linked to respiratory problem and poor air quality Glyyyyoxalated Polyacrylamide: Polyyyhydroxy alkanoates ( PHA) : Gives dry and wet strength Product of Renewable feedstock potentially Carcinogenic in Potential for dry and wet strength monomeric form
PaperCon 2011 Page 1687 In our earlier work
• We demonstrated on Kraft pulp made from Sugar Maple (Acer saccharum) chips that PLA applied on surface improved :
• TilId(35Tensile Index (35-100%) • % Stretch (20-40%) • Tear Index (10-100%) • Wet Tensile Index(50-250%)
• Hot water extracted, unbleached Kraft pulp which is hemicellulose depleted and lignin rich, responded the most favorably to PLA treatment in strength parameters whil e b ei ng abl e t o ret ai n it s b ulk . (Change in the chemical composition has a positive effect on interaction between PLA and fiber).
[Hasan, A. Bujanovic, B. and Amidon, T.(2009): “ Strength properties of Kraft pulp produced from hot-water extracted woodchips within the biorefinery” Journal of Biobased Materials and Bioenergy, V.4. 1-7 ]
PaperCon 2011 Page 1688 Figure 1: SEM micrograph of paper made from biorefinery pulp
PaperCon 2011 Page 1689 Figure 2: SEM micrograph of paper made from biorefinery pulp and treated in the surface with PLA (2% based on OD fibers)
PaperCon 2011 Page 1690 • Unbleached Kraft pulp from Hotwater extracted chips ihBifiihin the Biorefinery is the natura l step forwar did in exp liloring potential for PLA treatment. • However the SEM images revealed that the PLA was not uniformly distributed. • If PLA could be uniformly distributed by application in the WET END, it can further improve its prospects. • PLA by itself is not soluble in water, so if combined with Cationic starch it could be stabilized in papermachine white water stock.
PaperCon 2011 Page 1691 MATERIALS AND METHODS: HOT WATER EXTRACTION
Hot water extraction •• Wood conditionsconditions --SlSugar maple Performed in an M/K digester ((Acer saccharum)) •• •• OD chips - 500 g •• WtrtWater to wood drti ratio - 41414:1. •• Temperature profile - 45 minutes to 160 160 C and 120 minutes at 160C.C.
At the end of the extraction the liquor was drained, Chips were washed and collected, andkd kept in p lasti c b ags for pul pi ng
Yield 81.4% OD wood
PaperCon 2011 Page 1692 MATERIALS AND METHODS: KRAFT PULPING •• PliPulping C on diiditions
Temppperature profile - 60 minutes to 165 C ,,C --55 minutes at 165 C , HH--factorfactor 132 (HW extracted kraft ) --4545 minutes at 165 C , HH--factorfactor 536 (Regular kraft )
Active Alkali --16%16% on OD Chips Sulfidity ––25%25% Liquor to Wood -4:1- 4:1
•• HH--factor was adjusted based on the results of preliminary experiments to produce pulp of kappa number ~40
PaperCon 2011 Page 1693 MATERIALS AND METHODS: PULP CHARACTERIZATION •• Kappa number (Tappi T 236 cmcm--85)85) •• PFI beating of pulp (T 248 sp--08)sp 08) 5000 rev. •• CSF(T227 omom--4)4) •• Hand sheet preparation (T205 spsp--06)06)
** Strength properties tested --InternalInternal tearing resistance (Elmendorf type method, T 414 omom--04)04) --Tensile strength (constant rate elongation apparatus, T494 omom--06)06) --WetWet strength
PaperCon 2011 Page 1694 MATERIALS AND METHODS: PLA AS A REINFORCING AGENT •• PLA poly (dl(dl--lacticlactic acid)
PLA Poly (dl-lactic acid) Supplier MW 20K-30K Polysciences, Inc. Tg 54 C Cat.#165
• PLA solution in acetone, 0.8-1 g/L concentration • Experiments were performed at PLA level: On surface based on OD fiber w/w • 2% In Stock based on OD fiber w/w • 0.9% (max) • 05%(min)0.5% (min)
PaperCon 2011 Page 1695 MATERIALS AND METHODS: Starch AS A REINFORCING AGENT
AMYLOPECTIN N2 CONTENT (%) Supplier
Starch A 0430.43 Tate & ,Lyle
Starch B 0.3 Decatur IL 62525
•• Starch was first slurried by mixing dry powder with water •• cooked at 0.3% solids at 9595--979700C for an hour under constant stirring •• It formed a clear aqueous starch paste ready to be applied in stock. • PLA-Starc h m ix: Since PLA i s not so lu ble in water, PLA in acetone was mixed with the aqueous starch paste and together they formed a clear stable solution.
PaperCon 2011 Page 1696 MATERIALS AND METHODS: ADDITIVE DOSAGE
Test sheets Description Reinforcement method
Surface Wet-end
PLA PLA Starch % OD fiber % OD % OD fiber fiber CP Control Unextracted - - -
BP Biorefinery Hot Water Extracted - - -
BPPLA2 BP with 2% PLA sprayed 2 --
BPSA1 BP with 1% starch A in wet end - - 1
BPSB1 BP with 1% starch B in wet end - - 1
BPPLA0. 5SA0. 5 BP with PLA 0 .5% and Starch A 0 .5% - 050.5 050.5
BPPLA0.5SB0.5 BP with PLA 0.5% and Starch B 0.5% - 0.5 0.5
BPPLA0.9SA0.1 BP with PLA 0.9% and Starch A 0.1% - 0.9 0.1
BPPLA0.9SB0.1 BP with PLA 0.9% and Starch B 0.1% - 0.9 0.1
PaperCon 2011 Page 1697 PULPING RESULTS Kraft pulp from HW extracted chips vs. unun--extractedextracted chips
60 UT_K 53. 6 HWE_K 52.6 52.3 52.6 50 45.4 42.61 42.6 40
30
20 13.1 10
0 H-factor/10 Kappa Digester Yield Overall Yield
%OD% OD w ood %OD% OD w ood
PaperCon 2011 Page 1698 SHEET PROPERTIES of HWE vs. control pulp ( without any use of Additives)
37.68 40
35 UT_K 30 25 HWE_K 17.41 41 16.994 994 20 14.36 12.95 15 9.95 7.3 7.84 10 3.675 2.61 5 0
/g 0 10 1 *101 m * * N g /m2/m %%1 /g m/ m3/g TI, h, tc mN
Stre W_TI, N Bulk, c Tear_I,
PaperCon 2011 Page 1699 Figure : Effect of increasing amount of PLA in the PLAPLA--starchstarch B blend at the constant amount of starch B at 0.5% based on OD fiber on the bulkbulkon of HWE biorefi nery pu lp (BPPLA_ SB0. 5)
2
1.75 g
/ BPPLA_SB0.5 33 BP 1.5 CP
bulk, cm BPSB1 1.25
1 0 0.2 0.4 0.6 0.8 1 PLA, %OD fiber
PaperCon 2011 Page 1700 Figure : Effect of increasing amount of PLA on the Tensile index of HWE biorefinery pulp (BPPLA_SB0.5) using the PLAPLA--starchstarch B blend for starch B d05%bdODfibdosage at 0.5% based on OD fiber
40
35
30
25
TI, Nm/g TI, 20 BPPLA_SB0.5 BP 15 CP 10 BPSB1 0 0.2 0.4 0.6 0.8 1 PLA, % OD fiber
PaperCon 2011 Page 1701 Figure : Increasing amount of PLA in the PLAPLA--starchstarch B blend at the constant amount of starch B at 0.5% and the Tear indexindexTear of HWE biorefinery pulp (BPPLA_ SB0. 5)
10
/m2 7.5 gg BPPLA_SB0.5 BP 5 CP
index,mN/ BPSB1 r_r_ 2.5 Tea
0 0 020.2 040.4 060.6 080.8 1 PLA, %OD fiber
PaperCon 2011 Page 1702 Figure : Effect of increasing amount of PLA in the PLAPLA--starchstarch B blend at the constant amount of starch B at 0.5% based on OD fiber on the Wet Tensile index oo biorefi nery pu lp (BPPLA_ SB0. 5)
252.5
2 BPPLA_SB0.5 /g 151.5 mm BP CP 1 WTI, N WTI, BPSB1 050.5
0 00.20.40.60.81 PLA, %OD%OD fiberfiber
PaperCon 2011 Page 1703 Conclusion
• Reinforcement of sheets was achieved by adding the PLA- catiiionic starch hbldih blend in the wet en d. -This is important as it is convenient to add PLA-starch emulsion in the wet end stock • In addition, these experiments demonstrated that five parts of the cationic starch applied as a dry strength agent may be successfully replaced with one part of PLA with minimal loss of Tensile strength and improvement in Tear andWd Wet tens ile strengt h. • The PLA/starch combination enhances both wet and dry strength of the biorefinery pulp
PaperCon 2011 Page 1704 Acknowledgment
• Jeremy Zimmermann, Tate and Lyle inc, Decatur, IL for supplying their Stalok line of products • SEM imaging from Professor Robert B Hanna, SUNY ESF. • Funding from DOE, BRI, ESPRI
Thank you from
PaperCon 2011 Page 1705