The pulping p and deposition of macro. North Carolina State University Dept. of Wood and Paper Science

Transcription

1 The pulping p and deposition of macro stickies Xin Huo, Richard A. Venditti, Hou-min Chang North Carolina State University Dept. of Wood and Paper Science

2 What are stickies? Stickies in paper recycling are believed to be a mixture of ----Hot melts adhesives ----Pressure-sensitive i adhesives (PSA s) ----Wax ----Coating ----Wood derived extractives

3 Stickies A sticky particle is typically hydrophobic is tacky and depositable often adsorbs particulates/dissolved species Examples of adsorbed species might include talc, Calcium Carbonate, Inks, Toners, polymers

4 *The actual surface behavior of stickies depends on the adsorbed species. PSA Surface PSA Surface with CaCO 3

5 Stickies-Related Problems Product quality Dirty spots in paper * Operational problem Deposition on machine * Breaking web * Affected by adsorbed species.

6 Control and Removal Methods for Stickies Mechanical removal * Chemical control * Use of environmentally benign adhesive (recyclable adhesive) Control of waste paper quality Physical adsorption to paper p fibers * Others *Aff Affected dby adsorbed dspecies.

7 The effect of pulping conditions on the size of stickies after pulping Objective: how do components present in the pulper affect the size and shape of stickies after pulping Agglomeration?

8 List of Furnishes Copy Paper, alkaline CaCO 3 (11%) SW Market Pulp ph = 5.0, 5.7, 9.5 Bristol Paper Market Pulp + CaCO 3 (11%) Talc (11%) Clay (11%) Sized with AKD 2% Rosin, 4% Alum, Cat Starch (1.5 & 10%) 10% Cationic i Starch Alum (4%) All furnishes contained 0.5% acrylate based PSA.

9 Pulping Experiment Procedure : 400 g OD Pulp 2 g adhesive PULP HANDSHEETS 12%K, 40 C Dyeing 30 min Image Analysis

10 Dyeing Stickies for Contrast Enhancement Wire or HS Morplas Blue - Heptane Dye Solution

11 Image Analysis: Apogee Image Analysis System HP ScanJet 4C 600 dots per inch Threshold: 80% Avg. GSV Both sides of 4 PM Wires

12 Effect of Papermaking Components on Stickies Average Size After Pulping (Maelstrom Pulper) Talc(11%)+Mkt CaCO3(11%)+MktCO3(11%) Starch(1.5%)+Mkt Rosin/alum/starch In bristol Paper ph5.0+mkt ph9.5+mkt Market Pulp (ph=5.7) Copy Average Size (mm 2 )

13 Effect of Papermaking Components on Stickies Average Size after Pulping ( 450H Pulper) AKD Sized Paper Rosin/alum /Starch Bristol paper Starch (10%)+Mkt Rosin (2%)+ Mkt) Alum (4%)+Mkt Market Pulp Average Size (mm 2 )

14 MARKET PULP COPY PAPER

15 Effect of Paper Making Components on the Shape Stickies Market Pulp (ph=5, 5.7,9.5) Clay CaCO 3 Copy Paper Rosin/alum/starch Mkt Pulp w/ Cat. Starch Mkt Pulp w/ Talc

16 A closer look at polymer adsorption on stickies agglomeration To understand d the process of the stabilization ti of stickies (prevention of agglomeration or deposition) by starch.

17 Objective To understand the process of the stabilization of stickies (prevention of agglomeration or deposition) by starch.

18 Experimental Procedure Deionized water 0.2 gram of PSA particles (collected from reject of lab screen) Poly-DADMAC or starch 45 o C for 8 hours

19 PSA Particle Aggregates (no chemicals)

20 PSA Particles Gentle Stirring (0.05% Cat Starch solution)

21 Concentration and Charge of Poly-DADMAC Poly-DADMAC Concentration Charge Result (g/liter) (µeq/liter) 0 0 Agglomerate 4.83E Agglomerate 6.44E No agg. 9.66E No agg. 1.45E No agg. 2.42E No agg. 4.84E No agg.

22 Effect of Starch Stabilization on PSA Particles Ave erage Size of PSA Particles (m mmsq) Starch 700 (cationic starch w ith DS= ) 043) Starch 500 (cationic starch w ith DS=0.021) Starch OP (neutral starch) Poly-DADMAC (DS=1) PVSK (DS=1) Dosage of Polymer (% of OD fibers)

23 Stickies deposition on papermachine fabric Objective: determine how components present in the pulper affect the deposition of stickies on papermachine fabric

24 Deposition Procedure: 400 g OD Pulp 2 g adhesive PULP 12%K, 40 C 30 min DEPOSITION 0.5%K, 50 C 30 min PM Wires Dyeing Image Analysis

25 Stickies Deposition Tester Papermachie wire

26 Stickies Deposition Tester Motor Gears Paddle Water Bath

27 Stickies Deposition (Weight Method) for Various Papermaking Components (Maelstrom Pulper) Clay(11%)+Mkt Talc(11%)+Mkt CaCO3(11%)+Mkt Starch(1.5%)+Mkt Rosin/Alum/Starch in Bristol Paper ph5.0+mkt ph9.5+mkt Market Pulp(pH=5.7) Copy Mass of Deposits (g)

28 Stickies Deposition (Weight Change) for Various Papermaking Components (450H Pulper) AKD Sized Paper Rosin(2%)+ Mkt Alum (4%)+Mkt Second First Starch(10%)+Mkt Mass of Deposits (g)

29 Major Findings: The stickies will self-agglomerate in pulper without the interference of chemical additives Components in copy pypaper p like cat starch can disperse the stickies and make them more string-like Cationic starch, alum and talc can prevent, p deposition of the stickies very effectively