PIRA SIZING. Advantages of Vector SC versus Traditional cationic starch.

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1 PIRA SIZING Advantages of Vector SC versus Traditional cationic starch. 1. Introduction: The objective of internal sizing is to resist the penetration of liquid (control or limit) through a paper by the introduction of hydrophobic product. This operation on paper process: Reduces the water pick-up on Size-press, Improves the printability of paper, Helps to maintain the strength of packaging paper in a humid environment, The use of alkenyl succinic anhydride (ASA) for sizing of paper and board has become common. ASA is produced from the reaction of an olefin with maleic anhydride. ASA is normally emulsified with cationic starch immediately before its addition to the paper making system, in the thin-stock loop. ASA is extremely reactive and will react with hydroxyl groups on cellulose, starch and water. In many paper mills, cationic starch is already used as additive to enhance the strength characteristics and retention. Frequently a proportion of the starch already being used by the mill is directed to the ASA emulsification unit. In these cases it is rare for a study to be carried out to select the optimum starch for emulsification of the ASA Before examining this in more detail, it can be useful to keep in mind the following key factors that have an effect on sizing efficiency: Good distribution of ASA through paper making system, Good retention system (first pass retention). In this study, we ll show how emulsion and sizing effect could be improved, with Vector SC, a specific liquid product developed for ASA preparation, in comparaison with traditional cationic starch to cooked.

2 2. Protocol: A study with a Printing and writing furnish in our pilot plant was carried out. Chemicals agents, calcium carbonate, cationic starch and ASA emulsion were added, to simulate the mill process. Paper sheet have been produced and specifics tests have been done as size particle determination, Infra Red to estimate hydrolysis, retention, COBB. PREPARATION: Pulp Pulp commercial weight (g) long fibres (softwood) 185 short fibres (hardwood) 528 brokes 167 Pulp refining refining time (min) 30 final SR 30 pulp concentration after refining (g/kg) 8,29 Filler Nature Omyalite 60 (Ca CO 3 ) % of filler / cellulose weight 30 Chemical additives into wet end: Name Nature Ionicity paper making process Dosage Introduction contact time Qtity State point HI-CAT 1216A HI-CAT 1216A Ca CO 3 Level box 1 min 30 s 30% dry Cationic starch Cationic starch + After level box 1 min 20 s 0,48% dry + Before cleaners 35 s 0,12% dry mix C16-C18 ASA Before cleaners 35 s 0,27% Com PAA Before cleaners 25 s 240 g/t Com Here is sequence of introduction. Emulsions have been introduced (with Hi-Cat and VECTOR ) before cleaners. The amount takes care of our LAB pilot in order to have a COOB60 value of roughly 16/18. Hi-CAT 1216A is current Hi-Cat for dry strength and retention.

3 Emulsions preparation: All emulsions are produced with awaring Blender: Agitation speed: rpm. Agitation time: 5 mn, so energy to emulsion is constant During the study two different ratios (R) cationic starch to ASA. Were used. Glue concentration = 3%, so: R=1: 100 g of glue at 3%, 3 g ASA. R= g of glue at 3%, 10 g ASA. Solution characteristics: Several solutions of different viscosities and cationicity were tried. This file shows the list of products with solid content and viscosity. Globaly, the charge level (SCD) is about 900 µeq/dry g. Viscosities are different, for example, line 6, the product at 10% is the highest within VECTOR, and no comparison with Hi- Cat at same dry content. MS Viscosité V20 (mpa.s) SCD (µeq/g sec) Notice 1 HI CAT Vector SC standard 3 Vector SC acidic version 4 Vector SC high viscosity 5 Vector SC low viscosity 6 Vector SC very high viscosity 7 Vector SC lower N2 content The emulsion particles size and degree of hydrolysis were studied. It has been previously reported in literature, that higher the cationicity is, the more stable and efficient the emulsion will be. To compare our new product, a comparison with high nitrogen content Hi-Cat was made. A specifically preparation of cationic starch will improve sizing will be shown.

4 3. Emulsion and rheological behavior We ve tested Hi-Cat at 45 C (industrial condition after cooling) and Vector SC were tested at room temperature Size particles: Cationic Hi-Cat 3% MS 45 C Vector SC % MS 20 C Vector SC acidic 3% MS 20 C Vector SC % MS 20 C Vector SC % MS 20 C Vector SC 3% MS 20 C Vector SC % MS 20 C Glue viscosity (mpa.s) cationic to ASA ratio Time (hour) average diam (µm) ,8 2 2, , ,3 2 3, ,3 2 2, ,1 2 1, ,1 2 2, ,2 2 4, ,3 2 2, ,6 2 3, ,5 2 2, ,2 2 3, ,6 2 2, ,9 2 3, ,9 Line 3, we noticed than even after 2 hours at room temperature, the acidic version gives stable PSD. Another presentation:

5 Concerning the particles size distribution of the emulsions two trends were noticed, the finest emulsion is obtained with: Acidic version, Vector SC With cationic starch to ASA ratio of 0.3. It was also observe: Concerning Vector SC 20157, a better PSD for R=0.3 was found. Hi-Cat, with a cationic to ASA ratio of 1 is needed versus the above Vector ratio in order to give a comparable PSD Rheological behavior: All investigations were carried out with the AR 2000 rheometer from TA Instruments using concentric cylinders (14/15 mm). For viscoelastic determination, sinusoidal stress is variable and the frequency is constant. For flow determination, shear rate is variable. Viscosity (mpa.s) delta 20 C ( ) Samples 1 Hi-Cat 42 2 Vector SC Vector SC Vector SC Vector SC Vector SC Vector SC Acidic Very high viscosity Delta is the phase displacement angle. Figures between 45 and 90 give a viscous behaviour (liquid one) and figures under 45 an elastic behaviour (solid one). By elastic, it is meant that there is a degree of structure, with some hydrogen bonding. The lower the results, the greater the degree of bonding; there is existing links. When results are high, it s mean that there is less bonding (links) so a lower tendency to retrogradation. Pumping is easier and emulsification is therefore also easier. Relating to samples, there is no significant differences between all Vector apart line 6 (Vector at high viscosity). This gives with Hi-Cat the lowest delta values, indicating a poorer ability for emulsification. Vector SC has better behaviour for emulsion.

6 3.3. Hydrolysis: IR measurements have been carried out on samples in order to determine the degree of hydrolysis. Samples were been taken at time 0 and hour+2 at room temperature (20 C). To stop reaction, a dehydratation has been effected on samples. All samples have been tested I the same time. Emulsion based Vector SC mpa.s 20 C For the study, we have done IR in order to determine the acidic band, representative of hydrolusis. This method is a qualitative one but no quantification can be done. You will find here after tendency between all products %Transmittance ECHANTILLON 7 TEMPS Absence de la bande acide à 1710 cm1= HYDROLYSE 0. 5 ECHANTILLON 7 APRES 2 HEURES Emulsion based Hi-Cat Nombre d'onde (cm-1) %Transmittance Aorès 2 heures Temps 0 Bande. acide Nombre d'onde (cm-1)

7 Summary file: In the first column is ratio. In the two others, an estimation of hydrolysis based on IR measurement cationic to Hydrolyse Hydrolyse ASA ratio at time 0 after 2 h Hi-Cat 45 C Hi-Cat 45 C 0, VECTOR SC /20 C VECTOR SC /20 C 0,3 0 0 VECTOR SC acidic 1800/20 C VECTOR SC acidic 1800/20 C 0, VECTOR SC /20 C VECTOR SC /20 C 0, : no hydrolysis. +: very low hydrolysis. ++++: trend to hydrolysis. It was noticed that: Emulsions stability is better with a ratio (cationic starch to ASA) of 1. Vector SC is stable at R=0.3 even after 2 hours conclusions concerning emulsions: First conclusions in term of PSD, behaviour and hydrolysis are given compare to other products by colours (see legend). In orange, there is no significant variation observed, compare to others products. Hi-Cat Vector SC Vector SC acidic High viscosity Size Rheological Particules behavior Hydrolysis R=0,3 R=1 R=0,3 R=1 R=0,3 R=1 Values compare to others products positive effect no influence negative effect Best stability with Vector SC Best particle size distribution with acidic version. Easier emulsification with Vector SC.

8 4. In Paper making process: Objective is to check results on COBB and have a look at retention evolution. As explained at the begening, the amount of emulsion has been introduced befores cleaners in order to get 16/18 COBB 60 with traditional Hi-CAT. All VECTOR have been introduced to the same ratio for comparaison product base for emulsion Viscosity V20 (mpa.s) Glue temperaure - 3 % MS ( C) Starch to ASA ratio HI-CAT 45 1/1 93,1 79,6 81,3 16,0 19,81 HI-CAT 45 0,3/1 91,2 80,3 81,2 16,5 20,0 VECTOR SC /1 92,7 77,0 81,0 16,0 19,17 VECTOR SC ,3/1 91,2 77,9 81,1 16,5 19,39 VECTOR SC /1 91,1 72,9 80,2 18,0 19,18 VECTOR SC ,3/1 89,3 70,4 80,2 23,0 18,51 VECTOR SC /1 90,0 74,1 81,2 22,0 19,48 VECTOR SC ,3/1 88,5 70,5 79,9 25,0 18,54 VECTOR SC /1 90,9 71,7 78,7 24,5 16,43 VECTOR SC ,3/1 89,9 73,8 79,4 27,0 16,9 VECTOR SC /1 91,9 73,5 78,7 21,0 18,38 VECTOR SC ,3/1 89,6 68,8 78,4 21,0 17,2 VECTOR SC /1 89,3 68,9 78,8 23,5 17,23 VECTOR SC ,3/1 87,4 69,0 78,5 36,5 17,26 total retention (%) Filler retention (%) Grammage (g/m²) Cobb 60 moyen (g/m²) Ash 450 C (%) For all sequences, the ASA emulsion has been introduced separately from Hi-Cat 1216A at 1.2 kg/t used for retention. We notice that for example on line 2, total retention is improved with ratio of 1 compare to ratio 0,3. This with a stable value of COBB 60. Vector SC and Hi-Cat gives the best results in term of COBB: Vector SC because of the improved quality of the emulsion. Hi-Cat because of the higher first-pass retention. Vector SC optimum viscosity is 2000 mpa.s. Best COBB values are obtained with ratio cationic to ASA of 1 due to retention effect.

9 5. Industrial results: Packaging Paper: The objective was to clearly separate strength functionality from sizing in order to permit the customer to optimize dosing of Hi-Cat. The best VECTOR for sizing, the best Hi-Cat for strength. Production is based on 100% waste paper. This is a summary to obtain the same level of characteristics in term of strength and COBB. Figures have been obtained after optimisation period. ASA (kg/t) VECTOR SC (l/t) Cationic starch (kg/t) Global total ( /t) Starch total ( /t) ASA + HI-CAT ASA + VECTOR SC Average amount Average amount 1,15 0,98 0 1,57 10,50 7 Cost /t Cost /t 3,22 2,74 0 1,18 5,78 3,85 9,00 7,77 5,78 5,03 Profit /t 0,48-1,18 1,93 1,22 0,75 Annual Saving - base t paper First line (ASA with Hi-Cat ) is the average of historical production. Second line (ASA with VECTOR ) is the current solution. Further examples are available, some with better benefits others less, but in each case, we positive results were achieved for the customer with improved sizing and lower addition costs.

10 6. Conclusion: Many mills use cationic starch for ASA emulsification and good results in terms of sizing, retention and strength characteristics can be obtained. ROQUETTE can help you to select the optimum Hi-Cat for your paper process. However VECTOR SC is an excellent means of improving the emulsion quality and sizing efficiency. We normally propose a combination in order to give to our customers the best of both worlds: (Vector SC 20157) + (Hi-Cat for strength and retention) Emulsion with Vector SC Viscosity: 2000 mpa.s Cationic to ASA ratio: 0.3 Retention Selected product 1 to 3 kg/t Practically, the ASA emulsion formed using VECTOR is introduced into the HiCat delivery line to the paper machine