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Nordic Pulp and Paper Research Journal Vol 20 no. 2/2005 227LumiSilk 100 g KEYWORDS: AKD, Paper sizing, Relative humidity, Sizing efficiency SUMMARY: The role of relative humidity and unreacted AKD molecules on the sizing development of AKD (alkylketene dimer) was investigated using carbon-14 labeled AKD. A solvent sizing method was used to control the amount retained on paper and to achieve even distribution of AKD. The reaction ratio and sizing degree increased with relative humidity up to 80% due to the favorable exposure of AKD lactone rings for reaction

. Sizing emulsions prepared with alkyl ketene dimer (AKD) are widely used in domestic and foreign alkaline sizing. AKD is the preferred agent for both surface sizing and internal sizing and its use has been established in the paper industry to increase paper hydrophobicity and improve its printability (Garnier et al. 1999 , Mohammadi et al. 2004 , Minami et al. 2008 , Sunil Kumar et al. 2012 ). Many research papers have been published on the mechanisms of sizing. One of them is the mechanism of esterification, also known as covalent bond mechanism, including

New insights into the AKD sizing mechanism Kyle J. Bottorff and Mark J. Sullivan, Hercules Incorporated, Wilmington, Delaware, USA Keywords: Alkylketene dimers, AKD, Reaction mechanisms, Solid State "C NMR, Sizing, P-Keto acid, P-Keto calcium salt, P-Keto ester, AKD oligomers. SUMMARY: Paper samples sized with 13C labeled alkylketene dimer (AKD) dispersions were characterized by solid state carbon NMR resulting in direct evidence supporting the forma- tion of AKD-cellulose P-keto esters on AKD sized paper. A series of AKD reaction products that may

Nordic Pulp and Paper Research Journal Vol 21 no. 2/2006 245 KEYWORDS: Alkylketene dimer (AKD), AKD oligomers, Dispersion stability, Sizing degree, Pyrolysis-gas chromato- graphy, PCC-filled paper, Sizing performance SUMMARY: AKD oligomers are the major components occur- ring as impurities or by-products in AKD waxes produced at industrial level. In this study, a model of AKD oligomers was prepared from a mixture of stearic and palmitic acid chlorides, and converted to dispersions containing a standard AKD wax and the AKD oligomers in various weight ratios

Nordic Pulp and Paper Research Journal Vol 20 no. 2/2005 253LumiSilk 100 g KEYWORDS: Sizing, AKD, Surfactants, Fatty acids SUMMARY: The effects of some surface active substances on the AKD sizing have been investigated, particularly the impact of fatty acids and of non-ionic surfactants, commonly found in a deinked pulp. The wetting and the absorption properties of AKD sized handsheets were studied as a function of the size dosage, of the surfactant presence and concentration in the fur- nish. Moreover, the effects of the surface active substances were

240 Nordic Pulp and Paper Research Journal Vol 17 no. 3/2002 Keywords: Agglomeration, AKD, Alkylketene dimer, Disper- sion, Flocculation, Internal sizing, Retention. SUMMARY: Pre-flocculated AKD dispersions were used to size laboratory sheets. The cationic AKD dispersion was pre-floccula- ted in a Britt Dynamic Drainage Jar. Carboxymethylcellulose and white water from a linerboard mill were used as flocculating agents. The particle size distribution was determined to verify the flocculation. Laboratory sheets sized with pre-flocculated AKD disper- sions were

330 Nordic Pulp and Paper Research Journal Vol 19 no. 3/2004 KEYWORDS: AKD sizing, Alkyl ketene dimers, Bleached kraft pulp, Radioactive labelling, Surface charge, AKD reten- tion, AKD reaction, Extractives content, Pulp bleaching, TCF, ECF-pulps SUMMARY: The effects of pulp bleaching on alkyl ketene dimer (AKD) size retention, reaction and sizing efficiency were investigated using C-14 labelled AKD. The AKD-sizing effici- ency, using laboratory hand sheets made from differently bleached (ECF/TCF) softwood and hardwood pulps were inve- stigated. All pulps used

336 Nordic Pulp and Paper Research Journal Vol 19 no. 3/2004 KEYWORDS: AKD-sizing, Alkyl ketene dimers, Bleached kraft pulp, Radioactive labelling, AKD retention, Retention aids, AKD-dispersion SUMMARY: The effects of electrolytes and eight different cationic polymers on alkyl ketene dimer (AKD) size retention, extent of reaction and sizing efficiency were investigated using a C-14 labelled cationic AKD-dispersion. Sizing experiments were conducted in a standard British hand sheet former, using a Britt Dynamic Drainage Jar (BDDJ) to pre-shear the pulp suspension

Nordic Pulp and Paper Research Journal Vol 22 no. 2/2007 167 KEYWORDS: AKD-sizing, Alkyl ketene dimers, Radioactive labelling, AKD hydrolysis, Catalyzed hydrolysis, Size hydrolysis SUMMARY: Conditions for the hydrolysis of an Alkyl Ketene Dimer (AKD) dispersion was investigated. The investigated AKD dispersion was a C-14 labelled AKD, which on hydrolysis degrades to the corresponding ketone, releasing C14O2. By measuring residual activity in the dispersion, the extent of hydrolysis could be quantified. The kinetics of AKD-hydrolysis was investigated under

Nordic Pulp and Paper Research Journal Vol 21 no. 2/2006 237 KEYWORDS: TCF, ECF, Hardwood, Kraft, AKD, Edge pene- tration, Peroxide edge wicking index, Absorption, Liquid pack- aging board SUMMARY: To study the impact of extractable materials and xylan on the sizing efficiency of totally chlorine-free (TCF) bleached birch pulp and elemental-chlorine-free (ECF) bleached birch pulp, several pulps with different amounts of extractable material were studied. The content of extractable material in the pulp was shown to be detrimental for sizing efficiency