{"id":1249,"date":"2026-07-20T01:42:13","date_gmt":"2026-07-20T01:42:13","guid":{"rendered":"https:\/\/lypaperchem.com\/?p=1249"},"modified":"2026-07-20T01:42:14","modified_gmt":"2026-07-20T01:42:14","slug":"akd-surface-sizing-agents-enhancing-paper-performance-sustainability-and-production-efficiency-2","status":"publish","type":"post","link":"https:\/\/lypaperchem.com\/es\/akd-surface-sizing-agents-enhancing-paper-performance-sustainability-and-production-efficiency-2\/","title":{"rendered":"Agentes de apresto superficial AKD: Mejoran el rendimiento del papel, la sustentabilidad y la eficiencia en la producci\u00f3n"},"content":{"rendered":"<h3 class=\"wp-block-heading\">Agentes de apresto superficial AKD: Mejoran el rendimiento del papel, la sustentabilidad y la eficiencia en la producci\u00f3n<\/h3>\n\n\n\n<h2 class=\"wp-block-heading\">Introducci\u00f3n<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In the pursuit of high-quality paper and board, surface sizing has emerged as a critical process step that not only improves water resistance but also enhances surface strength, printability, and durability. Among the various surface sizing chemistries, <strong>AKD (Alkyl Ketene Dimer) surface sizing agents<\/strong> have gained significant traction for their ability to form a thin, hydrophobic layer on the paper surface while simultaneously boosting mechanical properties. Unlike internal (pulp\u2011added) AKD, which reacts with cellulose fibers throughout the sheet, surface\u2011applied AKD targets the topographical features of the formed paper, offering faster curing, lower dosage requirements, and synergistic benefits when combined with internal sizing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This article provides a comprehensive technical overview of AKD surface sizing agents, covering their chemical action, key performance indicators, application methodologies, and emerging industry trends. It draws on both established papermaking knowledge and the latest developments in sustainable barrier technologies, offering practical insights for mill operators, technical managers, and procurement professionals.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">1. The Role of Surface Sizing in Modern Papermaking<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Surface sizing is applied at the size press or gate\u2011roll coater after the paper web is formed and partially dried. Its primary functions include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Improving surface hydrophobicity<\/strong> \u2013 reducing liquid penetration (water, ink, oil) for better printing and packaging performance.<\/li>\n\n\n\n<li><strong>Enhancing surface strength<\/strong> \u2013 reducing dusting, picking, and linting during printing and converting.<\/li>\n\n\n\n<li><strong>Increasing stiffness and dimensional stability<\/strong> \u2013 especially important for lightweight papers and packaging grades.<\/li>\n\n\n\n<li><strong>Optimising print quality<\/strong> \u2013 providing a more uniform surface for ink or toner adhesion.<\/li>\n\n\n\n<li><strong>Enabling higher filler loads<\/strong> \u2013 surface sizing can compensate for the strength loss associated with increased filler content.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">AKD surface sizing agents belong to the reactive sizing family. They contain the same \u03b2\u2011lactone ring chemistry as internal AKD, but when applied on the surface, they react primarily with the exposed hydroxyl groups of surface fibres and with starch binder systems, forming covalent ester bonds that anchor hydrophobic alkyl chains right at the sheet interface.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">2. Product Features and Quality Parameters<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The LY\u2011AKD surface sizing series (developed as a next\u2011generation cationic emulsion) is designed for compatibility with both size\u2011press and gate\u2011roll applications. The product line offers varying solids content to suit different paper grades and operational requirements.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2.1 Key Performance Attributes<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Efficient surface film formation<\/strong> \u2013 the cationic emulsion readily interacts with anionic fibres and starches, creating a continuous, uniform hydrophobic layer that minimises water absorption (measured as Cobb value) and improves ink holdout.<\/li>\n\n\n\n<li><strong>Enhanced paper strength<\/strong> \u2013 besides sizing, the agent contributes to internal bond strength, tensile strength, and surface pick resistance, allowing mills to reduce the use of expensive dry\u2011strength additives.<\/li>\n\n\n\n<li><strong>Extended paper permanence<\/strong> \u2013 the covalent bonding of AKD is stable over time, reducing yellowing and maintaining performance throughout the paper\u2019s lifecycle.<\/li>\n\n\n\n<li><strong>Cleaner wet\u2011end and lower effluent load<\/strong> \u2013 because the agent is applied after the forming section, it does not interfere with wet\u2011end chemistry; it also reduces the need for internal sizing chemicals, lowering the organic load in white water and simplifying wastewater treatment.<\/li>\n\n\n\n<li><strong>Energy and productivity gains<\/strong> \u2013 faster curing at the drying section allows higher machine speeds and fewer breaks, while the reduced need for wet\u2011end adjustments streamlines grade changes.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">2.2 Technical Specifications (Typical Values for LY Series)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The LY\u2011AKD surface sizing range is available in different solids levels (approximately 15%, 20%, 25%, and 30%) to match the specific demands of various paper types:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Grade (General)<\/th><th>Solids Content<\/th><th>Recommended Paper Applications<\/th><\/tr><\/thead><tbody><tr><td>LY\u2011AKD\u201115<\/td><td>15 \u00b1 0.5%<\/td><td>Fine papers, writing &amp; printing grades (cultural papers)<\/td><\/tr><tr><td>LY\u2011AKD\u201120<\/td><td>20 \u00b1 0.5%<\/td><td>Higher\u2011grade cultural papers, lightweight coated base<\/td><\/tr><tr><td>LY\u2011AKD\u201125<\/td><td>25 \u00b1 0.5%<\/td><td>Kraft linerboard, testliner, corrugating medium<\/td><\/tr><tr><td>LY\u2011AKD\u201130<\/td><td>30 \u00b1 1%<\/td><td>Heavy\u2011duty packaging boards, high\u2011strength applications<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Common characteristics across all grades:<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Par\u00e1metro<\/th><th>Value<\/th><\/tr><\/thead><tbody><tr><td>Apariencia<\/td><td>White milky liquid<\/td><\/tr><tr><td>Ionic type<\/td><td>Cationic<\/td><\/tr><tr><td>pH (25\u00b0C)<\/td><td>2.0 \u2013 4.0<\/td><\/tr><tr><td>Viscosidad (25 \u00b0C)<\/td><td>&lt; 100 mPa\u00b7s<\/td><\/tr><tr><td>Solubility<\/td><td>Readily dispersible in cold water<\/td><\/tr><tr><td>Flammability<\/td><td>Non\u2011flammable<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The cationic nature ensures strong electrostatic attraction to negatively charged paper surfaces, improving retention and film uniformity. The low viscosity facilitates pumping, metering, and mixing with starch solutions.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">3. Application Guidelines for Optimal Results<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">3.1 Addition Point and Mixing<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For surface application, the LY\u2011AKD surface sizing agent is typically metered continuously into the cooked starch solution at the size\u2011press feed tank or the circulation tank. The recommended addition rate is <strong>5\u201325% of the starch solution volume<\/strong> (as supplied product), depending on the desired sizing degree and the paper grade.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In practice, the starch\u2013AKD blend is prepared at a coating concentration of <strong>6\u20138% s\u00f3lidos<\/strong> (total solids including starch and sizing agent). The mixture is then applied via a size press or gate\u2011roll coater at a pickup of approximately <strong>1\u20135 kg of sizing agent per tonne of paper<\/strong> (active solids basis).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.2 Internal (Pulp) Addition Option<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Although primarily a surface agent, the same product can also be added internally in cases where the mill lacks a size press or wants a combined effect. For internal addition, the agent is dosed directly into the thick stock (at the mixing chest) or into the thin stock (before the pressure screen). When used internally, the dosage is adjusted based on the pulp furnish and target Cobb values, but surface application remains the preferred route for most modern machines.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.3 Compatibility with Other Additives<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The cationic AKD emulsion is compatible with most starches (cationic, anionic, or oxidised), but it is advisable to avoid simultaneous addition with strongly anionic synthetic polymers that could cause precipitation. The pH of the starch\u2013AKD mixture typically ranges between 5.0 and 7.0, which is optimal for AKD reactivity and starch gelatinisation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">4. Storage and Handling Considerations<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">To preserve emulsion stability and reactivity, the following precautions are essential:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Temperature control<\/strong> \u2013 store at 4\u201330\u00b0C in a cool, well\u2011ventilated area, away from direct sunlight. Freezing should be avoided, as it can break the emulsion and cause irreversible coagulation.<\/li>\n\n\n\n<li><strong>Shelf life<\/strong> \u2013 the product remains stable for <strong>3 meses<\/strong> from the manufacturing date when stored under recommended conditions. Once the container is opened, it should be used promptly to prevent contamination or hydrolysis.<\/li>\n\n\n\n<li><strong>Packaging<\/strong> \u2013 available in 1000 kg plastic IBC totes or in bulk tanker trucks for large\u2011volume deliveries. The packaging is standardised for easy handling and automated unloading.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">5. Synergies with Internal Sizing Systems<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">One of the most compelling advantages of AKD surface sizing is its ability to work in concert with internal sizing agents. Many mills use a <strong>dual\u2011sizing strategy<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A reduced dose of internal AKD (or rosin) provides baseline water resistance throughout the sheet thickness.<\/li>\n\n\n\n<li>The surface AKD adds a strong, fast\u2011curing top layer that rapidly increases the Cobb value and surface strength.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This combination often allows a <strong>Reducci\u00f3n de 20\u201330%<\/strong> in total sizing chemical costs while achieving superior performance. Additionally, surface sizing can compensate for variations in internal sizing efficiency caused by furnish changes or wet\u2011end upsets, providing a more robust process.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">6. Environmental and Regulatory Advantages<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Modern AKD surface sizing agents align with the industry\u2019s drive toward <strong>greener papermaking<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Neutral\/alkaline operation<\/strong> \u2013 unlike acid\u2011rosin sizing, AKD does not require alum, eliminating sulphate discharges and reducing equipment corrosion.<\/li>\n\n\n\n<li><strong>Lower BOD\/COD<\/strong> \u2013 because the agent is applied on the surface and fixed to the fibre, less organic matter ends up in the white water circuit, easing the load on biological treatment plants.<\/li>\n\n\n\n<li><strong>Reduced energy consumption<\/strong> \u2013 the faster curing allows lower drying temperatures or higher speeds, cutting energy use per tonne of paper.<\/li>\n\n\n\n<li><strong>Food\u2011contact compliance<\/strong> \u2013 AKD is approved by the U.S. FDA (FCN) and meets European BfR recommendations for food\u2011contact paper and board, provided the product is manufactured to appropriate purity standards. Many surface sizing grades are formulated to have low extractable residues, making them suitable for food packaging, paper cups, and liquid packaging board.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">7. Market Trends and Innovations in Surface Sizing<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">7.1 The Shift toward PFAS\u2011Free Barriers<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">With increasing regulatory and brand\u2011owner pressure to eliminate per\u2011 and polyfluoroalkyl substances (PFAS) from food packaging, AKD\u2011based surface sizing has become a preferred alternative for grease\u2011 and water\u2011resistant papers. Recent developments focus on combining AKD with biopolymers (e.g., chitosan, cellulose nanofibrils) to achieve oil\u2011 and grease\u2011resistance comparable to fluorochemicals, without the environmental persistence concerns.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7.2 High\u2011Solid Emulsions and Micro\u2011Emulsions<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">To reduce transport costs and improve film\u2011forming properties, manufacturers are introducing high\u2011solid (up to 35\u201340%) and micro\u2011emulsion AKD products. These formulations yield finer particle sizes, better spreading, and more uniform coverage, often enabling lower application weights for the same sizing performance.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7.3 Tailored Solutions for Recycled Fibres<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Recycled fibre furnishes present challenges due to high ash content, fines, and hydrophobic contaminants. The cationic nature of the LY\u2011AKD surface series helps overcome these issues by improving retention on recycled fibres and reducing the negative impact of anionic trash. Studies have shown that surface AKD can significantly improve the strength and water resistance of 100% recycled paper and board, supporting the circular economy goals of the industry.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7.4 Digitalization and Process Control<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Advanced mills are adopting online sensors and automated dosage control systems that adjust the surface sizing agent feed based on real\u2011time moisture, Cobb, and surface strength measurements. This not only optimises chemical usage but also ensures consistent product quality, reducing rejected paper and increasing overall equipment effectiveness (OEE).<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">8. Practical Troubleshooting Tips<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Issue<\/th><th>Likely Cause<\/th><th>Recommended Action<\/th><\/tr><\/thead><tbody><tr><td>Poor sizing response (high Cobb)<\/td><td>Insufficient pickup, low starch solids, or excessive pH<\/td><td>Increase dosage, check size\u2011press nip pressure, or adjust starch concentration; maintain pH &lt; 7.5 in the size\u2011press mix<\/td><\/tr><tr><td>Foaming in the size\u2011press pan<\/td><td>Agitation, entrained air, or incompatible additives<\/td><td>Reduce aeration, add a suitable defoamer, or check for contamination<\/td><\/tr><tr><td>Streaks or uneven application<\/td><td>Poor film formation, roll wear, or viscosity variations<\/td><td>Clean the rolls, check metering pumps, and verify viscosity of the starch\u2013AKD blend<\/td><\/tr><tr><td>Yellowing or discoloration<\/td><td>Over\u2011drying or oxidation<\/td><td>Reduce dryer temperatures or add an antioxidant if necessary<\/td><\/tr><tr><td>Reduced shelf life or emulsion break<\/td><td>Temperature excursions or contamination<\/td><td>Ensure proper storage conditions and use clean transfer lines<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusi\u00f3n<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">AKD surface sizing agents have evolved from a niche additive to a cornerstone of modern paper and board production. The LY\u2011AKD surface series, with its cationic emulsion technology and adaptable solids range, offers papermakers a versatile tool to simultaneously improve water repellency, surface strength, printability, and production efficiency. When integrated with internal sizing strategies, these agents provide a cost\u2011effective, environmentally friendly, and regulation\u2011compliant solution for a wide spectrum of grades\u2014from premium cultural papers to high\u2011performance packaging boards.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">As the industry continues to embrace sustainability, digitalisation, and the replacement of persistent chemicals, AKD surface sizing will undoubtedly remain a key enabler of high\u2011quality, responsible papermaking. For technical teams looking to fine\u2011tune their surface sizing operations, the proven performance and easy application of AKD\u2011based systems make them a reliable choice for today and the future.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\"><em>For more information on the LY\u2011AKD surface sizing series, including sample formulations and application support, please contact our technical service team.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>","protected":false},"excerpt":{"rendered":"<p>AKD Surface Sizing Agents: Enhancing Paper Performance, Sustainability, and Production Efficiency Introduction In the pursuit &#8230; <a title=\"Agentes de apresto superficial AKD: Mejoran el rendimiento del papel, la sustentabilidad y la eficiencia en la producci\u00f3n\" class=\"read-more\" href=\"https:\/\/lypaperchem.com\/es\/akd-surface-sizing-agents-enhancing-paper-performance-sustainability-and-production-efficiency-2\/\" aria-label=\"Leer m\u00e1s sobre AKD Surface Sizing Agents: Enhancing Paper Performance, Sustainability, and Production Efficiency\">Leer m\u00e1s<\/a><\/p>","protected":false},"author":1,"featured_media":1136,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"class_list":["post-1249","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-product-deep-dives","generate-columns","tablet-grid-50","mobile-grid-100","grid-parent","grid-33"],"_links":{"self":[{"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/posts\/1249","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/comments?post=1249"}],"version-history":[{"count":1,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/posts\/1249\/revisions"}],"predecessor-version":[{"id":1250,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/posts\/1249\/revisions\/1250"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/media\/1136"}],"wp:attachment":[{"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/media?parent=1249"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/categories?post=1249"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lypaperchem.com\/es\/wp-json\/wp\/v2\/tags?post=1249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}