Alkyl Ketene Dimer (AKD Wax) CAS 144245-85-2

Introduction to AKD Wax

Alkyl Ketene Dimer (AKD Wax) is a waxy sizing agent composed of C14–C18 alkyl-substituted beta-lactone dimers. Under alkaline papermaking conditions, its reactive lactone ring opens and forms ester bonds with cellulose hydroxyl groups, anchoring hydrophobic alkyl chains to fiber surfaces to deliver water repellency.

Unlike acid rosin sizing which requires acidic conditions and alum, AKD works at neutral to slightly alkaline pH and is compatible with calcium carbonate filler. The beta-lactone ring is sensitive to hydrolysis; damp or overheated storage reduces reactivity and slows sizing development. Keep product sealed below 40 °C, and allow time for full cure after sheet formation.

AKD Wax Chemical & Physical Properties

Applications of AKD Wax

Wood-free paper internal sizing
Used as a reactive sizing agent for alkaline wood-free paper systems. It bonds to cellulose fibers to impart water repellency, and works compatibly with calcium carbonate filler formulations.

Containerboard & paperboard
Applied in recycled paperboard and containerboard grades. It blocks water channels in fiber networks to reduce edge wicking and improve overall water holdout performance.

Size press surface sizing
Delivered via size press alongside starch binders. It concentrates at the paper surface to enhance water resistance and ink holdout for better print quality.

Specialty printing papers
Provides controlled sizing for high-grade printing papers. It slows aqueous ink penetration to reduce feathering and deliver sharper, cleaner printed results.

Storage & Safety Precautions for AKD Wax

• Store sealed below 40 °C in a dry location, away from moisture, steam, strong acids, alkalis and oxidizers. Keep inner liners closed after opening and use opened stock within a few weeks.
• Not classified as hazardous under GHS. Molten wax can cause thermal burns; dust may irritate eyes and respiratory tract. Wear heat-resistant gloves, safety goggles and a dust mask during handling.
• Non-DG for standard transport. Stretch-wrap pallets and keep bags dry during shipping to prevent moisture ingress and hydrolysis.
• Verify acid value on receipt. Rising acid value indicates hydrolysis. Run small emulsion trials before full-scale production to confirm sizing performance.

AKD Wax FAQ

Q: Can AKD Wax be used in alkaline paper with calcium carbonate filler?

A: Yes. It is designed for neutral to slightly alkaline systems with CaCO₃ filler. The lactone ring esterifies cellulose and alkyl tails deliver water repellency with standard cure time.

Q: Why does AKD-sized paper need curing time before testing?

A: The esterification reaction proceeds gradually after sheet formation. Full sizing development typically takes 24–72 hours at room temperature, so early testing will underreport water resistance.

Q: How should AKD Wax be stored and emulsified to prevent hydrolysis?

A: Store sealed and dry below 40 °C. Melt gently at moderate temperature, emulsify into hot cationic starch under high shear, and minimize free water. Monitor acid value regularly.