EPOCROS™ Delivers Waterborne Polymer to Support Environmentally Friendly Construction Materials

Specialty chemicals that support safer, environmentally friendly construction materials are in high demand due to increasingly stringent environmental regulations. These materials wouldn't be possible without waterborne crosslinkers that don’t contain volatile organic compounds (VOC). Nippon Shokubai’s EPOCROS™ is one such product.

Ideal for film coatings and for modifying water-based paints and adhesives, EPOCROS™ is a unique waterborne crosslinker containing oxazoline functionalized polymers. It’s available in two types — water-soluble EPOCROS™ WS and an emulsion, EPOCROS™ K — both of which are fast-drying, improving film strength and resistance to water, solvents and heat.

About EPOCROS™ WS and K

EPOCROS™ WS can achieve high cross-linking density even if only a small amount is used. When EPOCROS™ WS reacts with carboxyl groups in an aqueous resin, the process generates zero outgassing. It can also be used as an effective adhesion promoter for polyethylene terephthalate (PET) substrates and other plastics like oriented polypropylene (OPP) and polyvinyl chloride (PVC). When used in adhesive formulations, EPOCROS™ WS cross-links with the carboxyl groups remaining in the PET. This enhances the performance of primers commonly applied to films. EPOCROS™ K provides excellent adhesion to polyesters. Its low glass transition temperature (Tg) enables crosslinking reactions on the surface of textiles while maintaining the flexibility of the substrate.

Advantages of EPOCROS™

A key advantage of EPOCROS™ is its storage stability under mixed conditions with aqueous resins when the carboxyl group is neutralized. Ammonia can achieve this neutralization, providing stability that is otherwise impossible with materials like carbodiimide and isocyanate.

EPOCROS™ is also a highly safe cross-linking polymer and features a low toxicity. It scored negative on the Ames Test and is considered a non-irritant in a Primary Skin Irritation Test.

Applications for EPOCROS™ include:

• Non-woven fabric binders
• Pigment printing
• Metal and leather coating
• Paint, coating and primers for plastics, building materials and vehicles
• Adhesives

Reactivity With Carboxyl Group

EPOCROS™ is highly reactive with carboxyl groups, which are common in many water-based resins. The reaction generates stable amide ester bonds without producing byproducts like outgassing. Its reactivity increases in temperatures ranging from 80 to 100ºF and higher. At room temperature, the reaction proceeds slowly but may be suitable for some applications.

Figure 1: Model Reactivity of Oxazoline Groups (Ethyl Oxazoline/Propionic Acid).

Compared to epoxy groups, oxazoline groups react better with carboxyl groups. The oxazoline groups can also react with aromatics like thiol and phenol groups, but not with alcoholic hydroxyl groups.

To learn more about EPOCROS™, contact us to download our technical document and safety data sheet.