VISIOMER® HEMA-P: Transparent Flame-Retardant for Waterborne Acrylic Coatings with APP

VISIOMER® HEMA-P is a polymerizable flame retardant material composed of a combination of phosphoric acid and methacrylate. The phosphate function is responsible for the flame retardant properties. VISIOMER® HEMA-P in combination with ammonium polyphosphate (APP) provides higher transparency in water-based wood coatings and exhibits excellent flame retardancy.

Elisabeth Clamer

Manager New Business Development Specialty Methacrylates

Spoken languages: german , english

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Benefits at a Glance

Perfect combination of VISIOMER® HEMA-P + APP (ammonium polyphosphate) enables:

Higher transparency for waterborne wood coatings
Excellent flame-retardancy

Transparent, Flame-Retardant Wood Coatings

The popularity of wood as a construction material is on the rise, driven by its renewability and sustainability. However, one significant drawback of using wood is its combustibility. To comply with various fire safety regulations, the use of flame-retardant and intumescent coatings has become essential.

There is a specific market need for clear flame-retardant and intumescent coatings. Interior applications (including furniture, wall paneling, doors and frames) call for coatings that not only enhance the aesthetics of the wood structure and color but also meet the necessary fire classifications.

With VISIOMER® HEMA-P it is now possible to produce acrylic waterborne coating resins that, when combined with a specific grade of ammonium polyphosphate (APP), to obtain transparent flame-retardant wood coatings (Figure1).

Figure 1: VISIOMER® HEMA-P acts as dispersant for APP and leads to a clear film

Positive Effects of VISIOMER® HEMA-P

Incorporating 10-30 percent of the functional co-monomer VISIOMER® HEMA-P into the waterborne dispersions ensures excellent dispersion of the flame-retardant APP. Through radical polymerization VISIOMER® HEMA-P becomes an integral part of the polymeric binder, resulting in a non-migrating solution.

Additionally, VISIOMER® HEMA-P serves as an intrinsic source of phosphorous, enhancing the flame-retardant properties of the coating formulation.

Positive Effect on APP

With its high phosphate content, the flame-retardant filler APP provides perfect flame-retardancy to wood coating formulations, however it usually also precludes transparency.

By combining APP with waterborne dispersions containing VISIOMER® HEMA-P the transparency can be significantly increased. (Figure 2)

Studies indicate that the dispersing power of VISIOMER® HEMA-P on the APP may enable the use of lower APP additions while achieving the same flame-retardant effects.

Figure 2: VISIOMER® HEMA-P enhances the performance of ammonium polyphosphate (APP) in achieving its maximum flame-retardancy

Evonik can support you with

A starting formulation for a 10-15 percent VISIOMER®HEMA-P emulsion polymerization
- How to effectively incorporate VISIOMER® HEMA-P into a stable polymer
A simple starting formulation for an intumescent coating
- Effective dispersion of APP and details on the specific APP-grade

VISIOMER® HEMA-P: An Overview

2-Hydroxyethyl-Methacrylate-Phosphate (HEMA-P) is a well-known adhesion promoter used in various applications including adhesives and coating resins. We offer VISIOMER® HEMA-P 70M and VISIOMER® HEMA-P 100. A comparison of these two products can be found in Table 1.

Figure 1: Structure of the active ingredient in VISIOMER® HEMA-P.

	VISIOMER® HEMA-P 70M	VISIOMER® HEMA-P 100
Supply	in 30% MMA	pure
Viscosity	40-75 mPa*s	3000 — 7000 mPa*s
P-content	10.6%	15%
Application Areas	Emulsion Polymerization Bulk Polymerization Reactive Resins	All application areas where MMA is critical due to VOC, odor, flammability or performance

Table 1: Comparison of VISIOMER® HEMA-P 70M and VISIOMER® HEMA-P 100.

The primary advantage of VISIOMER® HEMA-P 70M lies in its easy-to-handle viscosity, making it user-friendly in various applications. In contrast, the advantage of VISIOMER® HEMA-P 100 is the absence of methyl methacrylate (MMA) and its respective properties, which eliminates associated concerns such as odor, flammability, and safety issues.

VISIOMER® Specialty Methacrylates – Ready for the Next Level

Evonik’s Specialty Methacrylates team is committed to supporting you in finding the best solution for your next polymer design challenge. For more information about our VISIOMER® HEMA-P products, please do not hesitate to contact us.

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