Urea Formaldehyde Resin is a compression-molded thermosetting compound classified by filler type under its own ASTM specification. This page covers that classification and a documented trade-off between reducing formaldehyde emissions and maintaining water resistance.
What is it?
Urea Formaldehyde Resin, as a compression-molding compound, is specified under ASTM D705 in two types: Type 1, formulated with alpha-cellulose filler, and Type 2, formulated with cellulose fillers other than alpha-cellulose. Requirements cover apparent density, bulk factor, plasticity, particle size, color, specific gravity, flexural strength, impact resistance, water absorption, dielectric strength, and arc resistance.
Why should I use it?
- A dedicated specification classifies it by filler type with defined property requirements — see “What is it?” above.
- Its formaldehyde emission and water resistance are directly linked in ways worth understanding before you specify a low-emission grade — see Limitations.
How it’s used
In Plastics & Polymers, Urea Formaldehyde Resin is used as a compression-molded thermosetting compound under the property framework set by ASTM D705.
Limitations — when it isn’t the right choice
- Reducing formaldehyde emission by adding urea after synthesis measurably weakens water resistance. A 2018 peer-reviewed study used post-added urea to lower the formaldehyde-to-urea molar ratio from about 1.8 to 1.2, capturing unreacted formaldehyde to cut emissions. This caused a “debranching effect”: branched hydroxymethyl groups dropped from 13.94% to 1.82%, branched methylene linkages decreased while linear linkages increased, and low-molecular-mass components increased. The result was a looser cured resin structure that allows faster water penetration and hydrolysis. This was documented for one specific low-formaldehyde-emission approach; it should not be assumed that every low-emission urea formaldehyde grade loses water resistance to the same degree without checking its own data.