Chemical Composition of RetroFoam
RetroFoam is a kiln-dried aminoplast foam, where the “amino” term chemically refers to a urea nitrogen-based polymer. RetroFoam insulation is generated when the dry RetroFoam resin is combined with water and brought together with a Foaming Agent Catalyst (FAC) under air pressure. The FAC mixes with compressed air to generate a foam substrate that contains the catalyst needed to complete the polymerization process. The polymer forms around the air bubbles contained in the foam and becomes aminoplast foam.
Chemical classification of RetroFoam Resin
RetroFoam resin is technically classified as a urea-formaldehyde (UF) material, however this material is functionally different from Urea Formaldehyde Foam Insulation (UFFI) materials used during the 1970s. The older materials associated with UFFI were liquid resins that required formulation with an excess of formaldehyde that was needed to maintain the shelf life of the product. Liquid resins continue to polymerize after they are manufactured, therefore an excess of formaldehyde was needed to maintain the activity of the resin during transportation and storage from the point of manufacture to the point of use. The excess formaldehyde contained in these solutions was as high as 10%, which was directly responsible for the off-gassing issues associated with these liquid resins.
The kiln-dried resin used by PolyMaster was not available at the time of the general ban that was placed on the use of UFFI materials in the late 1970s, both in the US and in Canada. The RetroFoam resin is produced by reacting carefully controlled amounts of urea and formaldehyde under a heat and pH-controlled environment, which is stopped at the point that contains a specific molar ratio of polymers called “pre-polymers” based on polymethylol urea. This mixture is controlled by the manufacturing process itself that limits the formaldehyde content to 0.17% by weight. At a specified point during manufacture, the liquid resin is kiln dried into a free flowing powder that removes any volatile organic compounds (VOCs), including free formaldehyde, which normally exists as a gas or liquid (e.g. liquid > 37% formaldehyde).
The final product is a dry UF powder resin that contains no liquids, VOCs, or free formaldehyde. The material is mixed just prior to installation and therefore does not require an excess of formaldehyde to increase the shelf-life of the older UFFI products. After mixing with water, RetroFoam resin is catalyzed using a mild acid which is dispersed in the foaming agent.