ISO Resins

The letters cause more confusion than anything else in the catalogue, so they are worth settling first. ISO here is isophthalic acid, one of the raw materials used to build the polyester backbone. It is a chemistry description, not a certification, and it is unrelated to ISO 9001. A supplier may hold that certificate separately, but it certifies a quality management system rather than the performance of a resin batch.

What the isophthalic backbone buys is resistance to hydrolysis, the slow attack water makes on ester linkages over years of contact. That is why the industry specifies an isophthalic grade for laminates that stay wet or hold chemicals, and why paying for one on a dry indoor panel rarely earns its cost. Everything else about working with it is familiar: it is still an unsaturated polyester, still cured at workshop temperature with a peroxide catalyst.

This category holds the general isophthalic laminating resin and the supplier’s special-purpose isophthalic grades — tank lining, solvent, rock-bolt, filament winding, cooling tower, jute, SMC/DMC and tooling. Two other products in the range are isophthalic in chemistry but belong to their families by what they do rather than by their names: ISO Gelcoat is a surface layer and sits under Gelcoat, and ISO Fire Retardant Resin is chosen for fire performance and sits under Fire Retardant Resins. The full chemistry view is on the Isophthalic Polyester Resins page.