Black resin is most commonly used for structural foam molding. One reason is that regrind resin material is often used when suitable. We molded over 40 million pounds of recycled material in 2019. Structural foam is used for many outdoor and garden products. Green or brown materials are commonly used for these types of products. Other colors of resins are available and can be used. However, some colors, such as blue, can be affected by prolonged exposure to sunlight.