HDPE refers to a plastic used to make bottles for milk, juice, water and laundry products. Unpigmented HDPE bottles are translucent and have good barrier properties and stiffness. They are well suited to packaging products with short shelf lives such as milk. Pigmented HDPE bottles generally have better stress crack and chemical resistance than bottles made with unpigmented HDPE. These properties are needed for packaging such items as household chemicals and detergents, which have a longer shelf life. Injection-molded HDPE is resistant to warpage and distortion. It is used for products such as margarine tubs and yogurt containers. (Plastic Packaging Opportunities and Challenges, February 1992).