Environmental Stress Cracking Resistance Tester

Caltech Engineering Services offer Environmental Stress Cracking Resistance Tester specially designed for evaluating the effect of environment on blow molded polyethylene containers. In the presence of certain substances like, soaps, oils, detergents or wetting agents plastic containers may exhibit mechanical failure by cracking. A similar effect is witnessed under conditions of stress and cracking occurs at appreciably lower stress than in the absence of such environments or conditions.

Caltech’s Environmental Stress Cracking Resistance Tester is widely used for measuring the environmental stress cracking resistance of plastic containers, which is essentially the summation of various parameters. It is influenced by the container design, resin blow molding condition, treatments during and after production and other factors that affect this property. This test procedure helps plastic manufacturers to isolate and identify the effect of the related factors on stress crack resistance of the container.

ASTM D 1693: Environmental Stress Cracking of Ethylene Plastics "Bent Strip ESCR"

This test, which is carried out on molded specimens 1/8 in. or % in. thick (depending on the PE type being tested), 11/2 in. long and 1/2 in. wide. The specimens are first heated in boiling water to relax "frozen-in" stresses. A surface cut of a specified length and depth is then made on the sample parallel to the long axis with a mounted razor blade. The specimens are the stressed by bending them 180 degrees. The specimens are then placed in a rack that is put into a test tube containing the stress cracking agent. To accelerate the effect of the cracking agent, the test tube is placed in a bath at 50°C (122°F). Periodically, the specimens are inspected for visual cracks perpendicular to the cuts. At each inspection, the number of failures is recorded.

A polyethylene resin is considered to have failed when one half of the specimens in the tube show cracks perpendicular to the cuts.

• Outer body is fabricated from mild steel; duly powder coated.
• lnner bath is made of strong Stainless Steel.
• Temperature range : Ambient to 200 C
• Standard accessories such as cutting die, glass tubes, digital temperature controller, and
• rubber cork and foils.
• Six stations provided for faster and accurate testing.
• Designed as per ASTM D-1693.

Technical Specifications