How to Avoid Stress Whitening in Polypropylene

People don’t always like working under pressure, but stress is more than just a human issue. Everyday items endure stress as well, and like people, they can also show negative effects of undue pressure.

One example is stress whitening in products made out of polypropylene, a common polymer found in a wide variety of applications, including automotive interiors. Undue stress can damage these products, resulting in a white appearance that can ruin the look of your parts. You can’t always avoid stress, but Americhem can help you stop stress whitening before it becomes an issue.

What Causes Stress Whitening

Stress whitening starts when stress is created by the impact or tension upon a polymeric surface. In other words, if polypropylene gets hit or bent in a certain way, it may show signs of stress whitening either right away or even after some time has passed.

So Why Does it Turn White?

Stress can cause small breaks called microcrazes or microvoids, which are tiny fractures just below the surface of a material. These breaks reflect light differently than the undamaged parts of a polypropylene product, causing the area of impact or tension to appear whiter than before.

How Americhem Helps You Prevent Stress Whitening

You may not be able to stop every bad break (or bend), but that doesn’t mean that your products will be lost to the microvoid. Americhem can perform comprehensive testing regarding your color masterbatch, polypropylene copolymer, and molding process. This helps you not only find out if your product is prone to stress whitening, but also what can be done to make it more resistant.

The testing factors include:

• Color masterbatch formulation
• Resin selection
• Part thickness
• Significant force during processing

Stress whitening doesn’t haven’t to have to be a pain for your business. Give us a call at 1-800-228-3476 or contact us online today to solve your stress whitening problems.