1. What is Stress Whitening?

Stress whitening is a white line appear because of bending, stress or heat on your plastic products, including plastic bars and plastic food containers, etc.

2. What Cause Stress Whitening?

There are two possible causes of stress whitening. One is heat, the other is stress.

A. Heat causes stress whitening

Most PP plastic products contain crystalline and amorphous on their molecular chains. Over-heating Polypropylene plastic will turn white because the amorphous section is crystalize.

B. Stress causes stress whitening

Certain bending, impact or tension of plastic products will also cause whitening and can ultimately lead to failure to the product.

3. Why The Color White?

Naturally, plastics are always whitish or clear so more pigment is needed to absorb certain frequencies of light and give it a color. When crazing ( the point of stress) occurs, it will reduce the refractive index of the stress area, causing it to scatter and reflect all visible light wavelengths. That’s the reason why it turns white.

4. Why PP Plastic Products Still Worth Your Choice?

In the previous paragraphs, we know that the mainly cause of stress whitening will be heat and stress. Why PP plastic products like Easylockware plastic food containers still worth your choice? Check the characteristics of Polypropylene in our previous article (Everything You Need To Know About Polypropylene PP Plastic) and you will see why:

A. Heat-Resistant:

PP plastic food containers can deal with extreme temperatures between -20℃ to 120℃. So, it’s microwave and freezer safe. That is, daily use of Easylock plastic food storage containers won’t lead to overheated that we result in stress whitening.

B. Elasticity and Toughness:

Easylock plastic food containers have a good elasticity and toughness. It allows you to stack up several filled up food containers on countertop, pantry or in freezer. It’s tough enough to hold the food containers and won’t generate crazing unless you bend it deliberately.

C. Fatigue Resistance:

Even the most vulnerable part of the plastic food containers, the hinge wing of 4-side-lock lid which might be weaken during to repeatedly applied, has survived from the flexing test machine for more than million times of bending.

What these three features mentioned above indicate that Easylock PP plastic food containers are durable and have less risk of stress whitening if you obey what the use & care of Easylock plastic food containers says.

5. Conclusion:

Not all plastic products will be caught by stress whitening easily. Easylock is durable and is quite a perfect option as a PP plastic food storage containers. For more tips & tricks about plastic products or to wholesale Easylock plastic food storage containers, please check in www.easylockware.com.

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