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Clear Polycarbonate and Kostrate® for Injection and Blow Molded Parts

Difference between Acrylic, Clear Polycarbonate and Kostrate® for Injection and Blow Molded Parts

Clear polycarbonate and Kostrate are the most requested plastic solution SPI is receiving from customers right now. With exceptional transparency and high impact strength in low and high temperatures there are many products that benefit from the visual clear grades and heat strength each offers.

Classified as: Generic ABS+PC, polycarbonate (PC) is a group of thermoplastic polymers with chemical structures that contain carbonate groups. Polycarbonate is also valued for their low flammability and clear polycarbonate has replaced glass in many applications. Clear polycarbonate’s is lighter than glass and offers a similar level of transparency.

The unique properties of strength and clarity of clear polycarbonate lends itself to unique applications such as bulletproof windows, eyewear/ eye lenses that are break resistant, signage, digital storage media such as dvds, cds. Although yellowing can be a concern with clear polycarbonate adding a uv-stabilizer to the resin when it gets processed will minimize the discoloration.

As we delve deeper into the uses of colorized or clear polycarbonate and Kostrate®, another popular trait is the low BPA and BPA free ratings. Polycarbonates, including clear polycarbonate, have a very low BPA rating while Kostrate® is a BPA free plastic. Both are often used in food products from food packaging to kitchen utensils because they are safe and considered food grade quality. Search our other blog posts for more information on BPA safe clear plastic and it’s usage.

Comparisons of Acrylic, Clear Polycarbonate and Kostrate®

A highly desirable clear plastic similar in transparency to clear polycarbonate and Kostrate® is acrylic. Acrylic is known as a brittle clear category and polycarbonate is in the engineered plastics category. Kostrate® is a terpolymer, considered to be the gap filler between brittle clear plastics and engineered clears. As additional transparent plastic options, acrylic is an inexpensive and versatile material that can also be utilized for many applications to replace glass and other transparent material. Kostrate® is the only one of these three transparent plastics that is 100% BPA Free. The list of differences between clear polycarbonate and Kostrate® plus acrylic are not necessarily advantages or disadvantages between the three plastic substances. What makes one better than the other is relative to the end use product.

All three clear plastics are stronger and lighter than untempered glass, acrylic is 4 to 8 times stronger than glass and Kostrate® and polycarbonate is around 200 times stronger. Because of its impact resistance, using Kostrate® or clear polycarbonates to replace glass is preferred to acrylic in many cases due to acrylic’s susceptibility to cracking.

Other differences can be factors as well such as acrylic’s shiny appearance. In addition, clear polycarbonate and Kostrate® although more impact resistant, are easier to scratch than acrylic. None of these plastics are good choices for items that will be used on a stove. Polycarbonate is good for use to about 250 degrees F, Kostrate® can become distorted as such high temperatures and acrylic is only good to about 175 degrees F. Kostrate® is more durable with less chance of shattering than both polycarbonate and acrylic, plus offers the BPA free characteristic. All of these plastic options can be colorized also if transparency is not desired.

Be sure to review future blogs on clear polycarbonate and Kostrate® pros and cons.

Please give us a call if you are not clear what plastic choice will be best for your injection molded or blow molded part or product. Our experienced engineers have decades of knowledge in the field and keep current on plastic news and trends.