Foam Cores PVC vs PET

Customers frequently ask, "Which material is best for my job, PVC or PET?" My response typically is, "What is the purpose of your part?" Both materials have their strengths and weaknesses, which makes the selection process contingent on your project's specific needs. Here are some essential considerations highlighting the pros and cons of both materials.

Environmental Impact

The first factor to consider is ENVIRONMENT. Both materials are derived from oil; however, PVC is composed of 60% salt, a renewable resource. This gives PVC a significant advantage. Historically, PVC was known for containing heavy metals, but that’s no longer the case for PVC produced in North America and from credible overseas suppliers. The main downside of PVC is its limited recycling options in the U.S., as not many local municipalities accept #3 plastic in their recycling bins. Although there have been improvements over recent years, it’s still in the early stages.

In contrast, PET is likely the most widely recycled plastic globally. Items such as the water bottle on your desk, soda bottles, food clamshells, retail packaging, and cosmetic trays are all made from PET. The recycling systems for PET in the U.S. are robust and continue to expand each year.

WINNER: PET takes the lead due to the established recycling infrastructure.

Cost Considerations

Next, let's address PRICE. Presently, PET is priced lower than it has been in recent years, largely due to oil prices and increased extruding of this material. On the other hand, PVC pricing remains stable, often holding steady despite fluctuations in the oil market, as it contains less oil than PET. When comparing prices, PET is typically about 20% cheaper than PVC. Additionally, PET scrap holds a higher demand, resulting in a greater scrap value. Since the thermoforming process generates scrap, efficient scrap management becomes important. At CMI, we ensure to recycle 100% of all generated scrap materials.

WINNER: PET, since about 65% of the part's price is material, it's a straightforward choice.

Thermoforming Capabilities

When discussing THERMOFORMING, which refers to the ease of forming the part, both materials exhibit different characteristics. PVC typically operates at a slower pace compared to PET, which prefers pressure for forming. Notably, PET does not retain heat as well as PVC, which can lead to crystallization (turning white) if overheated. PVC allows for simpler tooling without needing a pressure box, which adds to the costs for custom tools. Further, PVC can be more straightforward to form, resulting in reduced debugging time and expenses. If rapid production is required, PET is preferable. However, PVC tends to perform better with taller components since it distributes the material more effectively.

WINNER: It’s a toss-up, depending on the part's size, job requirements, and tooling budget.

PET Insights

When we mention PET (Polyethylene terephthalate), we refer to virgin material. The term R-PET indicates recycled content. At CMI, we recycle all generated scrap, primarily turning it back into sheets for similar applications. However, much of the R-PET material originates from water and soda bottles, used for blow molding. This recycled form possesses different properties than its thermoforming counterpart. Importantly, R-PET's heat history decreases its structural integrity, which could lead to difficulties in forming parts and makes the material more prone to becoming brittle and weak. A reputable supplier usually guarantees the quality of R-PET materials.

Additional Considerations

Sealing: PVC is generally easier to seal than PET, which requires different tooling. Achieving a complete perimeter seal with PET can also be more difficult. In terms of clarity, both materials compare similarly, but recycled grades may present slight tints, influenced by the extruder’s feed stock.

WINNER: For these attributes, PVC comes out on top.

In conclusion, both materials are effective for thermoforming based on your needs. PET often emerges as the preferred material as many corporations (especially in Europe) are pivoting away from PVC. Additionally, alternatives like PET-G, which maintains the desirable traits of PVC while ranking #1 in recycling, exist, albeit at a higher price point.

At CMI, we’re ready to assist you in determining the best material for your project. Connect with us at www.cmiplastics.com or through email. I hope this information aids you in making informed material choices in the future.

For further insights, please explore our website on shrink roll.