EPE (Expandable Polyethylene) is a renewable polyethylene also known as pearl cotton. EPE is a non-cross-linked closed cell structure, produced as the raw material of low-density polyethylene (LDPE). EVA is acquired through copolymerization of vinyl acetate (VA) and ethylene (E). Both have similar qualities such as flexibility, shock absorption, water resistance, and thermal insulation. EPE and EVA can be produced with the same budget and often overlap in their functions. However, a close analysis of the two products shows crucial differences between EPE and EVA.
When it comes to durability, EVA is stronger than EPE. An average EVA foam tear strength and density are five times stronger than ordinary EPE. Due to their closed-cell structure, they both have excellent shock proofing and cushioning capabilities. However, EVA foam lasts longer compared to EPE. This makes EVA a bit expensive, making EPE a better choice if you are looking for a cost-friendly product.
EVA foam is more flexible than EPE form, as it has seven times tensile strength than EPE. Compressive elongation and strength follow suit. EVA’s has great recovery characteristics that make it a cheaper substitute for rubber in some applications such as trampoline pads and shoes. However, EPE is also a great packaging product as it stretches enough for wrapping shock-sensitive goods.
EPE’s thermal properties are better than EVA. The thermal conductivity of the latter range from 0.25-0.29 BTU/hr-ft°F, while that of EPE range from 0.01-0.02 BTU/hr-ft°F. Due to its low thermal conductivity, EPE has outstanding heat resistance, making it a great insulator for walls, roofs, and ceiling. Its effective temperatures fall between -58°-158°F. EVA is a better alternative past this temperature up to 176°F.
Uses and applications
Both EVA and EPE show super versatility, with applications ranging from soundproofing and insulation to packaging and sports equipment. For individuals who are concerned with cost-effectiveness over durability such as; car seats, carpet underlays, car door panels, packaging, and luggage lining; EPE is their best option. On the other hand, EVA leads in use of applications where the main concern is sturdiness. Examples of such products include; shoe soles, cervical collars, splints, exercise mats, and orthotic supports.
EVA is the best substitute for PVC as it doesn’t need plasticizers phthalates, and its BPA free. However, a few years back, it was found out that EVA has formamide. The latter helps in making the foam soft, but it is poisonous as it’s a developmental toxin. On the other hand, EPE is a closed cell that is lightweight and flexible. It is environment-friendly as it can be easily recycled and is 100% non-toxic.
Both EPE and EVA are great foam products for different purposes. They have many common characteristics meaning some of their functions may overlap. However, there are slight differences when it comes to durability, stretching power, thermal conductivity and toxic levels among other factors. Some of these differences may bring about an effect on the prices. It is, therefore, important, to understand the properties of each foam to know what’s best for you.