TORAYPEF® Polyolefin Foam

Technical Information | Superb cushioning

TORAYPEF® comprises foam cell walls in a closed-cell microstructure made of polyolefin foam that contains 89-97% air by volume. This structure and composition makes TORAYPEF® lightweight and sturdy and provides superb chemical and electrical properties. See the Table of General Properties of Major TORAYPEF® Grades for more information.

Foam structure

The properties of plastic foam—in particular, compressive, water-absorption, water-permeability and sound-absorption properties—hinge upon whether the foam has an open-cell or closed-cell structure. Leveraging Toray’s proprietary process, we have succeeded in obtaining a nearly 100% closed-cell foam structure in each grade of TORAYPEF® that allows absolutely no water permeation. These characteristics can be attributed to the extremely high degree of heat-insulation and buoyancy achieved by TORAYPEF®.

Mechanical properties

Ⅰ. Tensile properties

At a broad range of temperatures up to about 80°C, TORAYPEF® exhibits enough tensile strength and viscosity to withstand practical applications. Figure 1 shows the relationship between tensile strength and temperature.

Figure 1: Relationship between tensile strength and temperature

Figure 1: Relationship between tensile strength and temperature

Ⅱ. Compressive properties

Stress-strain curve
Figure 2 shows the stress-strain curve under compression. As you can see, a higher expansion ratio leads to smaller hysteresis loss and greater elasticity. Figure 3 compares the compressive stress-strain curve of TORAYPEF® to representative examples of rigid and soft foams. TORAYPEF® exhibits qualities that fall in between the two types of foam—in essence, TORAYPEF® could be considered a semi-rigid foam.

  • Figure 2: Compressive stress-strain curve Figure 2: Compressive stress-strain curve
  • Figure 3: Stress-strain curve of representative types of foam Figure 3: Stress-strain curve of representative types of foam

Ⅲ. Compressive hardness

Compressive hardness is expressed as the compressive stress value after 20 seconds at 25% compression. Figure 4 shows the relationship between compressive hardness and temperature. As you can see, compressive hardness increases at lower temperatures, as is the case with general plastics; however, that increase is merely slight in a highly expanded product.

Figure 4: Relationship between compressive hardness and temperature

Dimensions measured after leaving samples in a standard state for one hour after heating at 80°C. For the -20°C temperature, dimensions were measured in a low-temperature chamber.

Figure 4: Relationship between compressive hardness and temperature

※These data are representative examples of measurement values obtained using specific conditions. The values should not be used as a standard.