What the Super Light™ Insoles Do Not Include |
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| In the past, some insoles contained natural latex rubber foam. Besides being inferior foam for use in insoles, latex rubber can cause skin irritation and in the past certain additives in man made latex were linked to cancer. The Super Light Insoles are 100% Latex FREE. |
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| Polyvinyl chloride (PVC or Vinyl) is naturally a hard plastic, in order to turn it into soft foam for insoles; plastic softeners called plasticizers with phthalates are added. One problem with the plasticizers/phthalates used in vinyl foams is they are not molecularly bound to the PVC, making them very unstable and readily able to off-gas or migrate out of the vinyl foam. To make vinyl soft enough for foam about 50% plasticizers are added to the PVC. In other words there is a potential for about 50% of the weight of the vinyl foam to off-gas or migrate out of the foam. The second problem is that heat & pressure speed up off-gassing. When used as foam for insoles, body weight & body heat and the heat caused by friction help to accelerate the migration of the plasticizers/phthalates. |
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The third problem with plasticizers/phthalates after they migrate out of the PVC is that they can enter the body by several different means including being absorbed by the skin, inhaled, ingested with food or intravenously. Studies have indicated that phthalates can damage the liver, kidneys, lungs and reproductive system. On the performance side, vinyl foams with plasticizers tend to shrink, become brittle or hard and crack with age and do not perform well in extreme hot or cold temperatures.
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| Ethylene vinyl acetate (EVA) has long been used for mid-soles and insoles for footwear, but our in house tests all have shown that EVA breaks down too quickly to be considered for use as a high quality insole. Not being sure of the vinyl content of the E[V]A, we also feel it wise to avoid using EVA inside footwear. |  |
| The Super Light Insoles are 100% EVA FREE. |
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