Let’s talk about silicone!

We get a lot of questions about our silicone products like the #stasherbags and the #evereco silicone lids that we carry: What are they made of? Is it plastic or a rubber? Is it synthetic or natural? Is it safe? Is it better than plastic and if so, why? And in the end, is it recyclable or biodegradable?

We’d love to answer all those questions, it just takes a little bit of time — and a short chemistry lesson.

Let’s make sure we are on the same page: We want to talk about silicone (spelled with an “e” at the end), not silicon. For this we have to clarify the terminology first.

Silicon (without an “e”) is the fourteenth element on the periodic table. It’s hard and brittle crystalline solid with a blue-grey metallic lustre and it’s rarely found free in nature. But it is most widely distributed in dusts and sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass) after oxygen.

Silicones (spelled with an “e” at the end), are the stuff we want to tell you more about. Many people think silicones are a natural material derived directly from sand. They are not incorrect, but unfortunately it is not that simple.They are referring to Silica — or silicon dioxide which is the raw material used to make silicone resins. Beach sand for example is practically pure silica, and so is quartz.

Silicones are synthetic polymers made out of silicon, oxygen, and other elements like carbon and hydrogen. They are produced by reacting silicon with methyl chloride and then a further reaction with water, which removes the chlorine atom. This reaction produces polymers that are resistant to high and low temperatures and find applications in thousands of products and services, including health care, electronics, automotives and aerospace, textiles, construction, and as well in consumer goods.

Broken down, silicone is something of a hybrid between a synthetic rubber and a synthetic plastic polymer.

Is silicone safe?

While not a “100% natural” material like rubber, food-grade silicone made from silica is, as far as we know now, non-toxic and not health hazardous.. Products made with silicones are soft, flexible and easy to clean, resist moisture and chemicals, withstand very low and very high temperatures as well as ultraviolet radiation without leaching or off-gassing hazardous chemicals – unlike plastics, which contaminate food in these environments. Silicone is also odour and stain resistant, and hypoallergenic. It is durable, and more ocean-friendly than plastic.

However, not all silicone is created equal. Some manufacturers add fillers to the product to reduce the costs. Pure silicone does not change colour when twisted. So pinch and twist a flat surface on the item and if white shows through, you know that the product contains filler.  

Is silicone biodegradable or recyclable?

This man-made polymer is not biodegradable but it can easily be recycled multiple times – where facilities exist. It usually has to be sent to a specialized recycling company to be properly recycled. Due to its durability, though, silicone products are long lasting and will help reduce tons of single use plastics when taken care of properly.