Plastic Envelope Photo Courtesy of Associated Bag Company.

I have never used a plastic envelope myself, mostly because the mail I send has never consisted of more then Christmas cards and lengthy letters to pen pals. However, there a number of industries who employ people who need to send important and confidential documents that require more protection then the average paper envelope. This is why plastic envelopes were created, for the purpose of protecting mail to a better extent then paper packaging without having to pay to ship documents in a more expensive box. Other positive characteristics also make them a vital asset to the United States Postal Service and those that utilize its services.

Plastic envelopes are considered a style of plastic bags because of their shape and lack of definite structure, unlike plastic boxes or bins. They are often made out of clear plastics such as polypropylene or polyethylene, like many plastic merchandise bags, for visibility purposes. However, thin white plastic is also common for plastic envelope material. These plastics are all lightweight, which means they are cheaper to mail, and they are also fairly cheap to manufacture and buy. The process used to produce them is known as co-extrusion and involves creating a molten web of plastic resin three or four times over to form sheets that can then be sealed together to form an envelope.

How a plastic envelope may be sealed is another one of its major selling points. A permanent seal, which is a popular characteristic of plastic envelopes, provides tamper-proofing for important documents. Strong adhesives are applied so that once a plastic envelope is full and sealed, the only way to access what is inside is to rip open the envelope. The only downside to this system is the envelope is destroyed after a single use, but the protection guarantee is worth is for many plastic envelope purchasers. Re-sealable versions are also available, although obviously without the tamper-proofing guarantee.