Sten Gustaf Thulin’s creation of the plastic bag in 1962 was overlooked by most of the world for a decade. In 1977, the U.S. petrochemical group Mobil purchased the patent from Celloplast, who had acquired the U.S. version for Thulin’s Bag with handle of weldable plastic material in 1965. Since the Mobil Corporation was already established as a petroleum giant, it was able to produce the bag for a much lower cost and gain access to a much larger consumer base. In the same era, the United States was on the cusp of the latest evolution shopping habits: large, streamlined supermarkets to which consumers drove, instead of walked. Families and food markets were changing in response to each other, and shoppers now needed a reliable way to carry food for longer distances. It was becoming normal for urban and suburban shoppers to use multiple forms of transportation to get the groceries from the store to the home.
The expansion of plastic bag use has brought changes in size, color, and density. Although size and color are rarely of great importance when consumers are shopping, density is. Supermarket shoppers often experience the “double bag” solution, in which cashiers will double bag fragile or heavy items to ensure that, if one bag rips, the other bag will provide additional support. A movement against “lightweight bags,” those of with a density below 2.25 mils or 0.002 inches, have been banned in over 25 countries.  But why not just make the bags thicker? Originally, plastic bags were all relatively thick. But in [year/date range], retailers started using thinner bags in response to environmental critiques about plastic bags’ slow rate of biodegradability.  However, there has since been backlash by environmental activists pushing for laws banning bags of a certain thinness.
”Phase-out of Lightweight Plastic Bags.” Wikipedia. April 29, 2018. Accessed May 10, 2018. https://en.wikipedia.org/wiki/Phase-out_of_lightweight_plastic_bags#Africa.
 “Thick, Reusable Plastic Bags Aren’t More Eco-friendly than the Thin Ones Montreal Banned, Study Finds | CBC News.” CBCnews. January 14, 2018. Accessed May 09, 2018. http://www.cbc.ca/news/canada/montreal/plastic-bag-environment-1.4486494.