For many years (including the 1960's), Ex-Cell-O corporation held a patent on virtually every paper milk carton produced. Other liquids used the same carton and licensed the same patent. I often noticed Ex-Cell-O's patent on the cartons. Perhaps you didn't, even if you were old enough to drink from their cartons. I had my own painful reasons for noticing them. I believe the company still exists, and this may be part of them.
Here's a story about the milk carton that discusses Ex-Cell-O's role.
In the 1960's and '70's, we believed that Ex-Cell-O had many subsidiary companies. They were making all these $$ from their patent, and they wanted to use that capital to grow into a giant, before their patent lapsed. I suspect that they had the miserable experience of watching some of their ventures fail. The one that affected me was: Bryant.
Bryant manufactured drums and disk drives. One of their units held the astounding amount of 40 MB. (That was astounding for 1971, anyway.) The drive was about 5 feet long, 3 feet wide and 3 feet high. Inside that rectangular frame was an axle that spun very fast, twirling a few dozen platters that were each large enough to be used for coffee tables. The company I worked at (and owned stock in) relied on Bryant, and only Bryant, for their massive disk storage. But at some point a maintenance problem developed with these drives, and their downtime was a killer for us.
Our most memorable Bryant moment was when the drive train on one of these giant boxes froze. The entire, enormous box jumped off the ground, flew through the air, and landed three feet closer to one maintenance guy who watched it jump at him in horror. I suspect that Bryant was not a very successful way for Ex-Cell-O to spend their milk money.