You can search the US Patent Office's website for patents dating back to the mid 1970's.
http://patft.uspto.gov/
To determine if the patent for the product has expired, you should check the United States Patent and Trademark Office (USPTO) database or consult a patent attorney.
United States Patent and Trademark Office
The life of a patent is 17 years in the United States.
Basmti rice
Cheryl H. Agris has written: 'Practitioner's patent guidelines' -- subject(s): United States, United States. Patent and Trademark Office, Patent practice, Rules and practice
United States patent numbers 5,451,942; 5,956,674; 5,974,380; 5,978,762; 6,487,535. There are also other issued and pending patents in the United States and worldwide.
According to the US Patent and Trademark Office:A patent is an intellectual property right granted by the Government of the United States of America to an inventor "to exclude others from making, using, offering for sale, or selling the invention throughout the United States or importing the invention into the United States" for a limited time in exchange for public disclosure of the invention when the patent is granted.
United States Patent .
Title 35 of the United States Code
The United States Patent Office
The patent for MabThera (rituximab) in the United States expired in 2016, while in Europe, it expired in 2013. However, various formulations and uses may have different patent protections. Generic versions of the drug started becoming available after the patent expiration. Always check the latest patent and market information for updates.
The Composite railroad tie was patented by (keep in mind patented does not necessarily mean invented) Gordon E. Brown (United States Patent 4105159). The Combination Wood Plastic railroad tie was patented by Hong Man Lee (United States Patent 4286753). The Synthetic railroad tie was patented by Douglas L. Smith (United States Patent 6021958). The Metallic railway tie was patented by Mitchell Amos (United States Patent 1620730).