Question: I am adapting needlework-like designs used in pottery/chinaware by creating patterns for needleworkers. Much of the chinaware was produced in the 1800’s but some as late as the 1960s. I have sought and received permission where possible, but not in all cases because the companies no longer exist. What are the laws covering those designs for which I cannot get permission? 

We think you will be fine using the chinaware designs for needlepoint patterns based on the following factors:

Do you need permission? You don’t need permission for designs produced before 1928 as they are in the public domain. You likely don’t need permission for designs produced before 1963 because they would have to have their registrations renewed (and very few were). And you don’t need permission if the works were produced between 1963 and March 1989 and they did not include a copyright notice. In summary, you only need to be concerned about 1963 – 1989 designs with copyright notices.
Is it an orphan work? An orphan work is a work for which copyright clearance is required, but the identity of the owner of the work is unknown, or the owner is known but cannot be located. (In 2015, the Copyright Office analyzed the orphan works dilemma.) We suggest you use orphan works, provided you make (and document) your good-faith effort to locate the owners by searching copyright records. That should minimize liability issues.
Will the owner see your work? Even if the work is protected, you won’t have to be concerned about liability unless there is a chance that the current copyright owner recognizes the similarities and decides to act on it. Would the owner of a 50-year+ chinaware design be policing needlepoint designs in 2023? That seems improbable.
Are you licensing your needlework patterns to a third party? If a third-party company wants to license and sell your design, your license agreement will require you to indemnify the company against any possible lawsuits. If you wish to take a conservative approach, you should avoid licensing post-1963 designs for which you don’t have permission