Hi,
According to your description, you might want to change the regional settings for a Document Library only.
Since there is no such OOTB feature can meet your requirement, a workaround is that you can create a custom Web Part to display the data from Document Library and
take care of the options related to Regional Settings in the code behind.
Two demos below about how to create custom web part to display data from Document Library would be helpful:
http://www.codeproject.com/Articles/37530/Document-Library-Tree-View-Web-Part-for-SharePoint
http://sppractices.blogspot.com/2013/03/bind-sharepoint-2010-document-library.html
With the data retrieved, then you can modify the display of the data to meet the custom regional settings.
Best regards