"preservation purposes" is correct and usable in written English.
You could use the phrase to refer to the act of preserving something, like a historic structure or area of land. For example, "The fund has been set up to provide money for preservation purposes in the city."
In fact, the show's one weakness is that these constructions are shellacked for preservation purposes.
They are incorporated for food preservation purposes and to decontaminate surfaces in industrial environments.
For preservation purposes, original audiotapes cannot be played back, and must be digitized before use.
Please note, however, that for preservation purposes, readers are asked to use surrogates of the originals.
This collection is made up of 4 notebooks that will be individually wrapped for preservation purposes.
ANILCA set aside 104 million acres of federally owned land in Alaska for preservation purposes.
It is also not persuaded that the project has a preservation purpose, as it must for the landmarks commission to endorse and join the application for a zoning change.
That means the project not only produces an enormous output of digitized records for preservation purposes--it also filters text to find far more difficult words for computers to recognize.
These cores were coated with aluminum foil and sealed in plastic bags for preservation purpose.
Conservation purposes include preservation of land areas for outdoor recreation by or education of the general public, protection of "relatively natural" habitat, preservation of open space and historically important land area or a certified historic structure.
The human use of fungi for food preparation or preservation and other purposes is extensive and has a long history.
