technical grade vs technical-grade

technical grade and technical-grade both are adjectives.

Word	Noun	Adjective	Verb	Adverb
technical grade	No	Yes	No	No
technical-grade	No	Yes	No	No

As adjectives, technical grade and technical-grade are synonyms defined as:

technical grade and technical-grade: containing small amounts of other chemicals, hence slightly impure

technical grade (adjective)	technical-grade (adjective)
containing small amounts of other chemicals, hence slightly impure	containing small amounts of other chemicals, hence slightly impure