Ordinarily, the Korean-English patent translator won’t have too much difficulty distinguishing these terms. Carbonic acid is 탄산, while carboxylic acids are 카복실산.
But there is one term that causes no end of translator headaches when it turns up: 카본산 (literally “carbon acid”). From the structure of the word, “carbonic acid” may seem like the logical choice. But 카본산 is in fact more commonly used to mean “carboxylic acid.” Even in Korean government documents, one may find this term used for either carbonic acid or carboxylic acid.
Because 카본산 isn’t a standard chemical term, it’s always necessary to look at the context to be sure of the correct translation. A foolish consistency is the hobgoblin of bad translations.
But in most contexts — especially in polymer chemistry, where this term is especially common — the correct translation will be “carboxylic acid.”