Primary market research is research conducted by the company itself, in-house, or by a hired researched company, and secondary market research draws on data collected by others.
There are two possible markets for spray starch, a business-to-business market of establishments that launder clothing and linens, for example, dry cleaners, and consumers who iron their own clothing and linens.
In either case, what must be researched is the degree to which the clothing available even needs to be starched and ironed, a somewhat limited market today, I would guess. So much is available today in wrinkle-free fabrics.
Primary research could include surveys or focus groups to get a sufficient sampling to find out who actually uses spray starch. Secondary data might include data collected by supermarkets and drugstores to find out which geographical locations sell the most spray starch. This will be where the demand is, and advertising focused in those areas could persuade people to buy your brand.
You would need to have some idea what your competition is and what its features are so you can capitalize on any advantage your product has. This might involve primary research in the form of testing all spray starch products, and it might also involve secondary research collected by government agencies giving data of fiscal sales the industry.