Preservatives come in two main groups – the formaldehyde donors and the non-formaldehyde donors. Formaldehyde donors include DMDM hydantoin, diazolidinyl urea, imidiazolidinyl urea, and quaternium 15. Non-formaldehyde donors include everything else like phenoxyethanol and iodopropynyl butylcarbamate.The formaldehyde donors are more water soluble than oil soluble, and work by decomposing slowly over the life span of…