Feem ntau muaj ob txoj hauv kev los txhim kho cov roj tsis zoo ntawm daim ntawv los ntawm kev siv tshuab papermaking: ib qho yog txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau nws nws muaj ob txoj hauv kev los txhim kho cov roj ntawm daim ntawv los ntawm kev siv tshuab papermaking. Qhov thib ob yog siv cov roj repellent rau kev kho mob.
Cov ntaub ntawv pov thawj roj tuaj yeem muab faib ua ob pawg: fluorinated oil proof agents thiab non fluorinated oil proof agents. Perfluoroalkyl compounds siv hauv papermaking tuaj yeem muab faib ua peb pawg: perfluoroalkyl chromium complexes, perfluoroalkyl phosphate esters, thiab perfluoroalkyl copolymer. Ntawm lawv, toxicity thiab kev nyab xeeb ntawm perfluoroalkyl chromium complexes tsis tau lees paub los ntawm US Food and Drug Administration (FDA). Cov roj uas tsis muaj fluorinated yog cov tshuaj acrylic copolymer, uas tseem tsis tau siv dav.
