OPTICAL BRIGHTENER LIQUID FOR PAPER
The optical brightener applied in paper-marking process are mainly derivatives of stilbene bistriazine.
Based on sulphonation , there`re three types:
●GENERAL TYPE - APC: tetrasulphonic acid, having good fibre affinity, good stability to acid and alkali, good compatibility with starch.
Good performance in size press, pigment coating mixture. Suitable for continuous adding process.
●DIRECT TYPE - APB-L: disulphonic acid, good fibre affinity , high whitening strength , small dosage, very economic but weak stability to acid and alkali.
Applicable in stock, size press and pigment coating mixture.
●SURFACE COATING TYPE - APH: hexasulphonic acid, weak fibre affinity, excenllent effect at low PH value,
especially suitable for coating and surface sizing, with greatest brightening effect the the paper at present.