SFP Liquid (CI. 357)

SFP Liquid is a brilliant, urea free, hexasulphonated stilbene brightener, which can  be applied at the Size Press and in Coatings.
 
Properties
Chemistry: Derivative of Stilbene Disulphonic Acid
Appearance: Clear yellowish coloured liquid
Ionic nature : Anionic
Sp. Gravity: 1.10-1.12
Shade: Bluish to neutral white
Solubility: Soluble in all proportions
Substantivity: High
pH (1% aqueous solution): 8-10.5
 
NOTE: Performance of the product is irrespective of the colour of the product as such.
 
Stability
 
12months in closed container at room temperature.

	In liquor	On fibre
Acids	Good	Good
Alkalis	Good	Good
Hard water	Good	Good

 
Uses
 
SFP Liquid is an appropriate OBA to be used in Coating and Sizing applications against OBA of the same chemistry on equal strength.
 
Stability
 
SFP Liquid shows a high level of stability in storage and at cold temperatures. Prolonged storage at temperatures below 0°C can result in the product freezing but the product can be thawed without loss of effectiveness, if left to stand at room temperature or heated briefly to at temperature not higher than 60°C.
 
Fastness Properties
 
The product's light fastness is comparable to those of other OBAs with the same chemical constitution.
 
 
Safety & Environment
 
The usual hygiene and safety rules for handling chemicals must be observed in storage, handling and use.
Further information is given in the Safety Data Sheet.
 
 
SFP Liquid at the Size Press Application
 
SFP Liquid performs well with the conventional starches used at the Size Press. It can be used together with CMC, PVA, anionic, and weakly cationic synthetic sizing     agents. Its effectiveness is influenced by the pH of the base paper and the best effect is obtained, if the pH is above 5.0.
Typical dosage: 0.5-7.5 g/l SFP Liquid in Size Press liquor.
 
SFP Liquid in Coating
 
OBAs of the diamino stilbene disulphonic acid derivative class do not have adequate affinity for coating pigments and synthetic latexes based on copolymers of acrylic acid ester or butadiene styrene.
To achieve the best effect with OBAs, co-binders are essential as carriers. Suitable carriers for SFP Liquid are (in order of decreasing effectiveness) PVA, CMC, starch and synthetic co-binders.
The best effect of SFP Liquid is obtained with the following amounts of co-binders, based on solids content:
PVA 1.2 parts
CMC 1.2 parts
Starch 6.0 parts
Synthetic co-binders 0.4 parts
 
To a very limited degree, cross-linking agents based on melamineand urea formaldehyde are also effective as carriers for OBAs.
SFP Liquid can be used at pH 7-11 and does not affect the theological properties of various coating colours.
SFP Liquid can be added undiluted at almost any stage in the preparation of coating forulations.
Typical dosage: 0.2-1.0 parts based on the coating pigment.
(Depending upon the final brightness requirement)