FLUORESCENT
BRIGHTENING AGENT

(SARAF WHITE R LIQUID - For Polyester)
 

INTRODUCTION

SARAF WHITE R LIQUID is Fluorescent Brightening Agent for polyester fibres. It gives brilliant whitening effect which has good fastness to sublimation, light and wet processing. It can be applied by high temperature exhaust or pad-thermosol method suitable for whitening effect on texturised polyester and polyester/cotton. It is available as nonionic fluid dispersion greenish yellow in colour. The dispersion is miscible with water and can be diluted to any desired concentration by adding water to it. It is recommended to adjust the pH of the bath between 4.5 - 5.5 as whitening effect may be reduce in extremely acidic or alkaline condition.  

CHEMICAL DEFINITION

The FLUORESCENT BRIGHTENING AGENT is colorless fluorescent dye. It is also called OPTICAL BRIGHTENERS. In accordance with its definition as “COLORLESS” Fluorescent dyes, the Coloristic performance is that of fluorescent dyes, without absorbing light in the visible range of the spectrum. It absorbs ultraviolet rays present in incident sunlight. This absorb ultraviolet light is Re-Emitted by the FLUORESCENT BRIGHTENING AGENT which is of longer wavelength than the incident Ultraviolet light and is known as the Fluorescence light. This generally falls in the blue region of the visible spectra. The fluorescent light is then superimposed on the reflected light thereby restoring the balance of different colors and hence producing brilliant white effect.

PRETREATMENT OF FABRIC PRIOR TO WHITENING APPLICATION

 

The fabric at the loom stage (i.e. Grey cloth) contains yellow and brown impurities, which are partly removed from then by scouring (Boiling under pressure in an alkaline liquor in the presence of a powerful detergent & stain remover). The color of some of the residue impurities (Which are not removed by the scouring treatment) is destroyed usually by bleaching treatment under controlled condition of PH, Time, Temperature and the Concentration of the bleaching agent, so that hydrolysis (Degradation or Tendering) of the polyester does not take place. Finally for achieving brilliant whitening effect Fluorescent brightener are applied.

GENERAL PROPERTIES

SARAF WHITE R is FLUORESCENT BRIGHTENING AGENT for synthetic fibers. It has got very good yield & gives brilliant whitening effect, which has good fastness to sublimation, light, & washing. It is available as nonionic fluid dispersion greenish yellow in color. The dispersion is miscible with water and can be diluted to any desired concentration by adding water to it.

APPLICATION
METHOD 

 

SARAF WHITE R LIQUID is applied by thermosol method and exhaust method suitable for whitening effect on texturised polyester, Polyester/Cotton & knitted goods produced from texturised polyester, filament yarn. However it can be also applied by exhaustion method at the boiling temperature in the presence of carrier, one stage scouring-bleaching and whitening can also be done.

MATERIAL HANDLING SPECIAL CARE

 

Material should be stored in cool place and always the container/drum should be shaken vigorously before every use. PH of bath be strictly between 4.5 – 5.5 as whitening effect may be reduce in
extremely acidic or alkaline condition. Time and temperature given for thermosol process are general recommendation however same evaluated on basis of experience preliminary trials are more reliable since fixation condition depend on fabrics construction. The padded and dried fabrics should not be prolongly exposed to light since the unfixed whitener is very sensitive to light.

 METHOD OF APPLICATION 

Preparation of Dispersion :

The required amount of Saraf White R Liquid is weighted out and stirred with 20 times of its weight of soft
water at room temperature. The required volumes is made up adding more soft Water.

High-Temperature Method :

The bath is prepared with   

0.1 - 0.5 % Saraf White R Liquid

1.0g/l Suitable Dispersing agent

pH 4.5 - 5.5 with acetic acid

Material to Liquor ratio 1:10

The material is entered about 50ºC and the temperature is slowly raised to 130ºC with 45-60 minutes.
The treatment is continued for about 30-45 minutes. The material is then washed in cold water and soap at 60ºC - 70ºC for 10-15 minutes in2 g/l neutral detergent. 

PAD - THERMOSOL METHOD

Padding :

The fabric is padded through a pad-liquor containing 1-5g/l Saraf White R Liquid at room temperature keeping 60-80% exression. The padded fabric is dried at approximately 120ºC - 140ºC.

Fixation :

The fixation
condition depend on fabrics construction. Heavy or densely woven fabrics require higher fixation temperature or lighter fixation time than fabric with openweave. However, following fixation condition may be taken as general recommendation :

For Normal
Polyester & Polyester/Cotton : 190ºC-195ºC for 10 - 15 seconds.

For Texturised Polyester : 170ºC-180ºC

The
thermofixed material may be given rinsing and light soaping treatment with 2g/l neutral detergent at 60ºC-70ºC for 10 - 15 seconds.

Note: The recommendation are based on laboratory experiment and to be considered as guide lines only. For bulk production, it is necessary to carry out small scale trials to confirm with local condition.

FASTNESS
PROPERTIES

The fastness properties were tested on Polyester with 5g/l Saraf White R Liquid by Pad-Thermosol
method. The figures give information on changes in whiteness:

Light
:..........................................................5-6

Washing :

40ºC (Test
1)..................................................5

60ºC (Test
3)..................................................5

95ºC (Test
4)...............................................4-5

Perspiration
:

Alkaline..........................................................5

Acidic............................................................5

Dry
Cleaning..................................................4

Dry-Heat
Pleating :

Mild
(180ºC)..................................................5

Severe
(210ºC)............................................4-5

Water
:........................................................4-5

Sea Water
:.................................................4-5

Hypocholrite
Bleaching :.............................4-5

(Without
Grarantee)