Chemicals Based Technologies - Flourescent Brightening Agents and their Intermediates

Introduction

Indian consultancy and project management company offers to supply technology for manufacture of fluorescent brightening agents and their intermediates.

Fluorescent brighteners operate by the phenomenon of fluorescence and have distinct affinity for fibres and show fluorescence of appropriate colour. It must be colourless so that undesirable tones are not produced by it on the fibre.

Fluorescent brightening agents are similar to dyes and just as there is not a single dye which can be applied to all fibres, there is no one fluorescent brightening agent that can be used on all fibres. It is for this purpose that different chemical types of fluorescent brightening agents have been developed for different types of fibres.

Whitening of natural and man made fibres with fluorescent brighteners is carried out by treatment of the chemically bleached material where in the colour balance is restored by an additive process.

Process

The whitening agents for Cellulosic fibres (cotton and paper) and Polyamide fibres (silk, nylon, wool) are stilbene derivatives and are obtained by condensation of cyanuric chloride with Diamino stilbene disulphonic acid, followed by successive condensation with other amines like Diethanol amine, Monoethanol amine, aniline, Aniline-m-sulphonic acid, or Ammonia.

The first condensation with cyanuric chloride is carried out at lower temperature and subsequent condensation at higher temperatures. The products are then isolated by salting out with pure salt.

The whitening agent for polyester (White R, FBA 199) is obtained by the condensation of O-cyanotoluene with Terephthaldehyde in presence of Tri methyl phosphite and sodium methoxide. The product obtained is solubilised and then diluted for precipitation. It is filtered, crystallised from Dimethyl formamide and centrifuged. It is then sandmilled and blended with dispersing agents to get about 30% emulsion which is normally used for whitening purposes.

List of equipments:

• Glass lined vessels
  
• SS316 reactors
  
• Heat exchangers (SS316 and glass)
  
• MSRL drowning vessels
  
• Filter presses (PP)
  
• Centrifuges (MSRL, SS316)
  
• Filter Nutsches MSBL
  
• Pressure filter (Jacketed) SS316
  
• Sparkler filter
  
• Sand mill
  
• Storage tanks
  
• Boiler
  
• Hot oil unit
  
• Vacuum pumps
  
• Air compressors
  
• Scrubbers
  
• Driers

Areas of Application

Fluorescent brightener for cellulose fibres (fluorescent brightener 24, FBI and FB28) are applied either by exhaustion or padding method and either in cold or hot bath depending upon the type of agent being used, salt is used for maximum exhaustion. Most of these agents are stable to hypochlorite and chlorite bleach baths. All these agents have got very high affinity for cellulose fibres.

Fluorescent brightness for polyamide fibres (FB-253, FB-134) are normally applied from an acid bath (Acetic Acid or Formic Acid) both by exhaustion process or padsteam process. These can also be applied during bleaching, since most of these are stable to sodium chlorite and hydro sulphite bleach baths. They also have very high degree of whiteness when applied by thermosol process.

Advantages

The effluent treatment plant will consist of primary treatment, ultra filtration, secondary treatment and then incineration.

The primary treatment which will apply to about 10% of the total effluent will consist of the removal of dilute sulphuric acid with hydrated lime.

This treated effluent along with the alkaline effluent of other stages will then be passed through ultrafiltration equipments to remove salt.

This effluent will then be subjected to biodegradation using activated sludge and after clarifying the degraded mass will be subjected to incineration.

The solid wastes obtained are : 1. Gypsum from primary treatment of effluent can be used for cement plants/land filling; 2. Iron sludge - mixtures of ferrous/ferric oxides, can be converted to pigments.

Production Capacity

• Fluorescent brighteners for cellulosic fibres - 900 MT/A
  
• Fluorescent brightners Polyamide for cellulosic fibres - 300 MT/A
  
• Fluorescent brightners polyester for cellulosic fibres - 300 MT/A
  
• Intermediates (for captive cons.) 250 MT/A

Inputs Required

Development Status: Commercialised

Transfer Forms: Know-how, engineering consultancy, turnkey plant, training

For More Information, Contact:

Asian and Pacific Centre for Transfer of Technology
P O Box 4575
Qutab Institutional Area
New Delhi - 110 016, India
Tel : +91-(0)11-6856276
Fax : +91-(0)11-6856274
Email: rvijh@apctt.org

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