TEXTILE CHEMICAL

HOW TO FIND PERCENTAGE PURITY OF SODA ASH

  Chemical Formula      Na2Co3

  Molecular weight         106 gram per mole

  Equivalent weight         53 gram per mole

  Form                              solid

  Smell                             Non particular

  Solubility                       Good

       Soda ash is a mild alkali. It is used in scouring, bleaching, dyeing, printing and finishing to maintain pH on the basic side. i.e. It is very easily soluble in water.

   Method of Percentage Purity :

        About 1 to 2 grams  of soda ash is dissolved in 250 ml distilled water in a measuring flask and 10 ml of soda ash solution is tit rated against 0.1 N standard solution hydro chloric acid solution using methyl orange as an indicator in this method. End point is yellow to orange red.

   Chemical Reaction :

  Na2co3 +  2HCL  ------------------------->     2Nacl   +     H2O +   Co2

 Soda ash    Hydro      Neutralization          Sodium       water   Carbon

                 chloric                                     Chloride                 Dioxide

                   acid

   Formula :

 Percentage purity     Equivalent weight of soda ash X N of HCL X B.R          250

          of                =  -------------------------------------------------------------- X ----- X 100

     Soda ash              1000 X Weight of Soda ash dissolved in 250 ml             10

       N = Normality

      B.R = Burette Reading

                                                                   -------------------%

HANK DYEING MACHINE

   
    Hank dyeing consists of immersing large, loosely wound hanks of yarn into dye vats that are especially designed for this purpose soft, lofty yarns, such as hand knitted yarns are usually skein dyed.

 Roller Hank Dyeing Machine

   These machines are based on Hussong type of hank dyeing machines in design. These machines are very simple in design and operation.

   In the basic design of machine there is rectangular stainless steel tank with proper heating mechanism and have a false bottom above the heating coil.

   The tank is fitted with a temperature indicator and control sensor. There is an array of stainless steel rollers which are fitted on a suitable frame. The rollers can rotate in clock wise or anti clock wise directions with gear arrangement. The machine is fitted with stop/start system to control the roller movement. The hanks loaded on rollers can be lowered in the tank or lifted out by lifting or lowering the frame with the help of hydraulic system.

   Working of the machine :

    The hanks to be dyed are loaded onto the rollers bars by avoiding overlapping of hank, in lifted position. The dye bath is kept ready with proper liquor level and mixed homogeneously, preferably with an external circulation pump. The hanks are lowered into the dye bath and movement is started approximately 40-50% part of the hank remain the liquor and rest is exposed to atmosphere.

    The material is lifted up for addition of colors, chemicals, slat, alkali etc or for raising the temperature of dye bath. In case of in direct heating the dye bath temperature may be increased at set rate of heating, but in case of direct heating the temperature rise is step by step. The sample may be drawn at the completion of dye cycle and checked for shade, without stopping the machine. All operations can be done in the same machine.

   Advantages :

• It is simple in design and operation.
• Cost of the machine is not very high.
• All types of yarns can be processed such as cotton,mercerized cotton, viscose filament or even silk can be processed.

    Disadvantages :

• Only limited automation is possible
• Only 40-50% of yarn takes part in dyeing and rest is exposed to atmosphere, therefore hydro sulfite consumption is high in these machines.
• The liquor ratio increases with heating in case of direct injection of steam.

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TEXTILE BLOG: TEXTILE MANUFACTURING:  PROTEIN FIBERS   Animal hair consists of complex properties. The hair of sheep and goats is particularly important for textiles, wool...

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TEXTILE MANUFACTURING

 PROTEIN FIBERS

  Animal hair consists of complex properties. The hair of sheep and goats is particularly important for textiles, wool is by fat, the major animal fiber in quantity, but cashmere and mohair are significant for their market value. This class of fibers also includes the fine double filament secreted by the silk worm. The entire range of protein fibers accounts for only about 6% of word fiber consumption, and the proportion is even less in many developed countries where synthetic fibers are readily available. Quality wool, fibers such as cashmere and particularly silk, however, denote luxury and are priced accordingly.

  Proteins are complex polyamides, also called polypeptides, produced by the biological poly condensation of a mixture of a specific type of amino acid with a variable side - group. The amino acid composition and the sequences of the amino acid units along the polymer chain, characterize the structure of protein molecule. Protein molecules, however can adopt a variety of elaborate lying side by side, or cord-like arrangements of individual helical molecules wound around each other. In globular proteins, such as enzymes, the protein molecules adopt even more complex, but characteristic, configurations. In living tissue, proteins are frequently associated with other types of bio molecules in complex cellular structures. It is only in fairly recent times that the detailed morphology of wool fibers, and the way in which influences the dyeing process, has become clearer. 

TEXTILE MANUFACTURING

SYNTHETIC FIBERS

      In this blog about the synthetic fibers. Synthetic fibers are produced from simple organic chemicals, obtained mainly from petroleum. They are thus distinct from natural fibers and those made from regenerated natural polymers such as, cellulose. In particular the dyeing of synthetic fibers is quite different from that of natural fibers and the progress of each synthetic fiber has involved new dyeing technologies.

     The major polymers used for synthetic fibers are poly-amides, polyesters and poly acrylonitrile. The first two are products of poly condensation reactions and the latter of radical addition polymerization. Synthetic fibers have many excellent textile properties and comprise over 40% of all fibers consumed. Every type is available in a wide variety of modifications to suit market requirements. These includes mono or multi filaments or staple fiber of any denier or length and with a variety of different physical and chemical properties. Advantages of synthetic fibers is the relative ease with which physical and chemical modifications are possible. The favorable economics of the mass production of nylon, polyester and acrylic fibers are the result of solving many technical problems their production and use. The introduction of new types of synthetic fiber in the foreseeable future is often considered unlikely, but such pessimism may not be warranted.

 

     All synthetic fibers are produced by extrusion of continuous filaments, either of the molten polymer or of it is solution in a solvent, through tiny holes in a metal plate. This is called a spinneret. Extrusion of polymer filaments is called spinning but must be distinguished from the spinning of yarns of staple fibers by drawing an twisting. In melt spinning, the solid polymer filaments are obtained by rapidly cooling the extruded molten poly met, where as in solution spinning they remain after evaporation of the solvent, or coagulation in a bath of suitable chemicals.

TEXTILE CHEMICAL

HOW TO FIND PERCENTAGE PURITY OF ACETIC ACID

   Chemical formula                         CH3COOH

   Molecular weight                          60 gm/mole

   Equivalent weight                         60 gm/mole

   Form                                             Liquid

   Smell                                            Pungent

   Solubility                                      Good

    Acetic acid is a volatile organic acid. it is used in wet processing i.e. bleaching, dyeing and printing and finishing to maintain the pH on the acidic side i.e. - 7.

  Method to find our percentage purity :

    About 1 -2 gm of acetic acid is dissolved in 250 ml of distilled water in a measuring flask and 10 ml of this solution is tit rated against 0.1 N standard NaoH solution using phenolphthalein as an indicator. In this method end point is colorless to pink.

   Chemical  Reaction :

    CH3COOH         +     NaoH    ------------------------------>  CH3COONa     +  H2O

   Acetic acid             Sodium           Neutralization        Sodium acetate     water 

                               Hydroxide 

    Formula :

   Percentage     E.Q of CH3COOH x N. of NaOH x B.R           250    

   purity of    =  ------------------------------------------------- x   -----   x 100

   acetic acid      1000 x weight of  acetic acid dissolved in    10

                                                         250 ml

            E.Q = Equivalent weight

            N     = Normality

            B.R = Burette reading

                                                 

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