Sizing

BY

Vignesh Dhanabalan

SIZING Objective of Sizing

• To protect the yarn from abrasion

• To improve the breaking strength of the yarn

• To increase smoothness of yarn

• To increase yarn elasticity

• To decrease the generation of static electricity

• To decrease hairiness

• What is a add-on percentage ?

• How should the add-on percentage be…?

• Effect of low percentage…

• Effect of high add-on percentage…

• What will the parameters to be taken into consideration during sizing

Different zones of Sizing machine

Saw box and its Components

Components of Size paste

• Essential Ingredients

• Adhesive

• Wetting agent

• Binder

• Secondary agents

• Oxidizing / Reducing agent

• Weighting agent

• Brightening agent

• Anti foaming agent

• De-lustering agent

• Antistatic agent

Binders / Adhesive

Other Ingredients

• Wetting agent

• TRO – Turkey red oil

• Oxidizing agent

• Depends on the material

• Weighting agent

• Gypsum

• Calcium carbonate CaCO3

• Optical brightener

• Tinobal Blue / RaniPal

• Antifoaming agent

• TRO – Turkey red Oil

• Delusturing Agent

• Titanium Dioxide (TiO2)

• Antistatic

• Sapkostat oil

Uptake Percentage • At low level of uptake

• Cover by the size film

• inadequate covering leads to more abrasion

• More breakages.

• At high pickup rate

• Improves as the size add on increases

• the optimum level then warp breakage rate increases again largely due to the

loss of elongation and increase in bending rigidity of the yarns

Factors influencing uptake

• Type of size material, *Type of fiber

• Yarn spinning technology *Yarn count and twist

• Yarn hariness *Loom speed

Sizing calculations

Cont.…

Types of Sizing

Pure sizing: when the size pick up % is about 3 – 10 % it is called pure

sizing.

Light sizing: when the size pick up % is about 11 -16% it is called light

sizing.

Medium sizing: when the size pick up % is about 17 – 40 % it is called

medium sizing.

Heavy sizing: when the size pick up % is above 40 % then it is called

heavy sizing.

Size Paste Recipe Carded Yarn:

Modified Starch : 10.5 % on the weight of

water

PVA : 2.86 %

Acrylic Binder

(Liquid) : 6.6 %

Lubricant : 0.7 %.

Paste viscosity: 6.5±0.2 second, Solid: 12-

13%

Combed Yarn:

Modified Starch : 12.5 % on the weight of

water

PVA : 3.0 %

Acrylic Binder

(Liquid) : 6.91 %

Lubricant : 0.87 %

Paste viscosity: 6.4±0.2 second, Solid: 12%

P/C Blended

Modified Starch : 13 % on the weight of water

PVA : 3.6 %

Acrylic Binder

(Liquid) : 8.4 %

Lubricant : 0.87 %.

Antistatic : 0.5 kg

Paste viscosity: 7±0.2 second, Solid: 12-13%

Commercial procedure Take standard volume (700 liters) of water (normal temperature) into the pre-mixture through

water flow meter, start the stirrer.

Properly weigh all the chemicals required

Add modified starch, PVA and then Acrylic binder slowly into the pre-mixture.

Stir the mixture for 15 minutes

Start the stirrer of the cooker, transfer the mixture to the closed cooker from pre-mixture

vessel. Close all the open valves of the cooker.

Heat the cooker mixture with the injection of direct steam, steam will auto cut when the cooker

temperature reaches the preset limit (1100C). It takes around 30 to 35 minutes.

Cook the mixture for another 40 minutes, the temperature of the cooker will reach to around

120 to 1250C depending on the size recipe.

Start the stirrer of the storage vessel and then transfer the cooked size paste to respective

storage vessels.

Add lubricant with the size paste at storage

Maintain storage temperature at around 80-900C.

Properties of sized yarn

Benefits of sizing Harriness

Strength

Abrasion

Static charge

Elasticity Increases to certain limit

Disadvantages of Sizing • Cost of land and machine is high - Capital Investment

• Requires lot of labors – Labour involvement

• Working cost

• The process is long and it takes time

• There is a risk of degradation of yarn

• The yarn diameter is increased

• Requires robust loom

• It increases yarn stiffness

• The fabric needs to be desized before use

• Need knowledge and information about the size ingredients

• There is a risk of pollution

• Sizing changes the shade of colored yarn

• 100% size material cannot be removed

• Size material presence leads to uneven dying