SIZING

Name : MAZADUL HASAN SHESHIRID: 2010000400008Batch: 13th Batch (Session 2009-2013)Department: Wet Processing Technology Email: mazadulhasan@yahoo.comBlog: www. Textilelab.blogspot.com Southeast UniversityDepartment of Textile Engineering

PREPARED BY ©right

Sizing is the process of giving a protective coating on the warp yarn to minimize yarn breakage during weaving.

Sizing is the most important operation in preparing warp yarn for weaving especially with cotton yarn. The smallest error in sizing process may be very harmful. This may increase warp breakage rate on the looms and consequently reduce weaving production and quality. Therefore sizing is termed as the “Heart of Weaving”.

SIZING

Introduction: Sizing is the process of applying an adhesive coating on the surface of the

yarn. Sizing is applied into the yarn mainly to improve the weave ability of warp yarn by making it more resistant to action of weaving i.e. absorption, friction, tension & flexing. It also maintains good fabric quality by reducing hairiness, weakness & by increasing smoothness, absorbency of yarn. The most other features of the sizing is change of various physical properties.

Sizing is applied on to the fibre surface by various process and various recipes according to the requirements. The most commonly used sizing machine is Slasher sizing machine.

1. To increase the smoothness of the warp yarn.

2. To reduce hairiness of warp yarn.

3. To increase the strength of warp yarn.

4. In some cases sizing is now done to modify the character of the warp yarn. i.e. to

have an effect on fabric weight on fabric weight, stiffness, handle properties etc.

5. To improve the weave ability of warp yarn.

6. To maintain good fabric quality by reducing hairiness, weakness and by

increasing smoothness, strength of yarn.

7. To increase the tensile or breaking strength for cellulose yarn.

8. To increase the elasticity.

9. To remove the projecting fibers.

10. To reduce electrostatic formation for synthetic or blended yarn.

Objects:

1. Sized warp must be strong and elastic.

2. Yarn strength and loss in elongation should be within admitted limits.

3. The process must ensure the applications of required amount of size on the yarn.

4. The tension of warp yarn must be constant all the time.

5. The weavers beam must have a cylindrical shape, necessary winding density and the yarn length.

6. The sizing process must be efficient, economical and must ensure the production of high quality size warps.

Requirement of sizing:

Sizing Process Involves:

Types of sizing:Sizing may be classified into Four types on the basis of size% on the yarn.

1. Light Sizing :10% to 15%.

2. Pure Sizing :16% to 25%.

3. Medium Sizing:26% to 50%.

4. Heavy Sizing :50% to 100%.

Types of sizing:

Material/Chemical:

1. Adhesive.

2. Chemical.

3. Acrylic sizing agent.

4. Lubricant softener.

Operation Staff:

5. PRODUCTION MANAGER.

6. SUPERVISOR OFFICER.

7. SIZER.

8. ASSISTANT SIZER.

9. HELPER.

Properties of Size Ingredient

What is Size take-up %

Different Technique Of Sizing

Recipe cooking:In the figure A is a motor; B is a agitator getting direct motion from motor. C is a mixing tank. Size ingredients are mixed with the help of agitator in mixing tank. Size ingredients are added in mixing tank by the help of inclined lid (H) & steam supply from steam pipe. After mixing size- ingredients passed through the valve (D) & then pumped by pump (E) into cooking & storing tank (G).

Recipe cooking:

In the storing tank, steam is passed to maintain viscosity of size. Viscosities of size depend upon concentration & temperature of cooking tank (G). Before sizing is set to operate sizing liquor needs to be cooked, stored and transferred to the main m/c size box. Preparatory section in charge and/or sizing technologist gives the plan of

size liquor quality and quality (recipe), considering the following factors: Material to be sized i.e. yarn composition. Diameter of material to be sized i.e. total number of ends. Total weight of material to be sized.

Size mixing man prepares the size liquor as per instruction and record in the production register. The preparing sequence is as follows:

Main switch at the main control panel is switch on. Enter following set points for cooking process at the panel-

cooking temperature. water quality. cooking time.

Enter temp. set point for storage tank. Open water valve with push button, water will come in. When Agitator impeller is covered with water then switch on agitator with

the push button. Change with size powder, liquid size component etc. as per recipe.

Close and look cooker cover. Automatic cooking program will start-1. Steam valve will open. Temp. will increase from 55°c to 85°c.2. Agitator will be switched to higher speed.

After cooking temp. has been reached-1. Steam valve will close.2. Cooking temp. is maintained at a constant valve by temp. controller.3. Cooking time commence.

After cooking time is finished-1. Agitator will be switched from higher to lower speed and continue to run at that

speed.2. Cooker cover can be unlocked and opened to check viscosity and concentration.

For reservation of cooked size to storage tank-1. Open manual valve of the corresponding tank.2. Switched on size delivery pump with push button size is pumped in to the

corresponding storage tank.3. The size delivery pump is stopped automatically when the cooker is emptied or

the maximum level in the storage tank is reached.4. Switch on agitator of the corresponding tank with push button.

Recipe cooking:

This cooked liquor is transferred in the size box of the main m/c called sizing center. A steam pressure of 3.5 bar (maximum) is required in the sizing center for the following types of steam heating.

Direct heating (controlled by pneumatic control valve) for the size feed box and the size box.

Indirect heating (controlled by automatic or manual operated valve) for vent in the size and size feed box (water bath). Temperature of water bath must be as close as possible to the boiling point of water.

The direct heating system should be switched on as less as possible by temp. control to maintain a constant temp. of about 80 to 85°c in order to avoiding diluting the size liquor where by preventing fluctuation in viscosity and hence varying degree of sizing.

Recipe cooking:

The Important Features to be remembered During Sizing:

1. If the hairiness of the yarn is high then the concentration of the size would be high.

2. If the twist is high in the yarn then the concentration of the size would be high.

3. If the yarn (finer) count is high then the concentration of the size would be high.

4. If the yarn (coarser) count is high then the concentration of the size would be low.

5. If the temperature of the bath is high then the viscosity of the size would be less

and vice versa.

6. If the cooking time is more than the viscosity would be less.

The Important Features to be remembered During Sizing:

Effects of Sizing on Yarn:The amount of size add-on depends on yarn structure, sizing recipe, squeezing roller pressure, m/c speed.As the size add-on is increased—

The yarn becomes stiffer.

The yarn becomes less extensible.

The yarn becomes more difficult to weave.If a low add-on—

The yarn becomes hairy.

The yarn suffers from lack of strength.

The yarn becomes more difficult to weave.

GRAPH:If Sizing increase, Efficiency also increase up to optimum level.

SIZE % EFFICIENCY%Low 40

Good 75Standard 85Optimum 95

High 85Very high 75Extreme 40

GRAPH:

low good standard optimum high very high extreme0

10

20

30

40

50

60

70

80

90

100

40

75

85

95

85

75

40

size%

effici

ency

%

If Sizing increase, End Breakage% also increase upto optimum level.

SIZE % End Breakage%Low 70

Good 50Standard 20Optimum 10

High 20Very high 50Extreme 70

Low

Not good

Standard

OptimumHigh

Very high

Extrem

e0

1020304050607080 70

50

2010

20

50

70

size%

end

brea

kage

%

Sizing Ingredients-1. Starch.2. Binder.3. Softener.4. Anti-septic agent.5. Anti-static agent.6. Weighting agent.

Sizing Material & Chemical Used:

Starch:Starch is the main sizing ingredients. They coat the warp yarn with a film & impart smoothness by binding the projecting fibres to the yarn surface. The viscosity of the size solution is controlled by the amount of starch, the recipe, degree of mechanical mixing, temperature & time of boiling.e.g. Potato, CMS(Carboxy Methylated Starch),PVA (Polyvinyl Alcohol)

Binder:These materials penetrate into the yarn & contribute in increasing yarn strength. These materials can be used as an independent gum & substitute of starch products.e.g. Polyacrylamide, Polyacrylonetrile etc.

Softener:The hard fragile film is softened by addition of softener. They increase flexibility of yarn after sizing; e.g. Tallow, Soap, Japanese wax, Modified wax, Artificial wax.

Anti-septic agent:The size recipe consist starch which the protein substances in the favorable medium for the development of the micro-organism (Fungi, Mouldetc). The sized warp or grey cloth is stored for long time; the anti-septic agent is used to prevent the growth of micro-organism in the grey cloth.

Weighting agent:These agents are used to increase the weight of the fabric. The fabrics are to be sold at grey stage or require the special type of finishing to get fuller appearance are sized with the weighting agent.

Sizing Material & Chemical Used:

1. The recipe should be that which gives fewer end breaks.

2. It should be that which gives the least exfoliation.

3. It should be that which permits easy de-sizing.

4. It should give good fabric characteristics.

5. It should be compatible with machinery (e.g. it should not cause size build-ups

during weaving or blockages during slashing).

6. It should not cause any degradation of the textile material.

7. The cost of sizing plus the cost of weaving and finishing should be minimum.

THE FACTORS IN CHOOSING SIZE INGREDIENTS ARE-

Sizing recipe depends on yarn type, total ends.

Typical sizing recipe-

In 500 Liter Water•Starch : 10-20%of water.•Binder : 2-4% of water.•Softener : 0.5-1% of water.

Sizing Recipe:

Viscosity of the size recipe: If viscosity of the size liquor is not proper, it is difficult to penetrate for the size material to the core of the yarn.

Lubrication: Lubricant can exist at the surface or exist inside the structure and later work itself to the surface as the yarn rubs over a friction surface.

Degree of size penetration: It determines the stiffness for a given yarn bearing a given size. So if Degree of penetration is not proper, size take up% will be un-uniform.

Squeeze roller pressure: If the pressure of squeeze roller is not sufficient, size add-on may be increased or decreased.

M/C Speed: If m/c speed is high or low consequently size take-up% may be less or high correspondingly than the required take-up%.

FACTORS AFFECTING THE SIZE TAKE UP PERCENTAGE-

Machine Setup:

PARAMETER M/C RANGE SET VALUE

Sized Speed 1-120 m/min

40-45 for Fine Cotton45-50 for Yarn Dyed

Material.

50-70 for Solid Dyed Material.

Machine Description:Slasher sizing machine is a continuous sizing machine. This machine has a number of units. For an ideal sizing machine following units are most common,

1. Back beam unit

2. Sizing unit

3. Drying unit

4. Cooling unit

5. Dividing unit

6. Measuring & marking unit

7. Beaming unitThe machine in our lab is a semi automatic machine which is electrically driven by a heavy motor.

Machine Description:

Yarn Path / material flow diagram

Key Accessories:

1. REFRACTOMETER.

2. VISCOSITY CUP.

1. BENINGER ZELL SIZING M/C (SINGLE SIZE BOX).2. BEN SIZEMIX (COOKER).These sizing machines are equipped with BEN SIZEMIX size cooking & storage apparatus. A total of 12 (maxm) direct warped beams can be combined & sized to make weaver’s beam. Moreover an additional unwinding frame provides the facilities to size sectional warped beam.

Equipment:

MACHINE DESCRIPTIONTOTAL SIZING M/C : 01SECTION : 01M/C NAME : BENNINGER ZELL SIZING M/C.ORIGIN : GERMANY.MODEL : BEN PROCOMB ZB-20 SWATKECT 4/4/4.R.P.M. : 16-80 m/min.SIZE BOX : 1.BEAM CREEL : 12.VOLTAGE/FREQUENCY : 400V/50HzCONTROLED VILTAGE : 20V/DC.MAIN FUSE : 20 A.WORKING WIDTH : 2200 mm (between the flanges).SIZING BATH : Working Width 2200mm, Roller Width 2400mm, 2 Dip Rolls,

2 high pressure nip rolls with automatic regulation of the squeezing pressure, Size Bath in Stainless Steel, Automatic Size Supply Driven By Handy Mat, Pleva.DRYER : Cylinder dryer type ZT4/4 with 4 Teflon coated drums dia 800mm + 4 drums dia 800mm (possibility for adding 2 more drums), Steam Pressure 3.5-5 bar-147°C,automatic tension regulation by PC, Stainless Steel aspiration top with 2 ventilators. Automatic speed control MAHLO, dry separator, unroll device SWA.

M/C NAME : BEN-SIZEMIX.ORIGIN : GARMANY.CAPACITY : 600 Liter with Temperature regulation.STORAGE TANK : 1.45 Liter.PROCESS : SEMI-AUTOMATIC driven by PCBEN-SIZEMIX (quantity of water, temperature & cooking time).

Main parts Figure:

Main Parts:

1. Creel 2. Pre-Beam3. Feeding r/r4. Guide roller5. Tensioner roller

6. Sizing box

7. Immersion roller8. Sizing roller

9. Squeezing roller

10.Reverse box11.Cooking box 12.Steam pipe 13.Drying cylinder

14.Guide roller15.Moisture Roller16.Tension roller17.Lease rods18.V- reed19.Nipper roller20.Warp beam 21.Pressure roller

Back beam unit: In single end sizing yarns are taken from a creel rather than from a beam. This unit contains 12 carriers from where yarn is supplied. Indirect & direct process of yarn supply is frequently used for spun yarns. In case of indirect method beam creel is used. This beam creel can be arranged in various ways.

Sizing unit: In this unit a size box is used to apply size to the yarn. The warp sheet is guided through the solution means of the immersion roller & then through the squeeze roller where the yarns are pressed to maintain the required size to up percentage by the yarn. The size box temperature is controlled by flowing steam through pipe.

Drying unit: 14 heated cylinders consist of drying unit. This unit is required to dry the wet sized yarn rapidly, thoroughly & uniformly. A two cylinder dryer is too slow & it is difficult to maintain by it. But a multi-cylinder dryer is a good one to main in such a way that after drying. Yarn contains 6% water.

Description:

Cooling unit: In this unit there is cooling fan & a guide roller. The cooling fan supplies cool air which extinguish the yarn temperature & also remove the moisture.

Dividing unit: In order to prevent adhesion between the yarns, it is necessary to separate each sized end from the others. For this lease rod or breaker rods are used to divide the main warp sheet into single end.

Measuring & marketing unit: This unit consists of colouring bowl which contains easily removable colour. This colour is used for making on sized yarn. Also there is a measuring roller which measures the length of sized warp yarn.

Beaming unit: Finally the sized warp is wound on weavers beam.

Description:

Increase in breaking strength:During sizing, adhesive material creates bonds between fibres to fibres which increase the strength of yarn. It increases 20-40% breaking strength of the fibre.

Increase abrasion resistance:After sizing the gap between fibres are filled with size and coating on the outer surface of the yarn take place.

Increase in stiffness:After sizing, flexibility or pliability of yarn is decrease and stiffness is increased.

Increase in elasticity:As extensibility of the sized yarn decrease, more force has to be applied to extent the yarn. Hence elasticity increases.

Technological change due to sizing:

Increase frictional resistance:Application of size materials makes outer surface of the yarn smooth and hence occurs less friction.

Increase yarn diameter:Sizing means coating adhesive on the outer surface of the yarn. Hence sizing causes increase of diameter of yarn.

Decrease in extension:After sizing the gap between the fibre does not occur easily. So the extension decreased.

Decrease in electrostatic charge:Electrostatic charge is formed due to the friction between yarns and roller. Size materials contain moisture which reduces static friction.

Decrease hairiness: During sizing protruding hairs of yarn fix with yarn end so yarn hairiness decreases.

Technological change due to sizing:

Machine Start up:As the m/c is on enter all data/production parameter in the BEN PRECOMB unit at the head stock.Following data is entered-

1. Feed length and doff length.

2. Sizing degree i.e. pick-up%.

3. Tension and stretch over warp in different zone.

4. Drying cylinder temp. in different zone.

1. Sizing spots: Size material should be added gradually to the mixing tank for good mixing. If it is added at once, spots are appeared on the yarn.

2. Repeating warp streaks: This defect is due to uneven tension in the pre beam.

3. Shinnery:This defect due to the friction between the yarn and drying cylinder.

4. Sandy warp:Due to not crushed or grind the size material properly.

5. Ridge beam:This fault occurs due to uneven distribution of yarn in wraith.

Faults of Sizing:

6. Hard sizing:If the size materials are applied too much, the size becomes hard which cause hard sizing.

7. Improper drying:Under drying-Bacteria form-Yarn breakage-over drying-Hard sizing.

8. Size dropping:This defect due to not optimum the viscosity of the size solution.

9. Size stitching:Due to improper drying after sizing.

10. Uneven sizing: Due to over or under sizing. Due to over or under concentration of size liquor.

Faults of Sizing:

Calculation:

Required Chemical &no. of Mixing of Sizing Recipe:

1. Cost of land and machine is high

2. Requires lot of labors

3. Requires utility like gas, electricity etc and their cost is high

4. Cost of ingredients

5. The process is long and it takes time

6. There is a risk of degradation of yarn

7. The yarn diameter is increased

8. Requires robust loom

9. It increases yarn stiffness

10.The fabric needs to be desized before use

11.Need knowledge and information about the size ingredients

12.There is a risk of pollution

13.Sizing changes the shade of colored yarn

14.100% size material cannot be removed

15.Size material presence leads to uneven dying

Disadvantages of Sizing:

The process control programme in sizing should, therefore, comprise of the

following aspects:

1. Selecting the correct size receipe and size pick -up level

2. Ensuring correct preparatio of size paste

3. Control of

- size pick up

- stretch

-moisture content

-quality of beam

-machine speed

-machine efficiency

-a method to calculate the expected level of productivity

Process Control in Sizing