Dyeing Lab

MD.Khairul Bashar

Dyeing Lab

Physical Testing

Lab Dip/Chemical Tests

Mechanical

Physical Tests

» GSM» Fiber Diameter» Ends per inch» Linear Density

Chemical

» PCP» Blend composition» Identification of Fiber» Identification of Dyes» Solvent Extractable matter» Chloride Content» Sulphate Content» pH value of water extract» Moisture Content» Shrinkage to Water» Colour Fastness Tests

Mechanical

» Tensile Strength and Elongation» Breaking Strength» Bursting Strength of Paper» Tear Strength» Elmendorff Tear Strength» Air permeability of Paper» Pilling Test» Dry and Wet Rubbing (Crock Meter)» Ether Soluble Matter» Water Absorbency» Lead and its compounds» Scouring loss» Flammability

Generally some Testing here

Dimensional Stability to washing(Shrinkage)

Spirality/Twisting

Colorfastness to washing

Colorfastness to Water

Colorfastness to Perspiration

Colorfastness to Rubbing/Crocking

Colorfastness to Saliva

Colorfastness to Actual Laundering

Print Durability

Other Tests (please secify)

Fabric Weight

Thread Count

Pilling Resistance

PH Test

Yarn Appearance

Yarn Count

Quality Control TestingBroad range of testing facilities are available for finished products, materials

or components based on defined standards, regulations and customer's

requirements.

Standard Methods adopted

» American Society of Testing &Materials (ASTM)» American Association of Textile Chemists and Colorists (AATCC)» International Organization for Standardization (ISO)» European Norms (EN)» British Standards (BS)» British Standards for European Nations (BSEN)» Deutsches Institut fur Normung (DIN)» Japanese Industrial Standards (JIS)» Bureau of Indian Standards (BIS)

Shrinkage test Method

Shrinkage:Shrinkage is the process in which a fabric becomes smaller than its original size, usually through the process of laundry. Cotton fabric suffers from two main disadvantages of shrinking and creasing during subsequent washing.

There are two types of shrinkage occurs during washing

1) Length wise2) Width wise

Shrinkage % = (length of fabric before wash)-(length of fabric after wash))/ (length of fabric before wash) *100

Example:For Length,length of fabric before wash=55 cmlength of fabric after wash=52 cm

So, Shrinkage % = 55-52=3/55*100%=5.45 %

For Width,Width of fabric before wash=36 cmWidth of fabric after wash=35cm

So , Shrinkage % = 36-35=1/36*100%=2.77%

Here, Shrinkage is 5.45%. Normally shrinkage is acceptable less than 5%. But itCan Be change in case of buyer requirement.

DYEING LAB DEPARTMENT CALCULATION AND OTHERS

Lab dip is small swatch of fabric to define color and its recipe before it goes for bulk dyeing. Developing Lab dip is one of the primary jobs for a merchandiser to start an order execution. Lab dip is very important for dying factory. Because bulk production order depends on lab dips. Besides, lab dip plays an important role in shade matching & this is an important task before bulk production.

Lab Dip:

Lab dip is a process by which buyers supplied swatch is matched with the varying dyes percentage in the laboratory with or without help of “DATA COLOR”

Lab dip plays an important role in shade matching & and detaching the characteristics of the dyes and chemicals are to be used in the large scale of production. So this is an important task before bulk production.

Recipe preparation in lab dip

Common Stock Solutions:1. Red – 0.1%, 0.5%, 1.0%, 2.0% (very common)2. Yellow – 0.1%, 0.5%, 1.0%, 2.0% (very common)3. Blue – 0.1%, 0.5%, 1.0%, 2.0% (very common).

Preparation:i. To prepare 0.1% Stock solution, it is necessary to mix 0.1 g dye and 100

cc water.ii. To prepare 0.5% Stock solution, 0.5 g dye stuff is mixed with 100 cc

water.iii. To prepare 1.0% & 2.0% Stock solution similar procedure is followed.iv. To prepare 10% Stock solution of Soda ash, 10 g Soda is mixed with 100

cc water.Depth of Shade:0.5% to 5% shade for the goods.

Lab Dip Calculation :Usually following calculations are followed:

Dye Solution = (Shade % * Sample Weight) / (Stock solution %) (cc).Salt = (Shade % * Liquor) / 1000 (gram per liter, gpl).Soda Solution = (Shade % * 100 * Liquor) / (1000 * Stock solution %) (cc).

Sample Calculation for 0.5% Shade:Sample wt. = 5 mgMaterial liquor ratio = 1: 10Total liquor (5 * 10) = 50 ccDye solution required = (5 * 0.5%) / 1% = 2.5 ccSalt solution required = (50 * 25) / (20 * 10) = 6.25 ccSoda ash solution required = (50 * 10) / (20 * 10) = 2.5 ccWater required {50 – (2.5 + 6.25 + 2.5)} = 38.75 cc

Lab Dip:A lab dip is a swatch of fabric test dyed to hit a colorstandard. It is a process by which buyer’s suppliedswatch is matched with the varying dyes percentagein the laboratory with or without helpof spectrophotometer. Lab dip plays an importantrole in shade matching & this is an important taskbefore bulk production. In previous article of thisauthor we have to learn on flow chart on dyeinglab.

Objectives:

1. The main objectives in lab dip are as follows:

2. To calculate the recipe for sample dyeing.

3. To compare dyed sample with swatch by light Box or Spectrophotometer.

4. To calculate revise recipe for sample dyeing.

5. Finally approved Lab Dip (Grade: A, B, C & D)

Process Sequence of Lab Dip:

Lab Dip Requisition from buyer↓

Entry in the computer↓

First recipe is given by swatch/pantone number↓

First correction↓

Second correction↓

Grading of sample (A, B, C, D)↓

Yarn and knit sample send to buyer↓

Approved by buyer↓

Order for bulk production↓

Production card with approved sample and recipe send to production section.

Referance:

Lab, Book, Internet, etc.