Topics

61

Textile Engineering / About Sincerity of Garments Worker

« on: January 12, 2017, 10:08:10 AM »

How many workers are sincere in a compliant and Non compliant industry? Please mention the percentage and if possible justify your opinion.

62

Textile Engineering / Wal-Mart sued over fake Egyptian cotton

« on: November 17, 2016, 11:24:11 AM »

Leading US retail giant Wal-Mart is being sued by a group of consumers who claim the company continued to sell products falsely labelled as having been made with 100 per cent Egyptian Cotton from Indian textile business Welspun India for many years after it first became suspicious of their origin. The plaintiff, Dorothy Monahan of Michigan, claims Wal-Mart questioned the fibre content of Welspun India products as early as 2008, but waited until only recently to stop sales of its incorrectly labelled Egyptian cotton bed linens. If the action is successful it potentially paves the way for further, similar actions in the textile market and places the onus firmly on retailers to prove that the cotton they use in their products is correctly labelled with regards to origin.

------- Brett Mathews, Ecotextile,Published on Thursday, 10 November 2016

63

Textile Engineering / Printing Ingredients

« on: November 13, 2016, 02:59:28 PM »

1.   Dyes/Pigments
2.   Wetting agent.
3.   Thickener
4.   Solvents/dispersing agent
5.   Defoaming agent
6.   Oxidizing and reducing agent.
7.   Catalyst and oxygen carrier.
8.   Acid and alkalis
9.   Carrier and swelling agents.
10.   Miscellaneous agents

64

Textile Engineering / Steps in Textile Printing

« on: November 13, 2016, 02:58:48 PM »

Grey textiles / Raw materials

Preparation of textile materials (singeing, desizing, bleaching, scouring etc)

Preparation of printing paste

Printing (with a certain style and method)

Drying of the printed fabric (in the drier)

Steaming of the printed fabric
(To transfer dye into fiber, 100-1020 C, 15 min in a steamer)

After treatment (Soaping of washing)

65

Textile Engineering / Dyeing mechanism of reactive dye

« on: November 20, 2014, 08:21:51 PM »

The dyeing mechanism of material with reactive dye takes place in 3 stages:-
1.   Exhaustion of dye in presence of electrolyte or dye absorption.
2.   Fixation under the influence of alkali.
3.   wash-off the unfixed dye from material surface.

66

Textile Engineering / Stripping

« on: November 20, 2014, 08:21:01 PM »

Stripping becomes necessary when uneven dyeing occurs. By stripping azo groups (-N=N-) brom the dye is removed.
I) Partial stripping methods:
Partial stripping is obtained by treating the dyed fabric with dilute acetic acid or formic acid. The commanded conc. is betn 5 to 10 parts glacial aid or 2.5 –10 parts of formic acid per 1000 parts of water
Recipe: Glacial acetic acid = 5 – 10 parts
   Water   --> 1000 parts
   OR
   Formic acid   --> 2.5 to 10 parts
   Water   --> 1000 parts
   Temp   --> 70-100oC
   Time   --> Until the desired shade is obtained.
Process- The goods are entered and temp is raise to 70-100oC and the treatment is continued until the shade has been reduced to the desired amount thoroughly washing is then necessary to remove the products of hydrolysis.
II) Full stripping:
For complete stripping, the goods are firstly treated with Na2S2O4 Sodium hydrosulfite at boil. Then treatment is done at room temperature for 30 min.

67

Textile Engineering / Hydrolysis of Reactive Dye

« on: November 20, 2014, 08:18:59 PM »

Under alkaline condition, Reactive dyes react with the terminal hydroxyl group of cellulose. But if the soln of the dye is kept for long time, its concentration drops. Then the dye reacts with the hydroxyl group of water. The reaction of dye with water is called Hydrolysis of reactive dye.

68

Textile Engineering / Reactive Dye: Why so called?

« on: November 20, 2014, 08:15:52 PM »

Reactive dyes react with the fibers.
   Mainly react with cellulosic fibers
   e.g. cotton, jute, bast fibers, viscose, flax
It can be applied to protein fibers e.g. wool & silk.
Reactive dye contains reactive group and this reactive group makes covalent bonds with the fibers and becomes part of the fiber.
The general formula of Reactive dye can be written as follows:
D-X-Y
Here    D --> Chromophore of Dye post
   X --> Bridge
   Y --> Functional group
D-X-Y + Fiber --> D-X-Y-Fiber Covalent bond.
Reactive dyes water soluble
D-F + Cell-OH --> Dye-F-O-cell   F = Functional group
D-F + H-OH --> Dye-F-OH
         Hydrolysis

69

Textile Engineering / Why is 4-point system so called?

« on: June 09, 2014, 12:54:03 AM »

In this system the maximum penalty point for a fault is 4. for this reason this system is called 4-point system

70

Textile Engineering / Absorbency Test for Evaluation of Scouring

« on: June 09, 2014, 12:50:33 AM »

There are 3 types of absorbency test:

1. Immersion Test
2. Drop Test
3. Wicking Test or Stripe Test

71

Textile Engineering / Rectifying Inspection Plan

« on: June 09, 2014, 12:47:52 AM »

There are two types of rectifying plan:
1. Single Sampling Plan
2. Double Sampling Plan

72

Textile Engineering / Natural Dye

« on: June 09, 2014, 12:45:36 AM »

Pls Share your knowledge about sources of natural dye...................................

73

Textile Engineering / The 4 special inspection levels

« on: June 09, 2014, 12:42:35 AM »

These special levels can be applied in cases where only very few samples can be checked. "Four additional special levels, S-1, S-2, S-3 and S-4 […] may be used where relatively small sample sizes are necessary and larger sampling risks can be tolerated."
Under S-3 level, the number of samples to check is lower than under S-4, and so on.
 
In practice: for consumer goods, quality control is usually performed under the general levels.
The special levels are used only for certain tests that either take lots of time or destroy the samples. Another situation where special levels are appropriate is a container-loading supervision--to have an idea of what is inside the cartons, without spending too much time at that checking.

74

Textile Engineering / The 3 general inspection levels

« on: June 09, 2014, 12:41:30 AM »

Level I
Has this supplier passed most previous inspections? Do you feel confident in their products quality? Instead of doing no quality control, buyers can check less samples by opting for a level-I inspection.
However, settling on this level by default, in order to spend less time/money on inspections, is very risky. The likelihood of finding quality problems is lower than generally recommended.
 
Level II
It is the most widely used inspection level, to be used by default.
Level III
If a supplier recently had quality problems, this level is appropriate. More samples are inspected, and a batch of products will (most probably) be rejected if it is below the quality criteria defined by the buyer.
Some buyers prefer level-III inspections for high-value products. It can also be interesting for small quantities, where the inspection would take only one day whatever the level chosen.

75

Textile Engineering / Why different inspection levels?

« on: June 09, 2014, 12:38:53 AM »

There is a fairly obvious principle in statistical quality control: the greater the order quantity, the higher the number of samples to check.
But should the number of samples ONLY depend on the order quantity? What if this factory had many quality problems recently, and you suspect there are many defects? In this case, you might want more products to be checked.
On the other hand, if an inspection requires tests that end up in product destruction, shouldn't the sample size be drastically reduced? And if the quality issues are always present on all the products of a given batch (for reasons inherent to processes at work), why not check only a few samples?
For these reasons, different levels are proposed by MIL-STD 105 E (the widely recognized standard for statistical quality control).
 
It is usually the buyer's responsibility to choose the inspection level--more samples to check means more chances to reject bad products when they are bad, but it also means more days (and dollars) spent in inspection.