Wet Processing Of Garment: Some Facts

Northern India Textile Research Association, Sector-23, Rajnagar, Ghaziabad, U.P

Garment dyeing is gaining ground more rapidly as it fulfills the requirement of fashion-oriented customer instantaneously. Beside this it reduces the lead times and excess inventory significantly. In addition, it can be used as a method for short lot dyeing, where basic shades are supplemented with fashion shades.

In India most of the Garment industries is in unorganized sector. This sector is far behind the international standards in productivity and quality. The important reasons of legging behind of this sector are listed below:

1.Non- availability of qualified and trained operators/supervisors

2.Absence of quality control activities

3.Application of sub standard dyes and chemical auxiliaries

4.Lack of sophistication in the technology used in wet processing

Non- availability of qualified and trained operators/supervisors:

The problem related to non-availability of qualified and trained operators/ supervisors can be by resolved by recruiting suitable personnel. Keeping in mind the requirement of garment wet processors, NITRA has started a full time diploma course in garment dyeing and finishing. The Diploma holders are fully trained in garment wet processing.

Absence of quality control activities:

The absence of proper quality control in-house activities is the main reason, which affect the quality of the dyed and finished garment. Now the buyer is very quality conscious. To fulfill the quality requirement of the buyer it requires adopting stringent quality control standard in the dyeing and finishing. A few of the quality parameters/ problems which generally affect the quality of the buyer/ user ends are poor colour fastness properties in various agencies like washing, light, crocking etc., staining, tendering, yellowness and improper finishing effect. These problems may lead to rejection of whole lot. To check these problems following points should be taken in to accounts:

Carefully read the instruction given by the buyers related to quality parameters and standard to be followed i.e whether it is American standard or ISO standards etc. If there is no clear instruction it is always better to clarify the same before going to take assignment. Each standard is having its separate conditions. If sample is passed in one standard, it is not sure that it will also pass in another standards also.

During the desizing operation of the garments, it is always advised to check whether the sizing chemicals removed from the garment or not. A simple iodine test will be sufficient for this purpose. If the blue colour with iodine is indicated, it shows that sizing material is still present and desizing of the garment is not proper.

Check the absorbency of the garment before dyeing. If the absorbency of the garment is not proper, no uniform shade is obtained. A simple method to test the absorbency is to take out garment before few minutes of completion of scouring process, dry it and test the absorbency by drop test method. If the drop of water is absorbed within 5 seconds, one can say that the garment absorbency would be fine.

After pretreatment, before dyeing, dyer should be sure that garment is having neutral pH. This can be checked by pH paper.

Before dyeing, it is advisable to test the hardness of water. If the water hardness is very high it may hinder uniform dyeing of the garment. Now-a- days a simple kit is available to do testing of hardness of water. Generally the water hardness should be 0 to 5 ppm. If it is high, sequestering agent may be used.

Proper class of dyes should be selected as per the instruction of buyers and before going to dyeing operation, Garment dyers should read carefully the shade card of dyes to know the fastness properties of the dye and the dyeing instructions.

It has been seen that some time Garment dyers not washed/neutralized the garment properly after dyeing to save time and money. Avoiding this essential step some time create big problem among the fabric supplier, dyer and the buyer. If the fabric is not properly neutralized, it may have acidic or alkaline pH. If the fabric is having acidic pH, it may react with metal part of the button and may produce stains. Improper washing/neutralization some time produces tendering (degradation of fabric strength) effect in the garment.

Application of sub standard dyes and chemical auxiliaries:

The use of substandard dyes and chemical auxiliaries affect quality of garment adversely. Here also the good quality control activities can check this problem. This will not only improve upon quality but also impose proper check on the dyes and chemical auxiliaries supplier.

Lack of sophistication in the technology used in wet processing:

In India very old technologies are being used for wet processing of garments. Due to old technology garment processors are not getting production as per the international standards. Beside these buyers now wants more functions in the garments, which is not possible in the old wet processing technologies. Another draw back of old technology is that it uses huge quantity of water to process the garments. The availability of water require for wet processing is reducing day by day. If the water consumption is high in the wet processing, it will generate more effluent. Now pollution boards have set stringent norms for releasing effluent in the drain. Due to this the treatment cost of the effluent will be more.

With the rapid change in international scenario, it is the need of today to go for technology advancement in the garment dyeing and finishing. Now the buyer may wants different functions in the garments, which may not be fulfilled by the single machine. Therefore it is the requirement to have machines, which can perform various functions and integrated with information technology to deliver higher production at lower cost. A few of the new development in the in the garment dyeing machine are given below:

Facility to operate ambient temperature to 135oC so polyester blended garments can also be dyed in such type of machines.
Incorporated with hydro-extraction device
Reduce water consumption
Excellent energy saving capacity
Automatic electro pneumatic balancing with total vibration absorption, which means that foundations are not required
Microprocessor based operating system to better control on process parameters

Variable drum speed starting 1 rpm to the maximum inverter regulated spin speed
Very fast operation and no feed for handling during the garment-unloading phase
Possibility of applying easy and economic automation and robotic function during loading/unloading stage
Very fast loading times

Innovation in Garment finishing:

There are numerous reasons to add value to a product. The most obvious are to revitalize sales, achieve a premium price and differentiate the product from the plethora of others in the market. Less obvious but equally as important retailers and leading brand labels see unique products as one of the best ways to expand and diversify their line.

The development of unique fabric and garment finishes comes with a host of challenges. Finishes must be durable during the fabric finishing process; stable in the presence of other chemicals; wash-fast and evenly and consistently applied. Finishes also need to be financially feasible and environmentally friendly.

Micro encapsulation is one of the latest technologies used to impart an array of unique characteristics to a garment. Particles filled with active ingredients are applied to the fabric or garments for long lasting effects.

Micro encapsulated particles are anchored onto the fiber. As the wearer moves, the capsules are activated producing a slow release of the active ingredient. Active ingredients run the gamut including moisturizers, aloe, vitamin E, therapeutic smells and insect repellent.

Recent development on creating fading effect on denim garment by Ozone is in progress. In this method only ozone gas is used for fading denim thus paving the way of saving huge amount of water and energy utilized in the conventional denim finishing/fading operations.

About the author:

Dr. M. S. Parmar is presently heading two Departments - Research & Product development and Chemical Quality Evaluation Divisions. He has 16 years experience in Chemical Processing and Quality Control of textiles and garments. He has worked on various R&D projects related to chemical processing, Denim processing, Hosiery, Enzymatic processing, Natural coloured cotton, Organic cotton, Milkweed fibres etc.

He is a co-Author of a Book on Denim and authored two books, one in dyeing, printing and finishing and other in Knitting. His 40 Papers are published in various National and International Journals and presented 30 papers in conferences.

Neha Sharma has received her Master's Degree in Textiles & Clothing from Delhi University. She had worked as a lecturer in a Post Graduate College at ModiNagar. Presently working as a Research Associate, looking after activities of Garment Dyeing Dry-Cleaning & Finishing Technology program. Beside this also involved in various courses offered by Northern India Textile & Research Association. She has jointly prepared series of booklets (TABLETS) on various topics like care labeling, zippers, sewing of knits, stains, quality assurance in apparel manufacturing etc .She has credit no. of published papers in various journals/magazines.

Source: NITRA Email : nitra@vsnl.com