Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Introduction:

Resin & its use in Denim garments industry to create unique & vintage looks which add

value to denim garments & improves it sale ability in market. In 80’s we have seen Resin

being used to give non press , iron free trousers & now we are using in Denims to make

wrinkles & creases to look natural vintage which stays after multiple home laundries.

The present invention relates to processes and methods for treating Denim garments. In

particular, the invention relates to the treatment of denim made of cotton, cotton blends and

synthetic fabrics for the purpose of imparting no press properties thereto. [2]

Wrinkle finishing technique:

A wrinkle, also known as a rhytide, is a fold, ridge or crease in the cloth or garments.

Wrinkle is a particular type of pressure in the finished fabric. It is produced during finishing

operations by the thickness of the seam used to join pieces for processing. Wrinkle

resistance in a fabric is a desirable attribute, but it is not easily measured quantitatively.

Wrinkle resistance varies from quite low in many fabrics to very high in resilient fabrics. In

order to form a wrinkle, a fabric’s wrinkle resistance must be overcome. The fabric may,

however, produce strains and store potential energy that can become evident as wrinkle

recovery under suitable conditions. [1]

We may apply wrinkle finishing by two techniques

1. Tagging on whole garment

2. Pressing on specific area

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Objective of wrinkle finishing technique

1. Fashion and style purpose.

2. Popular design.

3. To create unique & vintage looks by wrinkle finishing which add value to denim

garments & improves its sale ability in market.

4. This requirement of buyer.

5. We get the whole area of the garment or partial or specific area of garment.

Flow chart of wrinkle finishing

Apparel

Apply resin

Pressing/ Clamping

Curing

Unload

Finishing

Using chemicals, Machine, Equipment & Raw material:

Material used: Resin

Machine or equipments used: Pressing machine, clip, industrial oven

for curing

Apparel types: Woven (pant/shirt) and knit (T-shirt) both

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Typical Resin treatment process for Non denim garments for Durable Press

finish:

Let’s talk about wrinkle free, durable press or crease free finish on non denim trousers. A

variety of techniques and additives have been suggested for use in the treatment of cotton

fabrics to obtain durable press properties. A typical process suggests the use of a low-

formaldehyde glyoxal resin (10%), a non-ionic wetting agent (0.2%), an amino functional

silicone (3%), a polyethylene emulsion (2%), and acetic acid to maintain pH in aqueous

solution wherein water comprises the remaining 84%. Then load the machine with the

garments prior to the addition of the liquid mix components. Once the mixture components

are added, the garments are allowed to soak for between six and ten minutes without

agitation. The offload & do hydro extract & semi dry. [2]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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[3]

Merit & Demerit of different resin application

Merit:

By applying resin on the garments to create creases in the clothing were creases are

wanted such as pant legs and sleeves on shirts.

Press clothing to create creases where wanted;

By oven curing it make cross link and create the wrinkle properties on garments.

It prevents the intermolecular slippage in the fiber core.

If we use formaldehyde free resin, it may not harmful

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Demerit:

It decreases the tensile & tear strength

It decrease the abrasion resistance

It gives an unpleasant odor

It gives unwanted harsh & stiff feel

It turns the fabric yellow after chlorine bleaching

Some time difficult to remove unfixed resin

The amount of time required to reach the target moisture level will depend on the weight of

the fabric, the temperature of the dryer, the duration of the drying cycle, and the extent to

which the garments are tumbled. However, it is important to keep the drying temperature

below a temperature which will cause the resin to set. [2]

Once the garments have been dried to the proper moisture level, they are ready for the

pressing and final cure steps. It is important to press and finally cure the garments without

substantial delay, i.e. delay of more than approximately 12 to 24 hours, depending upon the

weight of the fabric comprising the garments. Denim fabrics can be held between the drying

and the pressing steps longer than lighter weight fabrics, because they tend to more readily

retain moisture. Pressing of the garments in accordance with the present invention is done

with a garment press capable of exerting a vacuum on the garment through the lower plate

of the press. Initially, the garments are positioned with the aid of a vacuum to eliminate

wrinkles and they are subsequently subjected to a steam treatment for approximately five

seconds with the vacuum turned off. Steam is then applied to the garment through the top

plate of the press for approximately 5 seconds. Finally, the garments be pressed for non

denim to get wrinkle free, durable press finish or crunched for denim where ever 3D effect

needed and cured. [2]

The current technology of post cure being introduced for non denim garments process gives

an option to produce a garment with smooth drying and wrinkle resistant properties along

with sharp creases that are durable for the life of the garment. In this process the resin

is padded onto the fabric and dried at low temperature. The fabric is then cut,

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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garment constructed and creases pressed into the garment. A high temperature cure in this

configuration is given to cross-link the resin. This process, though giving excellent results,

has not been too successful with garment manufacturers owing to obvious limitations of

colors, styles and fabric weight, and the need for a direct interface between mills, garment

manufacturers and retailers. [2]

Chemicals being added to process & its functions

The non ionic wetting agent reduced surface tension of the fiber & allows chemical

penetration, so cross linking can take place throughout the fiber cross-section. A high

density polyethylene restores some of the lost tear strength and abrasion resistance by

providing lubrication. It also has a synergetic effect with silicone or fatty-based softeners to

improve hand feel. Among the silicone softeners, amino functional or reactive polysiloxanies

with silanol functional end-groups act as elastomeric finishes imparting higher crease

resistance, good dimensional stability and excellent soft handle. They can also reduce free

formaldehyde release by replacing part of the resin. [2]

Above processes and methods provides a commercially practicable method for imparting

durable press characteristics to fabrics containing cotton. Garments treated by the methods

set forth herein may be made to have durable press and softness characteristics which are

both superior and consistent from batch to batch and maintaining an acceptable level of

garment wear and durability [2]

Description

The wrinkle free finish is being done by cross-linking cotton. Permanent press finishes

function by forming cross-links between adjacent cellulose polymer chains. Then cross-

linked cotton does not allow fibers to shrink & thus wrinkles will not form. In todays’s world

DMDHEU- Di methyl Di hydroxyl Ethylene Urea is the main cross-linking agent.

With magnesium chloride as the acid catalyst to initiate a reaction, it forms cross links in the

amorphous regions of the fiber.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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There are many modified version of DHDHEU’s are available in market as tailor made

products, easy to use & with low formaldehyde. Formaldehyde release is always a big issue &

it may cause cancer to human body. Hence internationally free formaldehyde parameter

being set up to maximum 75 PPM. There are new inventions/ research being done

with no formaldehyde resin application but somehow or other it’s not so

popular either they are not as durable as resin or very high in cost to use in mass

production.

How Resin works:

Resins work by reacting the nitrogen atoms of each resin molecule with the hydroxyl group

of the cotton fabric. The reaction forms a linkage between the resin and the cotton fibers

giving the cotton on shrink pattern in which shape is being made & cured.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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[5]

Resin cross linking with cellulosic fiber

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Resins being cures in acidic pH with particular heat & temperatures. To maintain pH

catalysts can be used, as these are salts of acid. Oven curing is needed to reach right

temperature ( 145 – 160 C ) & time ( 7 – 22 min ) as per Resin tech bulletin advice.

Fabric strength loss may results up to 50 percent& it completely depends on fabric

weight, construction & fiber content. Shade change also occurs due to resin cross linking.[2]

There are two types of wrinkle process:

1. Permanent Wrinkle Process

2. Overall Wrinkle Process

1. Permanent Wrinkle Process:

Generally permanent wrinkle is doing on garments after all types of wet process wash

in dry position.

Permanent wrinkle is done on the garments made from all types of fabrics like,

Denim, Twill,

Canvas, Poplin, Corduroy, Knit & Polyester etc.

For permanent wrinkle we are use resin which is spray on garments

particular/specific area by nozzle.

Resin is diluted with water which is recommended by chemical supplier, generally

20% resin& 80% water.

After resin spray on respective area, then fold by buyer demand and clip attached

upon the folding area.

Now hangers the garment in to the hanger trolley, Trolley capacity approx. 80-100

pcs garments.

Then trolley with resin treatment garments put inside the Industrial oven.

Set temperature 140°c to 160°c, Time 20-40 minutes (if folding layer is less,

Less time required, if folding Layer is more, more time is required).

Start the machine.

When setting time is over, machines are automatically off.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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After heating time over garments with hanger will stay 10 minutes for cold in oven.

Now open the door and trolley with garment out from oven.

Open the clip from garment and go to quality section for quality checking & delivery.

[1]

2. Overall Wrinkle Process:

Generally overall wrinkle is doing on garments after all types of wet process & dry

process.

Overall wrinkle is done on the garment made from all types of fabrics like, Denim,

Twill,

Canvas, Poplin, Corduroy, Knit, Polyester, Viscose & Nylon etc.

Now tie the whole garment in tight position by thread.

For overall wrinkle, we are used resin in washing machine with water and run tied

garments for 5 to 10 minutes at 50°c temperature.

Then unload the garments from washing machine to trolley for hydro extractor to

remove the excess water.

Open the tie or cut the thread.

Now hanger the garments into the hanger trolley. Trolley capacity appreciates 80-100

pcs garments.

Then trolley with resin treatment garments put inside the Industrial oven.

Set temperature 140°c to 160°c, Time 50-70 minutes.

Start the machine.

When setting time is over, machines are automatically off.

After heating time over garments with hanger will stay 10 minutes for cold in oven.

Now open the door and trolley with garments out from oven and go to quality section,

checking& delivery. [1]

Methods of applying Resin on the denim garments

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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The major application methods currently used are based on the following processes:

garment-dip; spray application.

In the garment-dip method, garments are constructed from non-resinated fabric, then

impregnated with a resin formula similar to that used in the non denim garments process,

extracted to about 65 per cent wet pick-up and then tumble dried to 8-10 percent moisture

content, a critical factor that is determined using a moisture meter.[2]

In the spray method is a latest technology of wrinkle finishing, the resin is applied

by spraying it onto the garment during tumbling in an enclosed rotational device, or on

spray booth where garments being hanged to inflated balloons & sprayed a measured

quantity of resin solution. A microprocessor is used to meter the exact amount of chemicals

and to control the rotation time, desired wet pick-up, spray rate and process time. The

garments are then treated for different 3D effects, crunched or whatever designed intended

to produce, used for both menswear and women swear with the market moving towards

washed-down looks and softer handles.

Parameters to be considered while choosing denim

fabric for Resin finish

The garment finisher usually does not manufacture his own fabric and he may be faced with

unacceptable losses in tensile strength, tear strength and abrasion resistance in the fabric

when cross-linking. Because of the added value, garments rejects due to low strength may

prove to be more expensive than fabric rejects.

For producing an acceptable 3D effects Denim, several precautions must be taken in

fabric selection:

The base fabric must have sufficient strength to withstand 40-60 per cent

loss in tensile and tear strength and still maintain sufficient strength to

provide a garment of acceptable wear life and durability

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It must also have excellent absorbency to allow resin to penetrate into the

very interior of the fibres and form crosslink’s. Surface adhering resins do not

serve any useful purpose and are inefficient and wasteful

If the fabric is dyed the dye must be fast to acid catalysis and high

temperatures. Sulphur dyes, which are known to generate acid upon storage,

are to be strictly avoided & Lycra/Spandex based fabric also should be tested

on elongation before mass production.

Residual extractable on the fabric (like starch from size) can react with resin

and lower its effectiveness, a high degree of size removal is thus essential

Fabric pH should be between 6.5 to 7.0.

Selection of machinery & Oven(Curing)

Many aspects must be considered when choosing the technology; type or product (Tops &

Bottoms), process, time, temperature, 3D, and chemicals.

For high quality 3D crunching / whiskers, the two most important criteria are

temperature and control of cycle. Presses should be equipped with high-heat, cast aluminum

heads or with supplementary electrical heaters to give a processing temperature of

approximately 150 – 180 degree centigrade. This temperature is crucial as it starts the

curing process and controls the effects.

There are various types of 3D making equipments available in the market i.e. Wire crinkle,

Decca/crunching machines, then aluminum flex pipes & also manmade leg hangers on

which natural 3D effects being carried out.

While selecting an Oven, garment manufacturer must analyze their products to be produced,

place/space & capacity of production accordingly they can choose from medium to big size

of batch or continuous oven which is readily available with many machinery producers.

Curing is the process to place the fabric/garment at high temperature for allowing the

chemical to carry out the reaction process. Curing is usually used for fixation process. The

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cross linking of the resin is usually taken at constant high temperature for minutes. During

curing process, the surface temperature of the fabric is critical.

A tunnel oven is faster but requires a certain amount of garment preparation and a

material handling system to and from the tunnel. Air flow pattern in these ovens controls

temperature fluctuations, movement of the garment and effect formation and is therefore

the most important selection criteria. The air velocity is finally controlled, in as much that

temperature fluctuation has been brought down to a remarkable 3 degree Centigrade over a

single garment. Developments are also underway to perfect microwave curing technology.

As against normal convection curing, the temperature rise in microwave ovens is expected to

be quicker, uniform throughout the fiber cross section, and to give minimum damage to the

fiber.

There are many Resin suppliers available in the market & they sell their products in

combination of their own recipe & even they are expert enough to suggest you right resin

combinations for your denim garments to get unique look with low formaldehyde.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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Using resin on garments is only one major danger is leaching of free formaldehyde if resin is

not cured properly due to any parameters being ignored in a process i.e. Temperature and

time.

Hence for dealing with resin application skilled man power is pre requisite.[2]

Conclusion:

The scope of apparel wrinkle finishing is very broad, especially for denim. Only innovation

products will be able to open up new market and new horizons denim industry. Resin being

used to give non press , iron free trousers & now we are using in Denims to make wrinkles &

creases to look natural vintage which stays after multiple home laundries. Customers today

have a wide range of choices and the one who produces the best quality at a high competitive

price will survive and prosper. [4] Wrinkle finishing on apparel is an innovative and

enhanced result, which is giving a vintage look. Every washing factory now produces best

and distinct apparel.

Reference:

1. http://textilelearner.blogspot.com/2012/07/what-is-wrinkle-permanent-

wrinkle.html#ixzz3SSVgq9e8

2. http://www.denimsandjeans.com/denim/manufacturing-process/resin-treatments-

giving-value-addition-to-vintage-denim-garments/#comment-7493

3. http://www.slideshare.net/legendbd71/dry-washing-on-denim

4. http://www.dry-washing-on-denim-25-638

5. Thesis on a study of the resin finishing on wrinkle property of light weight 100% cotton

plain fabric by Ho long yi.