Antimicrobial Finishing on Apparels

Azmir Latif

Antimicrobial

AM means preventing or inhibits the growth of microorganisms or microbes

Antimicrobial agent

Any chemical which kills or

inhibits

the growth of microorganisms / microbes is known as AA

OBJECTIVES OF AM FINISHING

1. Preventing cross infection by microorganism

2. Reducing the formation of odour by protecting metabolism of microbes

3. For safeguard of apparel and textile products from staining, discoloration and quality deterioration

4. Protecting performance of apparels

Microbes cause cross infection

by microorganism and development odour

where the apparel is worn next to skin.

In addition, the staining and loss of the performance

properties of textile substrates are the results of

microbial attack.

WHY AM FINISHING FOR APPARELS

  The inherent properties of the textile fibres provide room for the growth

of micro organisms. Besides, the chemical processes may induce the growth of microbes. Humid and warm environment still aggravate the problem.

Apparels (like undergarments, sportswear, etc), medical bedding

mattresses & covers need antimicrobial finish.

Again, the consumers are now increasingly aware of the hygienic life styles and there is a necessity for a wide range of apparel products finished with advanced technological antimicrobial finishes.

WHAT ARE MICROBES ?

A variety of micro organisms like bacteria, fungi, algae and viruses. Microbes are the tiniest creatures not seen by the naked eye.

Bacteria are unicellular organisms, which grow very rapidly under warmth and moisture.

Sub divisions in the bacteria family are Gram positive (Staphylococcus aureus), Gram negative (E-Coli), spore bearing or non-spore bearing type.

Some specific types of bacteria are pathogenic and cause cross infection.

MICROBES

Fungi, molds or mildew are complex organisms with slow growth rate.

They stain the apparel fabric and deteriorate the performance properties of the apparel fabrics.

Algae are typical micro organisms, which are either fungal or bacterial. Algae require continuous sources of water and sunlight to grow and develop darker stains on the fabrics.

Dust mites are eight legged creatures and occupy the household textiles such as blankets bed, pillows, mattresses and carpets.

The dust mites feed on human skin cells and liberated waste products can cause allergic reactions and respiratory disorders.

Related Terms

1. Antibacterial agent :

Any chemical which kills bacteria (bactericide) or interferes with the multiplication, growth or activity of bacteria (bacteriostat).

2. Antifungal agent :

Any chemical which kills or inhibits the growth of fungi.

3. Antimicrobial Activity :

A measure of effectiveness of an antimicrobial agent.

.

Terms

4. Bacterial resistance :

Resistance to the development of bacterial growth

and accompanying odors, resulting from bacterial degradation

of fibres.

5. Mildew resistance :

Resistance to the development of unsightly fungal growths

and accompanying unpleasant, musty odors on materials.

.

Methods of AM Finishing 

The antimicrobial agents can be applied to the apparel and textile substrates by-

1. Exhaust

2. Pad-dry-cure 3. Coating

4. Spray and 5. Foam techniques

The substances can also be applied by directly adding into the fibre spinning

dope or can be applied during the dyeing and finishing operations.

 

Applying Techniques of AM Finishes  

(1) Treating with resin coating on apparel surface, or

(2) Cross-linking on apparel surface, or

(3) Use of graft polymers, or co-polymerization

(4) Chemical modification of the apparel fabric

(5) Micro encapsulation of the antimicrobial agents with the fibre matrix  

 

Commercial Antimicrobial Agents   

Ciba markets Tinosan AM 110 as a durable antimicrobial agent for

textiles made of polyester and polyamide fibres and their blends with cotton, wool or other fibres.

Tinosan contains an active antimicrobial (2, 4, 4'-Trichloro-2' - hydroxyl-dipenylether) which behaves like a colorless disperse dye and can be exhausted at a very high exhaustion rate on to polyester and polyamide fibres when added to the dye bath.

Clariant markets the Sanitised range of Sanitized AG, Switzerland for the hygienic finish of both natural and synthetic fibres. The branded Sanitised range function as a highly effective bacteriostatic and fungistatic finishes and can be applied to textile materials such as ladies hosiery and tights.  

 

 

 

 

Durability of Antimicrobial Apparels  

Temporary antimicrobial properties in apparels are easy to achieve in finishing but readily lost in laundering. Temporary antimicrobial textiles are useful only for disposable materials.

Durable antimicrobial function is quite challenging to achieve and can last more than 50 machine washes. 

 

Evaluation of AM Finishes  

Methods for evaluating or determining the effectiveness of

antimicrobial finishes can be divided into two types:

1. Quantitative and

2. Qualitative

In quantitative method, the number of bacteria, still living after an opportune contact time, is counted.

In both the quantitative and qualitative tests, it is essential to measure the bioactivity of a reference control sample without antimicrobial properties.

 

Where Can be Applied-1  

Sportswear/leisurewear/workwear:

To prevent bad odour produced by the bacterial decomposition of sweat and other body fluids.

Undergarments :

To control the growth of bacteria which thrive on suitable body temperature and moisture conditions, leading to skin diseases.

 

Applied-2  

Socks:

To make them free from unpleasant odour by controlling the growth of microbes.

Shoes: To avoid shoe odour and the stains on the shoelaces caused by bacterial growth, especially in rainy season.

Textiles in Museums:

To preserve textile monuments from microbial attack. 

 

Applied-3  

Sized Fabrics : To protect microbial growth due to the presence of warp size.

Medical Textiles : To impart antimicrobial properties on wound dressings and get freedom from microbes/ pathogens from apparels & textiles used in hospitals, nursing homes, medical and research facilities, and veterinary clinics for protection against infectious diseases.

 

Washing Vs AM Finishes    

Normal home-washing of apparels & textiles, which is generally under

mild conditions, does not completely remove the microbes.

In order to eliminate microbes, very severe laundering conditions, e.g., a temperature of 95 °C and strong detergents followed by bleach, are essential.

Any surviving microbes can quickly multiply again at each further wearing. This can be avoided by the application of antimicrobial finishes.

 

 

 

Types of AM Finishes   

Finishes are two types: 1. Biostats, i.e. bacteriostats, fungistats 2. Biocides, i.e. bacteriocides, fungicides

Antimicrobial is an agent that works against microbes. It can either inhibit their growth and reduce the undesired by-products or kill them together.

Agents which inhibit the growth of microorganisms and do not kill them are known as biostats, i.e. bacteriostats, fungistats.

Agents which actually kill the microorganisms are known as biocides, i.e. bacteriocides, fungicides.

 

 

 

Mechanism of Biocides    

All antimicrobials do not work in the same manner. The actual

mechanism of control of microorganisms by antimicrobials is extremely varied.

They leave the textile and chemically enter or react with the microorganism acting as a poison. Like an arrow shot from a bow or a bullet shot from a gun, they are used up in the process of working, or complexed with other chemicals in the process.

Again some antimicrobials consists of molecules that are chemically bound to fibre surfaces and remain affixed to the substrate, killing microbes as they contact the surface.

 

 

 

Antimicrobial Finishing Methodologies & Mechanisms of antimicrobial finishesA variety of chemical finishes have been used to produce textiles with demonstrable antimicrobial properties. These products can be divided into two types based on the mode of attack on microbes.One type consists of chemicals that can be considered to operate by a controlled-release mechanism.The second type of antimicrobial finish consists of molecules that are chemically bound to fibre surfaces.

Controlled-release mechanismThe antimicrobial is slowly released from a reservoir either on the fabric surface or in the interior of the fibre. This ‘leaching’ type of antimicrobial can be very effective against microbes on the fibre surface or in the surrounding environment. However, eventually the reservoir will be depleted and the finish will no longer be effective. In addition, the antimicrobial that is released to the environment may interfere with other desirable microbes, such as those present in waste treatment facilities. Molecules that are chemically Antimicrobial finishes bound to fibre surfacesThese products can control only those microbes that are present on the fibre surface, not in the surrounding environment. ‘Bound’ antimicrobials, because of their attachment to the fibre, can potentially

•be abraded away •or become deactivated •and lose long term durability. •Mechanisms of antimicrobial finishes

Antimicrobial finishes that control the growth and spread of microbes are moreproperly called biostats, i.e. bacteriostats, fungistats. Products that actually kill microbes are biocides, i.e. bacteriocides, fungicides.

Bound antimicrobials Several antimicrobial finishes that function at fibre surfaces have been commercialised.One popular product is based on octa-decyl-amino-dimethyl-trimethoxy-silyl-propyl-ammonium chloride. This material can be applied by either exhaust or continuous methods. After application, a curing step is required to form a siloxane polymer coating on the fibre surface. This coating immobilises the

•antimicrobial part of the molecule (the quaternary nitrogen)• and provides the necessary durability to laundering.

Another bound finish has been developed with PHMB, poly-hexa-methylene biguanide

Test Method:

ConclusionCotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. With advent of new technologies, the growing needs of the consumer in the wake of health and hygiene can be fulfilled without compromising the issues related to safety, human health and environment. The consumers are now increasingly aware of the hygienic life style and there is a necessity and expectation for a wide range of textile products finished with antimicrobial properties.