Fabric and Garment Finishing

Selection Criteria for spotting chemicals and factors for spotting

Spotting

By:

Manuraj Kumar

Vatsal Pant

SPOTTING

DEFINITION: Spotting is a specialized art in which a spot or stain is identified and removed using the proper chemical agent without damaging or affecting the clothing. Any stain that resists the normal washing or dry-cleaning process can usually be removed using a special treatment called spotting

WAYS OF IDENTIFYING SPOTS

Sight : quickest and most important

Feeling : whether it is hard, brittle

Odor : the smell of the stain

Location : the position of the stain

Solvent test : whether the stain can be removed by water or dry solvent

METHOD OF SPOTTING

Solution: mixture of two substances - solvent and solute .The most common way to remove soils and spots from fabrics is to dissolve them in solvents

Emulsification: In regular washing, emulsifiers should be added to the solvent (water) to assist it in efficient stain removal.

Chemical action: Two or more substances (here - the stain and the chemical applied) combine to produce one or more totally new substances. The new substance so formed is normally very soluble and can be rinsed away easily. Chemicals must always be used very carefully because of the danger that they will affect or damage the fibers.

Mechanical action: Mechanical action in spotting is done by using a dye brush, spatula, sponge, or spray gun. Important instance about all mechanical action is that it tends to wear or damage the fabric. Never for persistent stains, use more force than is necessary and continue the action only as long as necessary. Consider how the various fibers react to mechanical action and avoid actions that will injure them.

The spotting procedure begins by applying a stain remover to a clean towel and blot the spot. Checking for color transfer or spot removal.Wait as the spotting agent reacts with the staining material continuing to check for color transfer or spot removal.Proceed carefully, working from the outside of the spot toward the center until the spot is removed or there is no further chemical reaction.Rinse the spot to remove any excess cleaning agent.If any portion of the spot remains, repeat spotting procedures with the next sequence of spotting agents.For instance: If the stain is of unknown origin, always start with a volatile dry solvent, followed by a non-volatile dry solvent.If spot remains, treat with a neutral cleaning product followed by an alkaline cleaning solution then an acid cleaning solution then an enzyme digester.The next sequence of spotting chemicals begin with specialized chemicals, then bleaches, then dye and finally mechanical action.

SPOTTING AGENT -TYPE OF MATERIAL Cold Plus Water-Based Cleaner Mirachem NP 2520 Water-Based Cleaner Soy Gold 2500 Methyl Ester and Surfactants DPM Glycol Ether 90% Soy Gold 2500/10% Acetone Blend 90% Soy Gold 2500/10% DPM Blend 90% DPM/10% Acetone Blend

SPOTTING PROCEDURES AND SPOTTING CHEMICALS Cleaners use POG spotting agents to remove several types of contaminants before and sometimes after the garments have been cleaned in the machine. These spotting agents are suitable for removing: • tar; • ink; • shoe polish; • mascara; • lipstick; • oil-based paints; • nail polish; and • crayon. A number of different solvents are used in POG spotting agents. These include glycol ethers, mineral spirits, methyl ethyl ketone, acetates and various alcohols. Cleaners often find these solvents to be ineffective and many spotters prefer spotting agents that contain PERC and/or TCE. As mentioned earlier, PERC was extensively used in spotting agents in the past. Because cleaners were aware that PERC was under increasing scrutiny in the dry cleaning industry, the spotting chemicals were reformulated with TCE. Although TCE is also toxic, the industry perceived it as being less toxic than PERC.

SELECTION CRITERIA

A particular spot remover may completely remove one type of stain but not budge another kind of stain.

That same spotting agent may safely remove a stain on one type of fiber but cause damage to another fiber type.

Knowing the behavior or characteristics of cleaning products formulated for removing stains will help to:

• ensure greater stain removal success • reduce the risk of damage to the carpet • eliminate wasted time experimenting with different cleaning products

The general spotting solutions to include in a spotting kit are the following cleaning agents:

1. Acid spotter (pH 2-3): this solution is on the acid side of the pH scale and is useful for removing coffee and tea stains, browning, water stains and urine or feces stains. This will also help to neutralize alkaline based cleaners and stabilize fugitive dyes.

2. Neutral cleaning solution (pH 7): Since this spotter is neither acidic or alkaline it should be the first solution utilized on water soluble stains.

3. Alkaline cleaning solution (pH 9-10): This stain remover is for neutralizing acidic based stains. Examples include many food stuffs, vomit and blood. Some higher pH (over 10) alkaline spotters are effective in removing dye or pigment stains, however, dye loss or color bleeding may occur. Always pretest in an inconspicuous area for colorfastness.

4. Enzyme Digester: This spotting solution consists of living organisms which breakdown protein based soil into a water soluble stain. Situations that would be suited for this spotter include food spills like milk or blood stains. Enzymes are sensitive to high heat and are not active in cold temperatures.

5. Volatile dry solvent: These aggressive chemicals are effective in removing non-water soluble stains like gum, greasy and oily stains, tar, and ink. Caution should be exercised when working with this spot cleaner. Eye, respiratory and skin protection should be worn.

Apply this stain remover to a towel before applying to a fabric. Never over-apply or pour this spotter directly onto the carpet as it can dissolve latex and may result in carpet delamination.

6. Non-volatile dry solvent: This stain remover is also known as POG (paint, oil and grease remover) and is effective on non-water soluble stains. Use the same precautions as a volatile dry spotter when working with this form of dry solvent.

This solvent is best utilized in situations where more working time and slower solvent evaporation is desired. Water based cleaners may be used to rinse non-volatile dry solvent but rinsing with a volatile dry solvent are most effective in removing any oily residues from non-volatile dry solvents.

7. Specialized chemicals: This type of stain remover includes a rust remover, an ink remover or a dye remover. These spotting agents are formulated for a specific stain type

8. Bleaches and Strippers: There are two types of bleaches. Anoxidizing bleach changes the properties of a stain by adding oxygen. An oxidizer does not actually remove the staining material but instead makes it invisible by changing the chemical make up. This type of bleach is considered more permanent.

Examples include Sodium Percarbonate (All Color Bleach), Hydrogen Peroxide and Sodium Hypochlorite (Chlorine bleach)

A second type of bleach is a reducing bleach (stripper). This bleach type changes the properties of a stain by taking oxygen away. The staining material is not actually removed by a stripper. Only the chemical make up is changed. The change in chemical make up from a reducing bleach can often be reversed by adding oxygen (from the air or an oxidizing bleach).

Examples include Sodium Bisulfite, Sodium Hydrosulfite and Titanium Strippers.

All bleaches and strippers should be neutralized and rinsed after use. Sodium Percarbonate neutralizes strippers and Sodium Bisulfate neutralizes oxidizing bleaches. Bleaches should only be used after other methods have failed.

Oxidizing bleaches work best on natural (organic) stains and reducing bleaches work best on synthetic (man-made) stains, however, oxidizers can be used on synthetic stains and reducing agents can be used on natural stains.

Oxidizers work faster when an alkaline such as ammonia is added. Reducing bleaches work faster when an acid such as acetic acid or heat is added.

Always follow the bleach manufacturer's directions for use. Always pre-test in an inconspicous area or on a carpet sample before using

on the urine stain. Use the minimum amount of chemical necessary. Apply solution using a

sponge, cloth, or brush. Always work from the outside toward the stain center. When desired results are achieved, flush the stained area thoroughly

Although not included in a general spotter kit the following stain removal methods are listed. These methods require specialized training and practice.

1. Dye: When dealing with a situation of carpet color loss, an option is to spot dye or redye the entire carpet. Not all types of carpet fibers can be dyed as a method of stain removal. The fibers which can be redyed can only be recolored to the original or a darker color.

2. Mechanical Action: Utilized when a stain cannot be removed by cleaning. This stain removal method is a last resort and involves replacing the damaged carpet (burns or color loss) with a new bonded insert or "patch"

FACTORS

ISOLATION:The spotting process should be isolated from other workers. Process isolation is most effective when used in conjunction with good ventilation.

VENTILATION: Local exhaust ventilation (e.g. an exhaust hood) should be used to reduce solvent exposures during the spotting process. An exhaust hood should be located near the source of the spotting chemicals to prevent the vapors from entering the workers’ breathing zone. A slot hood at table level or a downdraft table exhausting to the outside of the building provides good protection for workers. Spotting tables equipped with an exhaust hood are now commercially available (See Figure 1).General ventilation should include both supply and exhaust air. Make-up air supply should be designed and used in conjunction with the exhaust system. An inadequate volume of make-up air may result in negative pressure areas, perhaps resulting in drafts that interfere with the exhaust hood. When make-up air is introduced, it should enter the opposite side of the room from the exhaust to prevent short circuiting. Ventilation systems in drycleaning shops should provide a minimum of 30 cfm of outside air per person.

WORK PRACTICES: Spotters should be trained in selective pre-spotting. They should know the proper techniques for stain removal and the correct way to use spotting chemicals in limited quantities. The spotter should recognize stains that will be removed in the drycleaning process and do not require prespotting. Spotters who are trained to reduce the number of treated garments will reduce personal exposures.

PERSONAL PROTECTIVE EQUIPMENT:The spotter should routinely use personal protective equipment (PPE) such as chemical resistant gloves and goggles to reduce dermal exposures. Gloves should be made of solventresistant materials, such as Viton® fluoroelastomer, polyvinyl alcohol, or unsupported nitrile. If a solvent permeates a glove material and breaks through to the inside of the glove, the glove can increase chemical exposure by trapping the chemical close to the worker’s skin. Manufacturers of PPE often assist in making the proper choices regarding glove types and life expectancy of the glove material, while considering the specific spotting chemicals being used. Different gloves may be needed for different types of spotting chemicals. Barrier creams may also be used but are less effective than gloves. Chemical splash goggles should be worn to prevent eye injury during spotting. Accidental contamination of the eye could result in minor irritation or complete loss of vision. An easily accessible eye wash station should be located near the spotting area. If chemical contamination of the eye occurs, prompt irrigation for at least 15 min can help limit the extent of damage (Figure 2).Figure 2. Chemical splash goggles, gloves, and an eye wash station located near the spotting station are all important to protect the health and safety of the spotter.