Bleaching agents and stain removal
The advanced stain removal expert should be well-versed in the use of bleaches.
Cleaning can be defined as removing unwanted foreign substances.
But stain removal is often accomplished by altering the color of the stain, rendering it invisible, instead of removing it. That’s where bleaches come into play.
You could compare bleaching action to rust removal — at least the final result. If you apply an acid to a rust stain, the rust remains. It’s the color of the rust that is made invisible.
With bleaching stains in textiles, you are doing the same thing: Making them invisible.
Categories of bleaches
For carpet and furniture cleaning, there are two types of bleaches that are safe to use without excess fear of causing damage to fibers and colors. These are:
- Oxidizing bleaches (such as hydrogen peroxide and sodium percarbonate)
- Reducing bleaches (such as sodium bisulfite and sodium metabisulfite).
Household chlorine bleach (sodium hypochlorite) is rarely recommended for use for on-location or in-house carpet or furniture cleaning. It is very aggressive and unpredictable, although it is used by some carpet and furniture cleaning professionals.
For most textiles, you can use a variety of oxidizers and reducers, but become completely familiar with the dangers of chlorine should you decide to use it.
How bleaches work
Oxidizing and reducing bleaches can be used after you attempt regular cleaning and spot removal steps.
Because of the chance of original textile color removal, obtain the customer”s permission before proceeding.
Sometimes they are needed to remove heavy or very noticeable stains, and repeated efforts are necessary.
Oxidizers work by adding oxygen to the stain and fabric. By adding the oxygen molecules to the stained area, you alter the appearance of the stain.
Remember: Stains are colors, and to have a color you have to have light and reflection. By altering the color molecule with added oxygen, you change the color appearance, rendering it invisible.
Reducers give you the same final result, but with a different path of delivery. They remove oxygen molecules from the textile and stain, again altering the color molecule that creates the stain’s color.
Oxidizers work best on organic stains (natural). Reducing agents work best on synthetic stains (manmade).
This doesn’t mean you can’t use an oxidizer on a synthetic stain, and vice versa.
Putting them to work
Stain identification is your first priority.
Since each type of bleach has an affinity for either natural or synthetic stains, you need to make the proper match.
Purchase your bleaches from a qualified formulator. These bleaches typically have detergents in them, a chemical to speed penetration of the bleach into the fiber. Plus, an MSDS is very important to have on hand.
Don’t worry at this point about how much to use, the dilution, or method of delivery of the chemical to the stain. Those directions will come from your chemical supplier.
But never mix any chemical, especially ammonia, with hypochlorite.
Adding a small amount of alkaline (such as ammonia) to an oxidizer makes it work faster. Alkalinity accelerates oxidizing bleaches.
Adding a small amount of acid (such as acetic acid, better known as vinegar) to a reducing agent makes it work faster. Acids accelerate reducing agents.
That natural fibers, like wool or cotton, are sensitive to many types of chemistry. Using sodium percarbonate (an oxidizer) with its natural high alkalinity is not recommended on some of these fiber types. The same caution applies to stain resistant nylon fibers. Liquid peroxide with a more neutral pH is better.
Remember: What you are trying to achieve is the alteration of the color molecule. Even if you can’t alter the color so it is completely invisible, often the remnants of the stain are removable with continued cleaning.