What are bleaches

Bleach in heavy-duty detergents: This is how you can wash yellowed laundry white again

In this article we will explain the effects of bleach to you. We will explain to you how bleaching agents are used and how they are chemically structured. After listing the common bleaching agents and displaying their history, you will find out when it makes sense to bleach an item of laundry.

Table of Contents

1. Application

Bleaches are used to remove unwanted color stains and yellowing from laundry. At the same time, bleaching agents also have a disinfectant effect - but they can also attack sensitive colors. Therefore, mild detergents and colored detergents usually contain no bleaching agents and heavy-duty detergents only become fully effective at higher temperatures.

2. Chemical basics

With all modern bleaching agents, the basis of the bleaching process is the release of aggressive atomic oxygen (O), which forms compounds with undesirable dyes - but also with sensitive textile dyes.

3. Common bleaches

In modern detergents and also in stain remover, you can almost exclusively find bleaching agents oxygenbasis - i.e., more precisely, bleaches that release oxygen from hydrogen peroxide. Bleaches were also used earlier chlorinebasis (sodium hypochlorite) - these directly release oxygen radicals. However, they have become uncommon because of the heavy burden on the environment.

Perborate, the most widely used bleaching agent in heavy-duty detergents, has recently been pushed back in favor of other agents, since boron compounds are difficult to break down and, in high concentrations in water, are harmful to plants. Today, percarbonate (based on sodium) is used more frequently in stain removers, stain tablets and modular detergents. However, due to its composition, this substance is difficult to integrate into heavy-duty detergents, which is why they often still contain perborate.

The bleaching agents perborate and percarbonate only become active at higher temperatures (more than 40 degrees). In addition, bleach activators are used as additives to fully activate them.

In dry cleaning, preparations with peracetic acid (a. Peroxodic acid) (CH3CO3H) used; Persacetic acid degrades quickly in wastewater and is therefore environmentally friendly.

4. Historical

In China and ancient Egypt, it had been around since about 5000 BC. Sulfur in use as a bleaching agent for textiles. Before the development of modern detergents in the first half of this century, laundry that was still damp was treated with what is known as Lawn bleach yellowed. As a result of solar radiation, hydrogen peroxide was developed, which releases oxygen radicals that destroy pigment substances - i.e. the bleach was ultimately based on the same cause as with modern detergents.

5. When can I bleach an item of laundry?

Under the care symbols on textiles, a group of symbols specifically indicates whether an item of laundry may be bleached or not. However, this refers to the separate, intensive bleaching process, not to the use of bleaching agents in the washing powder. For laundry items that do not allow bleaching, stain removers and bleaching stain removers should be used with caution. Delicates with sensitive colors should be washed with bleach-free detergents (mild detergents).

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Photo credits: Laboko / shutterstock (sorted by order in the post)