A Digest of Information on Sodium Percarbonate — Commonly Used in Laundry

What is sodium percarbonate? A one-stop look at the core raw material of “oxygen bleach” for laundry

1) A basic definition and identification

Sodium percarbonateIts common English name is Sodium Percarbonate, and in technical documents one also sees Sodium carbonate peroxyhydrate / Sodium peroxocarbonate / PCS / SPC and similar names. It is a kind of “addition compound of sodium carbonate (soda ash) and hydrogen peroxide (H₂O₂),” and is often called “solid hydrogen peroxide” or a source of “solid active oxygen.”

• A common chemical representation:Na₂CO₃·1.5H₂O₂(an equivalent way of writing it to 2Na₂CO₃·3H₂O₂ )

• CAS No.: 15630-89-4

• Appearance: white, odourless, granular / crystalline, convenient for dry-powder formula work

2) Why sodium percarbonate can “remove stains, bleach and deodorise”: the mechanism of breakdown in water and of active oxygen

The key to sodium percarbonate is:On meeting water it releases hydrogen peroxide, and at the same time brings in the alkalinity of sodium carbonate。

It can be understood in “two stages”:

1. Dissolution / dissociation (the carrier releases hydrogen peroxide)
   Sodium percarbonate → Na₂CO₃ + H₂O₂(it releases hydrogen peroxide in water)

2. Hydrogen peroxide then produces active-oxygen species
   In an alkaline environment (common in laundry formulas), hydrogen peroxide more readily forms active species with oxidising power, which then oxidise pigment-type stains (tea, coffee, red wine, fruit stains and so on) and help to deodorise.
   (For example, in some specification data, a 10 g/L solution of sodium percarbonate has a pH of about 10.5; or a 1% solution a pH of about 10.4–10.6。)

To get more of a result from a low-temperature wash: the relationship with “bleach activators” such as TAED

In laundry and disinfection, a common practice is to use sodium percarbonate (which supplies H₂O₂) together with **TAED (tetraacetylethylenediamine), so that, in the presence of hydrogen peroxide, TAED quickly undergoes “perhydrolysis” and generatesperacetic acid** and other strong oxidising bleach species better suited to low-temperature conditions. This is also the “active oxygen + activator” design approach common in many European powder / tablet detergents.

3) For sodium percarbonate used in laundry / detergents, the “key quality and formula indicators” commonly watched

Different sources (different plants, different grades) may all be called “sodium percarbonate,” but in the detergent industry, what really decides formula performance and storage stability is usually the following kinds of indicator (most can be found on a TDS / PDS / COA):

(A) Available oxygen / active oxygen

• This is the core indicator of sodium percarbonate as an “oxygen bleach”;

• coated productsbecause of a stabilising / moisture-proof outer layer, commonly show a “slightly lower lower-limit for available oxygen” in their specifications (because the coating itself does not contribute available oxygen).

(B) Coated vs. uncoated (whether there is a coating / stabilising coat)

• Coated: usually more emphasis is placed on storage stability, resistance to deliquescence, and compatibility with other ingredients in the formula (fragrance, enzymes, surfactants and the like); commonly found inlaundry powders, dishwasher powders, tablets, and bleach-booster powdersand the like.

• Uncoated: in some applications a faster dissolution / a higher available oxygen can be sought, but it is more sensitive to humidity and contamination.

(C) Bulk density

• A high bulk densityis favourable for making “concentrated powders / tablets / tight filling” and for lowering volume cost; some product documents directly emphasise that their high bulk density is suitable for compact formulations.

(D) Particle-size distribution and dissolution rate

• Particle size affects:

• The flow of the dry powder, the uniformity of mixing, and the amount of dust

• The speed of dissolution / release in water (and then the effectiveness of a low-temperature wash and a short wash)

(E) Moisture (the upper limit of water content) and stability indicators

• Sodium percarbonate can be induced to break down by water, heat, catalytic contaminants and the like; control of moisture and the moisture barrier of the packaging are very critical for long-term stability.

• Some plants provide still further indicators of stability measurement (for example a heat-flow / activity monitoring value measured under fixed conditions).

4) Typical uses of sodium percarbonate in laundry and cleaning

The following uses are all “common applications” clearly listed in several technical documents:

Household / commercial laundry and cleaning formulas

• Laundry powders & tablets: as the oxygen-based ingredient for bleaching, stain removal, deodorising and whitening

• Automatic dishwashing detergents: to provide oxidising stain removal / a cleaning-aid function

• Bleach boosters: to raise oxidising stain-removal power

• Denture cleaning agents: as an oxygen-releasing cleaning ingredient

Other industrial uses (not laundry, but common)

• As a source of oxidation or added oxygen in aquaculture / farming, for textile oxidation, wastewater treatment and the like (different grades and applicable regulations need to be confirmed separately).

5) Key points on safety, compatibility and storage

In transport / regulation, sodium percarbonate usually belongs to theoxidising solids. Under improper conditions it may break down and release oxygen and water vapour, and may promote combustion; so the usual points for storage and handling include: avoid becoming damp, avoid contact with incompatible substances, avoid metal contamination, keep away from heat sources and sunlight, and so on.

Taking one product’s data as an example, the document also lists its transport information (UN number / class) and hazard statements (for example markings such as “may intensify fire,” “harmful if swallowed,” “causes serious eye damage”). Please read the product’s SDS (safety data sheet) before use, and follow the SDS and the relevant regulations for the details of handling.

Where do German / Chinese / Korean / Japanese sources differ? A comparison using “publicly available specifications”

The difference is usually not that “a given country is necessarily better,” but that the “grade” and “coating / stabilising technology” each brand provides are different, and the specification windows (available oxygen, moisture, particle size, dissolution, bulk density) and test conditions are also different.
So when comparing, it is suggested that you set “both coated detergent grade” or “both uncoated” against each other.

Below is a digest of several representative documents that are often compared in Taiwan’s supply chain, and for which a publicly available TDS / PDS can be found.

A comparison table of representative publicly available data (based on each plant’s publicly available TDS / PDS specifications)

Note: the test methods / conditions of different documents may differ (for example the temperature and concentration of a dissolution-rate test). The purpose of the table is to let the reader understand “which fields to look at in a specification,” not to treat all the figures as directly comparable across the row.

1. Coated will make the available oxygen look slightly lower, but usually in exchange for better stability and formulatability
   In the same publicly available document one can already see the difference in the available-oxygen range of coated / uncoated (for example OCI, and a publicly available specification on the Chinese supply side).

2. A high bulk density (the 900–1200 g/L class) is friendlier to tablets and concentrated powders
   Several detergent PDS / TDS documents treat 900–1200 g/L as a common window, and some documents say directly that it is “suitable for compact formulations.”

3. The upper limits of the moisture specification differ greatly; in a high-humidity environment such as Taiwan, “moisture-proofing” should all the more be written into the purchasing specification
   In publicly available data, the upper moisture limits of different suppliers may fall in different windows such as 0.5%, 1.0% and 2.0%; and the safety / storage sections also clearly list “avoid becoming damp, avoid contamination” as key points.

4. A common feature on the Japanese side: particle-size grades are cut more finely, and there is a special processing line for “stable dissolution at high temperature”
   When high-temperature dissolution or a particular process is needed (for example some industrial cleaning), this kind of product line can be watched for.

5. The need for a low-temperature wash: an explanation of the “TAED activation” mechanism can be added in an article
   Simply put: sodium percarbonate supplies H₂O₂, and TAED then turns it into peracetic acid; this is why a low-temperature wash often needs to be paired with an “activator.”

A purchasing checklist for detergent or laundry operators:

• Ask the supplier for:the TDS / SDS / the COA for the batch

• Suggested COA fields (choose according to the needs of the formula):

1. Available oxygen / active oxygen

2. Moisture

3. Bulk density

4. Particle-size distribution (sieve analysis)

5. Dissolution rate (pay attention to the test temperature / concentration / method)

6. Indicators of catalytic contamination such as heavy metals / iron (Fe) (some suppliers publish these)

• Separately set storage / packaging requirements: moisture-proof, cool, avoid contamination (especially avoid metal dust, reducing substances, and organic contamination).

References (publicly available documents)

• Technical data for Evonik’s Sodium Percarbonate Q30 series (TDS, including available oxygen, bulk density, particle size, dissolution and moisture, and so on)

• Product data for Solvay Oxyper® SHC (PDS, including specifications, Germany-plant information, and safety / transport and hazard markings)

• Product data for OCI (Provox®) (PDS, including coated / uncoated specifications)

• A publicly available specification page on the Chinese supply side (including coated / uncoated available oxygen, bulk density, moisture, Fe and so on)

• Hodogaya product-line information from Japan (particle-size grades and coating / special processing)

• ECHA: a description of the mechanism by which TAED + sodium percarbonate generate peracetic acid in situ in water (an official assessment document)

How to use it at home: first look at the care label, then decide whether to soak

The English name of sodium percarbonate is Sodium Percarbonate; in Japanese it is written kātansan natoriumu, and in German Natriumpercarbonat. It is a solid of “sodium carbonate + hydrogen peroxide,” and on meeting water it releases hydrogen peroxide; it belongs to the oxygen bleaches. Baking soda is sodium bicarbonate, and has no bleaching action; the two cannot replace each other.

• First look at the bleach symbol on the care label: a triangle with a cross through it means do not bleach. Do not use it on wool, silk, leather, or garments labelled do-not-wash or to be washed with a neutral detergent.
• Do not soak coloured clothes in hot water for a long time. The Korea Consumer Agency tested 11 oxygen bleaches: put in the washer with detergent and washed at 25°C, none of them discoloured a blue test cloth; changed to a 30-minute soak in a 40°C bleach solution, all 11 discoloured the blue test cloth. For coloured garments it is suggested that you wash them with the detergent, or first test on a seam or other inconspicuous place.
• It is suitable for treating protein stains such as sweat and milk; greasy dirt cannot be washed clean by sodium percarbonate alone, and still needs to be paired with a laundry detergent.
• Follow the amount on the product pack. The powder dissolved in water is alkaline; wear gloves when you handle it.
• Absolutely do not mix it with a chlorine bleach (it may react violently or produce chlorine gas); keep it where children cannot reach it, and do not decant it into another container.

In what situations we suggest you do not do it yourself

What is set out above is the part you can do at home. But there are three situations in which we would suggest you not start yourself:

1. Coloured garments, luxury pieces, leather and animal fibres.Protein fibres such as wool and silk are easily damaged when they meet an alkaline oxygen bleach; leather and bonded technical fabrics are also vulnerable. Once this kind of thing is washed badly it cannot be put back; the laundry fee you save is usually far less than the garment itself.

2. Colour already transferred from something else (dye transfer).Rushing to bleach it yourself often makes it worse and worse, or even strips the colour from a whole area. Dye transfer has a better chance of being treated when it has just happened and the area is still small; the longer you leave it, the deeper the dye goes into the fibres, and the harder it is to save.

3. A large area, or an uncertain material.When you cannot read the care label, or a blend has uncertain fibres, asking first is safer than trying first.

If you are not sure whether it is worth treating,send us a photo on LINE and let us look first. We will first judge the material and how deep the dyeing is, and how far it can be saved, then quote; we start only after you agree, and the process is recorded on video from start to finish for review.If it truly cannot be saved, we will say so plainly already at the quote, and will not wait until you have paid to tell you. For charges for each service, see theprice list; for the process the first time you send something for a wash, see thenotes for first-time customers placing an order。