Why cheap rashguards bleed onto mats, gis and skin

We’ve seen it in a lot of academies: a blue or red mark on a white gi after training, and colour on the mat that is very hard to get out. In our experience, the cause is almost always a cheap rashguard.

Price alone doesn’t tell you everything, though. What matters is how the fabric was dyed and finished. Here is why colour moves onto other surfaces, and what to look at when you choose a rashguard.

How sublimation works

Rashguards are usually made from polyester or nylon, with spandex added for stretch. On polyester rashguards, one of the most common ways to apply the design is sublimation.

The design is printed onto special paper, then transferred to the fabric with a heat press. The temperature is usually around 190–205 °C, depending on the fabric and the printing system. With the heat, the dye turns into a gas and goes into the polyester fibres.

A design applied this way has no separate layer on the surface, so it can’t crack or peel. Conventional sublimation works on polyester; on untreated cotton it won’t give a lasting colour.

Sublimation can cover the whole rashguard, sleeves included. In our experience, quality rashguards are made this way. Every rashguard at Fighters.ge is sublimated.

When the design is printed on the surface

There is another way: the maker sews the rashguard from fabric that is already dyed, black, blue or white for example, then prints the design on top or applies it with a heat-transfer film. This can reduce production costs, because the same fabric works for different designs.

Big sportswear brands sometimes do this too. How long a surface print lasts depends on the materials and how it is applied. In our experience, these prints can crack and peel with heavy use, especially when the fabric stretches a lot and rubs against the mat.

A peeling design and bleeding colour are two different problems. The first only looks bad. The second is more serious.

Why the colour ends up on the mat

Polyester is coloured with disperse dyes. After dyeing, the excess dye left on the surface of the fibres is removed at the factory with an extra treatment.

If the dye isn’t properly fixed, or the excess isn’t properly removed, colour can move onto other surfaces. Heat, sweat and friction help it along, and rolling means all three at once.

Some mats are covered in vinyl (PVC). Certain disperse dyes can dissolve in the plasticisers in these covers and migrate into the surface. The result depends on the dye and the mat cover. Prompt cleaning may make a stain easier to remove; follow the mat manufacturer’s care instructions. Once it has soaked in, it’s very hard to remove and sometimes never comes out completely.

We’ve seen this in a lot of academies. In our view, choosing white mats is a big mistake for exactly this reason: every stain shows. Colour gets onto white gis too, sometimes after a single round.

How dye relates to your skin

Dye that comes out of the fabric can get onto your skin. Some disperse dyes, including Disperse Blue 106 and Disperse Blue 124, are known contact allergens. In sensitive people they can cause an itchy rash where the clothing touches the skin. The reaction can appear within hours, or only after several days.

Not everyone reacts. But sweat and constant friction can make allergic dermatitis worse, and both are common when training in a rashguard.

In the EU, certain azo dyes are restricted in textiles meant for prolonged skin contact, if they release listed aromatic amines above 30 mg/kg.

How to check a rashguard before and after you buy

• Check how the design is applied. A sublimated design has no separate layer: it should feel like the fabric itself, not like a layer of rubber or film.
• Check the fabric and the percentages. Polyester or nylon with spandex is the usual mix, but the composition alone doesn’t prove the colour will hold.
• If it has an OEKO-TEX STANDARD 100 label, check the certificate number in the official Label Check. The certificate covers harmful substances; it isn’t a guarantee that the colour won’t transfer to a mat. Check which product the certificate covers, too.
• Rub a damp white cloth over the darkest part of a new rashguard a few times. If the cloth picks up colour, contact the seller before training in that rashguard. It’s a simple check, not a lab test; a clean cloth does not prove colourfastness under every condition.
• Wash it on its own before first use, following the care label. If the water turns coloured, be careful: that rashguard may leave colour on the mat as well.

On jiujitsu.ge, read what gear a beginner needs and what can wait: What jiu-jitsu costs.