PBT is the standard fabric for competition and training swimwear, and it prints beautifully — until it does not. Print a PBT race suit by conventional sublimation transfer and the print area comes back stiff: a hard, papery panel where the fabric should be soft and elastic. It is not a defect in the print file or the fabric. It is what happens when an all-polyester PBT meets a process designed for higher-melting polyester.
We manufacture printed competition swimwear in PBT, both Italian Carvico and domestic PBT, and we handle this problem as a routine part of production rather than an exception. This page explains why it happens, what it costs a race suit, and how to tell whether a supplier has actually solved it. If you want our production method, that is a conversation — the process is our work, not a line on a webpage.
Why PBT Is the Fabric for Race Suits
Competition swimwear is one of the few garment categories where the fibre choice is not a preference. PBT — polybutylene terephthalate — dominates for reasons that show up the moment a swimmer is in the water for two hours.
- Chlorine resistance. PBT withstands repeated pool exposure far better than standard polyester blends and dramatically better than nylon. A nylon suit used daily loses its stretch and goes thin; a PBT suit holds.
- Elastic recovery. PBT snaps back after stretch. That matters on a compression garment, where the whole point is that the fabric keeps pulling against the body rather than relaxing into it.
- Low water absorption. PBT picks up little water, so the suit does not get heavy or sag when soaked.
- Shape retention. Race suits are worn tight. A fabric that creeps out of shape after a few sessions stops being a race suit.
Those four properties are why PBT is specified for kneeskins, training suits and club uniforms. They are also the reason this printing problem matters so much: you cannot simply switch to a different fibre to make printing easier without giving up the performance you specified PBT for in the first place.
The Printing Problem Nobody Warns You About
Sublimation transfer printing works by turning solid dye into gas. The printed transfer paper is pressed against the fabric at heat, the disperse dye vaporises, and the gas phase dye migrates into the polyester fibre and resets there. It is a dry process, it produces no water waste, and on polyester it gives excellent colour depth and a print that does not sit on the surface. That is why it is the default method for all-over prints on activewear and swimwear.
The method depends on one assumption: that the fibre can be brought close to the dye’s activation range without losing its own structure.
That assumption holds for standard polyester. It does not hold for PBT.
PBT softens at a lower point than PET polyester — the gap is real but not enormous, and that is exactly what makes it dangerous. The transfer process does not need to melt the fabric to cause damage; it only needs to soften the surface layer. Once the surface softens, the dye carrier and the resinous component of the transfer medium press into the fibre under the roll, and when the fabric cools the surface sets with that material locked into it. The result is a panel that has lost its drape and its stretch, with a dry, hard hand-feel.
This is not a mistake in the print shop. It is the physical consequence of running an all-polyester fabric with a relatively low softening point through a high-heat transfer. Any supplier printing sublimation onto PBT faces the same physics. The difference between suppliers is what they do about it.
What “Stiff” Actually Costs You on a Race Suit
Stiffness is easy to dismiss as a hand-feel complaint. On a competition suit it is a performance problem with three separate consequences.
Elasticity loss in exactly the wrong place
On a kneeskin, the printed panel is usually the large front body — the panel that has to compress the torso and hold the silhouette. If that panel loses elasticity while the unprinted side panels keep theirs, the suit no longer compresses evenly. The compression you designed into the pattern is no longer delivered where it matters most.
Stress concentration at seams
A stiffened panel does not stretch with its neighbours. Under load, the seam between the stiff printed area and the soft unprinted area takes the strain. On a garment worn tight and pulled on and off repeatedly, that is where a split starts.
Fit drift and drag
A panel that has stiffened does not follow the body the way it was cut to. Small gaps and ridges form against the skin, and on a race suit those are drag. The swimmer may not be able to explain why the suit feels worse, but it does.
How We Handle It
We do not treat this as something to be tolerated. Printed PBT competition suits are a product we manufacture, and solving the stiffening is part of the development work rather than a limitation we pass on to the buyer.
There are three places where the problem can be addressed, and each of them has a cost attached: the fabric itself, the transfer process, and what happens to the garment afterwards. Working on only one of them is not enough — every route has a trade-off in colour depth, production speed, or durability, and pulling one lever alone simply moves the problem rather than solving it.
What we do is balance all three. The exact combination is the result of production trials across many printed PBT orders, and it is not something we publish — partly because it is the work we have done, and partly because a published recipe invites a supplier to claim it without having tested it.
What we will say plainly: the printed area on our PBT competition styles is specified to keep its stretch and its drape, and we test for that before the garment leaves the factory rather than discovering it at the buyer’s end.
Verifying Any Supplier’s Printed PBT
Because this is a physical problem every PBT printer faces, the useful question is not “do you have this issue” — it is “can you show me you have solved it.” These are the checks that separate a real solution from a claim.
- Compare the printed panel against an unprinted area of the same garment. Not against a different fabric, and not against a photo. The printed and unprinted sections of the same suit should feel close in hand and should stretch to a similar degree.
- Stretch the printed area across the print and look at the surface. A correctly processed print moves with the fabric. A print applied over a softened surface cracks, whitens or lifts along the stretch direction.
- Repeat the stretch test after washing. Some stiffening is only visible after the first wash cycle, when the resin component of the transfer sets fully.
- Check the seam between printed and unprinted panels. Pull the two panels apart gently. If the print side puckers while the plain side stays flat, the two have different elasticity and the seam will fail under wear.
- Ask for the print on a sample before bulk, in your own colourway. Dark saturated colours and large solid print areas show stiffening more than light, broken-up designs. Testing on a pale print tells you nothing about how your black areas will behave.
- Ask what happens to the print in chlorinated water. A print that survives the transfer can still behave differently after repeated pool exposure — and chlorine is the environment the suit is built for.
Any supplier answering these questions with samples in hand is doing the work. A supplier answering them with a brochure is not.
Carvico and Domestic PBT: What Actually Differs
Buyers often ask us to choose between Italian Carvico and domestic PBT for a printed suit. The honest answer, in our experience, is that the performance gap is smaller than the price gap.
Domestic PBT has improved substantially. For a printed competition suit where the fabric is being processed at heat, the practical difference in how the fabric handles the transfer is modest; both are all-polyester and both present the same underlying challenge.
Where Carvico still shows an advantage is in consistency — batch-to-batch shade and hand-feel variation is tighter, and that matters on a large print run where the whole order has to match. If your market specifies Carvico by name, or your buyers test for it, we source it. If you are price-sensitive and your programme can accept normal batch tolerance, domestic PBT is a legitimate choice, and we will say so rather than upselling you.
Printed Competition Styles We Manufacture
Two of the competition styles in our current range are printed PBT, and both are built with this processing in mind:
- Soren Trinity strap competition swimsuit — an all-over abstract print across a low multi-strap trinity back and high-cut leg.
- True red splice racerback swimsuit — a printed centre panel against solid side panels, which places the print on the largest continuous surface of the garment.
For unprinted competition and training constructions, see the double cross-back training swimsuit and the open-back kneeskin tech suit. Our fabric library lists the PBT specifications we work with.
Frequently Asked Questions
Why does sublimation printing make PBT stiff?
The transfer process relies on heat to vaporise the dye into the fibre. PBT softens at a lower point than standard polyester, so the process window presses into the point where the fibre surface begins to soften. The surface sets with the transfer medium locked into it, which is what produces the hard hand-feel.
Is this a problem with our print file or with the fabric?
Neither. It is the interaction between an all-polyester fabric with a relatively low softening point and a high-heat transfer process. Any printer working with PBT meets it.
Can we just switch to a different fabric to avoid it?
You can, but you give up what PBT is specified for — chlorine resistance, elastic recovery and low water absorption. On a competition suit those are the whole point. The better route is to solve the printing rather than change the fibre.
How do we know your print will not go stiff?
Test it. Ask for a printed sample in your own darkest colourway, compare the printed panel against the unprinted area of the same garment, and repeat the stretch test after washing. We would rather you verify it on a sample than take our word for it.
Does Carvico print better than domestic PBT?
The performance difference is smaller than the price difference in our experience, and domestic PBT has improved considerably. Carvico’s advantage is tighter batch consistency, which matters on large runs. Both face the same printing physics.
What is the minimum order for a printed competition suit?
100 pieces per style per colour, splittable across sizes within a colour. Each distinct print is its own colourway with its own minimum, since the print has to be set for the pattern.
Start Your Printed Competition Line
If you are developing a printed PBT competition suit and want to know how we handle the stiffening, send us your design and target colourway. We will tell you what the print will do on the fabric before you commit to a sample run.
Request a free quote or read our sample policy if you would rather start with one suit in your hands.
