A UV protection primer under a membrane topcoat filters more than 80 percent of the UV in sunlight while holding visible-range transparency above 70 percent. Those are the two numbers the system has to hit at once: block the ultraviolet, keep the light and the look.
The primer is the lower half of a two-layer lacquer system on PVC architectural and tensile membrane. What it protects is not the coating above it.
What the primer is protecting
Ultraviolet light that gets through a topcoat is absorbed by the PVC directly underneath it. That thin boundary layer degrades, and the degradation can impair the bond between the lacquer and the PVC surface.
The consequence is specific: the membrane can lose adhesion at the interface while the topcoat film above is still intact and still performing on weathering and soil resistance. The visible failure is delamination or flaking, not a coating that has worn through. A surface inspection of the topcoat will not find it coming.
A primer that absorbs or reflects UV before it reaches that boundary layer removes the cause. The topcoat then does the job it is good at, which is weather, soil, and cleaning, and the adhesion underneath is not being consumed while it does so.
Single layer and two layer
Both configurations are used, and they answer different specifications.
Single layer. A PVDF topcoat applied directly to the PVC-coated fabric. It delivers outdoor durability, UV resistance, low soiling, and good cleaning behavior, and it is the specification across a lot of hall, tent, and cover work.
Two layer. A UV protection primer first, then the matching PVDF topcoat over it. This is what gets specified when the structure has to hold both appearance and adhesion across a long outdoor life.
The dividing line is service life and what the structure is worth, more than the fabric construction. A temporary event cover and a permanent tensile roof can be built on the same base material and still take different lacquer systems.
Send us your membrane fabric and we will coat it
Send a piece of the fabric you run and we will have the primer and topcoat applied to it and returned, so transparency and appearance are judged on your own material.
Request a SampleTitanium dioxide or zinc oxide
The light protection agent inside the primer is either titanium dioxide or zinc oxide, and both are supplied.
Titanium dioxide is the established absorber and the default where the membrane is opaque or lightly translucent. Zinc oxide is the alternative, and it is where the transparency question gets interesting: one zinc oxide primer grade is formulated for very high transparency.
That grade matters because architectural membrane is frequently specified for daylight. A tensile roof over an atrium, a stadium concourse, or a covered market is doing structural and lighting work at the same time, and a primer that dulls the membrane costs the building something the drawings assumed it would have. Where light transmission and visual clarity are part of the design, the very transparent zinc oxide primer is the grade to ask for by name.
ROWA Lack's published ROWAFLON primer grades are G-75368 with titanium dioxide, and G-75369 and G-75370 with zinc oxide, the G-75370 being the very transparent option. Matching topcoats go over them.
Why the numbers are stated as a pair
More than 80 percent UV filtered and more than 70 percent visible transparency describe the same film, and either number alone is easy to hit. A heavily pigmented layer blocks UV and kills the light. A clear layer passes the light and passes the UV with it.
The specification is the combination, which is a function of absorber choice, particle size, and loading in the primer. When a membrane is being evaluated for a daylit structure, ask for both figures on the actual grade rather than for a UV rating on its own.
Where this sits against the rest of the lacquer
PVDF is the chemistry used on architectural membrane for a reason that is separate from UV: it holds up outdoors and stays clean, and cleaning behavior is what a large white surface is judged on after a few years in service. On PVC-coated fabric the topcoat is also slowing plasticizer migration, staying suitable for the welding the fabricator uses, and carrying the finish.
The UV primer adds a job the topcoat cannot do from above, because by the time UV has reached the PVC the topcoat has already let it through. The rest of the selection logic across acrylic, polyurethane, and PVDF is covered in choosing a topcoat lacquer for PVC-coated fabric.
Specifying for a long service life?
Tell us the fabric, the structure, and the years it has to hold. We can put the single-layer and two-layer options in front of you with the transparency figures on the grade.
Talk to an ExpertWhat to settle before specifying
Five facts get a membrane system to a short list.
The base fabric. The PVC-coated polyester construction and its plasticizer system, plus the finish it carries now.
Service life. The years the structure is sold on, which is what decides single layer against two layer.
Translucency. Whether the membrane transmits daylight, and what light transmission the design assumed. This is what selects the absorber.
Fabrication. The welding method and seam requirement, since the lacquer sits in the weld zone.
The line. Application method, oven temperature and dwell, and line speed for both coats, since a two-layer system is two passes.
What to send us
Send a piece of the membrane fabric you run and tell us the service life and whether the structure is daylit. We will have the primer and topcoat applied to it and returned, so transparency and appearance are judged on your own material before a line trial.
P.A.T. Products supplies the ROWA Lack range across the United States, Canada, and Mexico, stocked in North America in working lot sizes. The full range sits on the coated textile lacquers page, and the manufacturer background is on the ROWA Lack partner page. Technical Data Sheets and Safety Data Sheets are available for every grade, and a Certificate of Analysis ships with each lot.
Frequently asked
What does a UV protection primer do on an architectural membrane?
It absorbs or reflects ultraviolet light before that light reaches the PVC underneath the topcoat. ROWA Lack publishes more than 80 percent of the UV in sunlight filtered, with transparency in the visible range held above 70 percent, so the membrane keeps its appearance and its light transmission while the PVC below is shielded. The primer goes on first and the weatherable topcoat goes over it.
Why does a membrane fail at the lacquer interface rather than at the surface?
UV that passes through the topcoat is absorbed by the PVC boundary layer directly beneath it. That layer degrades, and the degradation can impair the bond between the lacquer and the PVC surface. The topcoat film itself can still be intact and doing its job on weathering and soil resistance while the adhesion underneath it is going. The failure shows up as delamination or flaking rather than as a worn-through coating.
When is a single-layer PVDF system enough?
A single-layer PVDF topcoat delivers outdoor durability, UV resistance, low soiling, and good cleaning behavior, and it is specified across halls, tents, and covers. The two-layer system with a UV protection primer underneath is what gets specified when the structure has to hold appearance and adhesion over a long service life outdoors. Service life and the value of the structure decide it more than the fabric does.
Titanium dioxide or zinc oxide as the light protection agent?
Both are offered, and the choice follows how the membrane has to look. Titanium dioxide is the established absorber. Zinc oxide is the alternative, and one zinc oxide primer grade is formulated for very high transparency, which is what a translucent membrane needs when daylight transmission and a clean visual are part of the design. Ask for both against your fabric if appearance is being judged.
Can the primer and topcoat be trialled on our own fabric?
Yes. Send a piece of the membrane fabric you run and we will have the primer and topcoat applied to it and returned, so transparency, gloss, and appearance are judged on your own material rather than on a generic panel. A line trial follows on a stocked or sampled quantity. We stock the grades our customers run and ship them from North America.
Specifying a membrane system?
Send the fabric, the service life, and whether the structure is daylit. We will recommend a primer and topcoat, coat a panel on your own material, and quote lead time and minimum quantity with the sample.
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