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Application guide

Coloured FRP Sheet and Cladding Manufacturing

Opaque coloured sheet for outdoor use, made on an ordinary catalysed line. What UV stabilised actually buys, and why it has nothing to do with curing under a lamp.

Stabilised against sunlight, cured by catalyst like any other sheet grade.

Two different products get called FRP sheet. One is translucent and sold on the light it lets through. The other is opaque and coloured, sold on cover, appearance and how long it holds that appearance outdoors. This page is about the second. It is a production job rather than a fabrication job: a line runs the same sheet repeatedly, and the commercial question is whether run forty looks like run one, and whether either of them still looks right in five years on a roof.

What manufacturers build

Producers in this category make coloured roofing and cladding sheet, wall and partition panels, coloured sheet for industrial and agricultural buildings, boundary and screening panels, and moulded or laminated parts cut from the same stock. The product is usually corrugated or profiled, produced continuously or in press runs, and installed where it is seen.

Why this material suits the work

UV Stabilized Sheet Grade Yellow Resin is a pre-pigmented unsaturated polyester sheet grade that its supplier Technical Data Sheet (SPR-TDS-USY) describes as UV-stabilised — a benzotriazole-type UV absorber with a HALS light stabiliser — for outdoor sheet, cladding and panel work. Two things follow. The colour arrives mixed at the manufacturer rather than dosed on the line, which is what removes batch-to-batch colour drift from a production operation. And the stabiliser package addresses weathering in service, not curing: this resin is catalysed with a peroxide hardener at workshop temperature like any other sheet grade. The sheet’s values, including a 1,000-hour xenon-arc weathering result, are published on the product page with the issuer named; this guide does not repeat them.

Required resin characteristics

  • Pigment supplied already dispersed, so shade does not depend on dosing accuracy on the line
  • A stabiliser package aimed at sunlight exposure over the sheet’s service life
  • Wet-out behaviour suited to continuous or press sheet production rather than hand lay-up of a one-off part
  • Batch-to-batch consistency, because sheet installed together must match
  • A conventional peroxide cure, so an existing line needs no new equipment

Process context

In general industry practice the catalysed resin and reinforcement are brought together against a film or mould surface, consolidated to remove air, profiled if the sheet is corrugated, and cured before trimming to length. Weathering protection in composite sheet is described in the literature as coming from stabilisers compounded into the resin, from a surfacing veil that keeps a resin-rich layer at the face and delays fibre bloom, from a surface film, or from a combination. A stabilised resin is one input to that, not the whole answer, so the surface construction is worth settling with the manufacturer alongside the resin. Catalyst quantities, line speeds, cure conditions and veil selection belong to your own approved procedure and to the current supplier documentation.

Advantages

  • Colour mixed at the manufacturer removes hand-dosing as a source of variation between runs
  • A stabiliser package aimed at the one thing that ages an outdoor sheet
  • Conventional peroxide cure on existing equipment, with no light-curing plant involved
  • A standard pre-pigmented sheet grade remains available where sheet is sheltered or indoors

Common products

  • Coloured FRP roofing and cladding sheet
  • Wall, partition and screening panels
  • Sheet for industrial and agricultural buildings
  • Moulded and laminated parts cut from sheet stock

Common questions

Does this resin cure under a UV lamp?

No, and this is the confusion worth settling before anything else. UV stabilised describes additives that resist sunlight during the sheet’s service life. UV curable describes a resin that hardens when light reaches a photoinitiator, which is a different product class sold for repair and patching work. This grade cures with a peroxide catalyst at workshop temperature, as sheet grades do.

How is this different from the standard Sheet Grade Yellow Resin?

Both are pre-pigmented yellow sheet grades. The supplier Technical Data Sheet describes this one as UV-stabilised, with a UV absorber and a HALS light stabiliser, for prolonged outdoor exposure. Where sheet sits in direct sun for years that is the distinction to ask about; for sheltered or indoor panels the standard sheet grade may be the sensible specification.

How many years will the sheet last?

We do not publish a service-life figure, and a figure offered without context is worth little. The supplier Technical Data Sheet reports a 1,000-hour xenon-arc laboratory exposure result, which is a comparison point, not a lifespan. Service life depends on the resin formulation, the stabiliser and surfacing system, the sheet construction, how severe the climate is and how the roof is maintained. What can be said is what degrades: sunlight breaks down resin at the surface, which shows as discoloration, chalking and eventually fibres standing proud.

Do I still add pigment on the line?

No. The colour is part of the supplied resin. Avoiding hand-dosed colour variation between batches is the main reason a sheet line chooses a factory-pigmented grade in the first place.

Should I be asking about veils as well as resin?

For outdoor sheet, yes. A surfacing veil keeps a resin-rich layer at the exposed face and delays reinforcement fibres from showing through as the surface erodes. Choosing a stabilised resin and ignoring the surface construction only addresses part of the problem.

Related products

UV Stabilized Sheet Grade Yellow Resin →Sheet Grade Yellow Resin →Glass Fiber Mat →MEKP Hardener →FRP Polyester Pigment →Roof Light Resin →

Running a coloured sheet or cladding line?

Tell us the sheet you produce, the profile, the exposure it is installed into and the surface construction you use. We will review the grade and put any document question to the supplier.

Contact Samrat FRP Traders