Wholesale Puf Sandwich Panel For Wall China Factory - Bulk Supply and Specification Guide

Scope of Supply and Physical Form

Repeat loading drives the failure in cold-store envelopes long before the foam reaches its quoted lambda value. A 100 mm panel rated at 0.022 W/m·K still bows 3 mm over a 3 m span when the internal temperature cycles between -25 °C and +5 °C daily, and that deflection peels the steel-to-foam bond at the tongue-and-groove joint. We supply continuous-line PUF panels in 50-200 mm core thicknesses, 1 000 mm and 1 150 mm effective widths, and custom lengths up to 13.5 m to match container height. Facings are 0.4-0.7 mm AZ150 galvanized or 0.5 mm PVDF-coated steel; stainless 0.5 mm is available for aggressive wash-down zones. Every bundle ships with self-drilling stitch screws, butyl sealant tape, and PVC caps packed in the same crate so the site crew never waits for accessories.

What Actually Determines Performance

The limiting factor is rarely the headline specification. Thermal drift, not initial lambda, decides the 10-year energy bill. Blowing-agent diffusion raises core conductivity 8-12 % in the first 24 months; a panel that starts at 0.020 W/m·K settles around 0.022 W/m·K. Dimensional stability at -40 °C / +80 °C cycling controls joint integrity — panels that shrink > 1.5 % in length or > 2 % in thickness within 72 h at -20 °C will leak air at the vertical joints within two winters. Shear modulus of the foam core (typically 1.2-1.6 MPa at 40 kg/m³) governs racking resistance when the panel acts as a diaphragm; below 1.0 MPa the building relies entirely on the steel frame, adding secondary steel cost. Compressive strength at 10 % deformation must exceed 150 kPa for 150 mm panels spanning 4 m horizontally without intermediate supports.

Construction Method and Its Effect on Consistency

Fatigue appears at the stress concentration where the continuous line changes speed. Our double-belt laminator runs at 6-8 m/min with infrared pre-heating of the steel coil; this keeps the foam rise temperature uniform across the 1 200 mm width, eliminating the center-edge density gradient that causes camber. The pour head uses a high-pressure impingement mix (120-140 bar) with a static mixer calibrated daily by weight — not by timer — so the isocyanate index stays 105 ± 2. After demould, panels enter a 48 h conditioning tunnel at 45 °C / 40 % RH; this accelerates blowing-agent stabilization and locks in dimensional stability before the first cut. Cutting is done by CNC flying saw with diamond-tipped blades; tolerance on length is ± 2 mm, on squareness ± 1 mm/m. Every 50th panel is destructively tested for peel strength (minimum 0.45 MPa per EN 14509) and core density at three points across width.

Tooling Amortisation and Order Volume

A single colour change on the coil coating line costs 4 h downtime and 300 kg of scrap steel. For orders below 2 000 m² we batch colours into a weekly run; the buyer shares the changeover cost via a 3 % surcharge. Above 5 000 m² the line dedicates a full shift to that colour, removing the surcharge and cutting lead time from 18 to 10 working days. Custom lengths over 12 m require a special crating jig (one-time $1 200 tooling fee) but allow direct 40 ft HC loading without splice joints — a saving of 8 % installed cost on a 1 000 m² cold room.

Where This Product Beats Standard Alternatives

Compared to rock wool sandwich panels at the same U-value, PUF saves 35 mm wall thickness — translating to 3.5 % more rentable floor area in a 2 000 m² facility. Versus EPS core, PUF delivers 40 % higher shear modulus, allowing 1.2 m wider girt spacing and eliminating one row of secondary steel. The continuous line also guarantees facing-to-core bond consistency that hand-injected box panels cannot match; peel values on box panels scatter ± 30 %, while our line holds ± 8 %. For projects requiring FM approval, the double-catalyst PIR formulation on our line achieves Class 1 at 150 mm thickness where rock wool needs 200 mm and EPS is not listed.

Standard PUF (38 kg/m³)

Lambda: 0.022 W/m·K (aged)

Fire: EN 13501-1 B-s2,d0

Peel: 0.45 MPa min.

Cost index: 1.00

FM-Grade PIR (42 kg/m³)

Lambda: 0.020 W/m·K (aged)

Fire: FM 4880 Class 1, LPCB LPS 1181

Peel: 0.55 MPa min.

Cost index: 1.18

Quality Control and Batch Consistency

Each production lot (max 2 000 m²) receives a lot number stamped on the protective film at 1 m intervals. The QC folder ships with the cargo and contains: density certificates from the inline gamma gauge (reading every 200 mm), peel test reports from the start, middle, and end of the run, thermal conductivity sample tested at 10 °C mean temperature per EN 12667, and dimensional records for length, width, thickness, and squareness. We retain a 300 mm × 300 mm witness sample from every lot for 24 months. If a claim arises, the buyer cuts a 150 mm core plug from the suspect panel; we test it alongside the retained witness under the same lab conditions. Disputes resolve on data, not photos.

Questions Buyers Ask Before Ordering

Can we run a trial order of 500 m² to validate the line?

Minimum continuous run is 1 200 m² for a single colour and thickness because the pour head stabilizes after 300 m². Below that, the first panels show density drift up to ± 4 kg/m³. We can allocate 500 m² from a larger run of the same spec if another project shares the colour; otherwise the trial carries a 15 % setup premium.

What is the real lead time for a 3 000 m² order with custom length 11.8 m?

Coil procurement: 7 days if colour is in stock (RAL 9010, 9002, 7035, 5010), 21 days for custom RAL. Line scheduling: 3 days after coil arrival. Production: 2 days at 8 m/min. Conditioning: 48 h. Crating and load: 1 day. Total 14-28 calendar days ex-works. Add 7 days if the custom crating jig must be fabricated.

How do you handle the blowing-agent transition from cyclopentane to HFO?

The line is dual-feed; we switch blowing agent by valve changeover without stopping the laminator. Cyclopentane panels carry a GWP < 5 label; HFO-1233zd(E) panels carry GWP < 1. Both meet EU 2025 F-gas phase-down. Specify the agent at order — mixing agents in one project creates two different aged-lambda values and complicates energy modelling.

What warranty do you offer on delamination and thermal drift?

10 years against delamination (peel < 0.35 MPa) and 15 % max lambda increase from declared aged value, provided panels are installed per our fixing guide, joints are taped within 4 h of erection, and the building envelope maintains positive pressure ≥ 10 Pa in cold-store applications. Warranty excludes damage from over-drilling, chemical attack on facings, or structural deflection beyond L/200.

Next Step: Project Discussion

Send the panel schedule, fire rating requirement, and target U-value. We return a marked-up specification sheet with the exact foam grade, facing coil, and joint detail for your climate zone — plus a landed-cost model that splits coil, foam, freight, and accessories so you can compare against your current supplier line by line.

Open a project discussion — we reply within 4 working hours with the data pack.