Altropol AltroFoamFlex SF 280 – Flexible Polyurethane Foam 280 kg/m³ for Props & Industrial Parts
Altropol AltroFoamFlex SF 280 – Flexible Polyurethane Foam 280 kg/m³ for Props & Industrial Parts
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Premium Flexible Polyurethane Casting Foam for Props, Seat Cushions and Industrial Parts
Altropol AltroFoamFlex SF 280 is a two-component flexible polyurethane foam that you can process by hand or by machine. You mix component A (transparent) with the hardener NEUKADUR ISO 48 (brown) at a ratio of 100 : 38 by weight. At 25 °C the mixture has a viscosity of approx. 1,000 mPa·s, so it flows easily into moulds and cavities. After approx. 40 seconds it starts to foam; when free-risen, the volume increases about 3.8-fold and you get a firm, compressible foam with a density of approx. 280 kg/m³. The blowing agent contains no fluorinated hydrocarbons and the foam can be used in unheated moulds. Thanks to its high density it reproduces fine detail accurately, making it well suited to props and reproductions.
Professional use: mandatory diisocyanate training
The hardener NEUKADUR ISO 48 contains diisocyanates. Since 24 August 2023, this product may only be used industrially or professionally by workers who have completed the mandatory training on the safe use of diisocyanates (REACH Annex XVII, entry 74). Companies can register their staff via safeusediisocyanates.eu. You can find more information on our page working safely with polyurethane and diisocyanates.
Key Benefits
- Density 280 kg/m³: free-risen – a firm, flexible and compressible foam for parts that need to hold their shape.
- Detail-accurate: the high density picks up fine detail – ideal for props and precise reproductions.
- Mix ratio 100 : 38 by weight: matched to the set of 1 kg component A and 0.38 kg hardener – no leftover material when using a full set.
- Viscosity approx. 1,000 mPa·s: free-flowing mixture – fills even more complex moulds evenly.
- Start time approx. 40 seconds: enough time to mix and pour – while still allowing a fast production cycle.
- Free of fluorinated blowing agents: can be processed in unheated moulds – no preheating needed for free-rise foaming.
Typical Applications
- Props, set pieces and detail-accurate reproductions
- Seat cushions and soft, flexible parts
- Archery target backstops
- Parts for industrial applications
Processing instructions:
- Bring the material and workspace to at least 20 °C and work in dry conditions: the system is highly sensitive to moisture.
- Stir component A thoroughly before use.
- Weigh component A and the hardener accurately at a ratio of 100 : 38 by weight. For small quantities, use scales accurate to 0.01 gram.
- For manual processing, first pour component A into the mixing cup, add the hardener and mix thoroughly straight away, preferably with a high-speed stirrer at approx. 1,000 rpm.
- Pour the mixture into the mould immediately – the start time is approx. 40 seconds – and let it foam. For free-rise applications you do not need to preheat the mould. For integral parts with a rigid skin, preheat the mould to 45 to 50 °C.
- Close the containers tightly straight after each use.
Please note
- If the mixing ratio deviates by more than 3%, the stated properties will not be achieved.
- Larger quantities and higher temperatures shorten the working time considerably. Do not mix too much material at once.
- Altropol has not yet determined the rise and tack-free times (preliminary data sheet). Run a small test first when using a new mould.
- Do not use wooden spatulas or stirring sticks.
- Final properties are reached after approx. 7 days.
- Store the product in its tightly closed original container at 20 to 25 °C. The shelf life is stated on the label; the first two digits of the batch number indicate the week, the third digit the year. Use opened containers as soon as possible.
Manufactured by Altropol Kunststoff GmbH, German specialist in polyurethane and epoxy systems for mould and pattern making.
Professional Support
AltroFoamFlex SF 280 is a firm, flexible casting foam for props, seat cushions and industrial parts. Not sure about the right mould, mixing method or quantity for your foam part? Email us at info@siliconesandmore.com and we will be happy to help.
Product Properties
- Viscosity1000mPa·sViscosity of the uncured silicone
- Mix ratio100:38Mixing ratio A : B
Component Properties
- Color ATransparentColor of component A
- Color BBrownColor of component B
- Viscosity A1400mPa·sViscosity of component A
- Viscosity B500mPa·sViscosity of component B
- Density A1.02g/cm³Density of component A
- Density B1.21g/cm³Density of component B
Application
- Use caseProps, seat cushions, archery backstops and industrial partsIntended use
- Silicone type["PU"]Type of silicone or polymer
- Cure conditionRoom temperatureCondition under which the material cures
Processing
- Min. processing temperature20°CMaterial and room temperature
Foam Properties
- Foam typeFlexible foamType of foam
- Free-rise density280kg/m³Density of the free-risen foam
- Expansion3.8foldVolume increase on free rise
- Start time40secondsTime until the foam starts to rise
- Blowing agentFree of fluorinated hydrocarbonsAccording to data sheet
- Mould temperatureNot needed for free-rise foaming; 45 to 50 °C for integral partsRecommended mould temperature
Safety Information
The hardener NEUKADUR ISO 48 (component B) contains isocyanates and is classified with the signal word Danger: harmful if inhaled (H332), causes skin irritation (H315) and serious eye irritation (H319), may cause allergy or asthma symptoms or breathing difficulties if inhaled (H334), may cause an allergic skin reaction (H317), may cause respiratory irritation (H335), is suspected of causing cancer (H351) and may cause damage to organs through prolonged or repeated exposure (H373). Contains isocyanates, may produce an allergic reaction (EUH204). Component A (AltroFoamFlex SF 280 Comp. A) is not classified as hazardous under the CLP Regulation. Work in a well-ventilated room and do not breathe vapour or mist; if ventilation is inadequate, wear respiratory protection with an A2-P2 combination filter. Wear protective gloves to EN 374, for example nitrile rubber from 0.35 mm or butyl rubber from 0.5 mm, tight-fitting safety goggles and protective work clothing. People with respiratory or skin sensitivity (asthma, chronic bronchitis, chronic skin conditions) are advised not to work with the hardener. Wash your hands thoroughly after work and store the product locked up. Training on the safe use of diisocyanates is mandatory for industrial or professional use. For full information, consult the safety data sheets on this page; the supplied safety data sheet is authoritative. Component A is not classified as dangerous goods for transport.| Safety Pictograms | Safety Data Sheets (SDS) |
|---|---|
GHS hazard pictograms
 
Required protection (ISO 7010)
   |
| Signal Word | H‑code | Hazard Statement | P‑codes | P‑statements |
|---|---|---|---|---|
| Warning | EUH204 | - | - | |
| Warning | H315 | Causes skin irritation | P264 P280 P302+P352 P333+P313 |
|
| Warning | H317 | May cause an allergic skin reaction | P261 P272 P280 P302+P352 P333+P313 P362+P364 |
|
| Warning | H319 | Causes serious eye irritation | P264 P280 P305+P351+P338 P337+P313 |
|
| Warning | H332 | Harmful if inhaled | P261 P271 |
|
| Danger | H334 | May cause allergy or asthma symptoms or breathing difficulties if inhaled | P261 P284 P342+P311 |
|
| Warning | H335 | May cause respiratory irritation | P261 P271 |
|
| Warning | H351 | Suspected of causing cancer | P201 P202 P280 P308+P313 P405 P501 |
|
| Warning | H373 | May cause damage to organs through prolonged or repeated exposure | P260 P501 |
|
Technical data sheets
Frequently asked questions
What is the delivery time for my order?
Orders placed and paid on working days are in most cases shipped the same day. Weekend orders are processed on the next working day.
Indicative delivery times: Netherlands usually within 1 working day, Belgium and Germany typically 1–2 working days, other countries depending on destination and carrier. These are guidelines, not guarantees: peak periods, public holidays or carrier delays can have an effect.
What is the return policy?
You have 30 days to return after receipt. Email info@siliconesandmore.com within 30 days of delivery with your name and order number. The full conditions are in our return policy.
How can I track my order?
As soon as your order has shipped, you'll receive a track & trace code by email. It can take up to 24 hours before the code is active.
I have a problem with my order – how do I reach you?
Contact us via our contact page or email info@siliconesandmore.com. We're happy to help you quickly.
Can I order as a business?
Yes. Apply for a business account; we review your application within 3 working days. After that you order while logged in and pay on invoice, with payment terms of 14 days after delivery.
EU businesses outside the Netherlands with a valid VAT number order with VAT reverse-charged (0%, intra-community supply). The VAT number is stored in your business account; it cannot be added to an order after it has been placed.