Flame Retardant Polymer Powder for SLS

Flame Retardant Polymer Resin for SLA & DLP

Flame-retardant materials slow down the spread of fire because they are more resistant to catching fire and staying on fire, but they are not fire-proof. They are designed to minimize the risk of a fire starting when in contact with a small heat source, such as a small flame or an electrical fault.

There are a few ways that materials can achieve being flame-retardant:

• Using chemicals that react endothermically when heated. This means the chemicals involved in the reaction essentially absorb heat, reducing temperatures and slowing fires.
• Releasing an inert gas when heated, which acts to stifle the flames by cutting them off from oxygen.
• Having burning layers shield unburnt layers through the process of charring.

In general, any plastic components close to electrical current require some form of fire resistance or retardancy. Wire nuts, junction boxes, and internal cable supports are all examples of components at risk of catching fire if an electrical issue occurs. In addition, industrial machines, DIY tools, and household equipment, such as microwaves, toasters, and dishwashers all contain flame-retardant components.

In automative and aerospace industries, the insides of vehicles, such as the interior of a plane or the cockpit of a race car, also need to prevent the spread of fire to protect the human occupants.

In the product chart above, you’ll notice a range of certification standards to indicate a material is flame-retardant, but what do these really mean? Let’s take a look.

Underwriters Laboratories UL 94

UL 94 is probably the most common flame-retardant standard. This standard defines how flame retardant a material is by subjecting it to specific testing. The testing process involved to gain this certification includes having a part set alight repeatedly with an external flame.

To achieve the coveted 94 V-0 rating, the part must exhibit the following properties:

• Burning for less than 10 seconds after the first and second burn. This demonstrates how quickly parts made with the material would stop burning.
• Afterglow after the second flame needed to last less than 30 seconds. This is a good guide on how quickly the part cools after being set on fire. The longer a part remains hot enough to glow, the more likely it will reignite another part nearby.
• After being set on fire ten times, no material was allowed to drip that would ignite cotton batting. Dripping material that can ignite other material is a sign that a component could ignite further fires in its immediate surroundings.
• The combustion could not consume the whole sample. This is a useful measure of how difficult it is for a flame to travel along the material.

With 94-V.0 burning stops within 10 seconds on a vertical specimen, 94-V.1, and 94-V.2 means burning stops within 30 seconds, and so forth to 94-5VA and 94-5VB, which indicate a specimen will flame but stop burning within 60 seconds.

FAR 25.853

The US FAA (United States Federal Aviation Administration) designed a vertical Bunsen burner test to determine the flammability of materials used in airplane interiors including both cabin and cargo compartments. It’s called FAR 25.853, and it’s not uncommon to see a “FAR 25.853 – approved” stamp on some plastic products. To meet the standard, specimens are held vertically inside an enclosure and a Bunsen burner flame is applied from below for either 60 seconds or 12 seconds. After the flame application time has expired, the material is observed. Flame time, ignition time, burn length, and material drip flame time are documented.