Resin Column/What is Flame-Retardant?
Resin Column/What is Flame-Retardant?
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The terms incombustible, flame-retardant, flame-proof, and fire-resistant are similar but have slightly different roles.
• Incombustible:
A material that does not burn when lit. Typical examples include glass and metal.
• Flame-retardant:
A material that can catch fire but does not spread easily.
• Flame-proof:
A material that can catch fire but extinguishes itself when the fire source is removed and does not spread easily.
• Fire-resistant:
A term used for “buildings and structures.” It is a performance designed to not break down in the event of a fire, or to maintain its function for a certain period of time.
At first glance, the terms are very similar, but there are strict differences.
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< About UL94, the flame retardant standard for resins >
UL94 of the United States is widely used as a representative standard for evaluating the flame retardancy of resins.
In this standard, fire is applied to a resin plate, and the flame retardancy is evaluated in 6 stages (HB to 5VA) based on the state of combustion.
[Premise]
Fire is applied to a resin plate, and the grade is judged based on the burning time, the falling of the spark, and the presence of holes.
< Main criteria (image) >
• HB: Fire is applied, and the grade is judged based on the burning time and burning speed.
• V-2: Fire burns when lit, and the burned spark drops.
• V-1: Fire burns when lit, but the spark does not fall.
• V-0: Burns but does not remove tinder, shorter burning time than V-1
• 5VB: Burns but does not remove tinder. However, if directly seared with strong flame, holes will appear
• 5VA: Burns but does not remove tinder, highest grade without holes even if seared with strong flame
*In actual tests, detailed conditions such as burning time and number of times are specified, but here is only an overview.
As for the level of flame retardancy,
HB < V-2 < V-1 < V-0 < 5VB < 5VA
It is easy to understand if you imagine that the flame retardancy is higher as you move to the right.
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< Specific Applications by UL94 Grade >
• HB: Applications with low flame retardancy requirements
Packaging materials, home appliance exteriors, building panels, general plastic parts, etc.
• V-2: Applications requiring light electrical safety
Small home appliance parts, switch covers, parts inside home appliances, etc.
• V-1: General level for electronic equipment
Electrical component cases, power unit parts, motor covers, etc.
• V-0: Standard level required for electronic equipment
This level is required as a standard for many electrical and electronic equipment.
PC and TV housings, connectors, battery holders, etc.
• 5VB: For high-energy electrical equipment
Applied to parts used under stricter conditions.
Electric control panels, power supply cases, electrical components of industrial equipment, etc.
• 5VA: Applications requiring particularly high reliability for fire safety
Used for critical parts used in high-energy environments close to fire sources.
High-voltage equipment, EV battery cases, aircraft parts, etc.
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< Introduction to SEKISUI SEIKEI Co., Ltd.’s Flame-Retardant PP Sheet >
Finally, we will briefly introduce SEKISUI SEIKEI Co., Ltd.’s flame-retardant resin products.
SEKISUI SEIKEI Co., Ltd., has a line of flame-retardant PP sheets.
The flame-retardant grades correspond to “UL 94” HB to V-0 and can be selected according to the application.
• They have excellent electrical insulation and do not cause hydrolysis.
• This material complies with stricter environmental regulations and does not contain the six substances regulated by the RoHS Directive.
• It can be proposed as an alternative material for various flame retardant specifications.
• We can provide individual responses including design aspects such as color toning and embossed patterns.
We are already used by many customers in a wide range of fields such as electrical and electronic equipment, automobiles, and building materials, as introduced in this article.
Products made from Polyvinyl Chloride(PVC) are also flame retardant, but we do not conduct UL testing for all our company products. Please contact us for details.
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