Hot Melt Adhesive - 318U, in Compliance with UL94 V-0 Flame Retardant

The adhesives used in electronic appliances need to have heat resistance and flame retardant properties.

The European Union also stipulates that the adhesives used in electrical products must pass the UL94 V-0 certificate before they can be sold in Europe. The RoHS Directive and REACH regulations also clearly stipulate that when used in electrical and electronic products, the raw material ingredients must meet their safety regulations before they are allowed to be used.
Due to the above reasons, we have developed a hot melt glue stick for fixing electronic components. This product not only needs to meet the requirements of heat resistance and bonding strength, but also the ingredients must comply with RoHS and REACH regulations, and pass the UL94 V-0 level flame retardant test. 318U is an eco-friendly glue stick developed to meet these requirements.

318U is a polyolefin flame retardant adhesive certified by UL94 V-0. It is applied to fix the electrical components on the motherboard. Generally, the flame retardants added to flame retardant adhesives are complex and the ingredients often contain substances that are harmful to the environment. These harmful substances include heavy metals and antimony trioxide banned by EU RoHS Substances of Very High Concern(SVHC) banned by EU REACH and some halogen components. Among the common flame retardants, halogen flame retardants have the best flame retardant effect. This is why most flame retardant adhesives often add flame retardants containing halogen components.

However, with the growth of environmental awareness, a new generation of UL-certified flame retardant adhesive -318U has removed all these harmful substances and replaced them with environmental friendly phosphorus-based flame retardants. Besides, 318U greatly reduces the amount of flame retardant added and improves the bonding strength to various materials. Generally speaking, the amount of halogen flame retardants added is approximately 15% to 20%, such as 918A and 914W. The amount of phosphorus-based flame retardants is approximately 20% to 35%. But in 318U, the flame retardant proportion is lower than 10% and passed UL94 V-0 test. This shows that 318U is a major breakthrough for such applications.

Fig.1 is a brief description form to show Tex Year UL grade adhesive status.

We can detect 914W containing abundant quantity of heavy metal, Sb2O3, PBDE and halogen. These substances are harmful to the environment. 918A also contains these substances except PBDE. 318U is the only product in Tex Year without containing these harmful substances.
 

Items	914W	918A	318U
RoHS 2.0	With lead(Pb) 5 ppm	With lead(Pb) 5 ppm	Not detected
RoHS-Sb2O3	contain	contain	Not detected
REACH SVHC	With PBDE	Not detected	Not detected
Halogen Free (Green peace)	With Br and Cl	With Br and Cl	Not detected

(Fig.1 ) The above test items are all supported by test reports.
 

	Features	Benefits
1	High heat resistance, high adhesion strength	Easy to apply to electrical applications
2	APAO based	Good electrical properties
3	Low density	Lower glue consumption
4	Low flame retardant added amount	Reduce pipeline pollution and high bonding strength
5	Heavy metal free & Sb2O3 free & SVHC free & halogen free	To satisfy future RoHS & REACH regulations

UL94 Rating Scale

• HB: Slow burning on a horizontal specimen; burning rate < 76 mm/min for thickness < 3 mm or burning stops before 100 mm. 
• V-2: Burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are no inflamed. 
• V-1: Burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
• V-0: Burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. 
• 5VB: Burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole. 
• 5VA: Burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole. 

Adhesive chemists combine a number of additives to make fire retardant adhesives - and sometime even to quench flames (although this feature is harder to achieve nowadays with many goods manufacturers now requesting halogen-free formulations).

It is a perfect balance as these additives will cause interference to other adhesive properties such as strength, rheology, cure speed, flexibility, etc.



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