What is the UV aging resistance of hot melt adhesive particles after bonding? Must read for outdoor scene selection

hot melt adhesive pelletsAre you afraid of ultraviolet rays?

Hot melt adhesive particles are based on high molecular weight materials such as EVA, PO, PA, etc. These materials undergo photo oxidative degradation under long-term UV irradiation – molecular chain breakage, decreased cross-linking degree, resulting in yellowing and brittleness of the adhesive layer, and decreased bonding strength. Ordinary EVA adhesive particles can experience a 40-60% decrease in adhesive strength after 3-6 months of exposure to direct sunlight outdoors.

How to improve UV durability?

• 1. Choose a UV resistant modelModified rubber particles containing UV stabilizers (hindered amine light stabilizer HALS+UV absorber UVA), with a decay rate of less than 15% after 12 months outdoors
• 2. Avoid exposing the adhesive layerWhen designing the bonding structure, hide the adhesive line inside the overlapping surface to reduce the direct sunlight area
• 3. Dark colored adhesive particles are superior to light colored onesCarbon black or dark fillers themselves have a light blocking effect, and under the same formula, dark colored rubber particles have better UV durability
• 4. Add a protective layerCovering the glue line with a layer of UV barrier film or applying protective paint can extend the durability time by 2-3 times

UV durability ranking of different substrates

PA polyamide>PO polyolefin>EVA, PA based hot melt adhesive particles have the best UV resistance. Sunlife hot melt adhesive UV resistant model adopts PO based+HALS/UVA formula. Guangzhou Sunlife Trading provides accelerated aging test report, and the strength retention rate after 1000 hours of QUV irradiation is greater than 85%.

Frequently Asked Questions

• Q: Is placing indoor windows considered UV exposure?
  A: Calculate. The UV through glass is about 30-50% of that outdoors, and long-term placement by the window can also cause the adhesive layer to age, albeit at a slower rate than outdoors.
• Q: How much more expensive are UV resistant rubber particles than ordinary rubber particles?
  A: About 20-30% more expensive, but the service life is extended by 3-5 times under outdoor applications, and the overall cost is better.