What are the applicable scenarios for polyurethane hot melt adhesive particles? Horizontal evaluation of PUR, EVA, and APAO adhesives

Direct answer: Polyurethanehot melt adhesiveParticles (PUR) are most suitable for three types of scenarios – wireless adhesive packaging for high-end hardcover books and photo books, export paper boxes that require high and low temperature resistance, and photo albums and sample books with zero tolerance for glue opening. It forms a cross-linked structure through moisture curing, with significantly higher adhesive strength and temperature resistance than EVA, but it is more expensive and must be used up as soon as possible after opening.

Industry status: Not all activities are worth pursuing PUR

The most frequently asked question for printing factories in the past two years is “Can you make PUR adhesive packaging?” Customers heard that PUR is good and requested to switch to PUR, only to find that the cost increased significantly and production capacity decreased – PUR requires sealed adhesive, humidity control, and residual adhesive cannot be recycled back to the furnace. The real decision on whether or not to use PUR is based on the requirements of the live parts themselves, not the reputation of the adhesive.

Horizontal evaluation of three types of hot melt adhesive particles

User pain point: Choosing the wrong one is not because it doesn’t stick, but because it’s not cost-effective

• Ordinary teaching aids and brochures use PUR, which has sufficient durability, but the cost per ton has increased, and customers are unwilling to pay for the invisible strength.
• Using EVA to export picture books to cold regions, the spine of the book becomes brittle and cracks easily after winter transportation.
• The sample booklet of copperplate paper with film coating uses ordinary adhesive, which has poor adhesion between the adhesive layer and the film coating surface. The wettability of PUR can actually save the field.

How to determine whether PUR should be used or not

• Check the usage environmentPUR is preferred for those who need to experience high temperatures above 60 ℃ or low temperatures below 0 ℃.
• Look at the paperPUR has obvious advantages for difficult to stick surfaces such as thick copperplate paper, laminated paper, and synthetic paper.
• Watch BatchFor graphic and text fast printing stores that frequently change orders in small batches, the waste of PUR residue may be higher than the rework saved.
• Check the unit price spaceCustomers can only negotiate PUR if they can accept an additional cost of a few cents per book.

Suggestions for Sunlife Hot Melt Adhesive

Guangzhou Sunlife Trading usually does not recommend PUR in a one size fits all manner when matching products for customers. High cost-effective EVA type Sunlife hot melt adhesive can meet the folding and tensile requirements for regular binding of books and periodicals; Only high-end, export, and long-term storage of such live parts are recommended to be PUR coated, and corresponding suggestions for adhesive temperature, opening time, and residual adhesive management should be provided to avoid buying good adhesive but not using it effectively.

Frequently Asked Questions

How long can PUR hot melt adhesive particles be stored after opening?

After exposure to air, it will continue to absorb moisture. It is recommended to use it up on duty. Unopened products should be stored in a dry environment according to the manufacturer’s shelf life label, and should not be left open for a long time after opening.

Can PUR be mixed with EVA?

Not recommended. The curing mechanisms of the two are different. After mixing, they are prone to clumping in the glue pot, and the cleaning cost is high. Before replacing the glue, the pipeline should be thoroughly emptied and cleaned.