Important Types of Hot Melt Adhesives
Hot melt adhesives are a versatile and widely used solution in different industries ranging from edge banding and furnitures, bookbinding and graphics, packaging to endless DIY applications. Their ability to bond quickly and effectively, cost-effectiveness, and being eco-friendly, made them so popular.
In this article, we'll explore and compare EVA Ethylene Vinyl Acetate and PUR Polyurethane hot melt adhesives. By understanding the differences, you can better decide which type to choose for your projects.
EVA Hot Melt Adhesives (Ethylene Vinyl Acetate):
EVA hot melt glue is the most common and widely used type in various industries. They are popular because they offer a good balance of cost performance. EVA adhesives are typically used in edge-banding and furnitures, packaging, bookbinding, and as glue sticks for DIY applications.
Characteristics of EVA Hot Melt Adhesives:
Temperature Range: EVA adhesives are applied at moderate to high temperatures, usually between 120°C and 220°C, allowing them to bond quickly as they cool.
Adhesion: They provide good adhesion to porous surfaces like wood, paper, and plastics, makes it ideal for furnitures, books, and paper packaging products.
Flexibility: EVA adhesives can tolerate some movement and bending in the materials they bond, which is helpful in applications with slight flexibility.
Cost: EVA hot melts are among the most affordable types of adhesives, making them a cost-effective option for large-scale industrial use.
Applications for EVA Hot Melt Adhesives:
Packaging: EVA hot melts are a popular choice for sealing carton and boxes as well laminated paper packaging, providing strong, fast-setting bonds.
Edge-banding & furnitures: EVA hot melts are commonly used in furniture assembly and edge banding due to their strong adhesion and ease of application.
Bookbinding: The ability to bond paper quickly makes EVA adhesives a go-to for bookbinding textbooks, magazines, and graphics .
Limitations:
While EVA adhesives are versatile, they have temperature and durability limitations. As a thermoplastic material, EVA will soften above 80°C so the bond can be weaken. As well, for difficult-to-bond and non-polar materials, it can perform poorly in bonding.
PUR (Polyurethane) Hot Melt Adhesives:
PUR adhesives are highly durable and form incredibly strong bonds, making them suitable for demanding industrial applications.
Unlike EVA adhesives, which form bonds primarily through cooling, PUR adhesives undergo a chemical curing process that strengthens the bond over time. This makes them a much more permanent adhesive solution compared to EVA.
Characteristics of PUR Hot Melt Adhesives:
Curing Process: PUR adhesives absorb moisture from the air or materials after being applied and cooled, triggering a curing process that forms a strong and permanent bond. This additional curing process sets PUR apart from other hot melts.
Temperature & Chemical Resistance: PUR adhesives are highly resistant to heat, chemicals, and environmental conditions, making them ideal for outdoor applications and products exposed to harsh environments.
Adhesion: They bond well to a wide range of materials, including plastics, metals, glass, and wood, offering much stronger adhesion than EVA adhesives.
Applications for PUR Hot Melt Adhesives in furnitures:
Edge banding: PUR adhesives are becoming more popular for high-end furnitures, where "zero" bond-line and environmental factors are critical.
Profile wrapping: PUR adhesives are taking the place of EVA adhesives for wrapping window and door frames, where strong bonds and resistance to heat and chemicals are important.
Lamination: PUR adhesives are becoming the go-to choice for lamination due to their excellent bonding strength, smooth surface finishes and environmental resistance.
Limitations:
While PUR adhesives are highly durable and form incredibly strong bonds, they can be costly and are very strict about conditions (i.e. temperature and humidity), not to say that it requires additional gluing equipment and regular maintenance.
Conclusion:
EVA hot melt adhesives is ideal for most-diverse bonding tasks where cost performance and streamline production are among the priorities. Whereas, PUR adhesives offer superior strength and temperature resistance, but requires additional equipment setup, maintenance and training.
By understanding the strengths and limitations of both types of adhesive, you can ensure that you're using the right one for your project.
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Published by TIANJIN SHENG-WANG ELECTRONIC CHEMICAL PLANT
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