When to Use Liquild PUR Adhesive？

Cattie Adhesives – Liquid PUR Adhesive

What is Liquid PUR Adhesive?

Liquid PUR (Polyurethane) adhesives are reactive moisture curing adhesives known for Strong Bonds and Exceptional Heat, Cold and Moisture-Resistance; this makes liquid PUR adhesive an excellent choice for most difficult to bond, low energy substrates and they perform very well in extreme weather environments.

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Liquid PUR – One-component Cold Liquid moisture-cured polyurethane adhesives

– Our version of Industrial Strength  “Gorilla Glue”.

Our Liquid PUR adhesive forms permanent bonds by a chemical reaction with moisture from the substrate or environment.

These “Cold” Liquid PUR adhesives are liquid at room temperature so bonded parts must be pressed together and held during the curing process.

Standard Features:

• Great for wood, metals, ceramics, most plastics, HPL, Corian, stone and most porous/nonporous materials.
• 100% waterproof adhesive that bonds almost everything.
• Epoxy like strength; no mixing and fast cure time.
• Excellent Sandability.
• 100% solids and solvent free.
• Assembly time after glue application: 20-30 minutes.
• Application temperature: Above 50°F.
• Viscosity range: 4,000 – 10,000 cps.

Liquid PUR adhesive forms structural bonds to most difficult to bond substrates, and are especially good for gluing materials such as – carpet, wood, foam, metal and most plastics to each other. It is Not recommended for vinyl (PVC), polypropylene, polyethylene and polyolefins. Liquid PUR produces extremely durable, highly elastic bonds that perform well in both high and low temperature extremes.

Our Liquid PUR adhesives can be Custom Formulated to have Very High Initial Tack and a Very Fast Set up time from a few seconds, or up to Several Minutes of Open Time before setting up.

After Liquid PUR adhesive has been applied to a substrate it will start to cross-link and form a final bond. Depending on air humidity and substrate moisture conditions, PUR adhesive develops 50-80 % of its final bond strength in approximately 3 – 6 hours. The full reactive cure time is normally 24 to 36 hours after application.

PUR adhesives cure to a thermo-set material, maintaining their structural integrity once cured. PUR Adhesive has excellent temperature and environmental resistance – withstanding exposure to temperatures from -40°F to +300°F.

Our PUR adhesives are commonly used to bond Steel to Foamed polystyrene in large bonding areas. PUR adhesive is considered to be the best and most cost-effective adhesive for these types of applications. PUR adhesives are cured by reaction with atmospheric moisture to form a cross-linked thermoset system.

PUR adhesives can be formulated to have different open times and different rates of bond strength buildup. PUR adhesives are widely used for the bonding of large panels, such as in door manufacturing, garage door construction and the walls of recreational vehicles. PUR is also commonly used for laminating foil to sheet metal for the production of cans and bottle caps.

For bonding Large areas – Spraying or Roll Coating are often the best application methods for PUR adhesives.

PUR adhesive forms very strong permanent bonds to most materials including:

Solid Woods,  MDF/Particle Board,  Metal, Paper, Glass,  Wooden Veneer,  Clear Plastic Boxes,  Plastics,  PVC,  Foils.

Are you considering a PUR adhesive vs. Solvent based adhesives?

Polyurethane Adhesives (PUR) should be seriously considered when switching away from a Solvent-based adhesive system. PUR adhesives have numerous advantages over solvent-based adhesives.

The primary advantages of using PUR adhesive include:

The reduced cost of the adhesives, on a /lb. basis.
NO HAP’s or VOC’s, 100% Solvent Free.
The elimination of a plant explosion risk; lower insurance costs.
No more need for air pollution control devices.
The removal of dryers in the production line.

Some considerations on PUR  vs. Solvent-based adhesive:

The initial expense of new equipment to apply the PUR.
The special handling and fast clean up requirements with PUR.
PUR is more prone to cross linking and has lower resistance to solvents.

Our PUR adhesives are commonly used in the following Applications:

Profile Wrapping
Difficult to Bond-PET,PE,BOPP,UV

Foam & Mattress Fabricating
Furniture & Cabinet Assembly
R. V. and Panels
Woodworking and Picture Frames
General Product Assembly

Our PUR adhesives are available in 5 Gallon Pails, 55 Gallon Drums and 250 Gallon Tote bins, to meet a wide range of user applications.

What is Polyurethane PUR Hot Melt?

Polyurethane hot melt, commonly called PUR hot melt, is an adhesive that is heated and dispensed from a cartridge or slug using a heated gun or piece of bulk dispensing equipment. In comparison, traditional hot melt comes in stick or pellet form. PUR is also unique because it solidifies through moisture in the air to form a strong bond that will not re-melt. 

Because of its strength, durability, and fast set time, PUR is ideal for a wide variety of applications in woodworking, finish carpentry, shoe repair, furniture repair, broken glassware repair, laminate countertops, construction and remodeling, and more. It is also simple to dispense, cost effective and bonds to a lot of different substrates. 

PUR Hot Melt Uses

Polyurethane hot melt uses expand into a lot of manufacturing and product assembly applications across the world.  Applications for PUR adhesives often involve strong bonds to wood, plastics, fabrics, leather and many other materials. They are becoming increasingly popular because of how versatile they are.  

If you want to learn more, please visit our website Jiwei.

PUR can be applied as a bead or sprayed for covering large surface areas. These adhesives also come in a wide range of open times and viscosities allowing them to cater to specific application needs. 

Common Applications for PUR Hot Melt

• Automotive Manufacturing
• Door, Window and Floor Manufacturing
• Filter, Textile and Panel Assembly
• Woodworking and Edgebanding
• Spray Applications

The Difference Between PUR Hot Melt and Regular Hot Melt

Traditional Hot Melt Bonds

The biggest difference between PUR hot melt and traditional hot melt is the type of bond they create. Think of a traditional hot melt bond as a wax bond. You heat it up until it becomes liquid, apply it , and stick your two parts together.  

If you were to heat the parts back up, it would become liquid again and you could easily take the substrates apart. This isn't to say there aren't some very strong hot melt adhesives out there; this is just how the chemistry works.  

Polyurethane (PUR) Hot Melt Bonds

PUR hot melt is different than traditional hot melt in the bonds that it forms. It is dispensed in the same way with the adhesive being heated to a liquid state for application. But as it cools, PUR hot melt reacts with moisture in the air and changes chemically to create an incredibly strong bond. This bond then continues to strengthen over 24-48 hours until it is fully cured and super strong.  

Check out this tensile strength test between traditional hot melt adhesives and PUR hot melt adhesives:

Benefits of PUR Adhesives

• Stronger than Traditional Hot Melt
• Involves a Chemical Change - Not Just Thermal Bond
• Is Easy to Dispense - No Mixing Required
• Can Replace More Expensive Structural Adhesives
• Has Many Options for Open Time and Viscosity
• Is Cost Effective

Drawbacks of PUR Hot Melt

Up until this point it's been all roses and unicorns, but we're here to tell you there are some drawbacks to PUR hot melts. Remember that chemical change we talked about that gives PUR its strength and durability? Well, that chemical change that makes PUR the "Andre the Giant" of hot melts also comes with some downsides. 

Because PUR hot melt reacts with moisture in the air, it must also be protected from moisture before it is used. This means it has to be packaged in airtight cartridges or foil and cannot be exposed before use. It also means that PUR hot melt carries a shelf life of around 12 months (traditional hot melts have none). 

To modify a quote from Spiderman, “With great bonds comes great responsibility.” And this responsibility is a more difficult cleaning process. Large equipment used to dispense PUR must be cleaned and purged regularly with PUR hot melt cleaner because after the adhesive sets, it is very difficult to remove. This is not as big of a problem with cartridge-based adhesives as there are disposable nozzles that eliminate the need to purge and clean them.  

Drawbacks of PUR Adhesives

• Carry a Shelf Life of Around 12 Months (Traditional Hot Melts Have an Indefinite Shelf Life)
• Make Cleaning Guns and Equipment More Difficult
• Require More Specialized Guns and/or Dispensing Equipment

Applying PUR Hot Melt 

PUR hot melt can be dispensed either from PUR cartridge guns or from bulk equipment.Choosing what system is best for you will depend on your application and the volume being dispensed.

Using Cartridge Systems 

More popular than ever is dispensing PUR from smaller, less expensive cartridge guns. These easy-to-use dispensing systems are affordable and aren’t tethered to bulky melters that hinder movement and application freedom. Infinity PUR cartridges are available in 50 gram and 10 ounce sizes and work with all standard cartridge guns. 

50 Gram Cartridge Systems

The 50 gram PUR hot melt cartridges offer a low cost and simple way to dispense PUR. These systems are often used for woodworking, light product assembly and repairs. 

50 Gram PUR System Benefits

• Versatile Cordless or Corded Gun
• Low Cost
• Simple Operation
• Total Mobility / Freedom of Movement

10 Ounce Cartridge Systems

10 ounce PUR cartridge systems allow for higher output and more adhesive choices. The adhesive applicators are more expensive but still more affordable than large bulk dispensing systems. These applicators also connect to an air compressor allowing for effortless air-powered dispensing. They are available in both bead dispensing and spray dispensing options.

10 Ounce PUR System Benefits

• Pneumatic for Effortless Dispensing
• Lower Cost than Bulk Equipment
• Simple Operation
• Good Mobility
• Spray or Bead Extrusion Options

Using Bulk PUR Adhesive Systems

Bulk PUR hot melt adhesives require large, industrial equipment.Theyare a great option for automated or extremely high-volume dispensing applications. There are equipment drawbacks in terms of cost and maintenance but also cost savings using PUR in bulk sizes. The two most common bulk sizes are HOLZ-HER slugs used in edgebanding equipment and foil-wrapped slugs used in high volume and automated PUR equipment. Bulk PUR can also allow for more formulation options as it is less difficult to manufacture and pack. 

HOLZ-HER Slugs

For HOLZ-HER Edgebanding Machines

Bulk PUR Slugs

For Bulk PUR Dispensing Systems

Just a Little More PUR Information

We hope this overview has been helpful and you now better understand PUR hot melts applications as well as how they are dispensed.  

If you are looking for more details, kindly visit Liquild PUR Adhesive.