How to Save Money When Buying PUR adhesive

Polyurethane hot melts are being used more and more in industries from high volume manufacturing to DIY and home repair. This is because PUR hot melts have some amazing characteristics that appeal to a huge set of users. PUR hot melts are non-toxic, quick setting, offer great temperature and weather resistance and are affordable at any volume requirement. Here is the Complete Guide to Polyurethane PUR hot melts to answer any questions you may have about this exciting adhesive technology. 

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Overview: the PUR hot melt technology

Discovered in the s in Switzerland, the PUR hot melt technology has enjoyed increasingly popularity, first across Europe, and then across the Atlantic in the U.S.A.

• What exactly is PUR? Polyurethane, or PUR, simply is a string of polymers that share similar chemistry, typically linked together by urethane (carbamate, an organic compound derived from carbamic acid).

• What's different from traditional hot melts? PUR is a so-called “reactive” adhesive because a chemical reaction needs to take place for the strong adhesive bond to work. Some moisture needs to be present to spark that chemical reaction and create the adhesive bond. The good news is that sufficient moisture exists in the air around us and usually in the material being glued.   

     - A 24-hour period of curing allows the moisture in the air to react with the PUR hot melt to create the strong bond.

     - PUR eliminates VOCs. The advanced technology and its chemical reaction with moisture free PUR hot melt from the need for solvents or formaldehyde—ensuring both a safer work experience and final product.

Characteristics of PUR hot melt

Following are key characteristics and benefits of using PUR hot melt as your go-to adhesive.

• It creates a stronger and longer lasting bond than traditional hot melt.

• It is flexible and adapts to different uses: it can be set hard or remain rubbery.

• It tolerates the widest temperature range and therefore is just as effective for indoor and outdoor applications.

• It is fast-curing. (Note: if the atmosphere tilts towards arid, it may need a longer curing time.)

• It achieves a high-quality bond with products that typically are difficult to bond, including nonporous materials. It works with materials that are different from each other.

• Less of the adhesive is needed for a strong bond, and less is wasted during the application process.

• PUR is known for its ease of use: no mixing or measuring is required.

• Its ease of use and fast curing time translates into more rapid production, which leads to lower labor costs.

• Once set, it can be sanded and/or painted, and it will not shrink or curl.

Top applications for PUR hot melt

Many industries now incorporate hot melt technology into their processes. Everything from footwear to mattresses to boat construction has pivoted to gluing with PUR hot melt in order to maximize ease of use and flexibility, take advantage of temperature and moisture tolerances, and reduce labor time. Below are brief descriptions of the top four applications for PUR holt melt.

• Cabinetry and furniture making rely on hot melt adhesives. This blog offers specific tips on assembling cabinets and drawers using a hot melt adhesive— which “provides superior strength, precision and quality without the time or expense of a hammer and nails.” Looking for information on APAO hot melt to use as a furniture adhesive? Look no further than this blog for specifics.

• Woodworking—whether it’s your hobby or your commercial industry—benefits from an array of PUR hot melt applications. Rapid curing and low strength properties make this adhesive your go-to in the woodworking shop. If you are on the design end of woodworking, nothing supports your design work like hot melt glue for creating maquettes to finalize your design.

The website Canadian Woodworking & Home Improvement suggests that you “Stack and hot-glue many pieces to save time in the shop,” and “When working with small parts, use hot melt glue to fasten them to larger pieces to make machining them safer.”

The blog, Woodworking Hot Melt Essentials, helps guide you through the experience of selecting the right adhesive or the job at hand. Two top PUR products for use in woodworking are available here and here.

• Product Assembly: Versatility is the name of the game when it comes to Product Assembly adhesives. PUR hot melt does the job regardless of how tough your bond substrates are. It adheres to plastics, glass, PVFs, aluminums, stainless steel and other metals. Most electronic and automated assembly lines benefit from a fast-curing adhesive that doesn’t need drying time or measuring, and bonds regardless of temperature swings or contact with water. 

As our blog, How Hot Metal Molding Can Replace Traditional Epoxy in Manufacturing, states, “The advantages of low pressure hot melt molding over traditional epoxy include ease of application, the elimination of curing times and an environmentally friendly process. Hot melt molding is particularly useful within the automotive and medical device industries which require the preparation of connectors and switches that need to be sealed and protected from water and dust.”  

     A top PUR product for general assembly use may be found here.

• Construction: Hot melt technology excels when it comes to window sealants, gaskets, foams, corrugated, fabrics, plastics, particle board, and light metal applications. Flooring, remodeling, countertops, and shower walls all benefit from hot melt adhesives’ ease of use and quick curing time. Let our blog on Solid Surfaces guide your use of hot melt adhesives in areas such as bathrooms.

Key differences between PUR hot melt and traditional hot melt

The PUR hot melt technology, with its chemical reaction with moisture, has reduced or eliminated heat-related disadvantages of traditional hot melt.

• PUR hot melt works better with substrates that are sensitive to high temperatures.
• Bonds remain strong at higher temperatures with PUR technology.
• PUR’s reactive technology creates a higher strength bond than most other adhesives.
• The quick cure time and superior bond strength mean that in a manufacturing environment, the substrate bonds formed by PUR’s reactive chemistry will not loosen.

• PUR’s flexibility, along with its wide temperature tolerance, and water and chemical resistance ensure its effectiveness in a wide range of both indoor and outdoor environments.

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

The future of PUR is here

Looking for a replacement for the discontinued Titebond HighPURformer line? Our Infinity PUR offers you the same formula and cartridges for ease of transition.

Your success is our business: please contact us with any questions about our products or applications. 

Related Products: Infinity Bond Flex 50 PUR Hot Melt Applicator

Goto BGP to know more.

Related Products

Polyurethane PUR hot melt is a great match for indoor and outdoor applications that need to stand up to the trials of time and harsh conditions. Today we will share our top tips for PUR adhesives, no matter the project! 

Overview of Polyurethane Hot Melt Adhesives

PUR hot melt has a hybrid chemistry designed to create and maintain a secure bond in wet environments, extreme temperatures, high-flexibility situations, and other less-than-ideal settings. 

It combines the advantages of traditional thermoplastic technology with the performance characteristics of reactive adhesive chemistries. It is extremely strong, can be engineered for flawless application in a variety of settings, and is the perfect choice in harsh environmental conditions.

PUR Best Practices

Dispensing Tips

Correct dispensing is vital to ensuring the performance of your adhesive. There are two main tips for preparing a cartridge for dispensing, first make sure to choose the correct temperature setting. Second of all, make sure to properly preheat your cartridge.

1. Choosing the Best Temperature Setting

These adhesives can be applied at temperatures ranging from 185-285 degrees Fahrenheit, which is a lower temperature than other hot melt formulations. Choose the "low temp" setting on your PUR cartridge gun for the most effective dispensing. 

The PUR applicator from Infinity Bond offers a powerful 500-watt heater and a dual (high and low) temperature settings. When using the Infinity PUR choose the green "low temp" setting for all 50 gram PUR cartridges.

2. Properly Preheating the Cartridge

Another tip of working with PUR hot melt is to make sure to properly preheat your cartridge for at least 15-20 mins before attempting to dispense the adhesive. Failing to properly preheat the cartridge will cause the plunger in your gun to break from force. With a properly preheated cartridge, the plunger will extrude the adhesive easily. 

Shelf Life of Polyurethane Hot Melt Adhesives

The typical shelf life of Polyurethane hot melt adhesives is 12 months. This is significantly shorter than other traditional hot melts. Make sure to follow these tips to prolong the shelf life of your polyurethane adhesive.

1. Proper Storage to Prolong Shelf Life

If unopened, PUR hot melt should be stored in a foil pouch in a cool, dry place. Proper storage will prevent premature activation, and keep it dry from rain or any other moisture. 

Did you know that you can cap and reuse a cartridge? If done properly, it is a great way to minimize adhesive waste. To recap a cartridge, first, extrude a one-inch bead of adhesive to remove all air from the tube. Next, securely attach the cap and store in a cool, dry place. If recapped and stored properly you can extend the shelf life of your Infinity Bond 50-gram cartridge up to 12 months. 

Polyurethane Hot Melt Cure Time

Understanding the chemistry behind these adhesives can save you a lot of frustrations later on. Although it is dispensed like a traditional hot melt, it will take much longer to fully cure, a full 24 hours to be exact. 

PUR hot melt adhesives generally have a longer cure time than other types of hot melt adhesives. They undergo a chemical change when they react with moisture in the air. Although PUR seems super-strong after 20 minutes, we always recommend waiting the full 24 hours before placing stress on the substrates and bonds.

We carry a variety of different cartridges with different open times. Common open times are 30, 60, 90, 120, and 150 seconds. If you are looking for a 30 second open time, we recommend the Infinity PUR WW30. We recommend Infinity PUR WW60 for a 60 second open time, and Infinity MP75 for longer (75 seconds) open time. 

Have Questions? Contact Us For a Personalized Product Recommendation

No matter the application, there's a PUR hot melt that will produce great results. The Infinity Bond line are available in 50 gram and 10-ounce cartridges and bulk sizes. Check out our selection of PUR hot melts today.