PUR Bookbinding Adhesive

PUR bookbinding adhesive is a reactive polyurethane hot melt adhesive specially designed for high quality book manufacturing. PUR cures by chemical reaction with ambient moisture, unlike conventional hot melt glues which bond by cooling and solidifying, and the bond cannot be remelted, reversed or broken down by heat or humidity.

The process takes place in two steps. PUR sets within seconds when applied and the binding line can be operated at normal production speed. The polyurethane chemistry moisture-cure reaction finishes in the next 24 to 72 hours, resulting in a flexible, waterproof and structurally sound permanent bond for the life of the book. The outcome is a flat back that remains stable even under heavy use and will maintain its integrity in all climates.

For high-end books, coated paper stocks and digital print substrates where the quality of the finished book is paramount, PUR bookbinding adhesive is the industry standard.

Not certain if PUR is the appropriate specification for your manufacturing? Consult our adhesive experts and receive a definite recommendation within 24 hours.

Why Choose PUR Bookbinding Adhesive for Premium Publications?

PUR bookbinding adhesive

PUR bookbinding adhesive is superior to traditional hot melt systems for premium bookbinding applications. Whether it’s lay-flat opening and superior coated paper adhesion, or long-term durability, PUR enables publishers and printers to create books that look better, perform better, and last longer.

Lay-Flat Performance

A book that does not close easily is not of good quality and will not be a good reading experience. Once cured, PUR adhesive will not crack and will not provide excessive resistance to the spine’s bend. This versatility lends itself to the production of photo books, art books, children’s books and other high quality publications.

Superior Adhesion to Coated Papers

Traditional hot melt adhesives can be challenging to use with coated papers such as gloss, matte, and others. PUR bonds extremely well with coated stocks and provides excellent performance even in the most demanding applications, while minimizing the potential for page separation.

Ideal for Digital Printing

Digital printing substrates may have special bonding requirements because of toners and specialty coatings. PUR adhesive works well with digitally printed materials and is a great choice for short-run printing, print-on-demand books and customised publishing applications.

Long-Term Durability

During the life of a book, it is opened and handled many times, exposed to temperature fluctuations, and stored in different conditions. PUR adhesive is extremely durable and will retain binding integrity over time when fully cured, thus it can be used for reference books, archival publications, high-value printed materials, etc.

Moisture and Heat Resistance

PUR adhesive is highly resistant to humidity and temperature changes. This extra protection is beneficial in difficult environments to maintain the quality of the binding and in the overall service life of the final product.

Need the perfect PUR bookbinding adhesive for your printing or publishing job? Call us for product suggestions, technical support and sample testing.

Technical Specifications

Parameter	Standard PUR Grade	Low-Viscosity Grade
Appearance	Amber / Yellow Pellets	Amber Pellets
Softening Point	N/A (thermoset after cure)	N/A (thermoset after cure)
Melt Viscosity @ 120°C	8,000–15,000 cps	4,000–8,000 cps
Recommended Application Temp.	110–130°C (230–266°F)	100–120°C (212–248°F)
Open Time	8–20 seconds	6–15 seconds
Initial Set Time	10–30 seconds	8–20 seconds
Heat Resistance (post-cure)	Up to 100°C	Up to 90°C
Cold Crack Resistance	–20°C	–20°C
Water Resistance	Excellent (post-cure)	Excellent (post-cure)

The technical data mentioned above is only for reference and may be different under different application conditions, different substrates and different production environments. Testing under production conditions is recommended for optimum performance. Technical data sheets and application instructions are available in detail and are available upon request.

Applications of PUR Bookbinding Adhesive

PUR bookbinding adhesive is used in a wide range of high-quality applications in the publishing and commercial printing industry where high bond strength, flexibility and long-term durability are required. It is especially recommended for coated papers, digital printing substrates and high value publications for superior binding performance.

Photo Books & Art Books

Heavy coated paper stocks are commonly used in photo books and art publications, which require a stronger binding system. PUR bookbinding adhesive ensures strong adhesion and lay-flat qualities, enabling readers to open the book easily without compromising the integrity of the binding. It’s perfect for photo books, coffee table books and fine art publications.

Hardcover Books

Hardcover and case-bound books are intended to be handled many times and must be bound with an adhesive that will resist repeated handling. PUR bookbinding adhesive will provide superior flexibility and durability once cured, ensuring the strength and stability of the spine during the life of the book. It is commonly employed in hardcover books, reference books, educational publications and archival materials.

Digital Printing

Toner layers and specialty coatings can make digital printing substrates challenging to bind. PUR is a preferred choice of adhesive for print-on-demand books, personalized publications, short-run production, and digitally printed catalogs, as it is a reliable bond for digitally printed papers. It performs consistently well, allowing printers to produce professional binding quality in a variety of digital applications.

Coated Paper Books

Gloss, matte, silk coated and art papers demand an adhesive that provides strong and consistent adhesion. PUR bookbinding adhesive for coated paper books helps to prevent page separation and can guarantee stable performance even in severe publishing conditions. It is used in the production of high-end catalogues, corporate brochures, annual reports, and high-end marketing materials.

Premium Catalogs & Brand Books

Laminated covers, UV coatings and specialty finishes are common features on high-end catalogs and brand publications. PUR bookbinding adhesive can provide a stable bond on such difficult materials, which can ensure the stability of the cover and its long-term performance during shipping, storage and daily use.

Need the perfect PUR book binding glue for your paper stock or printing method? Please reach out to our staff for product suggestions, technical assistance and sample testing.

What You Should Know About PUR Spine Glue & Side Glue

There are two different applications of PUR bookbinding adhesive in the bindery, with different performance needs. When it comes to gluing books, the right adhesive will make them durable, flexible and professional.

PUR Spine Glue for Perfect Binding

Applied to the milled spine, PUR spine glue provides excellent adhesion to coated paper and digital printing substrates. It has a flexible chemical bond which enables the spine to open flat without cracking, resulting in high pull strength of the pages and durability. PUR spine glue is ideal for photo books, art books, hardcover publications and for any high-value binding application, outperforming conventional hot melt adhesives in maintaining structural integrity.

PUR Side Glue for Structural Stability

The side edges of the book block are glued together with PUR side glue for stability and to retain the cover. It is able to resist high page count, repeated handling, and temperature and humidity changes. It is ideal for books with many pages, high-end catalogs and premium case-bound publications that need to stand the test of time. Where traditional EVA adhesives fall short, PUR side glue ensures consistent performance.

Our technical staff will be able to make recommendations for spine and side glues that are best suited for your machine, paper stock and production needs.

Frequently Asked Questions

Is PUR bookbinding adhesive compatible with standard EVA binding equipment?

Not directly. PUR adhesive must be stored in a dedicated glue pot that has a moisture-resistant, sealed tank to avoid premature curing. Open EVA glue pots are not recommended for PUR because they allow the adhesive to come into contact with the surrounding environment. PUR-compatible tank and applicator systems are available from most of the big binding machine manufacturers such as Kolbus, Müller Martini and Horizon. If you are considering switching to PUR we can advise you on the equipment required for your machine model.

How does moisture curing work, and does workshop humidity affect the process?

PUR adhesive cures when it comes into contact with moisture in the paper substrate and in the air. The cure is hastened by higher humidity and slowed by lower humidity. In practice, most commercial binderies are using a humidity range that is between 24 and 48 hours cure time. Cure time can be prolonged to 72 hours in very dry environments..

How long before PUR-bound books can be trimmed, packed, and shipped?

The thermoplastic set offers adequate strength to stack and convey immediately after initial handling, after the book leaves the binding line. Trimming, three-knife cutting and packing for shipment should be done after the moisture cure is complete, usually 24–48 hours after binding. If trimming occurs prior to full cure, it can cause stress on the spine bond, and affect final peel strength.

How should unused PUR adhesive be stored after opening?

After opening, PUR bookbinding adhesive should be immediately re-sealed in its moisture barrier packaging. The curing reaction will start in the remaining adhesive when exposed to ambient humidity, which will shorten the useful life of the adhesive. Never put partially cured adhesive back into a new bag.

How does PUR glue pot cleanup differ from EVA?

The pot is only to be reheated for EVA cleanup to remove any adhesive residue. PUR cleanup is a special PUR purging compound used to remove and neutralise any remaining adhesive before it sets in the system. The process is longer than EVA cleanup, but easy to perform when using the proper materials.

Work With a Manufacturer Who Specialises in PUR Adhesive

Adhesive (Shanghai) Co., Ltd. has been developing PUR bookbinding adhesives for over 20 years. Our dedicated reactive PUR formulations are designed for high end publishing and not a second line product. All batches are bonded to stability of over 99%. ISO, CE and CARB certified production for consistency.

We serve the highest quality print shops, commercial binderies and distributors in more than 30 countries. From a standard PUR grade for production to a custom formulation to match a particular substrate, open time or viscosity, we can provide it.

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