ByPUR hot melt adhesiveThe bound books are tenacious in the surrounding environment, especially heat and low temperature resistance. We tested this through experiments. First simulate the temperature adaptability that the glued book will face in winter. The two books bound by PUR glue and EVA glue are put into the refrigerator at the same time. The set temperature is -20 degrees and the placing period is 12 hours. After 12 hours, the two books are removed from the refrigerator. The opened pages are compared. The book bound by EVA hot melt glue will produce brittle cracking sound. The book stickers have been opened and the pages are dropped, while the book bound by PUR glue is still intact. The high-temperature durability of PUR hot melt adhesive is tested in a hot environment. The books bound by PUR hot melt adhesive and EVA hot melt adhesive can be put into a drying room under the same conditions. The temperature of the drying room is 50 to 55 degrees. After being placed in such a temperature environment for 6 hours, the book adhesive layer bound by EVA hot melt adhesive gradually becomes soft, and as the book stickers fall off, the PUR adhesive is still intact. Under the idealized condition of book raw materials, there is no problem for PUR glue to be set at a temperature of -40 to 120 degrees. This is its good characteristic of integrating into hot and cold natural environment, far exceeding other hot melt adhesives, overcoming the burden of book binding temperature and quality hazards.

When ordinary hot melt adhesive is used to bind the book block on the printing paper with transverse silk lines and the coated paper with irregular lines, a large number of wrinkles will be generated at the pipe trench. However, the bonding temperature of PUR adhesive is low (the normal operating temperature is 120 degrees), which is not easy to lose the water flow of the internal structure of the printed paper at the spine. At the same time, the PUR adhesive layer has certain plasticity in the drying process, so that the paper fiber can be restored. Binding books and periodicals with PUR hot melt adhesive only needs to be roughed and slotted in an appropriate way, and the actual operation is appropriate. There will be no degumming and page removal, and the appearance will be adjusted after binding into a book. Also, because PUR hot melt adhesive is used less than other adhesives during binding, adhesive is rarely squeezed and extravasated when wrapping the adhesive, side adhesive and upper cover tuto, and there will be no uneven levels or vacancies during smooth edge cutting, thus keeping the structure of the spine stable.

PUR hot melt adhesive layer forming strong, with strong resistance to soluble, PUR hot melt adhesive is the only one that is resistant to both soluble and grease binding raw materials. The PUR hot melt adhesive layer formed by dry manic forming can penetrate into the oil and organic solvents used in printing, such as hydroxyhexane ketone and alcohol, etc., so that it gradually softens and even melts. With EVA hot melt adhesive softens and compressive strength decreases, the quality of books will be adversely affected by the risk of falling off. It is not difficult to see that PUR glue will not be affected by organic solvents, maintaining the original compressive strength of the adhesive, and greatly promoting the improvement of the quality of book binding.

For many years, the book core of the round-ridged hardcover book has been bound with a lock line. Before the book core bound with the lock line should be coated with a layer of flexible adhesive. A survey in the European market shows that brushing PUR hot melt adhesive on the book core that has been rounded can immediately set and chemically cross-link and solidify the book core, which can keep the round ridge appearance for a long time without wrinkle. PUR hot melt adhesive is a good choice for round back fine decoration pulp back,

It has the unique characteristics of smooth forming and high adhesion, which is more suitable for the binding of hardcover and the needs of readers. According to the calculation of relevant experts, using this binding method can save about 20%-30% of the cost, so PU binding is lower in cost and better in quality than thread binding. The new generation of PUR hot melt adhesive can be used to strip the circle together, brush PUR adhesive on the book core, and then strip the circle and ridge, so as to obtain a more special ring-shaped spine, because the PUR adhesive layer and the book core need to be dried in the ring-shaped condition, thus the continuity of the ring-shaped book back can be maximized. However, when the general hot melt adhesive binds the book core, it is usually glued first and then rounded, so the circular continuous moistening cannot pass the actual binding effect of PUR adhesive water bonding.

PUR hot melt adhesive has so many benefits, but it has not been widely used. Its core problem is cost. Although the price of PUR hot melt adhesive is about three times that of ordinary hot melt adhesive, the total number used is only half of that of ordinary hot melt adhesive. This number is especially important when considering the cost of a book. For example, a 16k book, about 2.5cm thick, costs about 0.1 yuan for ordinary hot melt adhesive, while it costs about 0.16 yuan for PUR hot melt adhesive to glue the same book. There is also an equipment maintenance cost for the selection of PU glue, and the modification of binding machinery and equipment will cost about 30-400000 yuan. It is these costs that limit the marketing promotion of PUR glue.