Relationship Between Open Time Of EVA Hot Melt Adhesive And Operating Speed Of Production Equipment

In perfect binding production, three times must be strictly controlled when using hot melt adhesive: the opening time, the curing time, and the cooling and hardening drying time. The opening time refers to the time it takes to apply the adhesive to the spine; the curing time is the time it takes to bond the cover to the spine; and the cooling and hardening drying time is the time after curing when the book, covered and set, is ready for cutting. Only after these three times can the book achieve its desired shape and be properly finished.

These times for using hot melt adhesive are closely related to the operating speed of the equipment. For example, the opening time for hot melt adhesive is generally 7-15 seconds, which is precisely the time the perfect binding machine takes to mill the spine. From the application of the adhesive to the bonding of the cover and spine (excluding the gluing of the spine card), this process must be completed within 15 seconds to achieve a good bonding effect. If the equipment operates slowly and the bonding work cannot be completed within 15 seconds, the bonding effect will certainly be unsatisfactory, resulting in weak adhesion, failure to bond properly, and problems such as the book coming apart or pages falling out after binding. Therefore, the open time of hot melt adhesive must take into account the normal operating speed of the perfect binding machine. The curing time of hot melt adhesive is generally the same as the open time, although users may prefer a shorter curing time to facilitate the bonding and shaping of the books.

In addition to open and curing times, the cooling, hardening, and drying times must also be accurate, especially for adhesives used on perfect binding production lines. This is because such production lines are interconnected, running from collating to book cutting. The time it takes for the book to be conveyed from the cover to the cutting area must follow a specific pattern to ensure ideal book cutting. In other words, the conveying time must ensure that the book has cooled, hardened, and dried by the time it reaches the cutting machine to guarantee a good cut. This process should be completed within 3 minutes; otherwise, it may cause spine deformation, unstable finished product dimensions, and sticking to the cutting blade, affecting the quality of the finished product and causing unnecessary losses. Therefore, the length of the book conveying device (conveyor belt) in the production line must be selected according to the different operating speeds. The common length of the conveyor belt is between 40 and 55 meters, and it can be longer or shorter as needed. However, it is essential to ensure that the books with covers are cooled on the conveyor belt for more than 3 minutes.