The German Inatec Gmbh company has developed a new system that can be moved between the paper feeding device of the binding equipment and the cover station, extrude PUR to complete the gluing of the cover, and paste the cover on the book block. In this way, the paper material is easy to glue, so the effect is very good, and the spine after the cover is also very smooth. The pressure of the cover station determines the penetration effect of the PUR glue.
The latest technology developed by Nordson pumps PUR glue into a heated tube and then squeezes PUR to the lower end of each book. Since last year, three sets of this system have been installed in the United States and several sets are in use in Europe. The glue nozzle of this system can be opened and closed under control to control the flow of glue. This innovation can also always isolate the extrusion device from the air to avoid the waste of PUR. This is mainly because PUR will solidify when exposed to air for a long time.
Nordson's technology is best used on new or modified binding machines to achieve the most satisfactory results. Therefore, when the book block passes through the extrusion head, there is no need to change the height of the book holder and it is more stable. The pressure applied by the cover station ensures that the PUR penetrates into the spine.
It is recommended not to use PUR on older wireless binding equipment. The machine wears too much and the accuracy is difficult to guarantee.
Cost problem
One of the main problems of PUR is cost. Although the price of PUR is about three times that of ordinary hot melt, but the amount used is only half of ordinary hot melt. This number is quite important when considering the cost of the entire book. For example, an 8.5 × 11-inch book is about 1 inch thick. A typical hot-melt solution costs about 1.3 cents (assuming $ 1.35 per pound). Using PUR to glue the same book costs about 2 cents. Minute. A manager said that the cost of using PUR to increase is very insignificant, 100 books only increased by 70 cents, but using PUR can save a lot of attention and avoid many complaints.
Many PUR users did not choose to use hot melt because of this difference in cost. In addition, once you start using PUR, the operator can quickly become familiar with the equipment settings and produce high-quality products.
In terms of cost, maybe some users will mention that there is a cost of equipment modification when using PUR. Because PUR is a 55-gallon drum (or a 5-gallon drum for small users), the binding equipment needs a device to transfer these materials to the glue pot or to the extrusion head, the most commonly used It is a container handling device. Such a device may cost between US $ 25,000 and US $ 50,000, while the application system costs an additional US $ 25,000-35,000.
Productivity issues
The curing (drying) time is also a matter of general concern. Although the first-generation PUR process can be cut online, it must be done 24 hours after binding to ensure the strength and regularity of the book.
The second-generation PUR was developed in 1994, and can already be cut online, the thickness of the stack has increased, and it can be cut only 4 hours after binding.
The curing time of the third-generation PUR only takes 1 hour, although there is still a considerable amount of moisture in the paper. After cutting, you can pack it immediately. But this also has a certain negative effect. Because PUR can quickly reach the relative strength, the PUR in the glue pot becomes very heavy, which is more obvious in a humid environment.
Finally, the fourth-generation PUR is also very mature and thinner than the third-generation PUR, but has the same strength and can be stored for a longer period of time. The current generation has largely replaced the second and third generation of PUR, and is also well used in the latest extrusion systems.
Due to the fast drying speed of this new adhesive, the production efficiency has been significantly improved, and the flexibility of the enterprise has also been improved.
The future of PUR
PUR is widely used in medium-sized printing companies, and is mostly used for the binding of periodicals and annual reports. Since most of this type of work is coated paper or horizontal thread paper, there will be more and more users using PUR in the market. In addition, more and more publishers are also aware of the advantages of PUR technology, and are beginning to turn to this method to obtain better quality and product durability. Even some small businesses have begun to experiment with the PUR binding process.
Hardcover books are the main field of PUR binding in the future. Because the cost advantage of PUR binding covers is higher than Smythe lock thread, and the fourth-generation PUR technology can achieve online rounding, many hardcover book manufacturers have begun to carry out this technology. Research. The number of PUR applied to hardcover books will gradually increase, and people will more and more realize that this technology can save costs without sacrificing product quality.
Promote to customers
Although printing companies and bookbinding factories are beginning to understand the benefits of using PUR, their customers may not be willing to use this more expensive adhesive. A commercial bookbinding factory in the United States discovered a way for customers to approve this process: they did an experiment for the client, bound the same book in two ways with EVA and PUR on a cold night, and then opened this in the morning Two books, found that the book bound with EVA has cracked, while the book bound with PUR is intact. Through a small experiment, customers were convinced of the application of this new process.
In addition, PUR is less sensitive to temperature. Suppose you put a book in a car in winter, or in summer, you can find that the book bound by the EVA method is damaged, but the PUR is not affected.
If you spend a little more cost but can get better product quality, why not do it?
There are also some operations that require the use of PUR strong adhesives. For example, a book with a glossy surface and very smooth paper, the ink has penetrated into the binding line, and it has been die-cut and covered with a liquid film. At this time, PUR has become the only adhesive that strongly binds pages.
In summary, printing plants and bookbinding plants can perform multiple glue tests on an unknown paper material in order to achieve the best customer satisfaction and the least complaints. Some experts believe that testing should become a routine task and should satisfy every customer requirement as much as possible.
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