4. Plastic pot
According to experts, the plastic pot used by PUR can be either a traditional plastic pot or a specially made plastic pot. Nordson, based in OH, USA, is a manufacturer of pre-molten containers and nozzle extruders. They have also developed some Single wheel device that can be matched with existing binding equipment. A few years ago, KOLBUS developed a special glue pot for its own binding equipment. Closely thereafter, Martini also developed PUR plastic pots for some of the company's products, such as Corona, Acoro and others. Star binding equipment.
5. Closed extrusion system
Usually the closed extrusion system consists of a premelting device, a box and a connecting tube. Because of this piece of technology, the popularity and development of the PUR binding technology is limited, and many companies are trying to improve the system.
Germany's Inatec Gmbh has developed a new system that can move between the paper feeding device of the binding device and the cover station, extrudes the PUR to complete the gluing of the cover, and sticks the cover to the book block. This method is very effective because the paper material is easy to glue, and the spine after the cover is also very smooth, the pressure of the cover station determines the penetration effect of PUR glue.
The latest technology developed by Nordson pumps PUR glue into a heated tube and then pushes PUR to the lower end of each book. Since last year, this system has been installed in the United States in three sets and there are also several sets in use in Europe. The system's nozzles can be turned on and off under control to control the flow of glue. This innovation also keeps the extruding device isolated from the air and avoids waste of PUR. This is mainly due to the prolonged exposure of the PUR to air curing.
Nordson's technology is best used on a new binding machine or a modified binding machine to achieve the most satisfactory results, so when the book block passes through the extrusion head, there is no need to change the height of the card reader and it is more stable. The pressure exerted by the cover station ensures that PUR penetrates into the spine.
It is recommended not to use PUR for older, glue-binding equipment. Machine wear is too great and accuracy is difficult to guarantee.
Cost problem
The most important issue of PUR is cost. Although the price of PUR is about three times that of ordinary hot melts, the amount used is only half that of ordinary hot melts. When considering the cost of the entire book, this figure is very important. For example, an 8.5 x 11-inch book, which is about 1 inch thick, costs about 1.3 cents (assuming $1.35 pounds per pound) for a typical hot melt. Using PUR to squeegee the same book will cost about 2%. Minute. A manager has shown that the cost of using PUR growth is very insignificant, and 100 books have only grown by 70 cents, but using PUR can save a lot of heart and avoid many complaints.
Many users of PUR did not choose to use hot melt because of the difference in cost. In addition, once PUR is used, operators can quickly become familiar with the equipment settings and produce high-quality products.
On the issue of cost, some users may mention that there is still a cost of equipment modification with PUR. Since the PUR is a 55-gallon drum (or a 5-gallon keg for small users), the binding device needs to have a device to transfer these materials to the glue pan or to the extrusion head, the most commonly used It is a container handling device. One such device costs about $25,000 to $50,000, and the application system costs an additional $25,000 to $35,000.
The problem of production efficiency
Curing (drying) time is also a common concern, although the first generation of PUR process can be made online cutting, but it must be 24 hours after binding to ensure the strength and orderliness of the book.
The second-generation PUR was developed in 1994. It can already be used for online cutting, and the stack thickness has also been increased. It is only necessary to perform cutting within 4 hours after binding.
The curing time for the third-generation PUR is only 1 hour, and it does not matter if there is still a significant amount of moisture in the paper. After cutting, you can package it immediately. But this also has a certain negative effect, because PUR can quickly reach the relative strength, so the PUR in the plastic pot becomes very heavy, in wet environments, this situation is more obvious.
Finally, the fourth-generation PUR has also been very mature, thinner than the third generation, but with the same strength, it can also be stored for a longer period of time. The current generation has largely replaced the second and third generation PURs, and it is also used well 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 company has also been improved.
The future of PUR
PUR is used in medium-sized printing companies, mostly for binding magazines and annual reports. Since most of this type of job is coated paper or cross-hatch paper, there will be more and more users of 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 achieve better quality and product durability. Even some small businesses have begun to try PUR binding process.
Hardcover book is the main application field of future PUR binding. Because the cost advantage of PUR binding cover is higher than Smythe lock line, and the fourth generation PUR technology can realize online rounding, many hardcover book manufacturers also begin to carry out this technology. Research. The number of PUR applications in hardcover books will gradually increase, and people will increasingly realize that this technology can save costs without sacrificing product quality.
Promote PUR to Customers
Although printers and binders are beginning to understand the benefits of using PUR, their customers may be reluctant to adopt this more expensive adhesive. A commercial binder plant in the United States discovered a way for customers to endorse this process: they gave their customers an experiment to bind the same book with EVA and PUR on a cold night and then open it in the morning. In both books, it was found that books bound with EVA had been cracked, and books bound with PUR were intact. Through a small experiment, the customer convinced the application of this new process.
In addition, PUR is less sensitive to temperature. Suppose you put a book in the car in the winter, or in the summer, you can find that the books bound by the EVA method have been destroyed, while the PUR has not been affected.
If you spend a little more on the cost but you can get better product quality, why not ?
There are also some jobs that require the use of PUR Adhesives, such as a book with a shiny surface and a very smooth paper. The ink has penetrated into the gutter and has been die-cut, covered with a liquid film and requires high-strength binding. At this time, PUR became the only adhesive that strongly glued the pages.
In summary, printers and binders can perform a variety of 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 be a daily task and should satisfy every requirement of customers as much as possible.
