Discussion on the Development of PUR (I)

What is PUR Adhesive?

PUR adhesive is a polymer compound with a urethane bond (NH-CO-O). It is a rigid and soft hot melt adhesive with a large melting point and cold-resistance span. The melting point can reach 180°C. -40°C. PUR Adhesives have many advantages: they cure when exposed to air, and cannot be re-melted like EVA hot melt adhesives. This feature determines the strength of PUR adhesives and their strong bonding; the amount of PUR adhesives used Very provincial, the equivalent book, the amount of EVA hot melt adhesive is 1/3; it is thin, so the penetration is very strong; after drying the adhesive layer is thin, the thinnest can reach 0.3mm, while the minimum EVA can only reach 0.8mm; Environmental protection is good, because all the work is carried out under confined conditions, there is no problem with the health of the operating workers; in addition, it achieves wireless binding and solves the aesthetic problems of books and magazines. In short, it has truly achieved the “five changes” (automation, diversification, informatization, digitization, and environmental protection) of printing, and it has become the new darling of the new generation of bookbinding adhesives.

China's book binding market is very large. There are nearly 1,000 publishing units in China, and about 8 billion books are published every year. It is worth pondering that in the United States, 30% of publications have used PUR adhesives, and China faced such a huge post-press binding market, but it was almost a collective absence for this “feast” because the temptation to be beautiful was In front of it, PUR adhesives are not perfect, and the high cost, difficulty in adapting the sizing equipment, and the special process of product manufacturing have constrained its conception of “book binding”. Traditional enterprises struggling to survive seem to be far less able to “high and far” PUR adhesives.

To achieve its beauty, PUR adhesives have to be used in large-scale applications in China's post-press binding. How long is the application of domestic PUR adhesives in line with international standards? With these questions, the journal interviewed the teacher of post-print binding Wang Huaizhu.

"Outside" hot "inside" cold market

In fact, the popular PUR adhesive is not a new thing. PUR adhesives have long appeared in aircraft, shoes and hats and Other industrial manufacturing, but they have only been sought after by the printing industry in recent years. PUR adhesives were first tried for general paperback binding in North America, and it has now been found that PUR adhesives have a higher value in applications such as hardcover books, annual reports, catalogs, yellow pages, and magazines. Today, PUR adhesives have been rapidly promoted in North America. From the beginning of development in 1995 to now, the number of manufacturers has been increasing year by year. To date, at least 50 companies have used PUR adhesives. Faced with the large-scale development of PUR adhesives abroad, we can not help but notice that there are many differences in the specific actions of domestic companies compared with foreign companies.

The first is the lack of understanding. Many companies feel unfamiliar with this new technology. PUR adhesives are still in the stage of literacy and knowledge popularization in China. Second, due to the problem of ideas, it is difficult to abandon the old technology and adopt new products. Finally, the cost is high. Limitations, even if they fully recognize the advantages of PUR adhesives, are still on the sidelines.

In fact, domestic companies first consider the issue of survival, and their own funds are limited. They can only see the technology for one to two years. We understand this. Domestic companies must participate in this work, must have strong technical capabilities, are familiar with this process, and at the same time can help customers to integrate PUR adhesives and adhesives into post-press binding, and solve various after-effects for them. problem.

Obstacles to the Development of PUR Adhesives in China

The reason for users to wait and see comes from the fact that there are still many unresolved problems in PUR rubber binding.