Application of PUR hot melt adhesive
In recent years, with the overall improvement of the technical strength of packaging and printing, prepress design, packaging and printing, and post-press technology are all developing in a higher, faster and more precise direction. Nowadays, there are many binding adhesives to choose from, such as PUR hot melt adhesive, butadiene acetate) hot melt adhesive, PVA refrigeration solvent, etc. Let's first understand PUR hot melt adhesive.
In recent years, with the overall improvement of the technical strength of packaging and printing, prepress design, packaging and printing, and post-press technology are all developing in a higher, faster and more refined direction,There are now many options for binding glue, suchPUR hot melt adhesive, butadiene acetate) hot melt adhesive, PVA refrigeration solvent, etc. Let's first understandPUR hot melt adhesive.
PUR hot melt adhesive reacts with the molecular structure of the adhesive and the moisture in the air and the book core to produce an irreversible adhesive joint dry-solid structure, and Z finally forms a more stable and durable adhesive layer to ensure the quality of binding. PUR glue appeared in 1989 and was evaluated and applied on North American binding system software as early as possible. Through more than 20 years of development trend, PUR hot melt glue has achieved rapid development in Europe and America, especially in high-end books and magazines. Some countries in South America also clearly stipulate that teaching materials must be bound with PU glue. It is not difficult to see that the selection of PU glue is a development trend of binding development trend.
PUR hot melt adhesive is tailor-made to adapt to various different weights of printing paper, varnish oil on plastic film, printing ink and other related materials. This is an inorganic compound containing urethane bonds, and the tail end of its polymer chain is polyether polyol (polyester, polyether, etc.) and its low-content diol (chain extenter) and isocyanate-supported polymer. Diols and isocyanates reflect the production of rigid polymer chain segments, and isocyanates reflect the production of soft polymer chain segments, so PUR hot melt adhesive is a new hot melt adhesive with both tough and soft characteristics. It has a condensation reaction against moisture in the air, producing a particularly strong adhesive layer with the printing paper.
PUR hot melt adhesive has obvious practical effect on solving the problem of film or printed paper products coated with subfilm and UV varnish on the surface. It is determined by the characteristics of positive and negative electrodes of polyurethane material molecules. It can be better integrated with the coating on the surface to produce a stable adhesive layer and achieve the practical effect of high-quality glue adhesion.
The change of the weight of the printing paper and the difference between the coating and the printing ink used will not harm the adhesive effect of PUR hot melt adhesive. The new PUR product can stick various types of coated paper together. According to relevant experiments, the tensile strength of the printing paper using PUR hot melt adhesive is 40%-60% higher than that of the general adhesive.
For the existing adhesive, if the employee accidentally touches the printing ink on the binding network of books and periodicals, the binding quality of books and periodicals is likely to have problems, and PUR hot melt adhesive will not have binding product quality problems for this kind of situation.
Compared with standard EVA hot melt adhesive, PUR hot melt adhesive has a smaller amount of adhesive coating on the back of books. Although the clamping force is reduced, the compressive strength is not reduced but increased. PUR hot melt adhesive dispensing is much softer than standard EVA hot melt adhesive, so books and periodicals are opened neatly, and can be better shared without tapping with your hands when reading. The neatness of books improves the comfort of readers in reading articles.
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