In the production and use of EVA hot melt adhesive in our country, binding is generally divided into two kinds of high speed adhesive and low speed adhesive, high speed adhesive curing speed is slightly faster, low speed adhesive curing speed is slightly slower; According to the adhesive material is divided into offset paper, coated paper with glue and so on; And there are glue and side glue, in order to adapt to the strength and needs of the adhesive, so as to achieve a good bonding effect. Use hot melt adhesive to master the preparation process before use, such as pre-glue, temperature, etc.

1. Preheating of EVA hot melt adhesive

Before the use of EVA hot melt adhesive, the first thing to do is to preheat and melt the solid adhesive. There are two ways of preheating: one is oil bath preheating, that is, the jacket melting pot preheating; The other is preheated by electric plate, which is preheated directly by electric plate device in the preheated pot. Preheating time is generally in 2 hours, when the colloid reaches the required heating temperature, and has good liquidity, that is, after preheating qualified, and then through the constant temperature pipe will release the glue liquid to the temperature in 160 ~ 200℃ working glue pot, for the use of adhesive binding books.

2. Adhesion strength and adaptability of EVA hot melt adhesive

In the actual production process, the adhesive force of hot melt adhesive will be different with the temperature of hot melt adhesive heating, the adhesive material is different and good, the width and depth of the milling back, the height of the glue, and the operation speed of the binder is different, get different bonding effect.

(1) the heating temperature of hot melt adhesive

The softening point of hot melt adhesive should generally be above 80 ° C, that is, when heated to 80 ° C, the colloid should begin to soften and dissolve. This temperature is only the temperature of hot melt adhesive melting, in order to make its melting to the extent of bonding books, heating temperature has to rise to 130 ~ 180℃. At this temperature, the viscosity of the colloid, fluid, viscosity and so on are suitable for the bonding of the book.

(2) the relationship between the difference of the book paper and the gluing temperature

The production of books this volume of paper texture is different, so the temperature of glue should also be different. This is not only because the fiber of the paper is different, more importantly, because of the type of paper, texture of the different colloid to produce different thermal conductivity, so that its cooling rate changes. Take the thermal conductivity of coated paper (also known as coating paper) and letterpress paper (non-coating paper) as an example, the cooling rate of the former glue is faster than the latter. Because the coating paper in the coated paper contained in the inorganic than non-coating paper letterpress, news, cardboard, etc., about 10 times high, and inorganic has good thermal conductivity, it can make the hot melt adhesive cooling speed.

For example, when the glue temperature is 170℃, the tensile test value of the hot melt adhesive of non-coating paper can meet the expected requirements, and the tensile value of coating paper can not reach. Therefore, in the coating paper glue, must increase its strength and improve the temperature of the glue.

(3) the relationship between the opening time of EVA hot melt adhesive and the running speed of production equipment.

Binding process in production, the use of hot melt adhesive when there are three times must be strictly controlled and controlled, that is, when open, curing and cooling hardening drying time. Opening time refers to the time when the glue is applied on the back of the book, curing time is the time when the cover is glued to the back of the book, cooling, hardening and drying time, and the time when the book with the cover is cooled and finalized after curing. Only through these three times, the book can finalize the design and achieve the ideal processing.

Use hot melt adhesive of this a few times, is closely linked with the equipment running speed, such as the opening time of hot melt adhesive is commonly 7 to 15 seconds, and this time is the adhesive binder for milling back transfer time, start from daub glue solution, to cover and the book so far) (excluding sticky book paper, this process must be completed in 15 seconds or less, the hot melt adhesive with good bonding effect can be achieved, if the equipment running speed is slow, finished the cementing job in 15 seconds, then the binding effect is not ideal, there will be a binding, glue, book after book out, off the page fault, etc. Therefore, the opening time of the hot melt adhesive should take into account the normal operation speed of the binder. The curing time of hot melt adhesive is generally the same as the opening time. Of course, users hope that the curing time will be shorter in order to facilitate the bonding of books.

In addition to opening and curing time, it also requires the basic accuracy of cooling, hardening and drying time, especially the glue used in the production line of wireless adhesive binding. Because this kind of production line is a linkage assembly line from the page matching machine to the book cutting, and its various parts are intersected with each other. Put the cover on the bag and send it to the publisher

Part time must conform to certain rules, to make the book cutting meet the ideal requirements, that is a book delivery time to ensure that the books in book cutting machine parts, should has cooled and hardened dry, to make the cutting finished product guarantee, the process should be completed in three minutes, otherwise there will be a great book deformation, the size of the finished product

Stability, stick knife phenomenon, affect the quality of finished products and cause undue losses. Therefore, the length of the book transmission device (conveyor belt) of the linkage production line should be selected according to the different running speed. The length of the conveyor belt is generally between 40 ~ 55 meters. It can also be long or short according to the need, but we must ensure that the cover is wrapped well

Books should be cooled for more than 3 minutes by moving on the conveyor belt.

The quality of book binding is determined by many factors such as paper, hot melt adhesive, binding material and process