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For EVA hot melt adhesive used for binding, it can be divided into high-speed adhesive and low-speed adhesive according to different curing times. The curing speed of high-speed adhesive is slightly faster, while the curing speed of low-speed adhesive is slightly slower. According to the material of the book, it is divided into laminated paper and copperplate paper adhesive. It is divided into back glue and side glue according to different usage positions. Choose different EVA hot melt adhesives to meet the strength and requirements of the adhesive, in order to achieve a good bonding effect. When using EVA hot melt adhesive, it is necessary to master the preparation procedures before use, such as preheating, temperature, etc.
Before using EVA hot melt adhesive, the solid adhesive must be preheated and melted. There are two preheating methods: one is oil bath preheating. Another method is to preheat with an electric heating plate, which means using an electric heating plate device to preheat directly in the preheating furnace. The preheating time is generally 2 hours. When the gel reaches the required heating temperature and has good fluidity, the glue is released into a working glue pot with a temperature of 160~180 ℃ through a thermostatic pipe,used for binding books, etc.
In the actual production process, the adhesive strength of hot melt adhesive will vary with heating temperature, different adhesive materials, milling width and depth, adhesive thickness, and the operating speed of the binding machine, resulting in different adhesive effects.
The softening point of hot melt adhesive is generally above 80 ℃. That is to say, when heated to; 80°C At this point, the colloid will begin to soften and melt. This temperature is only the melting temperature of hot melt adhesive. In order to melt it to the point where it can bond books, the heating temperature must be raised to 140-180 ° C. At this temperature, the viscosity and strength of the colloid can be suitable for book binding.
The temperature for gluing should also vary depending on the quality of the book paper. This is not only because the fibers of the paper are different, but more importantly, due to the different types and textures of the paper, the thermal conductivity of the colloids is different, which changes the cooling rate. Taking the thermal conductivity of copperplate paper and non copperplate paper as an example, the former has a faster adhesive cooling rate than the latter. Because the inorganic substances contained in copperplate paper are about 10 times higher than those in non copperplate paper, adhesive paper, etc., and the inorganic substances have good thermal conductivity, which can make the hot melt adhesive cool faster
For example, when the adhesive temperature is 170 ℃, the tensile test value of hot melt adhesive for non copperplate paper can meet the expected requirements, while the tensile test value for copperplate paper cannot. Therefore, when applying adhesive to copperplate paper, it is necessary to increase the temperature of the adhesive solution to enhance its strength.
The relationship between the opening time of EVA hot melt adhesive and the operating speed of production equipment.
In wireless binding production, three time stages must be strictly controlled when using hot melt adhesive, namely opening time, curing time, and drying time for cooling and hardening. Opening hours refer to the time when glue is applied to the back of a book. The curing time is the time it takes for the cover and back of a book to stick together. Cooling, hardening, and drying time refers to the time it takes for a book with a cover to cool and solidify after curing. Only after these three stages of time can this book be finalized and achieve the expected shape.
The correct sequence for carbonization of residual glue in the glue can is:First, cool down to the softening range where the glue can still flow (about 120-140); Drain the remaining adhesive (℃), then use specialized cleaning adhesive or high flash point cleaning agent to circulate and soften the carbon residue, and finally use a copper […]
When maintaining high-performance operation of the hot melt adhesive machine, you can take many measures to reduce downtime and improve system performance. Please remember that downtime equals production loss. 1) Apply hot melt adhesive at the correct temperature. Using the correct settings can avoid many troubles. You may also want to try using a metallocene […]
Hot melt adhesive granulesWhere is the cheapest wholesale? The question of ‘where is cheap’ is about channels, but the real question is’ where is the lowest overall cost ‘. There are roughly three types of wholesale channels: direct supply from manufacturers, distribution agents, and e-commerce platforms. Whether it is cheap or not depends on the […]
Direct answer:Hot melt adhesive particles belong to thermoplastic materials and can theoretically be melted repeatedly, but in most cases, “recycling and reuse” on the production site is not cost-effective or safe.There is only one situation that can be recycled – clean residue that has never been used on the machine and has not been contaminated; […]
