Third, using EVA hot melt adhesive environment and conditions
Nowadays, there are more and more book books on the use of EVA hot-melt adhesives for wireless binding. Almost all large, medium, and small-scale processing plants in the country are in use, and there is still a rising trend in the future. This is due to the use of such adhesives to produce books. Fast, short cycle, good book appearance, saves several steps. However, due to the eagerness of printing companies to launch, strive for more activities, and more processing, they have neglected the scientific nature of the environment and conditions of using hot melt adhesives, and thus there have been many problems in processing. Here are some points for the use of reference:
1. Impact of temperature and humidity in production plants
EVA hot melt adhesive is a kind of thermoplastic adhesive. The open time after painting is affected by the temperature and humidity of the room. Generally, the temperature in the room (ie the workshop) should be kept at a constant temperature. The best temperature is between 15°C and 26°C. The humidity should be maintained. About 50%. However, it is understood that in the units that use hot melt adhesives throughout the country, it is very rare to achieve this requirement. Therefore, when there are many areas that use hot melt adhesives, there are many summertimes of excessive use of plastic bubbles, which are difficult to cure and cool. In the winter, adhesive curing, shortening of the cooling time, stickiness or stickiness, and breaking of books after sticking occurred. In other regions, because of the high humidity, the book after the cover is indeterminate, and it cannot be cut. These phenomena are directly related to the temperature and humidity of the working plant. So ask:
(1) Conditional units, it is best to install constant temperature equipment and humidity measurement equipment in the factory building with wireless glue binding equipment to ensure the normal temperature and humidity.
(2) Some unconditional units must also strive to create conditions for scientific and standardized management and production. In the absence of these conditions can temporarily grasp the following principles: When the summer temperature is high, the use of hot melt adhesive temperature should be reduced by about 10 °C, so that the glue opening and curing time can basically meet the reasonable requirements.
(3) Books made by wireless glue binding shall be guaranteed to have a temperature of between 1 and 45°C in the warehouse or workshop where they are stored, and are forbidden to be stacked against the wall, by heating (in winter), by the windows and in the open air. Avoid moisture or excessive heat to deform the paper, causing the adhesive to change, causing irreparable damage.
Fourth, the use of EVA hot melt adhesive should pay attention to matters
EVA hot melt adhesive, unlike ordinary cold glue, according to its characteristics, must also grasp and pay attention to the following points in use:
1. To understand and grasp the various models and technical performance (including technical parameters) of EVA hot melt adhesives. Different types of hot-melt adhesives have different opening times and curing times. In particular, the use period of Xiajiao and Dongjiao must be strictly differentiated. When the temperature is different, the opening and curing time will also change.
2. When using EVA hot melt adhesive, avoid direct heating with open flame, be sure to use spacer oil solution heating (boiling point of water to 100 °C), or use sealed electric heating plate.
3. The solid EVA hot melt adhesive must be preheated with a preheating device before it is used, and then released into a working plastic case for the adhesive glue. The warm-up time is usually about 2 hours. When glue is used, no solid glue block (that is, glue that has not been preheated) can be directly mixed into the plastic housing to prevent the fluidity of the glue from being poor or the glue from being completely melted on the back of the book. Book appearance quality.
4. Preheat the amount of glue in the plastic pot to grasp properly, after the amount of excessive colloidal melt, it will deteriorate aging, viscosity, affect the adhesion.
5. During the opening time of the hot melt adhesive, all the bonding processes must be completed. If the machine stops in the event of a fault, the books in the book holder must be removed in time. Special attention should be paid to the fact that the book block above the rubberizing wheel must not stay.
6. When repairing the wireless glue-binding equipment for a long time, the pre-adhesive and the working glue pan should be closed to prevent the aging of the gel.
7. The temperature of the molten colloid must be strictly controlled within the scope of use.
8. To clean the pre-adhesive pans and working plastic boxes regularly, keep the insides of the glue pans clean and prevent impurities in the glue liquid from depositing and accumulating, affecting the accuracy of the temperature control, and even causing the failure of the thermostat to cause the colloid to burn. Generally, under normal production and operation conditions, the preheated plastic pot should be cleaned once every 3 months; the working plastic box (for rubber coating) should be cleaned once every half month. Clean up the plastic pot to set a system to facilitate implementation.
Author / Wang Huaizhu