Shanghai hot melt glue machine in the production of optical cable. In the production of products, the waterproof and moisture-proof performance requirements of optical cables are more stringent. In the cable, it is necessary to prevent water from penetrating radially into the cable and to prevent water from flowing longitudinally in the cable. The method of preventing water from infiltrating into the optical cable mainly relies on the water blocking effect of the metal strip, which is similar to the cable, so that the optical cable manufacturer can use the hot melt adhesive to bond the metal strip of the optical cable. To prevent water from flowing longitudinally in the cable, most of the current methods of filling grease are used. This method has certain drawbacks, that is, the filling amount of the ointment is not well controlled. If the grease is filled in too much, the metal tape will be squeezed into a cylindrical shape, and the grease will be squeezed out. When the grease is squeezed to the metal tape, the metal tape will not be bonded, resulting in no peeling force at the metal joint. To the standard requirements, even the complete bonding is not possible, so that the anti-radial leakage effect of the metal strip is greatly weakened; if the filling amount of the ointment is too small, the grease in the cable is not filled, so that the longitudinal water seepage performance of the optical cable is prevented. Reduced, resulting in failure of the longitudinal water seepage test of the cable. The use of hot melt adhesive as a water blocking ring can effectively solve this problem. In the optical cable, a water blocking ring is made with hot melt glue every lm or so, so that the water cannot flow longitudinally in the optical cable, and the water blocking ring It does not affect the bonding effect of the metal strip lap joint. The water blocking ring is also made of a hot melt adhesive machine. A hot melt tape is sprayed on the flat metal strip before the metal strip has been curled into a cylindrical shape. The nozzle for making the water blocking ring should be able to spray the strip of hot melt adhesive. The length of the hot melt adhesive tape sprayed by the hot melt adhesive machine is the same as the width of the metal strip. When the metal strip is rolled into a cylindrical shape, the hot-melt tape forms an annular shape, and the core and the metal strip are tightly adhered and tightly sealed. The process and the properties of the hot melt adhesive should ensure that the hot melt adhesive has not been completely cooled when the metal strip has just been rolled into a cylindrical shape, so that the hot melt adhesive fills the gap of the core to seal and block water. In the production, the position of the nozzle should be determined through experiments according to the performance of the hot melt adhesive and the jacket production speed. In order to block the gap between the center reinforcing core and the loose tube of the stranded cable, the reinforcing core should be coated with a layer of hot melt adhesive on the surface of the reinforcing core before the loosening of the loose tube. When the loose tube is stranded, the layer of hot melt will fill the gap between the reinforcing core and the loose tube to prevent longitudinal flow of water. In the production, after the loose tube is twisted, in order to maintain the stability of the core, the yarn or the belt should be tied outside the stranded loose tube. When using a water blocking ring, the stability of the cable core should be maintained by using a skein. Because the cable core after the yarn is only required to be in the manner of a water-blocking ring between the longitudinally wrapped metal strip and the cable core; if the strap is used, the ring-shaped hot melt adhesive nozzle should be used before the wrapping of the strap. The core is sprayed with a hot melt adhesive ring, and then wrapped around the bag to form a water blocking ring between the tape and the longitudinal metal strip. When the optical cable or cable has an inner sheath, a water blocking ring is formed between the inner sheath and the longitudinal metal strip.
The use of hot melt adhesive to bond water between the loose tube and the reinforcing core also improves the temperature characteristics of the cable. It is well known that when the cable is exposed to external temperature changes, the components in the cable will have a cold shrinkage and thermal expansion effect with temperature changes. Since the thermal expansion coefficient of plastic is much larger than the thermal expansion coefficient of the optical fiber, when the temperature is low, the shrinkage of the loose tube is much larger than the shrinkage of the optical fiber. At this time, the optical fiber in the optical cable is slightly bent, so that the attenuation of the optical fiber is increased; when the temperature is high, loose. The elongation of the sleeve is much larger than the elongation of the optical fiber, which causes the optical fiber in the optical cable to be subjected to a tensile force, so that the crack of the optical fiber is expanded, and the attenuation of the optical fiber is increased and the life is reduced. The reinforcing core adopts steel wire, and its thermal expansion coefficient is much smaller than that of ethylene or PBT. Therefore, when the loose tube and the reinforcing core are adhered by the hot melt adhesive, the loose tube is restrained by the reinforcing core, and the temperature is changed to loosen the sleeve. The amount of change in the tube is greatly reduced, thereby improving the temperature characteristics of the cable. Preferably, the cable water blocking ring uses an elastic hot melt adhesive which is soft and condensable. Thus, when the cable is bent, the hot melt adhesive does not crack. According to the current experience, domestically produced hot melt adhesives based on EVA and EMAA fully meet the requirements for use.