It is divided into two types: molding method (using dry glue as raw material) and casting method (using liquid polyurethane as raw material).
(1) Molding method
1) The main raw material rubber is mainly neoprene, and the reinforcing layer is usually made of steel wire rope or aramid rope. Requirements for strong ropes include high elongation, low elongation and low thermal deformation.
2) Two methods of forming parting and forming drum:
The mold method is divided into five steps, the first step, the patch cloth (lapped with 45° obliquely); the second step, the embedded rack; the third step, the winding rope, the single tension requirement reaches 78-100N; Four steps, filming, with a 0.5mm thick film multi-layer package to the specified thickness; the fifth step, add the outer hoop, put it into the vulcanization tank for vulcanization.
The forming drum method is carried out on a single drum forming drum. First, attach the hanging tape to the forming drum, wrap the wire rope, and attach a layer of tape to complete the forming of the embryo.
（3) Vulcanization in two ways.
a. The iron hoop pressure vulcanization is suitable for the semi-finished product formed by the die method, pressurized by the iron hoop, and then vulcanized by placing it in a vulcanization tank or a flat press.
b. The rubber sleeve vulcanization is suitable for the forming of the drum formed by the drum. The embryo with the forming drum is sleeved on the rubber sleeve and sent to the vulcanization tank, and simultaneously pressurized and heated inside and outside. The first stage is 0.3~0.4MPa vapor pressure, which is maintained for 2~3min; the second stage is further pressurized to 0.8~1MPa, and continues to the specified curing cycle.
(2) pouring method
Polyester polyurethane is used as the main material and is completed in four steps.
1 Polycondensation is carried out by using adipic acid and ethylene glycol as raw materials to obtain a dihydroxy-terminated polyester.
2 Add toluene diisocyanate to the polyester and extend the chain to form a prepolymer.
3 Vacuum and defoam the prepolymer.
4 Add the curing agent MOCA, stir evenly, and pour into the cavity with the strength layer preset. After heating, solidifying and demoulding, the finished product is obtained.
application
The synchronous toothed belt is thin and strong, and is resistant to flexing. Therefore, the transmission speed is high and the transmission efficiency is high, up to 100 kW. It is used to replace the chain or gear transmission, which can reduce noise and save lubricating oil. Therefore, it is widely used in precision machine tools, computers, chemical fiber machinery, textile machinery, automotive transmission systems and general machinery.