1. The method of the joint The methods of the conveyor belt joint are: mechanical joints, cold bonding joints, hot vulcanized joints and other commonly used methods. Mechanical joints generally refer to the use of belt buckle joints, this joint method is convenient and fast, and it is relatively economical, but the efficiency of the joint is low, easy to damage, and has a certain impact on the service life of conveyor belt products. In PVC and PVG full-core flame retardant and antistatic conveyor belt joints, this joint method is generally used for products below grade 8 belts. Cold-bonded joints, i.e. the use of cold-bonded adhesives for joints. This joint method is more efficient than mechanical joints, and it is also more economical, and it should be able to have a better joint effect, but from a practical point of view, because the process conditions are relatively difficult to master, and the quality of the adhesive has a very large impact on the joint, so it is not very stable. Hot vulcanized joints have proven to be the most ideal joint method, which can ensure high joint efficiency, but also very stable, and the joint life is also very long, easy to master. However, there are disadvantages such as process trouble, high cost, and long joint operation time.
2. The joints of the layered conveyor belt can be made of mechanical joints, cold bonded joints, hot vulcanized joints and other joints as needed. Generally, cold-bonded joints and hot-vulcanized joints adopt stepped structure joints.
3. Joints of PVC and PVG whole-core flame retardant conveyor belts Because the structure of the whole-core belt is relatively special, the joints are not easy, so most of them adopt the mechanical joint method, that is, the belt buckle joint. However, for belts above level 8, in order to ensure the joint effect, the method of hot vulcanization joint is generally used. The structure of the joints is all finger-shaped joints. The hot vulcanized joint process of PVC and PVG full-core flame retardant conveyor belt is more complex, and the requirements for equipment are also relatively high.
4. The joint of the steel wire rope core conveyor belt The joint of the steel wire rope core conveyor belt is the most complex technology of all conveyor belt joints, not only the process is more complex, but also the size parameters of the designed joint. Different levels of products use different joint structures, please refer to GB9770 standard for specific structures.
Conveyor belts can be divided into general conveyor belts, special function conveyor belts, flame retardant conveyor belts, wire rope conveyor belts, etc. The rubber prescription is described as follows: the rubber used in the various components of the general conveyor belt of flame retardant conveyor belts includes four types: covering rubber, buffering glue, cloth layer rubber, and cloth layer glue.
1. Covering glue: When used, it is subject to the charge, wear and microbial corrosion of items, as well as the aging effect of various ethnic groups. Therefore, the request for masking glue is in good tensile strength (≥18Mpa) and abrasion resistance (abrasion ≤ 0.8cm3/1.61Km), aging resistance, biological corrosion resistance. Therefore, it is also requested to have excellent viscosity and other process functionsThe prescription is intended to be as follows: raw rubber is mainly natural rubber or excessive styrene-butadiene rubber, and the glue content is 50%~55%. The vulcanization system adopts a conservative cooperative system of sulfur and propellant. In the natural rubber prescription, the sulfur dosage is 2.5 quality parts, and in the styrene-butadiene rubber prescription, the sulfur dosage is 1.5~2.0 quality parts. The propellant is normally used in combination with M and DM, and the propellant CZ, NOBS and other after-acting propellants are suitable for rubber compounds containing styrene-butadiene rubber. The flame retardant conveyor belt reinforcing agent can be selected with high wear-resistant carbon black, medium super wear-resistant carbon black, etc., and the dosage is 40~50 quality parts. The types of hardeners commonly used are inorganic oil, light oil, pine tar, coumarone resin and alcohol resin.
2. Buffer glue: The buffer glue is between the covering glue and the core layer of the conveyor belt, which can increase the adhesion of the two, and can attract and evacuate the charging force of the escort items, and play a buffering role. It is required that the rubber should be stored in excellent adhesion (the adhesion between the glue and the cloth ≥3.15N/mm), large inertia, small heat generation, good heat dissipation, and good process function. Raw rubber is normally used in combination with natural rubber and butadiene rubber, and the glue content is 50%~55%. It is advisable to use low-sulfur cooperation in the vulcanization system to improve the adhesion between the adhesive layer and the cloth layer. The propellant adopts a combined system of M, DM, TMTD. Carbon black is rarely used with high wear-resistant and semi-reinforcing carbon black, and the amount of flame retardant conveyor belt should not be too much, generally within and outside the 10 quality content. The hardener is a type with good viscosity, such as pine tar, liquid coumarone, etc.
3. Rubbing: The secondary function of wiping is to decompose the core canvas layer to the whole. It is required to have excellent adhesive function (the friction strength between cloth and cloth is not less than 4.5N/mm), fatigue resistance (the number of bending positions of the cloth layer ≥ 25,000 times/full peeling), and there must be residual plasticity (plasticity 0.5~0.6) and anti-scorch and other process functions. Raw rubber is mainly natural rubber, and 20~30 quality styrene-butadiene rubber is used, with a glue content of 50% inside and outside. The vulcanization system is the same as the normal sulfur and propellant system. The propellant normally adopts the combination of M and DM, or withdraws a large number of TMTD to slow down the vulcanization process, but care should be taken to prevent the rubber from scorching. Carbon black should be semi-reinforced, carbon black or other soft carbon black, with a dosage of 10 quality parts inside and outside. The amount of coumaron resin and alcohol resin should be appropriately increased for the rubbing rubber mixed with styrene-butadiene rubber, or the adhesion of the cloth layer should not be increased.
4. Glue: It is similar to rubbing, but the glue content is slightly higher than that of rubbing, and the plasticity is slightly smaller, and the plasticity is better than 0.4~0.5.
