Rubber products in the vulcanization, the rubber is vulcanized rubber products often appear when the quality defects, not only affect the appearance of the product quality, and even affect the inherent quality of the product. Through the observation and analysis of the reasons for the occurrence of bubbles on the vulcanization, developed a solution to the problem, to minimize the occurrence of bubble phenomenon, improve the appearance of the product quality.
Rubber products vulcanized product bubbles are many factors, the key reasons are raw materials, compound mixing processing, process operation, curing equipment and mold and other factors.
First, the basic process of rubber products
With the rapid development of modern industry, especially the chemical industry, a wide range of rubber products, but its production process, but basically the same.
Second, the preparation of raw materials for rubber products
The main materials of rubber products are raw rubber, with agents, fiber materials and metal materials. (Cotton, hemp, wool and all kinds of man-made fibers, synthetic fibers) and metal materials (steel wire, copper wire), and the like is used as the base material; the matching agent is the auxiliary material added to improve the performance of the rubber products; Is used as a skeleton material for rubber products to enhance mechanical strength and restrict product variants.
During the preparation of the raw material, the ingredients must be accurately weighed according to the formula. In order to make the raw gum and the compounding agent can be mixed with each other, some materials need to be processed:
Raw rubber to cut rubber, broken into small piecesSuch as paraffin, stearic acid, rosin, etc. to be crushed;
Powder containing agent containing mechanical impurities or coarse particles need to be removed;
Liquid compounding agent (pine tar, ancient malon) need to heat, melt, evaporate moisture, filter impurities;
Matching agent to be dry, or easy to agglomerate, mixing the old can not be dispersed evenly, when the vulcanization of bubbles, thus affecting product quality;
Third, the rubber products of plastic refining
Raw rubber is flexible, lacks the necessary performance (plasticity) during processing, and therefore is not easy to process. In order to improve its plasticity, it is necessary to plasticize raw rubber; so that the mixing agent is easy to evenly dispersed in the raw rubber; at the same time, in the calendering process also helps to improve the permeability of the compound (infiltration Fiber fabric) and molding fluidity. The long process of biodegradation of raw rubber, the formation of plasticity process is called plastic. There are two kinds of plastic molding and thermoplastic mixing. Mechanical plasticization is not too high temperature, through the plastic mill mechanical squeeze and the role of friction, so that the degradation of long chain rubber molecules become short, from high elastic state into a plastic state. Thermoforming is the burning of raw rubber into the hot compressed air, under the action of heat and oxygen, so that the degradation of long-chain molecules become short, in order to obtain plasticity.
Fourth, the mixing of rubber products
In order to adapt to a variety of different conditions of use, to obtain a variety of different properties, but also to improve the performance of rubber products and reduce costs, must be added in the raw rubber with a different agent. Mixing is the plastic blend of raw rubber and mix agent, placed in the mixing machine, through the mechanical mixing effect, so that with the agent completely and evenly dispersed in the raw rubber in a process. Mixing is the rubber products in the production process of an important process, if the mixing is not uniform, can not give full play to the role of rubber and complex agent, affecting the use of the product performance. The compound obtained after mixing is known as a compound, which is a semi-finished material for the manufacture of various rubber products, commonly known as a compound, which is usually sold as a commodity. The purchaser can use the compound to be directly processed and vulcanized Need for rubber products. Depending on the formulation, the blend has a range of different grades and varieties that offer different options.
Fifth, the molding of rubber products
Molding method in the rubber industry is also a very important molding method, the rubber cut or punch into a simple shape, adding heating mold, in the molding at the same time curing, the product is hot off the mold. Many rubber mold products such as gaskets, shock absorbers (such as aprons, plastic sheet) and so on are produced by this method.
(1) main equipment
There are presses and molds. The role of the press is to apply pressure to the plastic through the mold. In the rubber processing, the press is called flat vulcanizing machine. The main parameters of the press include nominal tonnage, platen size, working stroke and plunger diameter, which determine the area, height or thickness of the press molded product, and the maximum molding pressure that can be achieved. Mold according to its structural characteristics, can be divided into overflow, not overflow and semi-overflow three, of which the most use of semi-overflow.
(2) the process
It is divided into feeding, closing mold, exhaust, curing, stripping and mold cleaning, etc. If the products need to be embedded in the molding, the insert should be placed before feeding. The main control conditions are pressure, mold temperature and molding time.
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