(1) plastic raw rubber to make elastic raw rubber into a buried state of the process known as plastic refining. The purpose of the plasticizing is to reduce the elasticity of the raw rubber,Rubber Products to increase its plasticity, and to obtain proper fluidity to meet the requirements of various processing processes such as kneading, calendering or press forming, vulcanization and mortar manufacturing, sponge gelling.
Plastic has a mechanical plastic refining method and chemical smelting method. The former through the plastic molding machine mechanical damage, reduce the flexibility of raw rubber, to obtain a certain plasticity. The latter through the chemical role of chemicals, so that raw plastic to achieve the purpose of plastic. The essence of the plasticizing process is that the macromolecules of rubber break down into molecules with relatively small molecular weights, resulting in a decrease in viscosity and an increase in plasticity.
(2) Mixing of the compound The process of mixing the various compounding agents into the raw rubber to produce a uniform quality compound is called kneading. The basic task is to create a meet the performance requirements of the compound, so that rolling or extrusion molding,Rubber Products coating and curing and other subsequent processes to be normal. The mixing process is the process of homogeneously dispersing the carbon black and other compounding agents in the raw rubber. The surface of each granule must be completely surrounded and moistened by the rubber.
Used to prepare plastic rubber, rubber mixing equipment are open mixing machine (referred to as open mill), closed mixing machine (referred to as mixer).
The working principle of the lapping machine is that the two hollow cylinders which are rotated in opposite directions are relatively rotated at different speeds, and the two rollers are of the same size. Raw rubber or rubber with the rotation of the roller under the action of friction was involved in the two roller gap. Due to the different speed of the two rollers and the speed of the gradient effect,Rubber Products raw rubber or rubber by a strong friction shear, rubber molecular chain fracture, in the surrounding oxygen or plasticizer under the action of the formation of relatively small molecular weight stable molecules , After plastic molding rubber can be improved, after mixing can be obtained uniform quality of the compound.
What are the molding methods for rubber products?
Commonly used molding methods to create some complex shapes such as leather cups, seals rubber products, with the formation of the yin and yang mold will be placed in the mold heating molding.
Read: the characteristics and causes of discarded products of rubber molded products
Second, extrusion molding
Extrusion molding, also known as extrusion molding, extrusion molding equipment is commonly used in rubber extruder, working principle and plastic extruder similar. The material through the extruder hopper into the barrel, through the barrel and the role of rotating screw, the rubber side by the thermoplastic,Rubber Products while the screw forward forward, continuous through the nose and by means of mouth mold made of various Complex cross-sectional shape of the products or semi-products, such as tire tread rubber, tube tire tube, pure hose, hose inside and outside the plastic and cable and cable skin.
For the more complex rubber products, like tire tread, hose, wire surface coating needs to be made by injection molding method.
It is a plastic with a certain plastic into the extruder hopper inside the screw squeeze through a variety of mouth type is also called a model for continuous modeling of a method.
Before the rubber material must be preheated to make the compound soft, easy to squeeze out to get the surface smooth, accurate size rubber products.
Read: rubber extrusion molding principle and characteristics
Third, injection molding
Injection molding of the injection molding rubber is the injection of the slurry through the feeding device directly from the barrel into the model of vulcanization production methods, and plastic injection molding is similar. Using injection molding, molding cycle is short, high production efficiency, labor intensity, high product quality. Mainly used in the production of seals, vibration pads and footwear.
Rubber injection molding process, including feeding, plasticizing, injection, packing, curing, die and so on. Six mold rubber injection molding machine schematic diagram, the first pre-mixed rubber material by the hopper into the barrel, under the action of the screw rotation, the rubber compound along the spiral groove to the front of the barrel, rubber material along the spiral groove in the process , When the stirrer and deformation,Rubber Products coupled with the external heating barrel, the temperature quickly increased, plasticity increases, when the rubber material to reach the front of the barrel, the injection cylinder forward to the front of the barrel nozzle and the model of the gate contact, And then injection cylinder injection, the compound into the mold cavity through the nozzle and hold for some time, in the packing process, the compound at high temperature vulcanization stage until the mold, the system into the next injection stage, and the cycle Go on.
Injection molding has significant advantages:
① simplify the process, reduce the number of operators;
② reduce energy consumption by about 10%;
③ improve production efficiency 4 to 7 times;
④ improve the uniformity of products, stability, size accuracy and pass rate;
⑤ reduce the flash, save the compound;
⑥ easy to operate, low labor intensity, high degree of mechanization and automation. Therefore, in recent years, injection molding technology has received more and more important attention, and in the production of rubber products has been rapid development.