1. The basic process
With the rapid development of modern industry, especially the chemical industry, rubber variety, but the production process, but basically the same. In general solid rubber (gum) as raw product, its production process including:
Mastication of raw materials to prepare → → mixing → forming → → finishing → test vulcanization
2. Prepare raw materials
The main materials are crude rubber adhesive, compounding agents, fibrous materials and metal materials. Wherein the gum as the basic material; complexing agent in order to improve certain properties of rubber products and adding auxiliary materials; fibrous materials (cotton, linen, wool and a variety of man-made fibers, synthetic fibers) and metal materials (steel, copper) as rubber reinforcing materials, in order to enhance the mechanical strength, limiting product variants.
In the raw material preparation process, the ingredients must be accurate in accordance with Formulation. In order to make raw rubber and compounding ingredients can be uniformly mixed with each other, the need for certain materials for processing:
1. The basic process
With the rapid development of modern industry, especially the chemical industry, rubber variety, but the production process, but basically the same. In general solid rubber (gum) as raw product, its production process including:
Mastication of raw materials to prepare → → mixing → forming → → curing → break test
2. Prepare raw materials
The main materials are crude rubber adhesive, compounding agents, fibrous materials and metal materials. Wherein the gum as the basic material; complexing agent in order to improve certain properties of rubber products and adding auxiliary materials; fibrous materials (cotton, linen, wool and a variety of man-made fibers, synthetic fibers) and metal materials (steel, copper) as rubber reinforcing materials, in order to enhance the mechanical strength, limiting product variants.
In the raw material preparation process, the ingredients must be accurate in accordance with Formulation. In order to make raw rubber and compounding ingredients can be uniformly mixed with each other, the need for certain materials for processing:
To bake raw rubber soft 60--70 ℃ in the drying room, then cut plastic, gel breaking into small pieces;
Bulk ingredients such as paraffin wax, stearic acid, rosin to smash;
Powdered ingredients to be screened if they contain mechanical removal of the impurities or coarse;
Liquid ingredients (pine tar, coumarone) requires heating, melting, evaporation of water, filter impurities;
Complexing agent to be dried, or easy to agglomerate, can not be uniformly dispersed when mixing the old, bubbles during vulcanization, thus affecting the quality of products;
3. mastication
Raw rubber elasticity, lack of essential properties (plasticity) during processing, it is not easy to process. In order to increase its plasticity, so to raw rubber mastication; Thus, while it is easy kneading ingredients uniformly dispersed in raw rubber; Meanwhile, calendering, molding process also helps to improve the rubber penetration (penetration fiber fabric inside) and forming mobility. The long-chain molecules gum degradation, a process called plasticity formation mastication. Raw rubber mastication method of mechanical mastication and mixing two kinds of thermoplastic. Mechanical mastication is not too high in temperature by the action of mechanical compression and friction mastication machine, so that degradation of long-chain rubber molecules shortened by highly elastic state to a plastic state. Thermoplastic raw rubber mixing is to pass into the hot air, under the action of heat and oxygen, so that the degradation of long-chain molecules becomes short, thereby obtaining plasticity.
4. kneading
In order to adapt to different conditions, access to a variety of performance, but also to improve the performance of rubber products and reduce costs, it must add different ingredients in the raw rubber. Kneading is to mastication after the complexing agent is mixed with raw rubber, rubber mixing machine on by mechanical mixing action to make ingredients fully uniformly dispersed in raw rubber in one process. Kneaded rubber production is an important step in the process, if uneven mixing, it can not give full play to the role of rubber and compounding agents, impact product performance. After kneading the resulting compound, known as the rubber, it is manufacturing various rubber products, semi-finished materials, commonly known as plastic materials, are usually sold as a commodity, buyers can take advantage of direct molding compound, which is made vulcanization We need rubber products. Depending on the recipe, mix a range of different properties of different brands and varieties of choices.
5. Forming
In the rubber production process, using a calender or extruder wide range of pre-formed shape, the size of each different process, called molding. Molding methods are:
Calendering for the manufacture of a simple sheet, plate products. It is the mix through a calender pressing into a certain shape, a certain size film forming method called rolling. Some rubber products (such as tires, tape, rubber hose, etc.) of textile fiber material, must be coated with a thin layer of glue (glue on the fiber, also called gum paste or eraser), coating processes are generally completed on the calender. Fibrous material before rolling the need for drying and gumming, drying purpose is to reduce the water content of the fibrous material (to avoid evaporation of water bubbling) and raising the temperature of the fiber material in order to ensure the quality of the rolling process. Dipping step is necessary before hanging plastic, the purpose is to improve the bonding properties of the fiber material and rubber compounds.
Extrusion molding rubber products for the more complex, such as a tire tread, hose, wire, plastic coated surface need the extrusion molding method of manufacture. It is to mix a certain plasticity, and placed into the hopper of the extruder, extruded at a screw, through a variety of mouth (also known as templates) in the shape of a method for continuous extrusion Previously, the compound must be warmed up rubber soft and easy extrusion to obtain a smooth surface, accurate dimensions of rubber products.
Molding molding method can also be used to manufacture certain complex shapes (such as cups, seals) rubber products, with the forming of the male and female mold, the plastic material is placed in a mold thermoforming.
6. vulcanization
The plastic rubber into an elastic rubber vulcanization process is called, it is a certain amount of vulcanizing agent (such as sulfur, vulcanization accelerators, etc.) was added to the semi-finished products made of raw rubber (vulcanization carried out in the tank), the provisions of temperature heating, insulation, making raw rubber between linear molecules generated by "sulfur bridges" and cross-linked network structure established body, so that the plastic material into a vulcanized rubber having high elasticity. Since the crosslink bonds are primarily composed of sulfur, so called "curing." With the rapid development of synthetic rubber, the vulcanizing agent and now many varieties, in addition to sulfur, there are organic polysulfide, peroxides, metal oxides Wait. Therefore, those who make the plastic rubber-like structure, the elastic rubber into three-dimensional network structure of the process called vulcanization, who can play a "bridge" role in the rubber material substances are referred to as "curing agent."
Elastic rubber vulcanized called vulcanized rubber, also known as soft rubber, commonly known as "rubber." Is one of the most important vulcanization process of rubber processing, rubber products must be cured to achieve the desired performance. Uncured rubber, is in the use of no value, but less sulfur (vulcanization degree is not enough, the curing time was not able to achieve the best condition) and persulfate (curing time exceeds significantly decreased performance) are making rubber performance. Therefore, the production process must be strictly controlled curing time to ensure that the vulcanized rubber has the best performance and longest life.
7. support measures
In order to achieve performance, support measures should be added in the production process:
7.1 increase the intensity - is equipped with a hard carbon black, mixed with phenolic resin;
7.2 increase the wear resistance - is equipped with a hard carbon black;
7.3 tightness demanding - less highly volatile components;
7.4 increase heat resistance - the introduction of new curing process;
7.5 increases resistance to cold - through the gum solution sticks mosaic, reduced crystallization tendency, the use of low temperature plasticizers;
7.6 increase flame resistance - not flammable chemicals, less softeners, flame retardants (such as: antimony trioxide)
7.7 increase resistance to oxygen, ozone resistance - use of diamine protectant;
7.8 improve the electrical insulating properties - high structure with filler or metal powder, equipped with antistatic agents;
7.9 improve magnetic - using strontium ferrite powder, aluminum, nickel and iron, barium iron powder as filler;
7.10 improve the water resistance - the use of lead oxide or resin curing system, equipped with a low water absorption fillers (such as barium sulfate, clay);
7.11 increase oil resistance - fully crosslinked, less plasticizer;
7.12 increase acid level - multi-purpose filler;
Improve the high vacuum of 7.13 - equipped with less volatile additives;
Reduce the hardness 7.14 - Bulk filling softener
8. The classification of rubber products and its application in the car
Rubber products are widely used, there are many varieties. The use according to points, usually divided into two major categories of industrial and civilian use. Industrial rubber products mainly include: tires, belts, hoses, offset, tape and tape products, seals, vibration-damping member, latex products, hard rubber, rubber insulation products, rubber rollers and rubber linings.
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