Plastic is a kind of synthetic polymer material with plasticity. It with the synthetic rubber, synthetic fibers to form today's daily life indispensable three synthetic materials. Specifically, the plastic is a natural or synthetic resin as the main component, adding a variety of additives, in a certain temperature and pressure conditions can be molded into a certain shape, at room temperature to maintain the same shape of the material. Plastic products is the use of plastic as the main raw materials processed from the daily necessities, industrial supplies collectively. Including plastic raw materials, injection molding, plastic and other products of all products.
Plastic and other materials compared to the following aspects of the performance characteristics:
Plastic is a lighter material with a relative density distribution between 0.90 and 2.2. Obviously, can the plastic float on the water? In particular, foam plastic, due to microporous, lighter texture, the relative density of only 0.01. This feature allows the plastic to be used in products that require weight reduction.
The vast majority of plastic on the acid, alkali and other chemical substances have a good resistance to corrosion. In particular, commonly known as the plastic king of polytetrafluoroethylene (F4), its chemical stability even better than gold, on the "aqua regia" cook for a dozen hours will not deteriorate. Because F4 has excellent chemical stability, is the ideal corrosion-resistant materials. Such as F4 can be used as a corrosive and viscous liquid pipeline material.
Ordinary plastic is a bad conductor of electricity, the surface resistance, volume resistance is large, with the number that up to 109 a 1018 ohms. The breakdown voltage is large and the dielectric loss tangent is small. Therefore, the plastic industry in the electronics industry and the machinery industry has a wide range of applications. Such as plastic insulated control cables.
In general, the thermal conductivity of plastic is relatively low, equivalent to steel 1 / 75-1 / 225, foam microporous
Contains gas, its insulation, sound insulation, shock better. Such as polyvinyl chloride (PVC) thermal conductivity of steel is only 1/357, aluminum 1/1250. In the heat insulation capacity, a single glass-plastic window is 40% higher than the single glass aluminum window, double glass 50% high. After the combination of plastic form and hollow glass, in the residential, office, ward, hotel use, save the winter heating, summer air conditioning expenditure, the benefits are very obvious.
Some plastic hard like stone, steel, and some soft as paper, leather; from the plastic hardness, tensile strength, elongation and impact strength and other mechanical properties, the distribution of a wide range, there is a great use of choice. Due to the small proportion of plastic, high strength, and thus have a higher specific strength. Compared with other materials, plastic also has obvious shortcomings, such as easy to burn, the stiffness is not as high as metal, aging resistance is poor, not heat and so on.
Plastic products produced by the molding of plastic processing the key link. Various forms of plastic (powder, pellets, solutions or dispersions) are made into articles or blanks of the desired shape. Forming up to thirty kinds of methods. Its choice depends mainly on the type of plastic (thermoplastic or thermosetting), the initial form and the shape and size of the product. Plastic processing Thermoplastics commonly used methods are extrusion, injection molding, calendering, blow molding and thermoforming, etc., plastic processing thermosetting plastics generally use molding, transfer molding, also with injection molding. Lamination, molding and thermoforming are shaping the plastic on a flat surface. The above plastic processing methods, can be used for rubber processing. In addition, there are liquid monomer or polymer as raw materials such as casting. In these methods, extrusion and injection molding with the most, but also the most basic molding methods.
Mechanical processing of plastic products Manufacture of plastic processing methods such as metal and wood to manufacture plastic products of a very precise or small quantity, but also as an auxiliary process for molding, such as sawing of extruded profiles. As the performance of plastic and metal and wood, plastic thermal conductivity is poor, thermal expansion coefficient, low modulus of elasticity, when the fixture or tool pressure is too large, easy to cause deformation, cutting heat and easy to melt, and easy to stick in the tool on. Therefore, the plastic for machining, the tools used and the corresponding cutting speed and so should adapt to the characteristics of plastic. Commonly used mechanical processing methods are sawing, shearing, punching, car, planing, drilling, grinding, polishing, thread processing. In addition, the plastic can also be cut off with laser, drilling and welding.
The production of plastic products to join the plastic processing of plastic parts to join the method of welding and bonding. Welding method is the use of welding wire hot air welding, the use of hot-hot welding, and high-frequency welding, friction welding, induction welding, ultrasonic welding. Adhesive method can be used according to the adhesive, divided into flux, resin solution and hot melt adhesive.
The purpose of surface modification of plastic products is to beautify the surface of plastic products, usually including: mechanical modification, that is, with the file, grinding, polishing and other processes to remove parts on the burr, burr, and modified size, etc .; finishing, including coating system Surface, with the solvent to make the surface brightened, with a patterned film coated with the surface of the product; Shi Cai, including painting, printing and hot stamping; metallization, including vacuum coating, plating and chemical silver plating. Plastic processing Hot stamping is in the heating, under pressure, the hot foil on the color foil layer (or other pattern layer) transferred to the workpiece. Many household appliances and construction products, daily necessities, etc., are used in this method to obtain metal luster or wood and other patterns.
The production of plastic products with the bonding, welding and mechanical connections and other methods, so that the production of plastic parts assembled into a complete product operations. For example: plastic profiles, after sawing, welding, drilling and other steps assembled into plastic window frames and plastic doors.