The application of modified PP plastics in the field of household appliance is new
The application of modified PP plastics in the field of household appliance is new
As one of the four general plastic materials, PP has excellent comprehensive performance, good chemical stability, good forming performance and relatively low price. But it also has the strength, modulus, hardness low, low temperature impact strength difference, forming shrinkage big, easy to age and other shortcomings. Therefore, it is necessary to modify it so that it can adapt to the demand of the product. For PP material modification is generally by adding mineral enhanced toughening, weather resistance, glass fiber reinforced, flame retardant modification and super toughness modification approaches, each kind of modified PP has a large number of applications in the field of household appliances.
Mineral filler modified PP
Mineral filling modification is the most widely used method of modification. Add calcium carbonate, talcum powder, silica grey stone, glass microbeads, mica powder and other minerals to PP raw materials. These minerals can be not only to a certain extent, improve the mechanical properties and impact toughness of PP material, reduce the PP material molding shrinkage rate to strengthen its dimensional stability, and because the minerals much of a difference on cost and PP matrix, and can greatly reduce the cost of PP material.
At present, the application of mineral filler modified PP in household appliances mainly includes: the inner barrel, the wheel and the entrance of the drum washing machine, etc.; The sealing bar of microwave oven, speaker horn and speaker bracket; The shelf of the refrigerator; The shell and base of the rice cooker.
Many of the components of microwave ovens are also made with mineral enhancement and toughening PP materials. For example, the oven door body's sealing bar, microwave speaker horn, speaker bracket, etc. Due to the addition of minerals, the heat resistance temperature can be further improved on the basis of the high heat resistance temperature of PP materials, so as to meet the requirements of microwave oven for high temperature.
In recent years, a sharp increase in the prices of raw materials, under cost pressure, many injection molding manufacturers are considering using polystyrene instead of ABS or modified PP products replace polystyrene products to reduce costs, so appear a large number of examples of successful alternative PP material polystyrene. For example, with the selection of mineral enhancement and toughening PP materials instead of the original polystyrene materials, the cost of raw materials can be reduced by 1,500 to 2,000 yuan per ton. Due to the large amount of consumption, haier group alone will consume about 1000 tons of this material in a year. In addition, a number of refrigerator companies in the refrigerator are also replaced with minerals for toughening PP materials, such as kelon appliances, mealin appliances and other companies. Although the mechanical properties of the modified PP materials than the polystyrene is a bit poor, twisted, shrink mark, poor rigidity were problem, using the characteristics of good toughness and high MFR PP material, will product redesign, wip transfer parts of side and end face add entities to strengthen, so design makes products stiffness poor problem basically solved, which can save the cost of materials in large quantities.
Used for the plastic parts on the rice cooker of PP modified materials mainly divided into the high gloss and heat resistance, electric cooker shell with high gloss, and base the heat resistance of high material required.
The shell of the rice cooker was mainly made of ABS before. Due to cost pressure, it is now mainly used to replace ABS with modified PP. Rice cooker shell material requirements with high gloss, low shrinkage performance, can be improved by using the method of mineral filler contractility, but on the choice of mineral should choose small influence on the surface gloss of glass beads, barium sulfate, calcium carbonate, etc., and, when necessary, can also through the nucleating agent, lubricant, fluorescent agent to improve the surface gloss.
Weathering modified PP
Due to the PP with unstable tertiary carbon group, after light, heat, oxygen, prone to aging degradation and lead to change color, strength degradation and other issues, which limits its application in outdoor products. Therefore, the service life of PP materials can be greatly improved by the resistance modification of PP. The modified material is mainly used in the manufacture of household appliances that are used in the open air for years, especially for the outdoor host shell of the air conditioner, to replace the traditional metal spray housing.
The outer shell of air conditioner should be tested in different climates such as sun, rain and cold, and meet the long-term use requirement. Is made of plastics instead of metal welded technology by Japan's sumitomo and mitsubishi chemical corporation was the first to cooperation in the early 1990 s developed and put into use, this technology overcomes the original metal plastic shell process of complex, high cost, weight, easy to rust (can affect the whole machine performance and service life), and other shortcomings, eventually reduce the labor intensity of workers, reduce the energy consumption and prolong the service life. In addition to the air conditioner, the outdoor air conditioner, the axial flow of the air conditioner, and the vents of the heating fan are also used for waiting for PP. In recent years, with the increase of air conditioner production, the application of modified resistant PP in the product market has also increased gradually.
Flame retardant modified PP
In order to avoid fire, many countries now require that the materials used in electronics and electrical components in household appliances must be fire-retardant. In the flame retardant PP, 63 per cent of the requirements reached ul94v-0, 23 per cent of the requirements reached ul94v-2, 12 per cent DIN4102B1, and 1 per cent of other flame retardants. High crystallization of PP and flammability to the electrical and other industries need high level of flame retardant is difficult, and increase the cost more, but with the improvement of social demands for plastics, flame retardant, flame retardant PP increase, the proportion of the flame retardant PP annual growth rate of 8%.
As the PP belongs to flammable materials, it is generally used in the market to flame retardant modified by Br/Sb composite system. Through the flame retardant modification of PP products can achieve UL94V level 0, and 650 ℃ and 750 ℃ can glow wire and doesn't burn. The flame retardant modified PP material is commonly used to make components such as TV housing, washing machine control panel, wire control shell, refrigerator evaporating dish, air duct and other potential combustion hazards.
Glass fiber reinforced modified PP
Generally, the tensile strength of PP material is between 20M~ 30MPa, and the bending strength is between 25M~ 50MPa, and the bending modulus is between 800M~ 1500MPa. If the PP is to be used in engineering structures, it must be reinforced with fiberglass.
Generally speaking, the mechanical properties of PP products reinforced by glass fiber can be multiplied or even multiplied. In particular, the tensile strength reached 65 mpa to 90 mpa, the bending strength reached 70 mpa to 120 mpa, bending modulus reached 3000 mpa to 4500 mpa, the mechanical strength can completely with ABS and reinforced ABS products comparable to, and more heat. General ABS and ABS heat-resisting temperature between 80 ℃ ~ 98 ℃, and glass fiber reinforced PP material heat-resisting temperature can reach 135 ℃ ~ 145 ℃. It can be used to make axial fan and flow fan in refrigeration machines such as refrigerators and air conditioners, which cost much less than ABS.
In addition, it can also be used in the manufacture of high speed washer in the barrel, pulsator, pulley, so as to adapt to the high requirements for mechanical properties, used in the microwave oven, electric rice cooker base and handle such as higher requirements for heat resistance.
