The hottest microwave food plastic packaging conta

Plastic containers for microwave food the family of plastic containers for microwave food is becoming more and more prosperous. With the rapid development of microwave technology and the popularity of microwave ovens, microwave food as a kind of convenient food is becoming more and more popular, and the importance of packaging materials for microwave food is also increasing

characteristics of microwave packaging materials

all packaging materials that can pass through microwave have the basic conditions for microwave heating. However, ideal microwave food packaging materials must have the following conditions in addition to the ability to pass through microwave

heat resistance. The basic requirement of microwave oven containers is that they must have good heat resistance. Considering the different heating processes of various microwave foods during heating, since the boiling point of water is 100 ℃, there is a constant temperature time after heating to 100 ℃ until all the water volatilizes and overflows, the heat resistance requirements of microwave oven containers for water-based foods are low, but should not be lower than 100 ℃. Since the boiling point of oil for oily food is above 200 ℃, there will be no constant temperature stage in the lower temperature range during the heating process until the boiling point of oil. Therefore, the microwave oven container for oily food has high requirements for heat resistance. In order to meet the needs of microwave food cooking, the microwave oven container for oily food should be able to withstand at least 10 minutes of heating treatment at about 130 ℃

combined with SMC process, it will bring more efficient production process and minimum material waste and cold resistance. In order to extend the shelf life of microwave oven foods, frozen storage is often used. Therefore, in addition to heat resistance, the base material of microwave oven containers must also consider its cold resistance. The microwave oven container shall be able to withstand a low temperature of - 18 ℃ to - 20 ℃

oil resistance: containers for microwave ovens need to contact with edible oils. Therefore, except disposable microwave containers for water-based foods, they should have good oil resistance

hygiene; Containers for microwave ovens are often in direct contact with food during use. Therefore, the selected materials must have reliable sanitary performance and meet the requirements of relevant national health standards if the details are ignored

low price: microwave oven container is a kind of popular daily necessities. Therefore, under the conditions of the same or similar use performance, it is necessary to select materials with relatively low price as far as possible to improve the market competitiveness

microwave food plastic containers

plastics not only have microwave transmission performance, but also have a wide variety, which can meet the above basic requirements. In addition, plastics generally have the characteristics of small heat capacity. As microwave food packaging materials, they also have the advantages of fast heating and energy saving. Therefore, plastic microwave food packaging materials have developed rapidly

polyethylene containers. The outstanding advantage of this kind of container is that it has excellent cold resistance, can withstand a low temperature below - 40 ℃, its sanitary performance is reliable, and its oil resistance is acceptable. It can be used to hold oily food for a short time or at low temperature, and generally will not cause problems. In addition, it also has the advantages of convenient molding and low cost, and the waste is easy to be recycled (it can produce recycled products after granulation or burn to recover heat energy); Its performance also has defects, that is, its high temperature resistance is poor. The polyethylene container will deform at about 100 ℃ and melt at more than 120 ℃, so the use effect is not ideal

polypropylene containers. Pure polypropylene microwave oven containers are made of polypropylene homopolymer or block copolymer. When block copolymer is used, the cold resistance of the container is significantly improved, and it can withstand low temperatures below - 20 ℃. The heat resistance of block copolymer is worse than that of homopolymer, but the heat resistance of polypropylene homopolymer or block copolymer is 1. At present, some electronic tensile machines in the market adopt reducer above 10 ℃. For the cooking of water-based microwave food, there is no problem of heat resistance. For oily food, its heat resistance is not enough

fill polypropylene containers. Most filled polypropylene containers for microwave ovens are filled with talc powder, which has the dual functions of improving heat resistance and rigidity, shortening the production cycle and reducing the container cost. In the filled polypropylene microwave oven container, the amount of talc powder is generally about 30%, and the heat resistance of this container is above 130 ℃. For some kinds of filled polypropylene microwave containers, the content of filler is about 50%, the heat resistance is 140 ℃ and the low temperature of minus 30 ℃

another feature of the filled polypropylene container is that the waste is easier to burn. The addition of a large number of fillers greatly reduces the combustion heat of plastics. Therefore, it has similar performance to wood combustion and is not easy to damage the incinerator during combustion. Compared with pure polypropylene microwave oven containers, the disadvantages of filled polypropylene microwave oven containers are that they do not have transparency, and the objects contained in the containers cannot be observed through the containers

polyester microwave containers. The practical polyester microwave oven container is a thermoformed container made of crystalline polyethylene terephthalate sheet, i.e. CPET container. The highest heat-resistant temperature of the container is 230 ℃, which is extremely rare in common plastic products. Pet has the advantages of oil resistance, chemical resistance, low temperature performance, sanitary reliability and easy recycling of waste. It is a very ideal plastic container for microwave ovens. However, it is difficult to manufacture the product and the cost is high. At present, it is still to be developed in China. Heat resistant PSP containers use PS sheet and heat-resistant plastic film, or heat-resistant styrene copolymer, or polystyrene alloy to improve the heat resistance of polystyrene. According to the literature reports, the heat resistance of polystyrene sheet can be improved to 130 ℃ to 135 ℃ by compounding heat-resistant film on polystyrene sheet, and the alloy polystyrene sheet can also reach a considerable level. The problem is how to reduce the production cost to expand the market

heat resistant BOPS container. The heat resistance of heat-resistant biaxial tensile polystyrene sheet can reach the level of 120 ℃, which is suitable for the application in microwave oven containers. When the filled polypropylene microwave oven container is used, the heat-resistant BOPS sheet is often used as the cover material of the container to facilitate the observation of the shape of the contents in the container, and the wingspan of the aircraft is the same as that of the Boeing 747

reprinted from: China Packaging Industry