Development of PVDC composite membrane
BY：Enterprise News
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POST：2021-05-31
With the continuous development of packaging technology, the application field of plastic composite packaging materials is expanding. It can provide high barrier plastic packaging materials with good quality, fresh-keeping, flavor and shelf life. It has been rapidly developed and widely used in the packaging industry, especially in the food packaging industry.
High barrier packaging materials usually refer to the materials with high barrier effect on gas and liquid penetrants, which are shown in the following aspects: preventing the invasion of oxygen to oxidize and deteriorate commodities; Prevent the penetration of water or steam to make the goods damp and moldy; Prevent the penetration of aroma, carbon dioxide and peculiar smell, and make the goods taste and deteriorate.
The international plastics industry is used to measure the difference of barrier properties of plastics by the physical quantity of "transmittance". Usually 25.4 μ The contrast unit is the volume (cm3) of oxygen permeating through the plastic film with a thickness of 1 m2 in 24 hours at 23 ℃, a standard atmospheric pressure, a relative humidity of 50% RH. The value below 10 is called high barrier plastic; 10-100 is called medium barrier plastic; More than 100 is called ordinary barrier plastic. At present, EVOH (ethylene vinyl alcohol copolymer), PVDC (polyvinylidene chloride) and pan (polyacrylonitrile) have been industrialized as high barrier plastics (see Table 1). PVDC and EVOH are high barrier plastics which have been put into large-scale industrial application. According to statistics, in 1992, the output of high barrier plastics in the world was 1.26 million tons, of which the output of PVDC resin accounted for 1.08 million tons, accounting for more than 80% of the total output.
High barrier packaging materials usually refer to the materials with high barrier effect on gas and liquid penetrants, which are shown in the following aspects: preventing the invasion of oxygen to oxidize and deteriorate commodities; Prevent the penetration of water or steam to make the goods damp and moldy; Prevent the penetration of aroma, carbon dioxide and peculiar smell, and make the goods taste and deteriorate.
The international plastics industry is used to measure the difference of barrier properties of plastics by the physical quantity of "transmittance". Usually 25.4 μ The contrast unit is the volume (cm3) of oxygen permeating through the plastic film with a thickness of 1 m2 in 24 hours at 23 ℃, a standard atmospheric pressure, a relative humidity of 50% RH. The value below 10 is called high barrier plastic; 10-100 is called medium barrier plastic; More than 100 is called ordinary barrier plastic. At present, EVOH (ethylene vinyl alcohol copolymer), PVDC (polyvinylidene chloride) and pan (polyacrylonitrile) have been industrialized as high barrier plastics (see Table 1). PVDC and EVOH are high barrier plastics which have been put into large-scale industrial application. According to statistics, in 1992, the output of high barrier plastics in the world was 1.26 million tons, of which the output of PVDC resin accounted for 1.08 million tons, accounting for more than 80% of the total output.