Nano-inorganic modified polyvinyl alcohol coating solution with obvious advantages for milk packaging

With the continuous improvement of living standards, people's requirements for the quality of various types of food continue to increase, and thus the requirements for packaging are also increasing. People's requirements for food packaging have not only stayed in the basic quality deterioration of food within the shelf life, but more and more people began to pay attention to whether the quality of the packaged goods has been well maintained, requiring its pure taste and aroma. Under this consumption trend, various types of dairy products and food production companies have put forward higher requirements on the choice of packaging materials. In particular, milk, a very special drink, is very strict. First of all, it is necessary to prevent the intrusion of external bacteria; at the same time, milk reacts very sensitively to oxygen. Especially at high temperatures, oxidation reactions easily occur. Therefore, the oxygen barrier performance is extremely important. In addition, to prevent the volatilization of its own aroma, maintain its original quality. As a result, the current ordinary packaging materials in the market can no longer meet the higher requirements, and some packaging materials with high barrier properties show a strong momentum of development. According to experts, nano-inorganic modified polyvinyl alcohol coating solution has obvious advantages in high barrier packaging materials.

First, the nano inorganic-modified polyvinyl alcohol coating liquid is an excellent barrier material with excellent barrier properties, and a composite high-barrier liquid packaging film manufactured using the coating liquid can effectively prevent microorganisms in the atmosphere from being packaged. The secondary pollution, and to prevent the replacement of the gas and air required for microbial propagation of the packaged material, can effectively prevent the oxidation and deterioration of the packaged material, greatly prolong the shelf life, and prevent the volatilization of its aroma to ensure its initial quality level for a long time. Its barrier properties are not affected by any humidity. Secondly, the use of less materials and low manufacturing costs is only slightly higher than the price of the existing ordinary commercial packaging materials, far lower than plastic, aluminum, paper composite packaging and five-layer co-extrusion packaging film, with very good price performance ratio. Thirdly, the utilization rate of existing equipment is high, there is no need to purchase new equipment, and the dry composite equipment that general packaging companies have can meet the needs of use, and at the same time, it has strong operability and can easily be used by enterprises. accept.

In view of the above advantages, experts believe that the use of the coating liquid produced by the composite high barrier liquid packaging film, in the milk packaging film in full replacement of the current ordinary three-layer co-extruded milk packaging is very feasible.

According to reports, after the nano-inorganic modified polyvinyl alcohol coating liquid was applied to the milk packaging film, the packaging structure was as follows: a three-layer co-extrusion was performed to blow out a 70 μm polyethylene (PE) black and white substrate film on the substrate. The modified PVA was applied in a coating thickness of 0.7 g per square meter of dry weight and then printed on the coating. Finally, a dry composite 25 μm transparent polyethylene (PE) was used. The packaging film obtained by the above method has the following properties: the oxygen permeation amount is 6.6cm3/m24h0.1Mpa, the water vapor transmission rate is 4.3g/m224h, the peel strength is 2.3n/15mm in the longitudinal direction, and the transverse direction is 3.0 n/1.5mm. Its physical and mechanical properties and health indicators are in line with national standards. The more prominent advantage is that the structure completely protects the ink and does not fall off.

The packaging uses dairy milk companies to package fresh milk using ultra-high temperature instant sterilized packaging equipment. After being stored at room temperature for 50 days, the milk is tasted by the state-level taster. The conclusion is: normal taste and pure smell.

Source: China Food News