Research On Waterproof And Oilproof Performance Of Packaging Board For Fast Food Packaging

The performance of the packaging material will affect the quality of the contents.Waterproof and oil-proof paperboard is a barrier-coated paper,it can be used for packaging food or health products.Traditionally,coating methods or fluorine-containing compounds are often used to improve the barrier properties or biphobicity of paper materials,but there are problems such as difficult degradation of waste and migration of harmful monomers.With the continuous improvement of people's environmental awareness and safety requirements,degradable and environmentally friendly packaging materials have gradually become research hotspots.This article first explores the technical feasibility of the double-layer coating process to prepare waterproof and oil-proof paperboard;secondly,two kinds of carboxymethyl chitosan-based coated paperboard are prepared to discuss the influence of air permeability and polarity on the oil-proof performance of the paperboard respectively,meanwhile,modified polylactic acid-based coated paperboard is prepared to explore its waterproof and other packaging properties.Finally,exploring the water and oil resistance of the double-coated paperboard modified by carboxymethyl chitosan and polylactic acid.First,discussing the technical feasibility by double-layer coating process,with using carboxymethyl chitosan(CMCS)and polylactic acid(PLA)to prepare waterproof and oil-proof paperboard.The results show that after the white cardboard is coated,a CMCS/PLA composite coating with better barrier properties is formed on the surface of the cardboard.The oil resistance of the cardboard coated with 3.06 g/m~2 CMCS solution is significantly improved,and the oil resistance of the cardboard can meet the basic requirements of oil-proof packaging paper;when the coating weight of PLA is 15.86 g/m~2,the waterproof performance of the paper is better.The contact angle and Cobb value no longer change significantly.Secondly,the CMCS is modified to discuss the influence of air permeability and polarity on oil resistance.The CMCS and sodium carboxymethyl cellulose(CMC)are compounded to prepare CMCS/CMC coated paperboard.The results show that reducing the air permeability can improve the grease resistance of the coated paperboard,and the amount of CMCS/CMC coating continues,when it is increased to 6.12 g/m~2,the oil-proof of coated paperboard reaches to 9.CMCS has high polarity.It is compounded with sodium alginate(SA)to prepare coated paperboards with different surface polarities.The results show that the higher the CMCS content,the better the oil resistance of the coating,because their higher content of polar components leads to higher grease resistance,so the high-polarity coating has better oil resistance.The PLA is compounded with nano-zinc oxide(ZnONPs),and the influence will be discussed that ZnONPs on the water resistance and other properties of the coating.When the addition amount reaches to 4%,the Cobb value is reduced by 44%,indicating that the addition of ZnONPs can improve the water resistance of the material,and the operation is simple,which is convenient for industrial production.However,when investigating the mechanical properties of coated paperboard,it is found that the tensile strength was the largest when the additive amount was 1%.The reason is that the crystallinity of the coating is the largest at this time,and the crystallinity above this value is destroyed,resulting in reducing mechanical properties and heat seal strength.The addition of ZnONPs has little effect on the oil resistance of the paperboard,but it has a non-negligible effect on the antibacterial properties.The larger the addition,the more significant the antibacterial properties.Compared with PLA coating,the oxygen transmission rate of CMCS/CMC+PLA coated paperboard is reduced by 99%under 23?/50RH environment,and the barrier time to soybean oil is reduced.The water vapor barrier properties have also been doubled,even in a 38°C/90RH environment,the water vapor barrier properties have also been increased by 50%.Compared with the CMCS/CMC+PLA coating,the barrier properties of the CMCS/CMC+PLA/ZnONPs coating are further improved.With the increase in the amount of ZnONPs added,the barrier properties are also continuously improved.When the addition amount reaches 1.5%,The barrier performance of the coating to oxygen and heptane vapor is increased by 50%,the barrier to water vapor is doubled,and the oil resistance time can reach 20h.Although corona treatment can reduce the content of polar components of the CMCS/CMC coating,resulting in a slight decrease in the barrier properties of the composite coating to heptane,it is still a good oil-repellent coating.The antibacterial activity(A) of the coating with 1.5% ZnONPs added to Escherichia coli and Staphylococcus aureus exceeded 2,and the antibacterial rate of the coating exceeded 99%.Therefore,the use of degradable materials to prepare double-coated paperboard has good commercial prospects.