Preparation And Properties Of Linear Easy-Tearing Biaxially Oriented Nylon 6 Film

Biaxially oriented PA6(BOPA6)film has been widely used in the packaging field due to its excellent mechanical properties and better barrier properties.However,the straight-line tearing performance of BOPA6 film is poor.Improving the straight-line tearing performance of BOPA6 film can meet its needs in special fields,especially in liquid packaging or powder packaging.Therefore,it is of great practical significance to carry out the research on the straight-line tearing BOPA6 film.In this paper,BOPA6 film,biaxially oriented PA6/PET/AX8900 film,and biaxially oriented PA6/PA66 film were prepared by optimizing the formulation design and forming process,and the relationship between material formulation,preparation process and structural properties was studied.The main research contents and results are as follows:Firstly,Study on the preparation and properties of biaxially oriented PA6/PET/AX8900 film.Using PA6 as the matrix and introducing the PET phase to prepare five different blending ratios of PA6/PET/AX8900blended films and biaxially oriented films,the microscopic shape of the PA6/PET/AX8900 blended films before and after biaxial stretching were studied by SEM,DMA,DSC,etc.Morphology,thermodynamics and crystallization behavior,the linear tearing performance,mechanical properties,barrier properties and optical properties of the blend film were discussed.At the same time,the influence of the compatibilizer EAG(AX8900)on the compatibility of PA6 and PET was studied.The research results show that the addition of 3 wt%AX8900 has a significant compatibilizing effect on the PA6/PET blend film,and the PET is well dispersed in the PA6 matrix;When the amount of PET added was increased from 0 wt%to 35 wt%,the melting point of the PA6/PET/AX8900 blend film decreased.At the same time,due to the presence of rigid benzene rings in PET,the crystallization temperature dropped from 187.01 to 183.47;The mechanical performance test showed that when the amount of PET added was 25 wt%,the tensile strength of the PA6/PET/AX8900 film was increased by 25%compared with the pure PA6 film,and the elongation at break was basically unchanged.When the stretch ratio is 3×1,the tensile strength of the PA6/PET/AX8900 biaxially oriented film with a PET addition of 25 wt%is 88%higher than that of pure PA6;The results of the straight-line tear test showed that when the amount of PET added was increased from 0 wt%to 25 wt%,the tear deviation of the blend film decreased from 100%to 46%.After the PA6/PET/AX8900 blend film with a PET content of 25 wt%is biaxially stretched,the tear deviation is significantly lower than that of the unstretched PA6/PET/AX8900 blend film.When the stretch ratio is 3×1 When the PA6/PET/AX8900 blend film has a tear deviation of 3.2%;In addition,when the added amount of PET is 25 wt%,the barrier properties and haze of the PA6/PET/AX8900 blend film are improved.Secondly,Study on the preparation and properties of biaxially oriented PA6/PA66 film.Using PA6 as the matrix and introducing the PA66 phase,five different proportions of PA6/PA66 blended films and biaxially stretched films were prepared to explore the linear tearing performance and thermodynamic properties of the PA6/PA66 blended films before and after biaxial stretching.The results of dynamic mechanical analysis show that PA6 has good compatibility with PA66;Differential scanning calorimetry showed that when the addition of PA66increased from 0 wt%to 35 wt%,the crystallization temperature(T_c)of the PA6/PA66 blend film increased from 187.01?to 212.48?,and the melting point increased;mechanical performance test It is shown that when the addition amount of PA66 is 15 wt%,the tensile strength of the PA6/PA66 blend film is increased by 43.1%compared with the pure PA6film,and the elongation at break is increased by 49.36%.When the stretching ratio is 3×1,the tensile strength of the PA6/PA66 biaxially oriented film with 15 wt%of PA66 added is 33.22%higher than that of pure PA6,and the elongation at break is reduced;the straight-line easy tear test results show When the addition amount of PA66 is 15 wt%,the linear tear performance of the blend film is significantly improved compared to pure PA6,the tear deviation is reduced from 100%to 70.8%,and when TD=(1,2,3)As the MD stretch ratio increases,the straight-line tearing performance of the blend film has been significantly improved.When the stretch ratio is 3×1,the minimum tear deviation can reach 19.3%.Finally,Research on the rheological properties of PA6/PET/AX8900film in the double-stretching process.This chapter takes PA6/PET/AX8900 as the research object,and uses a biaxial tensile testing machine that can collect stress-strain curves to study the rheological behavior of PA6/PET/AX8900 film in the double-stretching process.The stress and strain calculation expressions of PA6/PET/AX8900 film in the biaxial stretching process at different stretch ratios are deduced,and the stress-strain relationship diagram of the PA6/PET/AX8900 film in the biaxial stretching process is established;Analyzing the stress-time curve in the shaping process,it is found that the elastic-plastic deformation in the stretching stage affects the stress contraction and relaxation phenomenon in the shaping stage,that is,the stress contraction in the shaping process is related to the elastic deformation in the stretching process,and the stress Relaxation is related to plastic deformation.Based on the fractional rheological model,the stress-time curve of the setting stage was fitted and analyzed,and it was found that as the setting time increases,the loss factor of the PA6/PET/AX8900 film shows a decreasing trend,and as the stretch ratio increases,the loss factor gradually increases.