▎ 摘　　要

NOVELTY - Barrier layer comprises an outermost waterproof layer, a base layer, a barrier layer, and an innermost layer that is in contact with the contents of the package. The barrier layer includes nanocellulose. The length of at least one dimension of the nanocellulose is less than 100 nm. The gram weight of the nanocellulose is 0.1-20 g/m2. The barrier layer has an oxygen permeability of less than 100 cm3/(m2.4h.0.1MPa) under the measurement conditions of air humidity of 0%RH, temperature of 23°C, pressure of 0.1 MPa and thickness of less than 100 μm. USE - The barrier layer is useful composite packaging material used for preparing packaging container of liquid or semi-liquid food e.g. milk and yogurt, and food packaging. ADVANTAGE - The barrier layer is green and environmentally friendly, has strong oxygen barrier, and degradability, can significantly reduce the environmental burden caused by traditional aluminum-plastic composite packaging materials that are difficult to degrade. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a composite packaging material.