The invention provides an ultrathin
polyethylene microporous breathable film. The breathable film is characterized by comprising an outer layer, a middle layer and an inner layer which are subjected to co-
extrusion forming through a
film blowing machine, and the inner layer is formed by blending, by weight, 45-60 kg of
calcium carbonate master batch, 25-30 kg of
polyethylene, 18-25 kg of ethyleneand
octene copolymerized
polyethylene and 1-3 kg of
lubricant; the middle layer is formed by blending the following materials in parts by weight: 60-70kg of
calcium carbonate master batch, 25-30kg ofpolyethylene and 1-3kg of
lubricant; the outer layer is formed by blending, by weight, 45-60 kg of
calcium carbonate master batch, 25-30 kg of polyethylene, 18-25 kg of
ethylene and
octene copolymerized polyethylene and 1-3 kg of
lubricant. The breathable film product produced through the film blowing process is excellent in physical and chemical properties of materials, meets the requirements that the
gram weight is 10-14
gsm, the
moisture permeability is 1800-3200 g / 24 h / m < 2 > and the
hydrostatic pressure resistance is larger than or equal to 50 mmH2O, the breathable film product is an upgraded and updated product of a traditional
curtain coating breathable film, and has the advantages of being low in
gram weight, high in breathability, resistant to
permeation and the like. The film produced by the patent technology is small in size
shrinkage rate so that colorful patterns can be formed after flexible surface printing, and the film is applied to
infant diapers.