With the development and progress of society, the use of sanitary products is becoming more and more common, and breathable membranes are becoming more and more popular in China's sanitary products market. Film blowing has been successfully applied to diapers, menstrual pants, sanitary napkins and other products, bringing a revolutionary solution to the bottom film of sanitary products. This paper mainly compares it with flowing breathable film.

1.Main differences between film blowing and flowing breathable film

(1) Different equipment

The production equipment of breathable film of the two methods is different. Specifically, the casting equipment is horizontal and the film blowing equipment is vertical. Therefore, the film blowing production line has requirements for the height of the factory.

(2) Different processes

The raw material particles of the two processes are different, and the melt index of the blown particles is relatively low; Blown film products are easier to have excellent mechanical properties; The stretching effect is different. The stretching rate of casting film is generally 2 times, and the blowing film can reach 4 ~ 5 times. The longitudinal mechanical property of blowing film is better, which is more suitable for positioning cutting printing.

(3) Different performance

The longitudinal tensile strength, whiteness, hydrostatic pressure resistance and longitudinal breaking tensile strength of film blowing are better than those of tape casting breathable membrane, and the permeability and transverse breaking tensile strength are equivalent to those of tape casting breathable membrane. Although its longitudinal fracture elongation is small, its longitudinal fracture tensile strength is large, which does not affect the use effect of the machine.

2.Characteristics and advantages of film blowing

(1) Features

Low ration: the conventional ration of flowing breathable film used for the bottom layer of diapers is 18g/ m2, and film blowing can reach 12~14g/ m2;

High production efficiency: since the breathable film produced by the film blowing method is a cylinder, which is folded into two pieces, and the casting film is one piece, the output of film blowing per unit time is twice that of casting film;

Excellent mechanical properties: the blown breathable film has excellent mechanical properties, especially the longitudinal outstanding deformation resistance;

The positioning printing effect is good: the fixed length fluctuation between the roll and the roll, the outside of the roll and the core of the roll is small and very stable.

(2) Advantages

Compared with the casting film with a quantitative amount of 18g/ m2, under the same quality, the area of the blown breathable film can be increased by 20%~3030%, helping enterprises reduce costs. At present, the yield rate of diapers in domestic enterprises is generally 92% - 95%, and the defective products are mainly caused by the fluctuation of positioning and cutting and the chromatic deviation of printing patterns. If the blown breathable bottom film is used, the yield of diapers can be increased by 3%~5% and the product cost structure can be effectively improved.

Efficiency advantage

Blown breathable membrane can be widely used in imported and domestic sanitary equipment, such as diapers, menstrual pants, sanitary napkins, etc. Due to the limitations of positioning, tension and other indicators, the tape casting breathable membrane has poor control and excessive waste discharge, which may make it difficult to improve the speed of the equipment. The blown breathable membrane can be applied to higher speed and more automatic equipment, so as to give better play to the potential of these equipment and improve efficiency.

(3) Application advantages of film blowing in diapers

The target ration is as low as 12~14g/ m2;

The positioning yield of diaper products has been increased to more than 99%;

The fixed length is stable, and the fluctuation is continuously stable in the range of 0~5mm;

For breathable film products with good performance and the same quantitative content, the film blowing has significantly improved the performance.

(4) Application advantages of film blowing on sanitary napkins / pads

The target weight is as low as 20~25g/ m2. For 30g/ M2 cast film, 25g/ M2 blown film has excellent substitutability;

Quantitative stability, and the deviation of single roll can be controlled within ± 5%;

Whiteness: the whiteness of blown film exceeds 90%, which can provide good coverage and pearlescent effect at the same time;

It feels softer and can be used as a cushion capsule.

Twenty years ago, the development of domestic cast film from ordinary PE to breathable film was a historic breakthrough, which played a positive role in solving the problems of damp and muggy users and diaper rash. Twenty years later, the popularization and application of film blowing technology in China will become a milestone in the history of sanitary membranes.