Polypropylene unidirectional tensile film

1. Performance and application

Polypropylene film is similar to high-density polyethylene film. By using a near distance unidirectional stretching process close to the width of the film, the film produced has less shrinkage in the amplitude direction, is not easy to tear in the transverse direction, and maintains the advantages of high longitudinal tensile strength. Therefore, a packaging film with large longitudinal and transverse strength and high longitudinal crack resistance can be prepared. Its biggest characteristic is that it has the unique twisting (knotting) performance of the unidirectional tensile film. It is widely used in the field of twist packaging. In addition, the flat wire cut from the film can be woven into a bag. Compared with the flat wire made by traditional methods, it can be woven into a woven bag with fewer cracks, less strength reduction before and after weaving, and higher production efficiency.

2. Production process

The production process of polypropylene unidirectional stretch film is similar to that of high-density polyethylene unidirectional stretch film, but the raw materials and production process conditions are different.

3. Production equipment

The equipment for the production of polypropylene unidirectional tensile film is similar to that for the production of high-density polyethylene unidirectional tensile film, but different in some places. For example, MFPU1090, a nearly wide unidirectional stretching device produced by Toshiba Machinery Co., Ltd., is used for unidirectional stretching of high-density polyethylene, and MFPU-13115 is used for unidirectional stretching of polypropylene.

4. Resin for production

There are special resins for polypropylene unidirectional tensile film, such as T-GS polypropylene resin produced by Qilu Petrochemical Company Olefin Plant in China, with MFR of 3g/10min.

5. Production process conditions

The differences between the production process conditions of polypropylene unidirectional tensile film and high-density unidirectional tensile film are as follows: ① the extrusion plasticization temperature is generally higher than 10-20 ℃; ② the tensile temperature is higher than 10 ℃; ③ The drawing ratio can be higher, 6-10 times; ④ The stretching distance can be wider, which is 60-1000 times of the thickness of the untensioned film; 5. The heat treatment temperature is about 10 ℃ higher, and the contact time between the film and the heat treatment roller can be longer.