Before, the sealing tape used for seams, its transparent tape material was used as glass paper, kraft paper, polypropylene film and so on. The pressure sensitive adhesive is coated on one side or double side of the base material, and its disadvantage is that the edge of the adhesive tape is easily tearing. In order to avoid this disadvantage, a high strength poly (vinegar) film was used. However, the cost of the poly (vinegar) thin film substrate is high, and it is difficult to be widely used.
Recently, the sealing strips used as corrugated cardboard boxes are mostly based on paper, cloth, polypropylene and PVC film. Apply hot melt glue on one side or two sides. The paper substrate strength is not high, the paper substrate and the use of different plastic film or textile reinforced transparent tape material, is not easy to pull with the hand, it is not convenient to use. The low temperature brittleness of the polypropylene and the transparent adhesive tape of the polyvinyl chloride membrane base material. Polyethylene and PVC base material, its stiffness is large, tensile modulus is large, elongation is 5%. The adhesive tape of this kind of material is used as the sealing of the frozen food container at low temperature. In the uneven surface of the surface of the guest, the tape will be stripped due to the tensile stress.
Manufacture of adhesive tape is easy to pull with the hand, while the tensile strength of transparent tape material is still very high. This kind of transparent tape material is cheap and convenient for popularization and application. Its production process is simple, and the cold resistance is very good. The base material of the adhesive tape is high density polyethylene (density is more than 0.94% grams / centimeter 3). The transverse and longitudinal drawing ratio is 6:1. polyethylene substrate coated with pressure sensitive adhesive (single and coated). On the other hand, the transparent adhesive tape is coated with another layer of pressure sensitive adhesive. A layer of paper can be sandwiched between the high density polyethylene film and the pressure sensitive adhesive.
No matter what form of the adhesive tape, a very important point is the transparent tape material of high density polyethylene density should be greater than 0.94% g / cm 3, and transverse to the longitudinal stretch ratio should be more than 6 times, the best is more than 10 times. The reason why the density of HDPE is not less than 0.94% g / cm 3 is the reason why transparent tape material is required to ensure that the substrate has high transverse strength at low temperature.