Analysis of Mechanical Properties of Tetra Pillow Corrugated Carton Containers (II)

(1) The mechanical properties of corrugated board decrease with increasing storage time. From Fig. 1 to Fig. 4, it can be seen that after storage for 7 months, the side pressure of the carton is reduced by 6%, the adhesive strength is reduced by 10:6, and the burst strength and the empty foil compressive strength are reduced by 20, respectively. %about. The change in its mechanical properties is not a rule, but overall it shows that in the first few months its performance has decreased compared with Shaan, and then it has been more gradual. In the experiment, it can be found that the change of the carton performance has a great relationship with the temperature and humidity of the storage environment. The experimental results are closely related to the changes of the climate temperature and humidity in Shanghai.

(2) Analyze the result of pressure resistance of empty tank

According to the gross weight of the carton of 4.5kg, the company’s freight car box is 2.5m high. The filled product can be stacked 17 layers. The safety factor is 3, and the qualified compressive strength of the carton is determined to be 211 9N. It can be seen that the carton is After 7 months of storage, the compressive strength has decreased significantly and cannot meet the transportation needs.

(3) The deformation of the carton in the direction of the force, to a certain extent, reflects the degree of damage to the carton under the force. The experimental results of stacking strength show that the compressive performance of the empty box is gradually weakened during use, and the deformation of the carton increases with the increase of the pressing time, but the increase amplitude gradually decreases. After the cartons were stored for 7 months, the amount of deformation in the stacking experiment increased significantly, indicating that the cartons that were stored in actual use were damaged more seriously.

(4) Analysis of causes

The main reason for the decline in the mechanical properties of the carton is the effect of air temperature and humidity. In the Jiangnan region, April-June is the rainy season and the air humidity sometimes exceeds 90%. In this case, the cardboard becomes damp and soft, the thickness of the cardboard is also reduced, and at the same time, the adhesive is hydrolyzed by moisture and the adhesive strength is reduced. The above reasons can cause the cartons to have reduced pressure resistance.

Many changes that occur after the carton is wet are not completely reversible, so even if the external conditions are restored to the original state, the carton's compressive properties will not be fully restored. In this way, after storage for a period of months, the mechanical properties such as edge pressure strength, adhesive strength, burst strength, and carton compressive strength of the carton are reduced as a whole, resulting in unqualified carton quality. Several points inspired the analysis of the declining mechanical properties of the carton and gained some inspiration.

(1) Change the storage and transportation environment of the cartons, avoid moisture in the cartons as much as possible, and strictly control the temperature and humidity of the air. It is best to store the carton in an environment with a relative humidity of about 50%.

(2) Carton stocks should be as small as possible, so that timely production can be used in a timely manner, and as far as possible, the inventory period of the carton should be controlled within 3 months.

(3) The use of good raw materials and good quality binders can, to a certain extent, reduce the effect of air humidity on the mechanical properties of the paperboard.

(4) Products packaged in new cartons can be packed in a 17-pile stack to reduce transportation costs. However, cartons should be stored in low-level digital magazines after storage for a period of time to ensure product quality and safety.

(5) The Tiro pillowed cardboard box cannot be stacked 17 layers in production and transportation after being stored for 3 months.

(Author/Cai Yongji)

"Printing Technology" corrugated box special issue 2005, 7