The demand for corrugated boxes with waterproof performance is growing, especially in vegetable packaging food household appliances and export products, which has greatly promoted the development of corrugated box manufacturing.
However, there is no clear test method for the waterproof performance of corrugated boxes in China. Here, the method of testing the waterproof performance of corrugated boxes is discussed for reference.
The waterproof carton has the strength to resist the corrugated carton. According to their water resistance, they can be roughly divided into three types:
Hydrophobic corrugated cardboard-processing the surface of corrugated cardboard, which is affected by water for a short time, condensing the water into droplets and preventing water penetration.
Hydrophobic corrugated cardboard is often used for vegetable packaging fruit and aquatic products. According to packaging and recycling conditions, it is divided into two types: the hydrophobicity of the surface and interior of the corrugated box and the hydrophobicity of the surface of the corrugated box.
Hydrophobic corrugated cardboard manufacturing process: In order to improve the water resistance of the base paper in the papermaking process, a paper waterproofing agent can be added to the pulp, or surface sizing can be applied to give the base paper water resistance. Generally, when linerboard is produced in a paper mill, a paper waterproofing agent is applied to the surface of the calender of the paper machine for coating. In the manufacture of corrugated board, the paper-making waterproof coating is applied on the corrugated board machine by a roller coater, or the paper-making waterproofing agent is sprayed on the surface of the cardboard by a spraying device.
Waterproof corrugated cardboard-also known as water-retaining corrugated cardboard, which is basically impervious to water in contact with water for a long time.
The corrugated cardboard is usually used for packaging aquatic products. In addition to being used for waterproofing, corrugated cardboard also has a waterproof layer on its surface, which is sometimes used for furniture that is easily scratched. Piano Packing precision machinery and other items.
Waterproof corrugated board manufacturing process: In the corrugated board bonding process, the waterproof and waterproof coating is applied to the surface of the board by spraying or roller coating, so that the board has good waterproof performance.
Strong waterproof corrugated cardboard-This kind of cardboard is in contact with water for a long time and is almost impervious to water. There are two methods for manufacturing high-strength corrugated board: one is a one-time processing method, which is to make the base paper waterproof in the papermaking stage; and the secondary processing method is applied to the corrugated board manufacturing stage through the coating method and the impregnation method. It is waterproof.
The waterproof performance of corrugated boxes can be tested by the following methods:
Corrugated spectrometer (only for hydrophobic corrugated cardboard and waterproof corrugated cardboard)
It can be used to determine the water absorption capacity of the Corbel absorber on the surface of corrugated cardboard. It can be carried out according to the water absorption measurement of GB/T paper and cardboard (Bob method). Cut the corrugated cardboard into 10 circular specimens with a diameter of 125 mm. Before placing the corrugated cardboard sample, make sure that the surface of the cylinder ring and the rubber pad in contact with the sample are dry.
Use a glass measuring cylinder to accurately measure 100 mL of distilled water and pour it into the gas cylinder. Then a round corrugated cardboard sample with a good weight is placed on the annular surface of the cylinder. The surface to be tested faces the direction of the water, and the sample is pressed. Cover the sample and fix it on the cylinder. Turn the cylinder 180° when starting the stopwatch. For each measurement 5 times, a certain amount of water is added according to the water absorption of the corrugated board sample.
Remove the sample from the cylinder and place it on a piece of absorbent paper. Please note that the sample face down with water. When it reaches 2s before the water absorption time, put two absorbent papers on the sample and use it on a flat and hard table. The smoothing roller rolls back and forth once within 4s to make the surface of the sample dry. Quickly take out the sample and weigh it to the nearest 0.001g. Please note that each sample can only be tested once and should not be reused.
If there is still excess water on the surface after absorbing water with absorbent paper, or the sample itself has penetrated water, the sample should be discarded. Finally, the drainage value of corrugated board can be calculated.
