2.2 Selection of Honeycomb Paperboard Raw Materials for Air Conditioning Packages
2.2.1 Honeycomb base paper is divided into honeycomb paper and honeycomb core paper. Due to the long history of honeycomb paperboard production in China, there is no special paper and its standard. Therefore, the paperboard paper core paper standard adopts the corrugated paper standard (GB/T3022-91), and the paperboard is made of cardboard paper. Standard (GB/T 13024-91).
2.2.2 The main performance index of honeycomb base paper: (only listed below are some of the major impacts on performance)
A, paper ration: that is, the amount of paper per square meter. Quantification of paper is the first consideration in the selection of raw materials for honeycomb paperboard. The higher the paper's weight is, the better the strength of the paperboard, and the less the paper core is pulled in production; otherwise, the paper core is easy to pull apart, but the strength of the paperboard is reduced. Therefore, in practical applications, it is not the lower the better, nor the higher the better, but should be selected according to the actual situation. Usually, the core paper of the honeycomb paperboard is the basis weight of corrugated paper, generally l20g/m2 to 180g/m2. Between, the dough paper ration between 200 g/m2 ~ 500 g/m2. For the air-conditioning packaging, the face paper of honeycomb paperboard is quantified with 250 g/m2 kraft paper, and the honeycomb core paper is made of corrugated paper with a basis weight of 130 to 150 g/m2. The smaller the basis weight of the core paper, the better the cushioning performance of the formed honeycomb paperboard, but the worse the compressive strength. We should choose different basis weight honeycomb core papers and base papers according to the different requirements of the packaged air conditioners. For example, Kelon's Honeycomb underlayment for window packaging machines and cabinets was cancelled because of the elimination of the paper chassis that was originally used for foam packaging. The cushion used at the bottom of the company was made of a large-quantity corrugated base paper as a honeycomb sheet. In order to avoid breaking the cellophane paper during transportation, at the same time, the paper edge is attached to the side of the honeycomb mat to prevent the honeycomb paper from directly contacting with the ground to wear, moisture and affect the compressive strength of the honeycomb paperboard. The more quantitative the honeycomb paper, the stronger the moisture resistance of the formed honeycomb paperboard, but the higher the amount, the higher the cost.
B. Directionality of paper: Paper has a certain degree of directionality. Since the fibers are arranged in the longitudinal direction of the paper, and the paper in the paper machine is subjected to a large traction force, the vertical and horizontal directions of the paper are greatly different. In the production of honeycomb paper, when the fiber direction of the core paper is perpendicular to the honeycomb paper, its compressive strength is high, and the compressive strength is higher by 10%. At present, China's cell-to-cell manufacturers have different fiber arrangements in honeycomb cores produced from honeycombs due to differences in production processes.
C. Moisture Content of Paper: The moisture content of the paper is the percentage between the weight reduced after drying to a constant weight at 105 degrees and the original weight. Water has a significant effect on the flexibility, elasticity and strength of the paper. When the moisture is too high, the paper itself is very soft, the strength is drastically reduced, and it is difficult to bond; when the water content is too low, the paper becomes brittle and breaks easily. Both are unfavorable for the production of hand-made honeycomb paperboards. Generally, the moisture content of the paper for the honeycomb paperboard raw material is between 8% and 12%. The moisture control of the honeycomb paperboard should be appropriate, otherwise it will seriously affect the compressive strength and cushioning performance of the paperboard. It is more appropriate to control the moisture content of the honeycomb board selected for air-conditioning packaging to be about 13%.
D, the paper's ring pressure strength: It is a 1 2.7mm high, perimeter 1 52mm paper ring is pressed to crush the force required, it has the greatest impact on the pressure resistance of honeycomb products, obviously, the ring The higher the compressive strength, the higher the compressive strength of the honeycomb paperboard, and the higher its carrying capacity. In general, the honeycomb core has a ring pressure of 4.4 n·m/g to 5.5 n·m/g, and the face paper has a ring pressure of about 6.5 n·m/g. In addition, the flat compressive strength of the honeycomb paperboard is related to the height of the honeycomb paper core. The flat compressive strength of the honeycomb paperboard tends to slowly decrease with the increase in the thickness of the honeycomb paperboard, and its cushioning performance increases accordingly. Usually choose 30 ~ 50 mm honeycomb cardboard as a cushion. For this reason, we often find it difficult to reverse this point. This is also the difference between the buffering performance and the supporting performance of honeycomb paperboard, that is, the contradiction between the flat compressive strength and the buffer strength.
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2.2.3 Adhesive
The quality of the adhesive directly affects the peel strength, shear strength, and compressive strength of the honeycomb paperboard, so the adhesive plays a very important role in the production of honeycomb paperboard.
The adhesives used in honeycomb paperboard currently fall into the following categories:
A. Corn starch glue: There is no essential difference between corn starch glue and common carton glue, but the solid content is slightly higher. This glue has the following defects:
The adhesive strength is low, and the adhesive layer completely loses its elasticity and becomes brittle after being cured. When subjected to external forces such as bending impact, squeezing, shearing, etc., brittle failure is easily occurred.
The aging resistance and the moisture resistance are not good, especially when the temperature is high and the humidity is prone to mildew. For example, Kelon once used honeycomb paperboard refrigerators and air conditioner cushions to perform pile-stacking experiments. After stacking for one month, the honeycomb paperboard was found to have mildew. Therefore, this problem must arouse our attention, especially for the honeycomb paperboard used for packaging household electrical appliances. White latex must be used to prevent the cardboard from being affected by mold. Kelon's current use of honeycomb paperboard is the use of white latex, the use of cardboard cardboard mold has never been seen more than six months.
B. White latex: The main ingredient is polyvinyl acetate. The real white latex is a non-polluting and non-toxic green product. Its product quality is stable, the production rate and elongation rate are high, and it is fast drying, good strength, and solid content. High, long life, suitable for large-scale operations. The honeycomb paperboard used for packaging air conditioning should use white latex, otherwise it is easy to mold. (to be continued)
