Why are the weights of some paper-plastic paper trays so different?

In recent years, the packaging industry has developed rapidly, and as an indispensable paper-plastic-paper tray factory, it has also ushered in a broad market. At present, environmentally friendly paper trays have gradually replaced many traditional packaging in the market, and they have great advantages in practicality, environmental protection and resource saving. At the same time, people’s needs are constantly diversified, which also puts forward higher demands on the packaging market.

For this reason, the raw material composition must be very stable, so what problems will the paper tray factory encounter in the process of customization?

1. What are the types of raw materials for paper, plastic and paper trays?
The more common ones are divided into two categories; one is raw pulp (such as: raw wood pulp, bamboo pulp, sugarcane pulp, straw pulp, etc.). The other category is recycling (such as: corrugated paper, newspaper, white-edged paper). In addition, according to customer requirements, different color base papers can be used to produce colored paper support products.

2. Why are the weights of paper support products inconsistent?

There are two main reasons, one is that the pulp concentration is changing. In the production process, the prepared pulp of a certain consistency will change as the formed paper tray leaves the pulp cylinder of the forming machine, and the pulp concentration will begin to change. The paper tray factory usually controls it between 2.56% and 3.6%. The second is that the vacuum is constantly changing. The negative pressure value of the negative pressure tank loaded by the air compressor in the forming process is also a variable. The superposition of the two variables leads to the same suction time. % change.

3. Why some colors you can’t do or can’t do well?

For the dyeing of paper-plastic-paper-support products, water-based dyes are mostly added in the pulping process based on the original pulp. First, the change in the concentration of the pulp also leads to changes in the concentration of the dye. Second, most dyes are very sensitive to temperature. (During the drying process, the color will also change with the temperature of the drying line, and the mold temperature will also change at different temperatures when the mold temperature is 150° to 250° during hot pressing). In conclusion, products with high color requirements should not be dyed.

4. Why is the product not smooth and tidy?

After the paper-plastic-paper-support product is formed, it is fully wet and will be deformed after the drying process. Then, the high temperature (150°~250°) and high pressure (3T~50T) of the plastic mold is used to restore the original designed geometric shape. The upper and lower mold clamping is subjected to vertical force, so the plane position is strongly stressed, the paper support appears smooth, and the inclined surface is not easily stressed and appears slightly rough. According to the actual requirements of product design, the smaller the slope, the more ribs, the smaller the plane, and the more the spherical arc surface, the lower the smoothness after shaping, which is the result of the process.

5. Why are there fine cracks on the surface of the product?

When the environmentally friendly paper support product is formed, the pulp fiber is naturally adsorbed into a group layer by layer, and the liquid pulp will not flow out in some grooves, so that the thickness of the paper support at different positions after drying will be different from the standard thickness in the design. error, then when it is squeezed by a strong external force during high-pressure shaping, the outer part of the fiber at the uneven thickness of the inner and outer layers will break, and it will appear as a fine crack from the surface. This phenomenon will not affect the strength of the paper tray packaging, so it is acceptable in the industry.

Post time: Jun-16-2022