How do the absorbency and breathability of paper sheets affect their use in writing, printing, and packaging?

The water absorption and air permeability of paper sheets have a crucial impact on the use effects of writing, printing and packaging, as shown below:

Paper with high water absorption can absorb ink better, help the handwriting to fix quickly, prevent the ink from spreading on the paper, ensure the handwriting is clear and not easy to smudge. This is especially important for writing tools such as pens and brushes.

However, if the water absorption of paper is too strong, it may cause the paper to become soft, feel bad, or even cause problems such as uneven paper surface and curling, affecting the smoothness and comfort of writing.

During the printing process, paper with moderate water absorption can better absorb ink or ink, and maintain the clarity and color vividness of the printed content. If the water absorption of paper is too strong, the ink may be absorbed too quickly, resulting in light colors and unclear images and texts; if the water absorption is too low, the ink or ink may not fully penetrate the surface of the paper, resulting in uneven printing or unclear image layers.
For laser printing paper, excessive water absorption may cause the paper to curl or deform, affecting the normal operation of the printer.

For packaging paper, appropriate water absorption can ensure the safety of the packaging contents. Paper absorbs a certain amount of moisture to prevent moisture from spreading in the air, thereby reducing the risk of moisture in packaged items. Excessive water absorption may cause the paper to become fragile and reduce its ability to bear weight, affecting the protective effect of the packaging.
Too low water absorption may cause the paper to lack a certain degree of elasticity and flexibility, and may not adapt well to external conditions in a high humidity environment, causing the packaging to deform or break.

Paper with better air permeability usually has a more delicate surface and uniform structure, which is conducive to the smooth movement of writing tools. This kind of paper can ensure smooth writing while avoiding pen tip wear caused by excessive friction.
If the air permeability of the paper is too poor and air circulation is restricted, the surface of the paper may be unevenly stressed during writing, resulting in partial damage to the paper or unsmooth writing.

Paper with better air permeability performs better in inkjet printing. It can ensure that the ink dries quickly, avoid ink penetration or diffusion, and ensure clear and bright printing.
If the air permeability of the paper is poor, the evaporation rate of the ink slows down, which may cause the printed ink to not dry for too long, resulting in smudges when wiping or blurred printing, affecting the final print quality.

In packaging applications, the air permeability of paper directly affects the protectiveness of items. Moderate air permeability helps prevent packaged items from getting damp or moldy due to excessive air humidity. For example, in food packaging, appropriate air permeability can help maintain a certain amount of air circulation in the package, avoid moisture accumulation, and extend storage time.
Excessive air permeability may cause the package to lose its isolation effect, and cannot effectively prevent the impact of the external environment on the internal items, resulting in insufficient packaging protection. Especially when factors such as air and moisture need to be strictly isolated, the air permeability of the paper needs to be strictly controlled.

In the writing and printing process, paper needs to find a balance between water absorption and air permeability. For example, some high-grade printing and writing papers require that the paper has a high degree of coordination in water absorption and air permeability, which can properly absorb ink or ink, and maintain sufficient air permeability to prevent the ink from diffusing or staying on the paper surface.
In packaging applications, the water absorption and air permeability of paper jointly determine the quality of the packaging. For example, the air permeability of paper used for food or medicine packaging can help the internal items avoid moisture or mold, while moderate water absorption helps maintain the strength and toughness of the paper.

For paper used in different environmental conditions, such as outdoor packaging, cold chain transportation packaging, etc., water absorption and air permeability need special consideration. Paper needs lower water absorption and moderate air permeability in a humid environment to ensure that its performance does not deteriorate due to moisture absorption; in a drier environment, paper with better air permeability can help maintain the balance of the internal and external environment of the package.

The water absorption and air permeability of paper are crucial to its performance in writing, printing and packaging. Appropriate water absorption and air permeability can improve the performance of paper, ensure the quality of writing and printing, and the protective effect of packaging. However, too high or too low water absorption and air permeability will have a negative impact on the performance of paper. Therefore, choosing the right paper in different applications and reasonably controlling water absorption and air permeability can achieve the best results.