VARIOUS PARAMETERS OF PAPER

Paper can be seen everywhere in our life, in the food industry, in the packaging industry, in the stationery industry, and so on. In people's impression, paper is always a white sheet, it seems that there is no special big difference, but in fact, the parameters of paper with different functions are completely different, and even the paper with the same use field has a different of parameters.

The most critical parameters are grammage, stiffness, caliper, whiteness, brightness, and glossiness. In certain industries with specific needs, such as food grade ivory board, there are edge penetration and dust levels.

Here's what these parameters mean:

Grammage: Grams of paper per square meter.

Stiffness: Strength resistance of paper or board to bending. Stiffness is proportional to the EI/W value, where W, E, and I are the mass, elastic modulus, and inertia of paper or board respectively. Paper stiffness is a very important index, that directly affects the size of the crease stiffness (another factor for die cutting pressure), thus affecting the finished product molding. The stiffness is small, the finished product is easy to collapse and warpage, stiffness is large, and the finished product is difficult to shape.

Caliper: Thickness of paper.

Whiteness: The whiteness of the paper surface, the ability of the paper to be fully reflected by light, is expressed as a percentage. Paper quality standards have clear requirements for whiteness, such as ivory board whiteness is not less than 92%.

Glossiness: Internal reflection factor of paper to main wavelength (45740.5) nm blue light under specified conditions.

Edge penetration: edge penetration can also be divided into edge penetration quality (The quantity of liquid seeping from a paper or board unit cross-section area under specified conditions) and edge penetration distance (Maximum penetration distance of liquid from unit section area of food grade cupstock under specified conditions).

Dust levels: The number of impurities (Any unwanted piece of material embedded in the pulp that exceeds the specified minimum size and presents a significant opacity relative to the surface of the page) per square meter of paper or board, or the equivalent area of impurities per square meter of paper or board (square millimeters).