1. stiffness on the importance of paper board
Stiffness is the strength of paper or paperboard against bending.For carton board paper and whiteboard, stiffness is a basic performance index, which directly affects the crease stiffness size (another influence factor is die-cutting pressure), thus affecting the finished product forming.Small stiffness, finished products easy to crush, warp;Stiffness, the finished product is difficult to shape.Packaging paper on stiffness requirements, different quantitative paper stiffness is different, generally proportional to the square of thickness, the thicker the stiffness of cardboard is higher impact of bending stiffness factors affect the stiffness of many factors.
The thickness and modulus of elasticity of paperboard are the most basic factors that affect the stiffness of paperboard or paper.When the thickness was unchanged, the stiffness increased with the increase of tightness. When the weight was unchanged, the stiffness increased slightly with the increase of tightness, but the general trend was a net increase.Paper board stiffness test methods stiffness measurement methods have fixed, also have not fixed Angle test sample bending strength, the specimen free bending test strength change, some test methods both.
2.make carton shape rules to control the crease force and stiffness of the proportional relationship
The reason for the irregular shape of the carton is that the crease force (the force required for the carton package to bend 90° along the indentation direction under certain conditions) is too small and deforms;Cause the cause of adhesion is not strong crease force is too large, and thus from the adhesive bounced off;The cause of the bending around the carton is that the indentation is too stiff relative to the cardboard, the indentation is trying to bounce off, and the cardboard is not stiff enough to stop it from bouncing off.
Therefore, it is necessary to control the proportional relationship between crease force and stiffness (the force required for the carton to bend 15° under certain conditions), so as to make a perfect carton.The paper box with appropriate crease force and stiffness ratio has a smooth and full appearance after forming on the high-speed automatic packaging line.
Stiffness value of the test can be produced by our company's stiffness instrument, specially used for a variety of paper bending resistance test of the basic instrument, suitable for the detection of low quantitative paper stiffness.It is a kind of high efficiency and easy to use instrument.