Determination of Paperboard Quality Control Stickiness and Strength (Part 2)

The specific test method is as follows:

Cut 10 samples of 25mm×80mm non-compressed corrugated cardboard from the sample to be tested. The direction of the corrugation is the same as the direction of the 25mm dimension. The edges of the specimen must be parallel and the error must not exceed 1mm.

Insert the needles into the corrugation between the corrugated holes. When inserting the needles, do not insert each boring hole. Pay attention to the separation. When separating the vellum and the vellum, you cannot separate the liner or core paper. Insert the upper and lower needles. To stagger the position, insert evenly, and then install the support.

Put the attachment with the sample into the center of the lower plate of the tester, start the tester, and press the attachment with the sample at a speed of 12.5±2.5mm/min until the peak and the paper or peak and core Paper or paper separation.

Record the value displayed on the meter, reading to the nearest 1N.

The result is expressed as follows: A = F/S where A denotes the bond strength of the sample and is expressed in N/m2; F denotes the force (average) required when the sample is separated, denoted by N: S The area of ​​the sample is indicated by m2 or cm2.

1. Several problems should be noticed when measuring the adhesive strength of corrugated cardboard:

2. The speed of the analyzer must be guaranteed to be 12.5±2.5mm/min, too fast or too slow and the speed will cause differences in the measurement results.

3. Cut the sample must be straight, its long side should be perpendicular to the direction of the corrugated.

4. Attachments must have support pieces, otherwise test errors may occur due to uneven pressure.

5, insert the needle attachment must pay attention to the separation site, the adhesion strength of the various parts in the production of the application of great significance.

6. As a result of the adhesive strength measured using the unsupported (comb) attachment, some may be the tensile strength of the corrugated paper.

Corrugated board adhesive strength is one of the physical properties of corrugated board. Different from other physical properties of corrugated board, it can better reflect the production process problems. Bursting strength and puncture strength are the main indicators of corrugated board. They reflect the physical strength of raw materials and the side pressure strength represents load. These have little relationship with the production process. The corrugated board adhesive strength reflects the tightness of the adhesiveness between corrugated paperboard sheets. We know that corrugated cardboard is a plate formed by the binding of cardboard and corrugated paper processed into corrugated corrugated wads. The processing of corrugated paper into waves is a production process. Bonding cardboard paper and corrugated corrugated paper is also a production process. From this we can see how close the bond strength of corrugated board is to the production process. In the past, when measuring the physical strength of corrugated cardboard, we often neglected the determination of the bonding strength. From the standpoint of using corrugated cardboard as a packaging material, it is possible to do so because we consider more of its protective function for the interior goods. However, if we look at the production process, it is obviously incorrect to ignore the determination of the bond strength.

In production practice, we found that the factors that affect the adhesive strength of corrugated board mainly include the following aspects:

One is the quality of the adhesive. This is the most important and most direct factor that affects the adhesive strength of corrugated board. The adhesive is made of starch or polyvinyl alcohol and other viscous substances and is made of other chemical substances. Its formulation, production process, and proportion of water are all responsible for the adhesion between the sheets. Paste mixing mistakes lead to unstable paste viscosity, and many carton manufacturers choose binders as the main task of QC team activities in the selection of quality control points.

The second is the quality of paper. In addition to the binder as an intermediate medium for bonding, the quality of the paper also has an effect on the adhesion. The quality of the paper should mainly pay attention to paper moisture, sizing, smoothness (roughness) and so on.

The third is the production environment factor. The environment is too humid; the initial viscosity between the sheets is too slow. When entering the next process, the separation is easy; the environment is dry, the binder loses moisture too quickly, and the sheet has not yet fully absorbed the binder, which also affects the bonding strength.

The fourth is equipment and processing factors. Such as corrugated pipe gap, the surface is not easy to cause local adhesion, roller pressure is uneven or insufficient, the speed of the speed can affect the quality of corrugated board adhesive.

The fifth is the shape factor. Different shapes have different areas of adhesion. Within a certain length, the greater the number of turns, the greater the area of ​​adhesion and the greater the strength of the bond.

Sixth, human factors. How much of the amount of paste used in production depends on the speed of bonding to adjust the amount of paste used.

The determination of the adhesive strength of corrugated board can not only understand the quality of corrugated board, but also can be used to control the quality of corrugated board production. When it is found that the adhesive strength of corrugated cardboard is insufficient, it can be analyzed to find out the unfavorable factors to overcome. As the analysis of the above factors, the key is the adhesive. If the paper, environment, shape and other factors change, the preparation of adhesives should also be changed accordingly in order to create a good corrugated cardboard. Through the determination of the adhesive strength of corrugated board, we can grasp the changes in the bonding quality of corrugated board and timely adjust the preparation of adhesives so as to achieve the purpose of reducing consumption, increasing output and quality, and making production enter a virtuous cycle. If it is an equipment factor, it is necessary to repair the equipment in time. If it is the impact of speed, it should be adjusted to the appropriate speed. By measuring the strength of the various parts of the corrugated paperboard, it is timely and clearly indicated on which machine the bad adhesion occurred. There is a basis for timely adjustment of the production process and improvement of the process.

By measuring the adhesive strength of corrugated cardboard, we can compare and understand the bonding effect of different adhesives. At present, various kinds of adhesives in the country emerge one after another, and the inventor of each adhesive agent claims that his invention is of high quality and low cost. By testing the sample, you can compare its advantages and disadvantages, and select the most suitable adhesive for your factory. This has great benefits for improving the process, using new materials, and saving costs.

In short, in the production process of corrugated paperboard, strengthening the detection of its adhesive strength can timely and accurately obtain the relevant information in production. It is very favorable to use this information to guide production, improve the process, and improve product quality. This article briefly discusses the determination of the adhesive strength of corrugated board and its application in production. Each company can flexibly use the actual situation of the company, and it will be able to produce greater benefits.

Author: Li wide source of information: "export packaging"