Self-adhesive label use common fault resolution
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I believe that most people were still unfamiliar with self-adhesive labels 20 years ago, but today, in our lives, we can use self-adhesive labels on the packaging of various commodities. It can be said that self-adhesive labels have been increasingly used in industries such as medicine, daily chemicals, clothing, and electronic products that are closely related to our daily lives. Nowadays, although people are no longer unfamiliar with self-adhesive labels, as professionals engaged in the production and research of self-adhesives, we often see some problems due to the lack of understanding of the performance of self-adhesive labels and the use of self-adhesive labels. The use of non-standard behavior causes failure. Below I share some of the cases that I encountered in my daily work due to improper use of the sticker.
Case 1: The label of the hail Ling label is dropped after labeling
A manufacturer that produces hail Ling needs to use a self-adhesive label on the lid of Sheng Bingling's plastic box. Since the hail Ling is placed in a plastic box, it should be placed in a low temperature of 38 degrees Celsius. The customer removes the product directly from the cold storage before the ice cream is shipped from the factory and immediately labels the lid. As a result, the attached labels all fell off the lid after a few hours.
Failure Analysis: This failure is mainly caused by the customer's lack of understanding of the performance of the adhesive. To clearly analyze the cause of the failure we must first understand several definitions of the adhesive. They are: the initial viscosity of the adhesive, the final viscosity, the lowest labeling temperature and the temperature range of use.
Microscopically, the surface of any substrate to be attached can be regarded as an uneven surface. After the self-adhesive label is attached to the surface of the object to be attached, the adhesive has just contacted the labeling substrate and has not completely leveled on the surface of the object to be attached. The bonding force between the adhesive and the surface of the object is weak, and the adhesive is exhibited. Viscosity is called the initial viscosity of the adhesive.
The adhesive is completely leveled on the surface of the substrate to be attached for a period of time after labeling (typically 24 hours after labeling). The adhesion of the adhesive to the surface of the object is maximized, and the viscosity exhibited by the adhesive is called the final viscosity of the adhesive.
The minimum temperature at which the adhesive can withstand labeling is called the lowest labeling temperature of the adhesive. In other words, it must be labeled at a temperature above the minimum labeling temperature to maintain good fluidity of the adhesive. If the temperature at the time of labeling is lower than the lowest labeling temperature, the adhesive will be frosted to affect the fluidity of the adhesive on the surface of the substrate to be applied, resulting in a decrease in the viscosity of the adhesive.
The label is applied to the substrate for a period of time. After the adhesive reaches the final viscosity, the temperature range that can be withstood during use is called the temperature range of the adhesive. The temperature range of the adhesive is wider than the range of the lowest labeling temperature.
The minimum labeling temperature of the adhesive used in the self-adhesive label used by Hail Ling Factory is zero at 10 degrees Celsius, and the temperature range after reaching the final viscosity is from minus 40 to 90 degrees Celsius. The main reason for the label drop is that the initial labeling temperature (minus 38 degrees Celsius) is lower than the minimum labeling temperature of this adhesive (10 degrees Celsius). In this case, the adhesive is frostbitten and loses fluidity. Good to level the surface of the object, causing the viscosity to drop and the label to fall.
Solution: After knowing the cause of the failure, there are two ways to solve it.
1. Replace the adhesive suitable for ultra-low temperature labeling, but this will greatly increase the cost.
Second, change the labeling process, the Hingling Ling factory first put the label on the lid of the plastic box in the environment of zero 10 degrees Celsius. After 24 hours, the adhesive reaches the final viscosity and then put the labeled plastic box into the cold storage. Since the adhesive reaches a final viscosity, the operating temperature ranges from minus 40 degrees Celsius to minus 90 degrees Celsius. Therefore, it can fully adapt to the low environment of minus 38 degrees Celsius, and the phenomenon of label drop is completely solved.
From this case we can see that it is very important to understand the initial viscosity, final viscosity, minimum labeling temperature and operating temperature range of the adhesive during the application of the self-adhesive label. Proper application of these features can save costs and reduce failures during use.
Case 2: The tire label is marked after labeling
Once, a tire manufacturer appeared to have dropped the label after labeling. The customer attached the label to two different brands of tires. One of the labels on the tire has fallen and the other has no such problem.
Fault analysis: After the phenomenon investigation, it was found that the surface of the tire that did not malfunction was smooth and there was no tire thorn (one small thorn on the surface of the tire). The surface of the tire that has failed has many tire thorns. It is understood that the customer labeling method is manual labeling and labeling is very fast, and the labeling gesture is basically to remove the label from the trend to the tread. According to the above phenomenon, we analyzed two main reasons for the label drop: on the one hand, there are many small thorns on the tread. On the other hand, since the label is not fully pressed when it is attached, the label that is attached to the trend is equivalent to being suspended on the tire surface and being placed on the top of the small thorn. More than 80% of the rubber surface of the label does not fit the solid (tread), so the label will of course fall.
Solution: Improve the method of manual labeling. When labeling, try to press the label as much as possible to make the adhesive contact with the surface of the substrate to be coated. Customer troubleshooting by improving labeling methods.
Case 3: Break labeling when labeling is automatically labelled
There used to be a company that often had irregular cracks in the labeling paper when it was labelled with an automatic labeling machine (this phenomenon is often called labeling), which brought great productivity to the company. influences.
Failure analysis: The reasons for this failure usually occur as follows
1. There is a crack in the edge of the label bottom paper.
After the die-cut label is processed into a finished product, the bottom paper is generally kept wider than the label, which is to facilitate the labeling when the customer is labeling. It is easy to split the bottom paper of the edge of the label into small cracks during the transportation and handling of the label package. The automatic labeling machine has a certain tension when labeling, and the label with a crack at the edge of the bottom paper is easily broken under the action of tension, resulting in labeling and breaking. In addition, there is also a situation in which the adjustment of the roller on the automatic labeling machine is inappropriate, which causes the bottom paper of the edge of the roller to be cracked to cause labeling and breaking. Generally, the labeling and breaking tape caused by the roller paper is damaged by the roller, and the crack of the bottom paper is relatively regular.
Second, the label is too tight and the glue is too tight.
If the rewinding of the finished label is too tight, the adhesive in the adhesive will be squeezed out and the glue will be bleed. The oozing glue will stick to the back of the bottom paper and the whole label will not be easily loosened. This situation is particularly evident during the summer. If the label is narrower than the narrow base paper, the tensile strength per unit area will not be too large. The automatic labeling machine has a certain tension during the labeling process. When a roll of labels with a bleed phenomenon is used for automatic labeling, it is likely that the label-removed liner is pulled off under the tension of the labeler and the tension from the inside of the body during the labeling process. Causes labeling and breaking. The labeling breakage caused by this situation is that the bottom paper breaks irregularly due to the tension pull, but the fracture surface is relatively uniform.
Third, poor die cutting
The quality of the die-cutting quality also has a great influence on whether the automatic labeling is easy to break. If the die-cutting pressure is too large, the bottom paper is cut through and the tensile strength of the bottom paper is lowered, resulting in labeling and breaking. The fracture surface of the labeling tape with the die-cutting is relatively uniform, and the crack is at the position of the die-cut line.
Fourth, the release layer is destroyed
If the release layer of the liner (usually a layer of silicone oil) is destroyed, it can also cause labeling. In this case, the labeling tape is broken, and the fracture surface of the bottom paper is jagged. The cause of the damage of the release layer is the defect in the production of raw materials, and the release layer may be scratched due to improper handling in the printing factory inspection and replenishment process.
Solution:
According to the reasons mentioned above, the number is set to solve the problem. Sometimes the fault of labeling the broken belt is not caused by a single cause, but the above several reasons are combined. For example, the company mentioned above is a labeling tape caused by two reasons: poor die cutting and rewinding.
Case 4: Thermal paper label printing misplacement
On one occasion, the customer reported that the blue base paper, which is also the product of the Glassine paper, has no problem on the thermal printer, but the white base paper has a problem of misalignment. The main performance is that after printing a few sheets, the printing position is gradually shifted forward or backward.
Failure analysis:
The thermal printer controls the step of the paper feed by scanning the distance of the label through the photosensitive head, and the light intensity of the photosensitive head can be adjusted. The blue base paper and the white base paper have different light transmittances, and the customer's printer previously used blue backing paper for printing, and the light intensity of the photosensitive head is adjusted to a high level. After replacing the label of the white base paper, since the light transmittance of the white base paper is higher than that of the blue base paper, the step scanning is unstable. In order to confirm this judgment, the customer is allowed to cover the photosensitive head with a small piece of white base paper, so that the light intensity of the photosensitive head is artificially lowered. The printing step of the printed label on the machine is very stable.
Solution:
The light intensity of the thermal head of the thermal printer is adjustable. When the material with a different color from the previous backing paper is used, if the step scanning is unstable, try to adjust the light intensity of the photoreceptor to solve the problem.
The above mentioned are just some minor faults that often occur in self-adhesive labels in everyday production applications. I believe that with the continuous understanding of the use of self-adhesive labels, we can better use the self-adhesive labels to reduce the frequency of failures.