The loss of adhesion of hot melt glue is an important factor causing the quality problems of disposable sanitary products. This paper introduces the difficulties in the investigation of hot melt pressure sensitive adhesive loss.
At ordinary times, the data is incomplete, and the operators cannot provide continuous and reliable production information. Due to the lack of data before the investigation, it is difficult to judge whether the loss of adhesion of hot melt glue is an accidental problem or a routine problem, and it is impossible to create a reliable standard of normal bonding strength. As a result, the investigation work needs to re accumulate data, and the investigation direction has developed to all aspects, affecting the speed and accuracy of the investigation work.
The retention samples of problematic sanitary samples and normal sanitary samples are insufficient. The inspection of disposable sanitary products belongs to destructive inspection, and one piece is damaged at a time. Therefore, the low number of samples will increase the error of the final test results and mislead the investigation direction. Usually, the accelerated aging test will be carried out at the same time of testing sanitary samples to compare the bonding strength level of hot melt glue after aging. Therefore, the number of health problem samples and normal health samples should be at least 20 pieces of each kind.
This is a common phenomenon in China at present, because domestic manufacturers pay more attention to sales and production, and there are many types of base materials and adhesives used. It increases the management cost to reserve samples for each batch of hot melt glue and base materials alone. Therefore, in this case, it is basically necessary to carry out backward extrapolation under the condition that there are no problems in the process and environment. The accuracy of the investigation must be reaffirmed.
The most complicated situation is that the loss of adhesion of hot melt glue is the comprehensive result of many factors. For example, the substrate is difficult to soak. For some reasons, its operating temperature is not within a reasonable range, the equipment is under pressure due to aging, and the glue amount is at the lower limit of the preset value. This requires primary and secondary analysis of multiple factors to find out the main influencing factors.
In a word, when investigating the problem of hot melt glue loss, we must unite and cooperate with procurement, production, quality and technology, and repeatedly verify the accuracy of the investigation direction until we find the cause of hot melt pressure sensitive adhesive loss and make improvement measures.