Preheated Plastic Container Labelling to Reduce Electrostatic Mispositioning
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Solution Overview
Problem
Challenges in reliably and correctly positioning labels on plastic containers due to electrostatic charging and unpredictable attractive forces, leading to mispositioning and wrinkling, especially at high throughput rates, and the risk of adhesive bonds detaching under mechanical stress during filling, particularly with carbonated beverages.
Innovation Solution
Heating plastic containers to a temperature range of 40°C to 60°C before labeling, utilizing residual heat from forming and coating processes, and applying a pressure-sensitive hot melt adhesive to enhance bonding and creep resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plastic containers are handled at high throughput rates, then productivity is improved, but electrostatic charging increases causing mispositioning and wrinkling of labels
Solution Approach 1:
The patent applies parameter changes by heating the plastic containers to a temperature range of 40-60°C before labeling. This temperature parameter change reduces electrostatic charging on the container surface, thereby improving label positioning accuracy while maintaining high throughput rates. The heated state prevents electrostatic attraction between the label and container that would otherwise cause mispositioning and wrinkling.
2Strength
If hot melt adhesive is applied to bond label to container, then bonding strength is improved, but adhesive bonds may detach under mechanical stress during filling
Solution Approach 1:
The patent changes the temperature parameter of the plastic container to 40-60°C before applying the hot melt adhesive. This temperature parameter change enhances the creep resistance of the adhesive bond, allowing it to maintain bonding strength under mechanical stress during filling operations. The heated container surface ensures the adhesive remains in an optimal state for bonding while resisting deformation under pressure.
Solution Approach 2:
The patent applies beforehand cushioning by pre-heating the plastic containers to 40-60°C before the labeling and filling processes. This pre-heating creates a thermal buffer that prevents the adhesive bond from weakening under subsequent mechanical stress during filling, thereby ensuring bond stability throughout the product lifecycle.
3Ease of manufacture
If plastic containers are cooled to ambient temperature before labeling, then processing simplicity is improved, but label positioning becomes difficult due to electrostatic forces
Solution Approach 1:
The patent changes the temperature parameter from ambient (cool) state to 40-60°C heated state before labeling. This parameter change eliminates electrostatic forces that interfere with label positioning, achieving both ease of manufacture and high positioning accuracy. The heating process is integrated into the existing production flow, maintaining simplicity while dramatically improving positioning precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves label positioning and bonding strength, reducing mispositioning and warping, and enhances creep resistance, especially for containers filled under pressure.
Implementation Method 1
the plastic containers are fed to the labeling machine in a heated state, in particular at a temperature of at least 30°C, preferably between 40°C and 60°C
Implementation Method 2
Such an adhesive is heated for processing until it becomes liquid or at least processable. In this state, the adhesive can be applied to an outer surface of the plastic container.
Implementation Method 3
A pressure-sensitive hot melt adhesive (PSA) is preferred. Its adhesive strength also depends on the mechanical pressure applied.
Data Source
Figure 1
AI summary
The invention relates to a method and a device (1) for treating plastic containers having an interior space enclosed by a side wall and a base section, which is accessible through a container opening. The plastic containers are fed to a labeling machine (17), where they are coated with a hot-melt adhesive and bonded to a label by the hot-melt adhesive. According to the invention, the plastic containers are fed to the labeling machine (17) in a heated state, in particular at a temperature of at least 30°C, preferably between 40°C and 60°C, particularly preferably between 42°C and 55°C.