Filter Element Hot-Melt Adhesive Thread Reduction
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Solution Overview
Problem
Filter elements bonded with hot-melt adhesive suffer from the formation of adhesive threads during application, which can detach and be entrained in fluid flows, particularly problematic in filtering intake air from internal combustion engines.
Innovation Solution
A filter element design using a hot-melt adhesive system with a mixture of polyester-based and polyamide-based adhesives, applied in regularly or irregularly interrupted traces, minimizing adhesive threads through dynamic mixing and application techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hot-melt adhesive is applied in interrupted traces or punctiform manner, then adhesive quantity is reduced, but adhesive threads form and detach during operation
Solution Approach 1:
The patent changes the chemical composition parameters of the hot-melt adhesive by adding paraffin wax (10-40 wt%) and stearic acid (1-10 wt%) to the polyester-based adhesive. This modification alters the adhesive's cooling and solidification behavior, reducing its tendency to form threads during application while maintaining effective bonding. The parameter change in chemical composition directly addresses the contradiction by allowing reduced adhesive quantity without compromising reliability.
Solution Approach 2:
The patent creates a composite adhesive system by combining polyester-based adhesive with paraffin wax and stearic acid. This composite material leverages the properties of each component: the polyester provides adhesive strength, while the paraffin and stearic acid modify the rheological behavior during application and cooling. The composite formulation resolves the contradiction between reduced adhesive quantity and prevention of thread detachment.
2Strength
If hot-melt adhesive is applied continuously, then bonding strength is improved, but adhesive threads form between application equipment and filter medium
Solution Approach 1:
The patent modifies the physical and chemical parameters of the adhesive system by incorporating paraffin wax and stearic acid. These additives change the adhesive's viscosity-temperature characteristics and cooling behavior, allowing the adhesive to remain less tacky during application and solidify more cleanly. This parameter change enables interrupted application patterns that maintain bonding strength while eliminating thread formation.
Solution Approach 2:
The patent employs periodic or interrupted application of adhesive in trace forms rather than continuous application. By applying adhesive in periodic intervals along the fold lines, the process reduces the formation of adhesive threads between the application equipment and filter medium, while the modified adhesive composition ensures that each application point bonds effectively, maintaining overall bonding strength.
3Reliability
If adhesive traces are applied perpendicular to folded edges, then bonding effectiveness is improved, but application complexity increases
Solution Approach 1:
The patent modifies the adhesive composition to include paraffin wax and stearic acid, which change the adhesive's flow and solidification characteristics. This parameter change allows the adhesive to be applied in simple linear traces perpendicular to the folded edges, as the modified composition ensures proper bonding effectiveness without requiring complex application patterns or equipment adjustments.
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
The solution significantly reduces the number of hot-melt adhesive threads, ensuring stability and preventing detachment during operation, particularly effective in filtration applications like intake air from internal combustion engines.
Implementation Method 1
Hot-melt adhesives are products that are solvent-free and more or less solid at room temperature and are applied to an adherend when hot and bond when cooled
Implementation Method 2
15-85% by weight of a first hot-melt adhesive which is polyester-based, and 15-85% by weight of a second hot-melt adhesive, which is based on polyamide
Implementation Method 3
Various non-reactive hot-melt adhesives based on polyesters or polyamides are known from the prior art
Data Source
AI summary
A filter element comprising a filter bellows which is formed from a flat filter medium and is folded in zig-zag form, the filter bellows being bonded by at least two adhesive traces, especially with regular or irregular interruption, composed of a hotmelt adhesive system which run along the filter medium, the hotmelt adhesive system comprising a hotmelt adhesive mixture, and the hotmelt adhesive mixture comprising 15 - 85% by weight of a first hotmelt adhesive which is polyester-based, and 15 - 85% by weight of a second hotmelt adhesive which is polyamide-based.