Vacuum Cleaner Filter Bag Laminate for Stronger Ultrasonic Welds
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Solution Overview
Problem
Vacuum cleaner filter bags made from recycled materials face challenges in achieving strong weld seams due to the inhomogeneous nature of their non-woven fabric layers, which have different melting points and chemical properties, making it difficult to achieve sufficient strength using existing ultrasonic welding methods.
Innovation Solution
Incorporating an intermediate layer of non-woven fabric or fibrous web with recycled polypropylene (rPP) as the main component between the support and fine filter layers, and optionally between the fine filter and capacity layers, to act as a welding assistant, enhancing the connection and tensile strength of the weld seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic welding is used to connect layers of recycled non-woven fabrics with different materials, then the manufacturing process is efficient and fast, but the weld seam strength is insufficient due to inhomogeneous materials with different melting points and chemical properties
Solution Approach 1:
An intermediate layer made of recycled polypropylene (rPP) is introduced between layers with different material compositions. This intermediate layer acts as a mediator that is chemically compatible with both adjacent layers, enabling effective ultrasonic energy transmission and melting. The rPP intermediate layer facilitates weld seam formation between dissimilar materials (e.g., PET and PP layers) that would otherwise be difficult to weld together, thereby maintaining high welding efficiency while significantly improving weld seam strength.
2Strength
If material strips of thermoplastic material are used to reinforce connecting seams, then the weld seam strength is improved, but the positioning and manufacturing complexity increases
Solution Approach 1:
The reinforcing function previously requiring separate material strips is merged into the intermediate layer itself. The rPP intermediate layer is integrated directly into the laminate structure during the web formation process, eliminating the need for separate positioning and attachment steps. This merging approach maintains enhanced weld seam strength while significantly simplifying the manufacturing process by reducing the number of discrete components and assembly operations.
3Quantity of substance
If a light fine filter layer is employed to achieve high proportion of recycled plastics, then the ecological benefits are maximized, but the weld seam strength decreases due to insufficient material mass
Solution Approach 1:
The rPP intermediate layer serves as a mediator that compensates for the limited material mass of the light fine filter layer. By positioning this intermediate layer adjacent to the fine filter layer, it provides additional thermoplastic material that can be effectively melted and bonded during ultrasonic welding. This allows the fine filter layer to maintain its lightweight, high-recycled-content design while the intermediate layer ensures sufficient material availability for strong weld seam formation.
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 use of rPP intermediate layers significantly improves the weld seam strength, allowing for a more stable connection between layers while maintaining the ecological benefits of using predominantly recycled plastics, and simplifies the manufacturing process by eliminating the need for cumbersome material strip positioning.
Implementation Method 1
an ultrasonic weld seam is typically created. In the process, longitudinal oscillations with frequencies of 20 kHz to 35 kHz and tool amplitudes of 5 μm to 50 μm are introduced into the non-woven fabrics to be connected under pressure. The frictional heat formed by the oscillations melts the material of the non-woven fabric.
Implementation Method 2
The frictional heat formed by the oscillations melts the material of the non-woven fabric.
Implementation Method 3
an intermediate layer of a non-woven fabric or a fibrous web which comprises the recycled polypropylene, rPP, as a main component... The melt of the intermediate layer, which comprises rPP, here acts as a welding assistant between the layers.
Data Source
AI summary
The invention comprises a vacuum cleaner filter bag with a bag wall, comprising: a support layer comprising recycled polyethylene terephthalate, rPET; a fine filter layer of a meltblown non-woven fabric comprising polypropylene, PP, PET and/or recycled polypropylene, rPP; and a capacity layer of a non-woven fabric comprising rPET, recycled textile material, TLO, and/or rPP; wherein the bag wall moreover comprises at least one intermediate layer formed of a non-woven fabric or a fibrous web and comprising rPP as a main component; and wherein the at least one intermediate layer is arranged between the support layer and the fine filter layer and/or between the fine filter layer and the capacity layer.