Laser Welding Foam Functional Bands
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Solution Overview
Problem
Existing methods for connecting foam layers with other functional layers in band-shaped structures often damage the foam's properties, such as porosity and compressibility, and are not suitable for all materials, especially in humid or chemically aggressive environments.
Innovation Solution
The use of laser transmission welding, specifically near-infrared (NIR) laser transmission welding, to connect foam layers with other functional layers, ensuring that the connection is stable and does not compromise the foam's properties, as it only heats the surface areas where the layers are in contact, avoiding the use of adhesives that can clog pores and withstand mechanical and environmental stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If needle punching method is used to connect foam layer to carrier tissue, then mechanical strength is improved, but foam structure and properties (porosity, compressibility) are massively damaged
Solution Approach 1:
The patent replaces the mechanical needle punching system with a thermal bonding system using hot melt adhesive applied via spray or roller. This substitution allows connection of foam layers without physical penetration, preserving the foam's porous structure while achieving adequate mechanical strength through adhesive bonding.
2Strength
If laminating method is used to connect layers, then connection strength is improved, but foam layer is compacted beyond technically desired level
Solution Approach 1:
The patent introduces hot melt adhesive as an intermediary substance between the foam layer and carrier tissue. This intermediary enables strong bonding without requiring direct high-pressure contact between the foam surfaces, thus preventing excessive compaction while achieving the desired connection strength.
3Strength
If bonding method with adhesive is used, then connection is achieved, but adhesive penetrates into pores and clogs them, leading to non-controllable deterioration of porosity
Solution Approach 1:
The patent applies adhesive locally to specific bonding zones rather than uniformly across the entire foam surface. By controlling the adhesive application to edge regions or specific contact areas, the foam's internal porosity is preserved while achieving sufficient connection strength at the bonding locations.
4Productivity
If ultrasonic welding is used to join layers, then connection speed is improved, but method can only be used for thermoplastic plastics and metallic materials, not elastic foam materials
Solution Approach 1:
The patent employs hot melt adhesive bonding as a universal joining method that works with diverse materials including elastic foams, thermoplastics, and metals. This multi-functional approach replaces material-specific methods like ultrasonic welding, enabling consistent high-speed joining across different material types without compromising foam elasticity.
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
This method provides a strong, durable connection that maintains the foam's porosity and mechanical integrity, even in humid or chemically aggressive conditions, and is applicable to a wide range of materials, including those that cannot be joined using traditional ultrasonic welding.
Implementation Method 1
The two layers are connected to one another by laser transmission welding, in particular by means of NIR laser transmission welding
Implementation Method 2
The two layers are connected under pressure and temperature. The connection of the two layers is achieved by fusing the surfaces. However, for this purpose, at least one of the layers is continuously heated to heat the contact surface of both layers to the necessary melting temperature
Implementation Method 3
The two layers are connected to one another by laser transmission welding, in particular by means of NIR laser transmission welding
Implementation Method 4
The connection of the two layers is achieved by fusing the surfaces
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a functional band (7) having a longitudinal direction and a transverse direction, comprising a foam layer (2) as well as at least one further functional layer (1), wherein the foam layer (2) and the further functional layer )1) are joined to one another by means of laser transmission welding, in particular by means of NIR laser transmission welding. The invention also relates to a method for the production of a functional band, comprising the following method steps: i) providing a compressible foam layer (2); ii) providing a further functional layer (1); iii) bringing together the foam layer (2) and the further functional layer (1); iv) joining the compressible foam layer (2) to the further functional layer (1) by means of laser transmission welding, in particular by means of NIR laser transmission welding. The invention further relates to a technical textile, in particular a fabric for use in a machine for the production or processing of a fibrous material web, preferably press felt of a paper machine, a sealing band or a textile-reinforced insulation material, comprising or made of a functional band (7) according to the invention.