Vehicle Sealing Panel with Bituminous Damping Layer
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Solution Overview
Problem
Existing sealing and soundproofing panels in vehicles face issues with detachment due to temperature and humidity variations, and they continue to produce vibrations that cause humming and acoustic distortions, despite increased rigidity and density attempts.
Innovation Solution
A sealing and soundproofing panel comprising a thermoformed polyethylene foam sealing wall with a density of less than 0.5 g/cm³ and a bituminous sound-absorbing material with a non-pressure-sensitive adhesive, which provides improved adhesion and damping properties, along with an anti-stick paint to prevent material sticking during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thicker and/or denser sealing and soundproofing panels are used, then the panel rigidity and sealing performance are improved, but the panel continues to produce vibrations that cause humming and acoustic distortions
Solution Approach 1:
The patent applies composite materials by combining a foam core layer with a bituminous sound-absorbing material layer. The foam core provides structural rigidity and sealing, while the bituminous layer dampens vibrations and absorbs sound. This composite structure resolves the contradiction by integrating two materials with complementary properties - one for strength and one for vibration suppression.
Solution Approach 2:
The patent changes the material parameters by selecting specific density ranges for the foam core (20-80 kg/m³) and specific physical properties for the bituminous material. By optimizing these parameters, the panel achieves sufficient rigidity for sealing while the bituminous layer's high damping capacity eliminates vibrations and humming sounds.
2Reliability
If pressure-sensitive adhesive is used to attach panels to the internal metal lining, then the panel is securely fixed, but the panel detaches under temperature and humidity variations
Solution Approach 1:
The patent changes the adhesive parameters by specifying a non-pressure-sensitive adhesive with viscosity between 30,000 and 2,000 mPas at temperatures between 160°C and 180°C, and a ring and ball softening point above 100°C. These parameter specifications ensure the adhesive maintains stable bonding properties across temperature and humidity variations, preventing panel detachment.
Solution Approach 2:
The patent replaces pressure-sensitive adhesive (mechanical bonding) with a non-pressure-sensitive adhesive system that cures through chemical bonding. This substitution eliminates the temperature-dependent mechanical adhesion issues, providing reliable bonding stability under environmental variations.
3Object-generated harmful factors
If bituminous sound-absorbing material is used, then vibration damping and sound absorption are improved, but the material sticks to itself during assembly causing handling difficulties
Solution Approach 1:
The patent introduces a release paper as an intermediary between the bituminous sound-absorbing material layers. This release paper prevents the bituminous material from sticking to itself during assembly and handling, while allowing it to bond to the foam core when the release paper is removed. This mediator resolves the contradiction by enabling easy handling while preserving vibration damping properties.
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 effectively prevents detachment under temperature and humidity changes and eliminates vibrations by damping energy through the mass and stiffness of the sound-absorbing material, improving acoustic comfort by reducing humming and distortion.
Implementation Method 1
at least one plate of sound-absorbing material secured to one of the faces of the wall by means of an adhesive layer
Implementation Method 2
the rest of the surface of the panel continues to emit vibrations which cause acoustic distortions of the loudspeakers
Implementation Method 3
said adhesive layer is obtained in a non-pressure-sensitive adhesive called non-PSA based on hot-melt polyolefin or hot-melt ethylene-vinylacetate (EVA)
Implementation Method 4
said sealing wall (2) is obtained in a physically reticulated closed-cell polyethylene foam
Implementation Method 5
said sealing wall (2) is obtained in a physically reticulated closed-cell polyethylene foam having a thickness of between 2 and 5 mm, a density of less than 0.5 g.cm-3 and a Young's modulus of between 4 and 30 N/mm2
Data Source
Figure 1~2
AI summary
The present invention relates to a sealing and soundproofing panel (1) for vehicles for improving the acoustic comfort of vehicles such as motor vehicles or the like, comprising at least one sealing wall (2) whose peripheral edge is suitable for being placed in a watertight manner against a structure of the vehicle, and at least one soundproofing material plate (3) attached to one face of the wall by means of an adhesive layer; said panel is remarkable in that said sealing wall (2) is obtained in a physically cross-linked closed-cell polyethylene foam having a thickness of between 2 and 5 mm, a density of less than 0.5 g.cm-3 and a Young's modulus of between 4 and 30 N/mm2, in that the soundproofing material plate(s) (3) are obtained in a bituminous material called IFF according to the acronym "Soundproofing in Fusible Sheet" having a density greater than 2 g.cm-3 and comprising bitumen, at least one mineral filler such as calcium carbonate and/or calcium oxide and/or similar, and at least one polymer, and in that said adhesive layer is obtained in a non-pressure-sensitive adhesive said to be non-PSA based on hot-melt polyolefin or hot-melt ethylene-vinyl acetate (EVA), said adhesive having an adhesive strength greater than 5 N/cm at room temperature.