Liquid-Applied Sound Damping Composition for Vehicle Noise Control
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Solution Overview
Problem
Current sound damping materials for motor vehicles, particularly liquid-applied compositions, face inefficiencies in installation, material usage, and environmental concerns, with a need for improved sound damping performance and reduced VOC emissions.
Innovation Solution
A waterborne polymeric binder with carboxy acid monomers and a filler ratio, combined with a thickener to achieve a shear-thinnable composition, providing enhanced sound damping characteristics and reduced environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solvent-borne epoxy or urethane-based materials are used for liquid-applied sound damping, then sound damping performance is achieved, but VOC emissions increase and odor issues occur
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system, transitioning from solvent-borne epoxy or urethane-based materials to a waterborne system containing polyvinyl butyral resin and acrylic polymer dispersion. This parameter change eliminates VOC emissions while maintaining sound damping performance through the synergistic combination of binders and optimized filler content (50-85 wt% of total composition).
Solution Approach 2:
The patent employs a composite binder system combining polyvinyl butyral resin (1-50 wt%) and acrylic polymer dispersion (1-50 wt%), along with a composite filler system including barium sulfate, calcium carbonate, and other mineral fillers. This composite approach achieves effective sound damping without relying on harmful solvent-borne materials.
2Reliability
If thick patches are used for sound damping, then vibration reduction is effective, but installation becomes labor-intensive and requires many different sizes and shapes
Solution Approach 1:
The patent applies liquid-applied sound damping composition that can be sprayed using robotic spray equipment, eliminating manual patch installation. The liquid formulation flows and conforms to complex vehicle body surfaces, then cures to form an effective damping layer without requiring pre-cut patches of various sizes and shapes.
Solution Approach 2:
The liquid-applied composition serves as a universal solution that can be applied to various vehicle body parts regardless of shape or size requirements. A single formulation replaces the need for multiple patch types, simplifying inventory and installation processes while maintaining effective vibration reduction.
3Ease of operation
If liquid-applied sound damping material is sprayed to cover multiple hot spots, then installation is simplified, but material usage and vehicle weight increase
Solution Approach 1:
The patent enables precise, localized application of sound damping material to specific vibrational hot spots identified through laser-assisted vibrational analysis. The liquid formulation can be sprayed in controlled patterns to treat only the necessary areas rather than applying material broadly across entire panels, reducing overall material usage and vehicle weight.
4Object-generated harmful factors
If waterborne polymeric binder with carboxy acid monomers is used, then environmental friendliness is improved, but sound damping performance may be reduced compared to solvent-based materials
Solution Approach 1:
The patent uses a composite binder system combining polyvinyl butyral resin and acrylic polymer dispersion in optimized proportions, along with a composite filler system containing barium sulfate, calcium carbonate, and other minerals. This composite formulation achieves effective sound damping performance while maintaining the environmental benefits of a waterborne, VOC-free composition.
Solution Approach 2:
The patent optimizes the concentration parameters of carboxy acid monomers (0.05-20 wt% based on polymer solids) and adjusts the glass transition temperature (Tg) of the binder to between -50°C and 80°C (preferably 0°C to 30°C). These parameter changes ensure the waterborne formulation achieves sound damping performance comparable to or exceeding traditional solvent-based materials while eliminating VOC emissions.
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 achieves improved sound damping performance with reduced material usage and virtually eliminates issues associated with solvent-based materials, while being environmentally friendly.
Implementation Method 1
a thickener in an amount sufficient to achieve a shear-thinnable composition that has a Brookfield viscosity of between 200,000-10,000,000 cP when not under shear conditions
Implementation Method 2
a water borne polymeric binder wherein said binder comprises from 0.05 wt. % to 20 wt. %, based on the total weight of polymer solids, of carboxy acid monomers, present as copolymerized monomers in pendant polyacid sidechain groups
Implementation Method 3
This invention is an improved sound damping composition comprising: (a) a water borne polymeric binder... (b) a filler... (c) a thickener
Data Source
AI summary
A liquid applied sound damping composition with a binder having from 0.05 wt. % to 20 wt. %, based on the total weight of polymer solids, of carboxy acid monomers, present as copolymerized monomers in pendant polyacid sidechain groups.