Single-Component Body Filler with Controlled Working Time
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Solution Overview
Problem
Conventional two-part body filler compositions for vehicle repairs have limited working time due to mixing errors and uneven curing, requiring rework and inefficiencies, while UV-cured systems are limited to shallow layers and lack a clear indication of sanding readiness.
Innovation Solution
A single-component, UV curable composition with a premixed combination of photo-initiators, thermal radical initiators, and cationic initiators that allows for user-controlled working time and deep curing, eliminating the need for mixing and providing a visual cue for sanding readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-part body filler composition is used, then the composition can be cured, but the working time is limited and mixing errors occur
Solution Approach 1:
The patent combines the polymer and free radical initiator into a single-component system, eliminating the need for separate mixing of two parts. The composition remains stable in the premixed state until UV irradiation initiates curing, providing both extended working time and reliable curing without mixing errors.
Solution Approach 2:
The free radical initiator is pre-incorporated into the composition in an inactive or dormant state during manufacturing. This preliminary preparation allows the composition to be stored and handled without premature curing, then activated on-demand by UV irradiation when needed.
2Loss of time
If UV light is used to initiate cure, then working time is extended, but cure depth is limited to shallow layers
Solution Approach 1:
The patent employs a dual-initiator system where UV light acts as the primary initiator for surface curing, and thermal energy acts as a secondary initiator for deep-volume curing. The thermal initiator is activated by the exothermic heat generated during UV curing, enabling cure penetration to depths exceeding UV penetration limits.
Solution Approach 2:
The patent utilizes the phase transition from chemical energy to thermal energy during the polymerization reaction. The exothermic heat generated by UV-initiated surface curing triggers the thermal initiator, which then drives the curing reaction in the bulk material, enabling deep cure through thermal energy propagation.
3Productivity
If more initiator is added to speed up cure, then curing time is reduced, but working time is reduced and overcuring occurs
Solution Approach 1:
The patent creates a dynamic, multi-stage curing process where the initiation rate changes over time and depth. UV irradiation provides rapid surface curing, while thermal diffusion gradually activates the thermal initiator in the bulk, creating a progressive curing wave that maintains working time while achieving complete cure.
Solution Approach 2:
The curing process occurs in distinct phases: first UV irradiation initiates surface curing, then thermal diffusion progressively activates the thermal initiator in the bulk material. This periodic, staged approach allows control over the overall curing rate while maintaining extended working time.
4Ease of manufacture
If visual approximation is used to measure initiator amount, then the process is simple, but inaccuracy leads to uneven curing
Solution Approach 1:
The initiator is pre-incorporated into the composition at precisely controlled concentrations during manufacturing, eliminating the need for field measurement and mixing. This preliminary preparation ensures uniform distribution and accurate dosing, guaranteeing consistent curing results while maintaining simple application procedures.
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 solution offers extended working time, reduced rework, and efficient bulk volume repair with energy savings, enabling thicker applications and improved shaping capabilities, while minimizing the need for secondary hardeners and providing a clear indication of sanding readiness.
Implementation Method 1
Free radicals are initiated by the inclusion of at least one photo-initiator... Once cure is initiated with an ultraviolet or infrared light source
Implementation Method 2
at least one thermal radical initiator, and at least one thermal cationic radical initiator... the light source need not illuminate the composition until cure is complete
Data Source
AI summary
A single component curable composition is provided that includes a resin curable by free radicals. Free radicals are initiated by the inclusion of at least one photo-initiator, at least one thermal radical initiator, and at least one thermal cationic radical initiator, all present in a premixed state as the single component. The composition is able to cure to a depth beyond the penetration of photons into composition. Once cure is initiated with an ultraviolet or infrared light source, the light source need not illuminate the composition until cure is complete. The resulting composition has a user selected working time that is effectively infinite and the viscosity stable while working prior to initiating cure. A method for repairing a surface imperfection on a vehicle body is also provided along with a novel cured mass with a thickness of up to 7 mm.