Aqueous Primer Coating Adhesion Cost Reduction
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Solution Overview
Problem
Current aqueous primers for plastic parts, particularly in automotive construction, are costly due to the use of hydrolysis-stable polyurethane dispersions, and there is a need for a more economical binder system that maintains adhesion and stone chip protection while allowing for electrostatic spray application.
Innovation Solution
A composition containing an aqueous polyurethane dispersion (PUD) with a specific ratio of styrene-polybutadiene copolymer dispersion (SBR), along with a reactive crosslinker component, to create a cost-effective primer that ensures good adhesion and stone chip protection, enabling electrostatic spray application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrolysis-stable polyurethane dispersions are used as binders, then adhesion and durability are improved, but cost increases significantly
Solution Approach 1:
The patent combines polyurethane dispersion (PUD) with styrene-polybutadiene copolymer dispersion (SBR) to create a composite binder system. The PUD provides adhesion and durability, while the SBR contributes to flexibility and cost-effectiveness. This composite approach allows achieving reliable adhesion performance without relying solely on expensive hydrolysis-stable PUDs.
Solution Approach 2:
The patent introduces SBR, a more cost-effective binder alternative, into the primer formulation. While SBR alone may not provide sufficient adhesion, its combination with PUD creates a balanced system that reduces overall binder cost while maintaining acceptable performance through the synergistic effect of both polymers.
2Ease of manufacture
If conventional primer formulations are used, then cost is reduced, but adhesion performance and stone chip protection deteriorate
Solution Approach 1:
The patent creates a composite binder system combining PUD and SBR in specific ratios (PUD: 30-80 wt%, SBR: 20-70 wt%). This composite formulation achieves a balance between cost and performance, providing adequate adhesion and stone chip protection while being more economical than pure PUD-based primers.
Solution Approach 2:
The patent optimizes the weight ratio of PUD to SBR to achieve the desired balance between cost and performance. By adjusting these parameters, the formulation achieves sufficient adhesion strength and durability while reducing dependency on expensive hydrolysis-stable PUDs, thus lowering overall material cost.
3Object-affected harmful factors
If aqueous primers are used to avoid solvent emissions, then environmental compliance is improved, but adhesion to plastics and stone chip protection worsen
Solution Approach 1:
The patent uses a composite binder system of PUD and SBR in aqueous formulation. The PUD component provides the necessary adhesion to plastics, while the SBR component enhances flexibility and contributes to stone chip resistance. This composite approach allows aqueous primers to achieve performance levels previously associated with solvent-based systems.
Solution Approach 2:
The patent optimizes the composition and molecular characteristics of the binder system to achieve adequate adhesion and durability in an aqueous environment. By adjusting the PUD/SBR ratio and selecting appropriate polymer characteristics, the formulation achieves sufficient performance for plastic substrates without requiring organic solvents.
4Productivity
If electrostatic spray application is enabled, then application efficiency is improved, but the primer formulation becomes more complex
Solution Approach 1:
The patent incorporates conductive carbon black as an intermediary additive in the primer formulation. This conductive pigment enables the aqueous primer to conduct electricity, allowing subsequent layers to be applied by electrostatic spraying. The conductive carbon black acts as a mediator that bridges the non-conductive nature of typical polymer binders with the requirements of electrostatic application.
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 composition provides excellent adhesion and stone chip protection, maintaining performance even after weathering, while being more economical than traditional hydrolysis-stable polyurethane dispersion-based primers, and allows for efficient application using electrostatic spray.
Implementation Method 1
allowing the subsequently applied layers to be applied by electrostatic spraying
Data Source
AI summary
The present invention relates to novel coatings which are applied from an aqueous phase to substrates such as plastics, and which are overlaid with other coatings. These coatings are characterised by particularly good adhesive strength, in particular on plastics, and are thus particularly commercial.