Water-Based PAI Lubricating Lacquer for Low-Temperature Curing
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Solution Overview
Problem
Existing polyamideimide (PAI) bonded coatings rely on cancerogenic, mutagenic, and reprotoxic (CMR) organic solvents, which are hazardous and may be restricted, and require high thermal curing temperatures that can deform materials like aluminum, making them unsuitable for many applications.
Innovation Solution
A water-based PAI bonded coating system using a co-crosslinking agent or co-binder, such as isocyanates, blocked isocyanates, nanoparticles, epoxides, or epoxy resins, to prevent bubble formation and improve adhesion, allowing for lower baking temperatures and eliminating the need for CMR solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If CMR organic solvents (NMP, NEP, DMF, DMAc) are used as solvents for PAI binder, then the PAI solution is easy to handle and coating can be applied, but the solvents are cancerogenic/mutagenic/reprotoxic substances that are hazardous and will soon no longer be permitted
Solution Approach 1:
The harmful CMR organic solvents are extracted and removed from the coating system entirely. The invention replaces them with water as the solvent and uses a co-crosslinking agent to achieve proper film formation and curing, thereby eliminating the harmful substances while maintaining coating functionality
Solution Approach 2:
The invention changes the fundamental parameter of the solvent system from organic CMR solvents to water-based system. By adjusting the formulation to include co-crosslinking agents and modifying the curing process parameters, the system achieves proper coating performance without hazardous substances
2Reliability
If high thermal curing temperatures (200-300°C for several hours) are used to cure aqueous PAI coatings, then the coating can be cured, but the component will deform due to thermal load
Solution Approach 1:
The invention changes the curing temperature parameter from high temperatures (200-300°C) to reduced temperatures (180-230°C). The co-crosslinking agent enables proper film formation and crosslinking at these lower temperatures, preventing component deformation while ensuring reliable coating cure
Solution Approach 2:
The invention creates a composite curing system by combining PAI binder with co-crosslinking agents (isocyanates, blocked isocyanates, nanoparticles, epoxides, or epoxy resins). This composite system enables effective curing at reduced temperatures through synergistic chemical reactions
3Reliability
If conventional aqueous PAI coatings are applied and cured, then the coating can be formed, but bubbles form on the component surface during curing resulting in poor surface quality
Solution Approach 1:
The co-crosslinking agent acts as an intermediary that mediates the curing process to prevent bubble formation. By controlling the crosslinking reaction and film formation kinetics, it eliminates the bubble formation issue while maintaining proper coating formation
Solution Approach 2:
The combination of PAI binder with co-crosslinking agents creates a composite coating system where the co-crosslinker prevents bubble formation during curing, resulting in excellent surface quality while ensuring reliable coating formation
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 excellent adhesion and wear resistance at reduced temperatures, preventing bubble formation and ensuring a high-quality surface suitable for tribological applications, with performance comparable to solvent-based systems in pin-disc tests.
Implementation Method 1
the co-crosslinking agent prevents the formation of bubbles on the component to be coated during the curing process
Implementation Method 2
The use of the co-crosslinker improves adhesion on the component
Implementation Method 3
a water-based, solvent-free polyaminedimide bonded coating which also contains PTFE as an aqueous latex
Data Source
AI summary
The invention relates to a polyamide-imide (PAI) lubricating lacquer which is free of organic solvents, hereinafter referred to as solvent-free, water-based PAI lubricating lacquer, and to the use thereof for the coating of metallic surfaces.