Threaded Part Rustproof Coating for Stable Repeated Tightening
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Solution Overview
Problem
Existing rustproofing techniques for threaded parts, such as bolts and nuts, face issues with increased friction coefficient during repeated tightening, leading to instability and potential hydrogen embrittlement, and require multiple coating treatments and organic solvents, which are costly and pose safety risks.
Innovation Solution
A rustproofing treatment liquid using a binder resin with silica and modified epoxy or acrylic resins obtained through graft polymerization with carboxylic acid-containing acrylic polymers, dispersed in water, to form a single-layer coating that stabilizes the friction coefficient without organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zinc plating layer is formed on the iron substrate to provide rustproof performance, then corrosion resistance is improved, but the friction coefficient gradually increases when tightening is repeated, leading to unstable tightening
Solution Approach 1:
The patent combines rust inhibition and friction coefficient stabilization functions into a single coating layer. This layer contains a lubricant (0.1-10 parts by mass) and a rust inhibitor (1-50 parts by mass) dispersed in a water-soluble resin, allowing both protective functions to be achieved simultaneously rather than through separate coating layers.
Solution Approach 2:
The coating layer serves multiple functions: it provides rustproof performance through the rust inhibitor, stabilizes the friction coefficient through the lubricant, and maintains adhesion through the water-soluble resin binder. This multi-functional approach eliminates the need for separate specialized layers for each function.
2Ease of operation
If a friction coefficient stabilizing layer composed of wax is formed on the zinc plating layer to prevent friction increase, then tightening stability is improved, but the coating layer is easily scratched, allowing rust to penetrate and cause hydrogen embrittlement
Solution Approach 1:
The patent merges the rust inhibition and friction stabilization functions into one integrated coating layer, eliminating the interface between separate layers that could become weak points. The water-soluble resin binder holds both the rust inhibitor and lubricant in a unified matrix that adheres well to the zinc plating layer.
Solution Approach 2:
The coating layer is a composite material containing water-soluble resin as the binder, rust inhibitor particles for corrosion protection, and lubricant particles for friction control. This composite structure provides both mechanical integrity and the desired functional properties simultaneously.
3Reliability
If a rust inhibitor layer and friction coefficient stabilizing layer are formed separately to achieve both rustproofing and friction stability, then reliability is improved, but the cost increases due to multiple coating treatments and the need for explosion-proof facilities
Solution Approach 1:
The patent consolidates multiple coating treatments into a single application process. The treatment liquid contains all necessary components (water-soluble resin, rust inhibitor, and lubricant) that can be applied in one step, eliminating the need for separate rust inhibitor layer and friction stabilizing layer applications, thereby reducing labor, time, and facility costs.
Solution Approach 2:
The patent changes the solvent parameter from organic solvents to water as the continuous phase. This substitution eliminates flammability concerns, removing the requirement for explosion-proof facilities while maintaining the effectiveness of the coating treatment. The water-soluble resin provides adequate binding without the safety hazards of organic solvents.
4Ease of manufacture
If organic solvents are used in the rust proofing treatment liquid to dissolve the binder resin, then coating performance is improved, but explosion-proof facilities are required and safety risks increase
Solution Approach 1:
The patent fundamentally changes the solvent parameter from organic to inorganic (water). The water-soluble resin dissolves or disperses in water to form the coating liquid, providing all necessary binding and film-forming properties without the flammability and toxicity associated with organic solvents. This parameter change eliminates safety hazards while maintaining coating effectiveness.
Solution Approach 2:
The patent converts the typically harmful organic solvents into harmless water. By using water as the solvent medium, the treatment liquid becomes safe to handle and apply without requiring special explosion-proof facilities, while still achieving excellent coating performance through the water-soluble resin binder.
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 enables a single coating treatment that maintains a stable friction coefficient during repeated tightening, enhances corrosion resistance, and eliminates the need for organic solvents, reducing costs and safety concerns while maintaining effective rustproofing.
Implementation Method 1
dispersed in water to form a single-layer coating
Implementation Method 2
form a single-layer coating that stabilizes the friction coefficient without organic solvents
Implementation Method 3
modified epoxy or acrylic resins obtained through graft polymerization with carboxylic acid-containing acrylic polymers
Implementation Method 4
stabilizes the friction coefficient during repeated tightening
Implementation Method 5
binder resin containing silica and at least one of a modified epoxy resin obtained by graft polymerization
Data Source
AI summary
Threaded parts such as bolts are rust-proofed by using a treatment liquid including a binder resin containing silica and at least one of a modified epoxy resin obtained by graft polymerization using a carboxylic acid-containing acrylic polymer as a side chain and a modified acrylic resin obtained by graft polymerization using a carboxylic acid-containing acrylic polymer as a side chain. By using this treatment liquid, coating treatment can be carried out at one time without need to use an organic solvent. There is an advantage that the friction coefficient does not increase even when tightening is repeated.