Low-Friction Cable Coating With Strong Alcohol-Wipe Adhesion
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Solution Overview
Problem
Cables and medical hollow tubes require a coating film that balances slidability and resistance to peeling off, especially when exposed to disinfecting alcohol, while maintaining adhesion strength and preventing stickiness.
Innovation Solution
A coating film formed from a rubber composition with fine particles and addition reaction type silicone rubber, which reduces air bubbles during curing, ensuring high adhesion strength and slidability by densely distributing fine particles on the surface, thereby maintaining surface irregularities and preventing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a coating film is formed on the cable surface to improve slidability, then the cable surface becomes less sticky and more slippery, but the coating film may peel off when the cable is bent or subjected to termination
Solution Approach 1:
The patent uses a composite coating film made of silicone rubber and fluororesin. The silicone rubber base layer provides strong adhesion to the cable surface, while the fluororesin top layer provides low friction and high slidability. This composite structure resolves the contradiction by combining materials with complementary properties - one that bonds strongly and another that slides easily.
2Ease of operation
If the coating film is made smoother to improve slidability, then the surface becomes more slippery, but the coating film becomes more prone to peeling off when repeatedly wiped with disinfecting alcohol
Solution Approach 1:
The fluororesin layer provides a smooth, low-friction surface for slidability, while the silicone rubber base layer provides mechanical strength and adhesion resistance. The composite structure allows the surface to remain smooth for sliding while the underlying layer prevents peeling during repeated wiping with disinfecting alcohol.
3Ease of operation
If a coating film is applied to the cable surface, then slidability is improved, but the adhesion strength between the coating film and the sheath may be insufficient, especially when air bubbles are present during curing
Solution Approach 1:
The patent specifies controlling the air bubble content during curing to 5% or less by volume, and optimizes the silicone rubber to fluororesin ratio (95:5 to 70:30 by mass). These parameter controls ensure proper curing and adhesion while maintaining the slidability properties of the coating film.
4Productivity
If the coating film is made thinner to reduce material usage and cost, then productivity is improved, but the resistance to being wiped off with disinfecting alcohol decreases
Solution Approach 1:
The thin coating film (5-50 μm) achieves both productivity and reliability through its composite structure. The fluororesin layer provides the wiped-off resistance property even in thin form, while the silicone rubber base ensures adhesion. This allows thin coating for efficiency while maintaining durability.
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 high slidability and resistance to wiping off, even after repeated exposure to disinfecting alcohol, while ensuring the coating film remains adhered to the surface without stickiness, enhancing the durability and performance of cables and medical tubes.
Implementation Method 1
a rubber composition including fine particles and an addition reaction type silicone rubber
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A cable includes a sheath, and a coating film covering a circumference of the sheath, the coating film adhering to the sheath. The sheath inlcludes at least one selected from the group consisting of oxidized titanium, cobalt oxide, iron oxide, manganese oxide, chromium oxide, copper oxide, nickel oxide, and carbon. The coating film is made of a rubber composition including a heat curing type rubber component, with a static friction coefficient on a surface of the coating film being 0.5 or less. An adhesion strength between the sheath and the coating film is 0.30 MPa or more.