Chemically Fixed Lubricating Layer on Elastomer Catheters
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Solution Overview
Problem
Catheters and similar medical devices face issues with lubricity due to the separation or peeling of resin coatings during movement within vessels or tracts, leading to reduced effectiveness and durability.
Innovation Solution
A surface modification method involving the formation of polymerization initiation points on rubber vulcanizates or thermoplastic elastomers, followed by radical polymerization using ultraviolet light and an alkali metal salt, such as sodium chloride or potassium chloride, to grow polymer chains that provide a chemically fixed lubricating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resin coating is applied to the catheter surface, then lubricity is improved, but the coating separates or peels during movement within vessels or tracts, reducing durability
Solution Approach 1:
Polymerization initiation points are formed on the catheter surface before the actual polymerization process. This preliminary preparation ensures that when polymer chains grow later, they originate from predetermined locations on the surface, creating a robust anchor structure that prevents peeling and separation during movement within vessels.
Solution Approach 2:
The patent uses polymerization initiation points as an intermediary structure between the catheter surface and the growing polymer chains. These initiation points act as anchoring sites that chemically connect the substrate to the lubricating polymer layer, ensuring strong adhesion and preventing the coating from separating during use.
2Ease of operation
If a lubricant layer is coated on the catheter surface, then insertion smoothness is improved, but the lubricity is reduced due to separation or peeling during movement
Solution Approach 1:
The patent applies local quality by creating polymerization initiation points specifically on the surface region where lubricity is needed. The polymer chains grow from these localized initiation points, forming a lubricating layer precisely where required, while maintaining strong chemical attachment to the substrate to prevent peeling during movement.
Solution Approach 2:
The invention creates a composite structure consisting of the catheter substrate, polymerization initiation points, and grown polymer chains. This composite material system combines the structural integrity of the original catheter with the lubricating properties of the polymer layer, while the chemical bonds between components ensure the layer remains attached during movement.
3Reliability
If polymer chains are grown on the surface by radical polymerization, then a chemically fixed lubricating layer is formed, but the process requires precise control of polymerization conditions
Solution Approach 1:
The patent utilizes parameter changes by controlling the polymerization process through UV light irradiation wavelength (300-400 nm) and the presence of alkali metal salts. By adjusting these parameters, the polymerization reaction proceeds efficiently to form chemically fixed polymer chains on the surface, achieving reliable attachment while managing process complexity through defined parameter ranges.
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 method results in surfaces with excellent lubricity and durability, reducing the rate of lubricity decrease during repeated movements, making the surface-modified devices suitable for applications like vascular catheters and mudguard fenders.
Implementation Method 1
radically polymerizing a monomer starting from the polymerization initiation points by irradiation with ultraviolet light having a wavelength of 300 to 400 nm
Data Source
Figure 1~2
AI summary
Methods are provided for surface-modifying a rubber vulcanizate or a thermoplastic elastomer. The methods allow these rubber vulcanizate or thermoplastic elastomer objects to have a lubricating surface layer chemically fixed thereon, instead of having a resin coating which has drawbacks such as a reduction in lubricity due to e.g. separation or peeling of the coating during movement within a vessel or tract. The present invention relates to a method for surface-modifying an object made of a rubber vulcanizate or a thermoplastic elastomer, the method including: step 1 of forming polymerization initiation points on a surface of the object; and step 2 of radically polymerizing a monomer starting from the polymerization initiation points by irradiation with ultraviolet light having a wavelength of 300 to 400 nm in the presence of an alkali metal salt to grow polymer chains on the surface of the object.