Fluororesin Abrasion Resistance via Electron Beam Crosslinking
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Solution Overview
Problem
Perfluoro type fluororesins exhibit low elastic modulus and abrasion resistance, making them unsuitable for high-load or high-temperature applications, and existing crosslinking methods either degrade mechanical strength or require harmful additives.
Innovation Solution
Introducing a carbonyl group-containing structural unit and irradiating the fluororesin with an electron beam in air at a temperature below its crystalline melting point to form a modified fluororesin with improved abrasion resistance without compromising mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinking is performed by irradiation at temperature of at least crystalline melting temperature, then abrasion resistance is improved, but melt viscosity decreases and shape of molded article cannot be maintained
Solution Approach 1:
The patent changes the crosslinking mechanism by utilizing carbonyl group-containing structural units that can undergo crosslinking reactions at temperatures below the crystalline melting point. This allows the molded article to maintain its shape while still achieving crosslinked structure for improved abrasion resistance. The carbonyl groups provide alternative crosslinking pathways that do not require melting the fluororesin matrix.
2Strength
If crosslinking agent containing vinyl group is used to improve mechanical properties, then mechanical strength is improved, but heat resistance and heat stability are deteriorated by unreacted vinyl groups
Solution Approach 1:
The patent extracts and eliminates the harmful vinyl group-containing crosslinking agents from the system. Instead, it utilizes carbonyl group-containing structural units that are already part of the fluororesin structure itself. These carbonyl groups undergo crosslinking reactions without leaving behind unreacted functional groups that would compromise heat resistance, thus improving mechanical strength while maintaining thermal stability.
3Strength
If electron beam irradiation is conducted in absence of oxygen, then crosslinking is achieved, but additional measures are required to maintain heat resistance
Solution Approach 1:
The patent enables the fluororesin to self-crosslink through its own carbonyl group-containing structural units without requiring external crosslinking agents or complex atmospheric control. The carbonyl groups naturally present in the modified fluororesin structure serve as self-sufficient crosslinking sites, eliminating the need for oxygen exclusion or other additional process measures, thereby simplifying the overall manufacturing process.
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 enhances the abrasion resistance of fluororesin-based electric wires and molded articles while maintaining mechanical strength, eliminating the need for additional additives that could harm their electrical and chemical properties.
Implementation Method 1
irradiating the fluororesin with an electron beam in air at a temperature below its crystalline melting point to form a modified fluororesin
Implementation Method 2
crosslink the fluororesin... the obtained molded product is irradiated with an electron beam and cross-linked
Implementation Method 3
irradiating the fluororesin with an electron beam in air... contains either one or both of a structural unit (a) having a carbonyl group-containing group
Data Source
AI summary
To provide a production method capable of improving the abrasion resistance of an electric wire or molded article using a fluororesin, by electron beam irradiation in air at a temperature where the fluororesin does not melt, and a method for producing a resin material containing a modified fluororesin whereby an electric wire or a molded article excellent in abrasion resistance can be obtained. A method for producing an electric wire, which comprises a step of irradiating an electron beam to an insulating layer containing a fluororesin and covering a conductor, to form an insulating layer containing a modified fluororesin, characterized in that the fluororesin has a crystalline melting point of at least 260°C, contains either one or both of a structural unit (a) having a carbonyl group-containing group and a main chain terminal group (a') having a carbonyl group-containing group, and a structural unit (b) based on a perfluoromonomer and does not contain a structural unit based on a hydrocarbon monomer (but excluding the structural unit (a)), and irradiation of the electron beam is conducted under conditions of a temperature of less than the crystalline melting point of the fluororesin and in air, to satisfy at least one of the following (1) to (3): 0.5≦Mb/Ma<1.2 wherein Ma represents a melt flow rate (g/10 min) of the fluororesin prior to the electron beam irradiation, and Mb represents a melt flow rate (g/10 min) of the fluororesin after the electron beam irradiation, 1≦Tb−Ta<6.5 wherein Ta represents a crystalline melting point (°C) of the fluororesin prior to the electron beam irradiation, and Tb is a crystalline melting point (°C) of the fluororesin after the electron beam irradiation, (3) irradiation dose of less than 30 kGy.