Heat-Resistant Halogen Resin via Silane Grafting
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Solution Overview
Problem
Existing methods for crosslinking halogen-containing resins, such as polyvinyl chloride and chloroprene rubber, using the silane crosslinking method face challenges including volatility of silane coupling agents and insufficient network structures, leading to poor heat resistance and outer appearance issues in electrical wires and cables.
Innovation Solution
A method involving melt-kneading a halogen-containing resin with an inorganic filler and a silane coupling agent, followed by mixing with a silanol condensation catalyst and exposure to moisture, to produce a heat-resistant crosslinked resin body that maintains integrity at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the silane crosslinking method is used to crosslink halogen-containing resins, then the heat resistance is improved, but the silane coupling agent volatilizes before participating in the grafting reaction
Solution Approach 1:
The silane coupling agent is pre-grafted onto the halogen-containing resin at a low temperature (50-80°C) before the crosslinking reaction. This preliminary grafting action ensures the silane coupling agent is fixed on the resin and will not volatilize during subsequent high-temperature crosslinking, resolving the contradiction between heat resistance improvement and silane coupling agent loss
Solution Approach 2:
The crosslinking process is divided into two separate stages: first, silane grafting at low temperature to prevent volatilization; second, crosslinking at high temperature to achieve heat resistance. This segmentation allows each reaction to occur under optimal conditions without the adverse effects of the other stage
2Reliability
If the silane crosslinking method is used on halogen-containing resins, then crosslinking is achieved, but insufficient network structures are formed leading to poor heat resistance
Solution Approach 1:
A silane coupling agent with specific functional groups (vinyl, epoxy, or isocyanate groups) is used as an intermediary to form strong chemical bonds between halogen-containing resin molecules. These intermediaries create a three-dimensional network structure that provides sufficient crosslinking density and improves heat resistance by forming a robust molecular framework
Solution Approach 2:
The crosslinking conditions are optimized by controlling temperature (80-100°C during crosslinking), time (1-24 hours), and silane coupling agent concentration (1-10 parts by mass per 100 parts resin). These parameter changes ensure complete crosslinking reaction and formation of adequate network structures for heat resistance
3Temperature
If conventional crosslinking methods are used, then heat resistance is improved, but specialized equipment like electron beam crosslinking machines is required
Solution Approach 1:
The invention replaces complex electron beam crosslinking equipment with a simple thermal crosslinking process. By using heat (80-100°C) to activate the crosslinking reaction between silane-grafted resin and moisture, the need for specialized electron beam machines is eliminated, simplifying the equipment requirements while maintaining heat resistance
Solution Approach 2:
The crosslinking process utilizes moisture from the environment or added water as a self-service reagent to trigger the crosslinking reaction. This eliminates the need for complex equipment to generate reactive species, as the system uses readily available moisture to achieve crosslinking and heat resistance
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
This approach effectively produces a heat-resistant crosslinked resin body that prevents melting at high temperatures and maintains excellent outer appearance, even with high inorganic filler content, without requiring specialized equipment like electron beam crosslinking machines.
Implementation Method 1
a method of obtaining a crosslinked resin, by obtaining a silane-grafted resin by allowing a grafting reaction of a silane coupling agent having an unsaturated group with a resin in the presence of organic peroxide
Implementation Method 2
bringing the silane-grafted resin into contact with moisture in the presence of a silanol condensation catalyst
Implementation Method 3
a crosslinking method in which heat is applied after forming, to decompose organic peroxide or the like and to allow a crosslinking reaction
Data Source
AI summary
A method that has a step (a) of melt-kneading 0.003 to 0.3 part by mass of an organic peroxide, 0.5 to 400 parts by mass of an inorganic filler, and more than 2 parts by mass and 15.0 parts by mass or less of a silane coupling agent, with respect to 100 parts by mass of a resin containing a halogen-containing resin, at a temperature equal to or higher than a decomposition temperature of the organic peroxide, to prepare a silane master batch; a heat-resistant crosslinked resin formed body obtained by the method, a silane master batch, a mixture and a formed body thereof, and a heat-resistant product.