Composition containing sizing agent for inorganic fibers and method for producing inorganic fibers
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Solution Overview
Problem
Conventional inorganic fiber sizing agents face challenges in achieving both improved heat resistance of the film obtained and long-term stability of a composition containing water and the sizing agent.
Innovation Solution
An inorganic fiber sizing agent-containing composition is developed, comprising a polyamide compound with specific constituent units A and B, and a nitrogen-containing compound, which is applied to inorganic fibers, such as carbon fibers, to enhance heat resistance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional inorganic fiber sizing agents are used, then the film can be formed, but the heat resistance of the film is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the sizing agent by incorporating specific polyamic acid compounds with controlled molecular weights (1,000-10,000) and specific constituent unit ratios (cyclic imide units 5-50 mol%, carboxyl units 5-50 mol%, hydroxyl units 5-50 mol%). These parameter changes enable the formation of films with improved heat resistance while maintaining composition stability during storage.
Solution Approach 2:
The patent creates a composite sizing agent system combining polyamic acid compounds with specific functional units (cyclic imide, carboxyl, hydroxyl) in defined ratios. This composite approach allows the film to achieve superior heat resistance through the synergistic effect of different functional units while the overall composition maintains long-term stability.
2Temperature
If the heat resistance of the film is improved, then the film can withstand higher temperatures, but the long-term stability of the water-containing composition deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyamic acid compound to 1,000-10,000 and controls the molar ratios of functional units within specific ranges (5-50 mol% each for cyclic imide, carboxyl, and hydroxyl units). These parameter optimizations enable the composition to remain stable in water-containing formulations while the resulting film achieves high heat resistance.
Solution Approach 2:
The patent introduces different functional units with specific local properties: cyclic imide units for heat resistance, carboxyl units for polarity and adhesion, and hydroxyl units for hydrogen bonding capability. Each functional unit contributes locally to different properties, allowing the overall composition to maintain stability while the film exhibits superior heat resistance.
Data Source
AI summary
Disclosed is an inorganic fiber sizing agent-containing composition that contains an inorganic fiber sizing agent and water. The inorganic fiber sizing agent contains a polyamide compound composed of a constituent unit A and a constituent unit B, and a nitrogen-containing compound. The molar ratio of the constituent unit A to the constituent unit B is constituent unit A/constituent unit B=49.0/51.0 to 43.0/57.0. The constituent unit A includes a constituent unit formed from a tetracarboxylic acid or a derivative thereof. The constituent unit B includes a constituent unit formed from a diamine or a derivative thereof. The nitrogen-containing compound is at least one selected from the group consisting of ammonia, a tertiary amine compound, and an aprotic nitrogen-containing heterocyclic compound. The mass ratio of the polyamide compound content to the nitrogen-containing compound content in the inorganic fiber sizing agent-containing composition is polyamide compound/nitrogen-containing compound=54/46 to 31/69.