Sizing agent for reinforcement fiber and applications thereof
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sizing agents for reinforcement fibers fail to simultaneously achieve excellent cohesion, abrasion resistance, uniform application, and good bonding between fibers and matrix resins, leading to suboptimal properties in fiber-reinforced composite materials.
Innovation Solution
A sizing agent comprising a polyamide with specific melt viscosity, a carbodiimide group-containing compound, and water, applied to reinforcement fibers to enhance cohesion, abrasion resistance, and bonding with the matrix resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-molecular-weight resins are used in the sizing agent to achieve high bonding strength and film strength, then bonding strength is improved, but fluidity decreases due to high viscosity, preventing sufficient wetting of the fiber surface
Solution Approach 1:
The patent changes the molecular weight parameter of the polyamide from high-molecular-weight to medium-molecular-weight range, specifically controlling the melt viscosity to be 500-5000 Pa·s at 230°C. This parameter change allows the sizing agent to maintain both adequate bonding strength and sufficient fluidity for uniform fiber coating.
2Stability of the object's composition
If conventional sizing agents are applied to reinforcement fibers, then cohesion is provided, but abrasion resistance deteriorates due to low elasticity and brittleness of the fibers
Solution Approach 1:
The patent creates a composite sizing agent system combining polyamide (providing cohesion and bonding) with silicone oil (providing lubrication and abrasion resistance). This composite approach allows the sizing agent to simultaneously improve cohesion and protect brittle fibers from abrasion during processing.
3Strength
If the sizing agent has high viscosity due to high-molecular-weight resins, then bonding between sizing agent and matrix resin is improved, but uniform application on fiber surface deteriorates
Solution Approach 1:
The patent optimizes the viscosity parameter of the sizing agent by selecting medium-molecular-weight polyamide with melt viscosity of 500-5000 Pa·s at 230°C. This viscosity range enables the sizing agent to flow uniformly along the fiber surface during application while maintaining adequate bonding strength with the matrix resin after curing.
4Strength
If additional heat treatment after drying is implemented to achieve good handling property and bonding, then bonding quality is improved, but productivity decreases and facility cost increases
Solution Approach 1:
The patent extracts the requirement for additional heat treatment by formulating the sizing agent with polyamide that has adequate bonding capability at medium molecular weight. The sizing agent achieves sufficient bonding strength through the optimized polyamide-silicone oil combination and controlled viscosity, eliminating the need for separate heat treatment steps and thereby improving productivity.
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 proposed sizing agent achieves excellent cohesion, abrasion resistance, uniform application, and strong bonding between fibers and matrix resins, improving the mechanical properties of fiber-reinforced composite materials.
Implementation Method 1
the sizing agent cannot sufficiently wet the fiber surface, and fails to uniformly coat the fiber surface
Implementation Method 2
a sizing agent containing a thermoplastic component which has a good handling property and exhibits good bonding to matrix resins
Data Source
AI summary
A sizing agent for matrix-resin-reinforcement fibers that simultaneously attains excellent cohesion and abrasion resistance of sized fibers, uniform size application on fiber surface and good bonding between sized fiber and a matrix resin; a synthetic fiber strand sized therewith; and a fiber-reinforced composite material reinforced by the sized fiber strand. The sizing agent contains a polyamide (A), a carbodiimide group-containing compound (B) and water (C), wherein the polyamide (A) has a melt viscosity ranging from 100 to 15,000 mPa·s at 150° C. and the compound (B) has at least two carbodiimide groups per molecule. The polyamide (A) is preferably a water-soluble polyamide.