Reinforcement Fiber Sizing Composition for Uniform Coating and Bonding
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Solution Overview
Problem
Conventional sizing agents for reinforcement fibers in thermoplastic matrix composites exhibit poor bonding strength and splittability due to insufficient heat resistance and nonuniform coating, leading to issues with fiber cohesion and composite properties.
Innovation Solution
A sizing agent comprising an ester compound with vinyl or acrylate groups and a polyoxyalkylene alkyl ether, which exhibits a dynamic surface tension of 40-55 mN/m, ensuring uniform coating and improved bonding between reinforcement fibers and thermoplastic matrix resins, along with the inclusion of aromatic polyester-polyurethane or aromatic polyester resins for enhanced heat resistance and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional sizing agents are used to coat reinforcement fibers, then fiber coating is achieved, but bonding strength between matrix resin and sized fiber is insufficient due to poor heat resistance
Solution Approach 1:
The patent changes the chemical composition parameters of the sizing agent by incorporating specific thermoplastic resins (polyester, polyamide, polyurethane) in controlled ratios (5-50% each) to achieve optimal heat resistance and bonding strength. The sizing agent also controls dynamic surface tension within 20-60 mN/m to ensure proper coating while maintaining thermal stability up to processing temperatures.
Solution Approach 2:
The patent creates a composite sizing agent system combining multiple thermoplastic resins (polyester, polyamide, polyurethane) with complementary properties. This composite formulation leverages the heat resistance of polyester, the bonding affinity of polyamide, and the flexibility of polyurethane to achieve superior overall performance that individual resins cannot provide alone.
2Manufacturing precision
If conventional sizing agents are applied to reinforcement fibers, then coating is achieved, but coating uniformity is poor leading to nonuniform spreading between single fibers
Solution Approach 1:
The patent optimizes the dynamic surface tension parameter of the sizing agent to fall within 20-60 mN/m, which ensures optimal wetting and penetration characteristics. This parameter control allows the sizing agent to uniformly spread between individual fibers and penetrate evenly throughout the fiber strand, achieving consistent coating uniformity.
3Stability of the object's composition
If conventional sizing agents form strong film on fiber surface, then coating stability is achieved, but splittability of sized fiber strands is poor
Solution Approach 1:
The patent incorporates polyurethane resin (5-50% of total resin content) which provides flexible molecular chains and elastomeric properties to the sizing agent film. This flexibility allows the coating to remain stable and adherent while still permitting the fiber strands to split easily during processing operations like warping and fabric formation.
Solution Approach 2:
The patent adjusts the molecular weight and glass transition temperature parameters of the thermoplastic resins used in the sizing agent. By selecting resins with appropriate Tg values and molecular weights, the coating film achieves optimal balance between stability for handling and flexibility for splittability during subsequent processing.
4Reliability
If sizing agent penetrates slowly into fiber strand, then coating coverage is achieved, but processing time increases and bonding performance deteriorates
Solution Approach 1:
The patent controls the viscosity and dynamic surface tension parameters of the sizing agent to optimize penetration kinetics. The dynamic surface tension is maintained within 20-60 mN/m to ensure rapid wetting and penetration into the fiber strand structure, reducing processing time while maintaining thorough coating coverage and bonding performance.
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 sizing agent achieves excellent splittability and bonding performance, improving the properties of fiber-reinforced composites by ensuring uniform coating and maintaining bonding integrity at high temperatures.
Implementation Method 1
the mixture exhibits a dynamic surface tension ranging from 40 to 55 mN/m determined by the maximum bubble pressure method
Data Source
AI summary
A sizing agent for a reinforcement fiber is used for reinforcing thermoplastic matrix resins and spreads on the reinforcement fiber surface and imparts both excellent splittability and bonding performance to thermoplastic matrix resins. The sizing agent includes essentially an ester compound (A) having a vinyl ester group, acrylate group or methacrylate group bonded to at least one of the chain ends of the main chain of the ester compound (A), and of a polyoxyalkylene alkyl ether (B) which is an adduct between an alkylene oxide and a C4-14 monohydric alcohol. When water is added to the sizing agent thereby producing a mixture with a nonvolatile content of 1 weight %, the mixture exhibits a dynamic surface tension ranging from 40 to 55 mN/m determined by the maximum bubble pressure method when bubbles are blown into the mixture at the rate of one bubble per 100 milliseconds.