Core-Shell Polymer Particles in Liquid Resin for Toughness

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Solution Overview

Problem

Existing curable resin compositions, such as epoxy resins, face challenges with high viscosity due to swollen rubber-like polymer particles, leading to reduced workability and fracture toughness in molded products.

Innovation Solution

A liquid resin composition with dispersed core-shell polymer particles having an elastic core layer, an intermediate layer with multiple double bonds, and a shell layer, which maintains low viscosity and high crosslinking density, preventing swelling and improving grafting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rubber-like polymer particles are dispersed in curable resin to improve toughness, then fracture toughness is improved, but viscosity increases and workability deteriorates

Engineering Contradiction:
Improvefracture toughnessVSAvoidworkability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies local quality by creating distinct layers with different functions: the core layer provides elasticity for toughness, the intermediate layer with multiple double bonds creates high crosslinking density locally to prevent swelling, and the shell layer provides compatibility with the curable resin. This layered structure allows each region to contribute specifically to preventing viscosity increase while maintaining toughness improvement.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the chemical parameter of the intermediate layer by using monomers with two or more double bonds, which fundamentally alters the crosslinking density compared to conventional single-double-bond monomers. This parameter change enables the intermediate layer to maintain low viscosity while providing sufficient crosslinking to prevent polymer particle swelling.

Inventive Principle:
Principle #35Parameter changes

2Strength

If polymer particle content is increased to improve toughness, then fracture toughness is improved, but viscosity increases and workability deteriorates

Engineering Contradiction:
Improvefracture toughnessVSAvoidpolymer particle content
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent creates a composite polymer particle structure combining three different layers: elastic core layer for toughness, intermediate layer with high crosslinking density for swelling prevention, and shell layer for resin compatibility. This composite structure allows the particles to contribute to toughness while maintaining low viscosity even at high concentrations.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If crosslinking density is increased to prevent swelling, then viscosity is maintained low, but grafting efficiency must be improved

Engineering Contradiction:
ImproveviscosityVSAvoidgrafting efficiency
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by equipping the intermediate layer with multiple double bonds before the grafting process with the shell layer. This pre-preparation ensures that when the shell layer is grafted, there are sufficient reactive sites available, leading to high grafting efficiency and high crosslinking density that prevents swelling while maintaining low viscosity.

Inventive Principle:
Principle #10Preliminary action

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 composition achieves low viscosity and high workability, allowing for increased polymer particle concentration without increasing viscosity, resulting in improved toughness and heat resistance in cured products.

Implementation Method 1

Through one of the double bonds, the monomer for intermediate layer formation is graft-polymerized with a polymer forming the elastic core layer to substantially chemically bond the intermediate layer and the shell layer and, at the same time, through the remaining double bond(s), surface of the elastic core layer is crosslinked

Methodology Applied
Scientific EffectGraft polymerization: Photopolymerisation

Data Source

PatentUS8742014B2Liquid resin composition and cured product using the liquid resin composition
Publication Date: 2014.06.03 KANEKA CORP

AI summary

An object of the invention is to provide a liquid resin composition with low viscosity while containing polymer particles. Further, another object of the invention is to provide a liquid resin composition containing a large quantity of polymer particles without increasing the viscosity of the liquid resin composition. A liquid resin composition of the invention is comprising a liquid resin component and polymer particles each having an elastic core layer, an intermediate layer formed with a monomer having two or more double bonds and coated on the core layer, and a shell layer coated on the intermediate layer; wherein the polymer particles are dispersed at a ratio of their volume average particle diameter (Mv) to their number average particle diameter (Mn) of 3 or lower.