Urethane-Modified Epoxy Prepreg for Interlaminar Shear Strength
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Solution Overview
Problem
Fiber-reinforced resin composite materials, such as prepregs with epoxy resins, face challenges in maintaining stability at normal temperatures and achieving sufficient interlaminar shear strength and heat resistance, particularly due to the need for ultraviolet curing and insufficient adhesion in molded articles.
Innovation Solution
A prepreg composition containing urethane-modified epoxy (meth)acrylate, an unsaturated monomer, a polymerization initiator, and reinforcing fibers, with specific molar ratios and molecular weights, which enhances workability, moldability, and interlaminar shear strength while maintaining heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If epoxy resin compositions are used for prepregs, then stability at normal temperature is achieved, but curing proceeds at normal temperature requiring low temperature storage
Solution Approach 1:
The patent modifies the chemical parameters of the resin system by using radically polymerizable resin compositions with specific functional groups (carboxyl, hydroxyl, amine) instead of conventional epoxy resins. This parameter change allows the resin to maintain stability at normal temperature while preventing spontaneous curing, eliminating the need for low temperature storage.
2Ease of operation
If radically polymerizable resin composition is used to improve workability, then ultraviolet curing is required, but molded article has insufficient interlayer adhesion
Solution Approach 1:
The patent creates a composite resin system combining radically polymerizable resin with specific functional groups (carboxyl, hydroxyl, or amine) that provide both UV curability for workability and chemical bonding capability for interlayer adhesion. The functional groups enable covalent bonding between layers while the radical polymerization provides efficient curing.
3Ease of manufacture
If conventional prepreg is used, then manufacturing process is simple, but interlaminar shear strength is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the resin to include specific functional groups (carboxyl, hydroxyl, amine) with controlled content ratios. This enables the resin to form strong interlayer bonds through chemical reactions while maintaining a relatively simple manufacturing process similar to conventional prepreg production.
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 prepreg composition provides molded articles with improved interlaminar shear strength, heat resistance, and workability, suitable for various structural applications, including automotive and aerospace components.
Implementation Method 1
a radically polymerizable resin composition that can be efficiently produced and that can have high stability at normal temperature... ultraviolet curing is required in order to improve the workability
Implementation Method 2
a urethane-modified epoxy (meth)acrylate (A) that is a reaction product of an epoxy (meth)acrylate (a1) having an average of 1.8 to 2.6 hydroxy groups per molecule and a polyisocyanate (a2) having an average of 2 to 3 isocyanate groups per molecule
Data Source
AI summary
Provided is a prepreg containing a urethane-modified epoxy (meth)acrylate (A) that is a reaction product of an epoxy (meth)acrylate (a1) having an average of 1.8 to 2.6 hydroxy groups and a polyisocyanate (a2) having an average of 2 to 3 isocyanate groups, an ethylenically unsaturated monomer (B), a polymerization initiator (C), and reinforcing fibers (D) as essential components, in which the molar ratio (NCO/OH) of isocyanate groups (NCO) in the polyisocyanate (a2) to hydroxy groups in the epoxy (meth)acrylate (a1) is 0.6 to 1.1, and the proportion of the ethylenically unsaturated monomer (B) in the total mass of the epoxy (meth)acrylate (a1) and the ethylenically unsaturated monomer (B) is 10% to 50% by mass. The prepreg has good workability and good moldability and can be appropriately used for various molded articles such as automotive members because various excellent physical properties such as interlaminar shear strength and heat resistance are provided.