Fiber sizing agent, fiber material, molding material and molding

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Solution Overview

Problem

Existing fiber sizing agents, particularly those containing aliphatic epoxy compounds, fail to provide sufficient sizing properties for carbon fibers, resulting in inadequate strength of molded articles made from carbon fiber reinforced plastics.

Innovation Solution

A fiber sizing agent comprising a vinyl ester resin with an alkoxy polyoxyalkylene structure and a urethane bond, combined with an aqueous medium, is used to enhance the sizing properties and strength of both glass and carbon fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fiber sizing agent containing an aliphatic epoxy compound and a compound having a terminal unsaturated group and a polar group is used, then the sizing properties of glass fibers are improved, but the sizing properties of carbon fibers are insufficient

Engineering Contradiction:
Improvesizing propertiesVSAvoidapplicability to different fiber types
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fiber sizing agent is designed to function effectively on both glass fibers and carbon fibers through a dual-component system. The aliphatic epoxy compound provides adhesion to glass fibers while the compound with terminal unsaturated group and polar group enhances compatibility with carbon fibers, making the sizing agent universally applicable to both fiber types without sacrificing performance on either.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sizing agent combines two distinct chemical compounds into a composite formulation. The aliphatic epoxy compound (first compound) and the compound with terminal unsaturated group and polar group (second compound) work synergistically to provide comprehensive sizing properties for mixed fiber reinforcements, addressing the limitations of single-component sizing agents.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a fiber sizing agent with aliphatic epoxy compound is used, then the sizing properties are improved, but the strength of molded articles is insufficient

Engineering Contradiction:
Improvesizing propertiesVSAvoidmolded article strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sizing agent forms a composite protective layer on fiber surfaces that not only provides sizing properties (reducing friction and preventing damage) but also enhances the interfacial bonding between fibers and matrix resin. This dual-function composite structure ensures both good sizing performance and high strength in the resulting molded articles.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the sizing function and strength enhancement function into a single sizing agent formulation. The combination of aliphatic epoxy compound and compound with terminal unsaturated group creates a synergistic effect where the sizing properties and molded article strength are simultaneously improved rather than traded off against each other.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS11168187B2Fiber sizing agent, fiber material, molding material and molding
Publication Date: 2021.11.09 DIC CORP

AI summary

A fiber sizing agent includes: a vinyl ester resin (A) having an alkoxy polyoxyalkylene structure and a urethane bond; and an aqueous medium. The fiber sizing agent has excellent fiber sizing properties for various fibers such as glass fibers and carbon fibers. A molded article obtained from a molding material including the fiber sizing agent is excellent in various physical properties such as bending strength, compressive strength, and interlaminar shear strength, and thus can be used, for example, for an automobile member, an aircraft member, a windmill member, and an industrial member.