Reinforcing fiber bundle and molding material

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Solution Overview

Problem

Conventional reinforcing fiber bundles used in thermoplastic resin compositions face issues such as shape change, partial fuzzy shape formation, and inadequate handling properties due to low interfacial adhesion with the matrix resin, particularly when the amount of fiber treating agent is small, leading to problems like peeling and surface roughness during tape winding molding.

Innovation Solution

A reinforcing fiber bundle comprising a propylene-based resin with specific molecular weight ranges and a carboxylic acid salt bonded to the polymer chain, combined with a reinforcing fiber, which maintains mechanical strength and stability, improving adhesion and handling properties by controlling the molecular weight distribution and content rate of the propylene-based resins within the fiber bundle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a small amount of fiber treating agent is used to simplify the manufacturing process, then the manufacturing complexity is reduced, but the interfacial adhesion between fiber and matrix resin deteriorates, causing shape change and fuzzy formation

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidinterfacial adhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the fiber treating agent by incorporating both polyolefin resin and polyamide resin in specific proportions (0.1-10 parts polyamide resin per 100 parts polyolefin resin). This parameter adjustment enables the treating agent to provide both polyolefin compatibility and polyamide-like adhesion properties, resolving the contradiction between manufacturing simplicity and adhesion reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fiber treating agent is designed as a composite material combining polyolefin resin and polyamide resin. This composite structure allows the treating agent to simultaneously exhibit properties of both materials: the chemical inertness and compatibility of polyolefin with the matrix resin, and the high adhesion capability of polyamide with the fiber surface, thereby maintaining reliable interfacial adhesion without complicating the manufacturing process

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional fiber treating agents are used to improve interfacial adhesion, then the adhesion between fiber and matrix resin is improved, but the fiber bundle becomes loose and prone to untied, resulting in poor handling properties

Engineering Contradiction:
Improveinterfacial adhesionVSAvoidhandling properties
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention adjusts the molecular weight parameters of the polyolefin resin component to be within 10,000-1,000,000, and controls the content ratio of polyamide resin to polyolefin resin at 0.1-10%. These parameter optimizations ensure that the treating agent provides sufficient adhesion while maintaining fiber bundle integrity and handling properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The treating agent is applied specifically at the fiber surface interface where it creates a localized gradient of adhesion properties. The polyamide resin component concentrates at the fiber-matrix interface to provide strong bonding, while the polyolefin resin component extends outward to maintain fiber bundle cohesion and handling characteristics, achieving both adhesion improvement and handling property preservation

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If laser welding method is used for tape winding molding to achieve high shape freedom, then the manufacturing versatility is improved, but excessive heat generation occurs near carbon fiber, causing resin deterioration and surface roughness

Engineering Contradiction:
Improveshape freedomVSAvoidheat generation and resin deterioration
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The fiber treating agent acts as a thermal intermediary layer between the carbon fiber and the polyolefin matrix resin. The polyamide resin component, with its higher heat resistance, absorbs and dissipates laser-generated heat, protecting the polyolefin matrix from thermal deterioration. This intermediary function allows laser welding to proceed effectively while preventing resin degradation and surface roughness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention modifies the thermal properties of the fiber-matrix interface by introducing the treating agent with specific thermal characteristics. The polyamide resin component raises the local heat resistance at the fiber interface, changing the thermal parameter profile to withstand laser welding temperatures without causing matrix resin deterioration, thus enabling versatile laser-based molding while preventing harmful thermal effects

Inventive Principle:
Principle #35Parameter changes

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 solution results in a stable shape reinforcing fiber bundle that enhances mechanical strength, dimensional stability, and adhesion to the matrix resin, reducing issues like peeling and surface roughness, and improves the manufacturing process by minimizing defects such as clogging and dust formation.

Implementation Method 1

a propylene-based resin (B) comprising at least a carboxylic acid salt bonded to the polymer chain

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

attempts are being made to improve interfacial adhesion between a fiber and a matrix resin by the surface treatment of a reinforcing fiber and addition of a sizing agent

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

there is a molding method using a laser welding method

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

heat generation in the vicinity of a reinforcing fiber such as a carbon fiber which is easy to absorb energy of laser to generate heat

Methodology Applied
Scientific EffectHeat generation: Heating

Implementation Method 5

the propylene-based resin (A) comprises more than 70% by mass but not more than 100% by mass of a component (A-1) having a weight average molecular weight of 150,000 or more

Methodology Applied
Scientific EffectMolecular entanglement:

Implementation Method 6

a fiber-reinforced thermoplastic resin molded article in which a reinforcing fiber is complexed with a thermoplastic resin

Methodology Applied
Scientific EffectVan der Waals force: Van der Waals Force

Data Source

PatentUS10899896B2Reinforcing fiber bundle and molding material
Publication Date: 2021.01.26 MITSUI CHEMICALS INC

AI summary

Disclosed are: a reinforcing fiber bundle with excellent mechanical property and handling property, which contains a propylene-based resin (A), a propylene-based resin (B) comprising at least a carboxylic acid salt bonded to the polymer chain, and a reinforcing fiber (C) wherein the propylene-based resin (A) comprises more than 70% by mass but not more than 100% by mass of a component (A-1) having a weight average molecular weight of 150,000 or more, the amount of the propylene-based resin (B) is 3 to 50 parts by mass per 100 parts by mass of the propylene-based resin (A), and the total content rate of the propylene-based resin (A) and the propylene-based resin (B) is 0.3 to 5% by mass in the whole reinforcing fiber bundle; and a molding material comprising the reinforcing fiber bundle and a matrix resin.