Reinforcing fiber bundle

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Solution Overview

Problem

Existing fiber-reinforced thermoplastic resin forming materials face challenges in achieving a balance between mechanical properties and fluidity during the forming process, with a need for improved continuous productivity and formability to produce complex shapes.

Innovation Solution

A continuous reinforcing fiber bundle is developed, comprising regions with specific characteristics such as fiber density, drape level, and hardness, and treated with sizing agents to enhance mechanical properties and fluidity, using interlaced sections formed by fiber separation and sizing agent application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fiber bundles consisting of many single yarns are used to improve fluidity during forming process, then fluidity is improved, but mechanical properties of shaped product deteriorate

Engineering Contradiction:
Improvefluidity during forming processVSAvoidmechanical properties of shaped product
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The fiber bundle is designed with non-uniform structure: regions near terminals have fewer single yarns (1,600 fibers/mm or less) to improve fluidity and drapability, while central regions have more single yarns (600-1,600 fibers/mm) to maintain mechanical strength. This local variation in fiber distribution resolves the contradiction between fluidity and mechanical properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fiber bundle is segmented into different regions along its length: terminal regions (150mm from ends) with lower single yarn density for better flow, and central regions with higher single yarn density for strength. This segmentation allows different parts of the same fiber bundle to serve different functional requirements.

Inventive Principle:
Principle #1Segmentation

2Productivity

If continuous production of intermediate base materials is implemented to improve productivity, then productivity is improved, but quality consistency becomes difficult to maintain

Engineering Contradiction:
Improvecontinuous production capabilityVSAvoidquality consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Sizing agents are applied to the fiber bundle in advance during continuous production, and interlaced sections are formed beforehand through controlled fiber separation. This preliminary treatment ensures that quality requirements are met during continuous manufacturing, maintaining consistency without requiring post-production adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention specifies precise parameter ranges (single yarn number per unit width of 1,600 fibers/mm or less in terminal regions, drape level of 120-240mm, bundle hardness of 39-200g) that can be controlled during continuous production. By maintaining these parameters within defined ranges, quality consistency is achieved throughout continuous manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Strength

If fiber bundle structure is optimized to improve mechanical properties, then mechanical properties are improved, but fluidity during forming deteriorates

Engineering Contradiction:
Improvemechanical propertiesVSAvoidfluidity during forming
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

Different regions of the fiber bundle have different structural characteristics: terminal regions have sparser single yarn distribution (1,600 fibers/mm or less) for better fluidity, while central regions have denser distribution (600-1,600 fibers/mm) for mechanical strength. This local differentiation resolves the contradiction between strength and fluidity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fiber bundle combines regions with different structural properties (low-density terminal regions and high-density central regions) into a single composite structure. This composite approach allows the material to exhibit both good fluidity (from terminal regions) and high mechanical strength (from central regions).

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3744884B1Reinforcing fiber bundle
Publication Date: 2025.07.09 TORAY INDUSTRIES INC
  • EP3744884B1 patent drawingFigure 1(I)~3
  • EP3744884B1 patent drawingFigure 4~6
  • EP3744884B1 patent drawingFigure 7~8

AI summary

This reinforcing fiber bundle is a continuous reinforcing fiber bundle that has a length of at least 1 m and is characterized by the number of monofilaments per unit width being at most 1,600/mm and the average number of fibers in the bundle being at most 1,000 in a region (I) described below, and the drape level found in a region (II) being 120 - 240 mm. In addition, this continuous reinforcing fiber bundle has a length of at least 1 m and is characterized by the adhesion amount of a sizing agent (I) in the region (I) described below being 0.5 - 10% by weight and the drape level found in the region (II) being 120 - 240 mm. Provided is a continuous reinforcing fiber bundle with superior mechanical properties, formability into complex shapes, and continuous producibility. Region (I): region up to 150 mm from terminal Region (II): region other than region (I)