Twisted Continuous Fiber Pellets for Resin Layer Thickness

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Solution Overview

Problem

Existing continuous fiber-reinforced thermoplastic resin pellets suffer from poor dispersion of reinforcing fibers in injection molded articles due to an uneven resin layer thickness, leading to compromised mechanical properties and appearance.

Innovation Solution

The pellets are manufactured by twisting a resin-impregnated reinforcing fiber bundle with a specific volume filling ratio and twisting pitch, ensuring an adequate peripheral surface resin layer thickness, achieved by adjusting the number of mono-filament fibers and twisting angle to maintain a volume filling ratio between 70% and 20% and a twisting pitch within 2.5 to 36 (m/rev·m), thereby optimizing fiber dispersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the reinforcing fiber bundle is concentrated in the center portion of the pellet cross section due to twisting, then the peripheral surface resin layer becomes thicker, but heat transfer to the reinforcing fiber bundle is deteriorated and dispersion in injection molded articles is poor

Engineering Contradiction:

Improveperipheral surface resin layer thicknessVSAvoidfiber dispersion uniformity

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the twisting pitch (P) within the range of 2.5 to 36 (m/rev·m) and the volume filling ratio (Vf) within 70% to 20%. By adjusting these parameters, the resin layer thickness is optimized to provide adequate heat transfer while maintaining uniform fiber dispersion in the pellet cross section, resolving the contradiction between resin layer thickness and fiber dispersion uniformity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the resin layer is formed on the surface of the continuous fiber-reinforced resin strand during pultrusion, then breaking and fluffing of reinforced fibers occurs less and stable operation is enabled, but the peripheral surface resin layer becomes too thick and deteriorates heat transfer

Engineering Contradiction:

Improvepultruding operation stabilityVSAvoidheat transfer efficiency

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent controls the twisting pitch parameter within 2.5 to 36 (m/rev·m) to regulate resin layer formation. This parameter control ensures the resin layer is thick enough to provide lubrication and stable pultruding operation while preventing excessive thickness that would impede heat transfer to the central fiber bundle

Inventive Principle:

Principle #35Parameter changes

3Strength

If the volume filling ratio is increased to enhance reinforcing effect, then mechanical strength is improved, but the peripheral surface resin layer becomes thinner and heat transfer is worsened

Engineering Contradiction:

Improvemechanical strength of injection molded articlesVSAvoidheat transfer to reinforcing fiber bundle

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The patent establishes an optimal range for the volume filling ratio (Vf) of 70% to 20% and combines it with specific twisting pitch control (P = 2.5 to 36 m/rev·m). This parameter combination ensures sufficient fiber content for mechanical strength while maintaining adequate resin layer thickness for effective heat transfer during injection molding

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

This method results in continuous fiber-reinforced thermoplastic resin pellets with improved fiber dispersion, enhancing the mechanical strength and appearance of injection molded articles by ensuring the reinforcing fibers are evenly distributed and the resin layer thickness is adequate.

Implementation Method 1

pultruding the resulting resin-impregnated reinforcing fiber bundle with twisting

Methodology Applied

Scientific EffectTwisting:

Implementation Method 2

letting a long reinforcing fiber bundle be impregnated with molten thermoplastic resin

Methodology Applied

Scientific EffectImpregnation: Absorption (physical)

Data Source

PatentUS9211654B2Continuous fiber-reinforced thermoplastic resin pellets and manufacturing method of the same

Publication Date: 2015.12.15 KOBE STEEL LTD

AI summary

To provide continuous fiber-reinforced thermoplastic pellets having a good dispersion property of a reinforcing fiber bundle in injection molded articles and capable of achieving a satisfactory outward appearance of the injection molded articles and satisfying a mechanical strength of the injection molded articles by fully exerting the reinforcing effect, and a manufacturing method of the same.In continuous fiber-reinforced thermoplastic resin pellets manufactured by letting a long reinforcing fiber bundle be impregnated with molten thermoplastic resin and pultruding the resin-impregnated reinforcing fiber bundle with twisting, followed by the cutting of a rod-shaped composition formed of the twisted resin-impregnated reinforcing fiber bundle into pellets, a volume filling ratio Vf, which is a proportion of a cross section area of the reinforcing fiber bundle in a cross section area of a pellet cross section in a direction perpendicular to a pellet longitudinal direction, is in a range of 70% to 20%, and a twisting pitch P given by P=L/d (where L is a traveling length of a twist in a rod-shaped composition longitudinal direction per rotation of the rod-shaped composition, and d is a diameter of a circle comparable to an area of a rod-shaped composition cross section) is in a range of 2.5 to 36 (m/rev·m).