Flat-Cross-Section Glass Fiber Spinnability and Strength

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Solution Overview

Problem

Long-oval-cross-section glass fibers exhibit poor spinnability and chopped strand productivity due to higher filament breaking frequencies and increased cutting blade abrasion, compromising dimensional stability and mechanical properties in glass-fiber-reinforced resin molded products.

Innovation Solution

The development of flat-cross-section glass fibers with specific dimensions and shape ratios, where the major axis ranges from 15.0 to 25.0 μm, the minor axis from 8.0 to 12.0 μm, and an irregular shape ratio of 1.5 to 3.0, along with a packing rate of 80.1 to 89.9%, optimizing the balance between spinnability and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If long-oval-cross-section glass fiber is used to improve dimensional stability and mechanical properties, then warpage resistance and tensile strength are improved, but filament breaking frequency increases during spinning

Engineering Contradiction:
Improvedimensional stabilityVSAvoidspinnability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the glass fiber cross-section by introducing a flat shape with specific dimensional ratios (major axis 15.0-25.0 μm, minor axis 8.0-12.0 μm, irregular shape ratio R between 1.5-3.0) and packing rate (80.1-89.9%), which resolves the contradiction between dimensional stability and spinnability

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If long-oval-cross-section glass fiber is used to improve dimensional stability, then warpage resistance is improved, but cutting blade abrasion increases during chopping

Engineering Contradiction:
Improvedimensional stabilityVSAvoidchopped strand productivity
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent modifies the cross-sectional geometry parameters to a flat shape with controlled dimensions and packing rate, which reduces cutting blade abrasion while maintaining warpage resistance, thereby improving chopped strand productivity

Inventive Principle:
Principle #35Parameter changes

3Strength

If flat-cross-section glass fiber with high packing rate is used to improve mechanical properties, then tensile strength is improved, but filament breaking frequency increases during spinning

Engineering Contradiction:
Improvetensile strengthVSAvoidspinnability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the balance between packing rate (80.1-89.9%) and irregular shape ratio (1.5-3.0) to achieve high tensile strength while controlling filament breaking frequency during spinning

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12195600B1Flat-cross-section glass fiber, glass-fiber-reinforced resin composition, and glass-fiber-reinforced resin molded product
Publication Date: 2025.01.14 NITTO BOSEKI CO LTD

AI summary

A glass fiber including a plurality of flat-cross-section glass filaments each having a cross-section in flat shape, the cross-section having a major axis in the range of 15.0 to 25.0 μm, a minor axis in the range of 8.0 to 12.0 μm, and an irregular shape ratio R, being the ratio of the major axis to the minor axis (major axis/minor axis), in the range of 1.5 to 3.0. The flat-cross-section glass fiber has a packing rate P, being the ratio of the cross-sectional area of each flat-cross-section glass filament to the area of a rectangle circumscribing the cross-section of the flat-cross-section glass filament, in the range of 80.1 to 89.9%, and the irregular shape ratio R and the packing rate P satisfy the following formula (1): 337.6≤P3/2/R≤421.2 . . . (1).