Long-fiber-reinforced resin composition surface appearance
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Solution Overview
Problem
Long-fiber-reinforced resin compositions used in molded articles often exhibit poor fiber dispersion, leading to unsatisfactory surface appearances, particularly in applications like automobile modules, where excellent external appearance is required.
Innovation Solution
A long-fiber-reinforced resin composition comprising a long-fiber-reinforced thermoplastic resin pellet with a modified polyolefin-based resin and a polyolefin-based resin for dilution, where the thermoplastic resin has a specific melt index and relaxation time, and the reinforcing fibers are adequately distributed to prevent fiber masses at the surface during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If long-fiber-reinforced resin composition is used to achieve high strength, then strength is improved, but fiber dispersion is insufficient causing fiber masses to appear at the surface
Solution Approach 1:
The patent changes the rheological parameters of the resin system by selecting specific thermoplastic resins with relaxation times of 0.1 seconds or less and controlling melt indices within specific ranges (100-250 g/10min for thermoplastic resin, 20-70 g/10min for polyolefin-based resin). This parameter optimization enables the resin to properly wet and disperse long fibers during injection molding, preventing fiber mass formation at the surface while maintaining high strength properties.
2Manufacturing precision
If fiber-reinforced resin composition is used to improve appearance, then surface appearance is improved, but the appearance is not as excellent as required for automobile module components
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: relaxation time (0.1s or less), melt index ratios (thermoplastic resin 100-250 g/10min, polyolefin-based resin 20-70 g/10min), and fiber content (20-60 wt%). This comprehensive parameter control achieves superior surface appearance with complete fiber dispersion, meeting the high aesthetic requirements for automobile module components.
3Manufacturing precision
If resin with short relaxation time is used to prevent fiber mass at surface, then fiber opening properties are improved, but resin selection becomes more restrictive
Solution Approach 1:
The patent establishes specific parameter ranges for resin selection: relaxation time of 0.1 seconds or less, thermoplastic resin melt index of 100-250 g/10min, and polyolefin-based resin melt index of 20-70 g/10min. These defined parameters provide clear selection criteria that balance fiber opening performance with practical resin availability and processing considerations.
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 composition achieves improved fiber opening properties and excellent appearance of molded articles, suitable for applications requiring high strength and aesthetic quality, such as automobile components.
Implementation Method 1
the relaxation time λ of the thermoplastic resin at an angular frequency ω=1 (rad/sec) calculated from the storage modulus G′ and the loss modulus G′′ measured by means of a cone-and-plate rheometer is 0.1 (sec) or less; the relaxation time λ of the polyolefin-based resin at an angular frequency ω=1 (rad/sec) calculated from the storage modulus G′ and the loss modulus G′′ measured by means of a cone-and-plate rheometer is 0.23 (sec) or less
Data Source
AI summary
A long-fiber-reinforced resin composition including (A) a long-fiber-reinforced thermoplastic resin pellet including a thermoplastic resin, a modified polyolefin-based resin modified with an unsaturated carboxylic acid or its derivative and reinforcing fiber and satisfying (A-1) the melt index of the thermoplastic resin is 100-250 g/10 min, (A-2) the relaxation time λ of the thermoplastic resin is 0.1 (sec) or less, (A-3) the content of the reinforcing fiber is 40-70 wt %, and (A-4) the content of the modified polyolefin-based resin is 1-5 wt %; and (B) a polyolefin-based resin satisfying (B-1) the melt index of the polyolefin-based resin is 20-70 g/10 min, and (B-2) the relaxation time λ of the polyolefin-based resin is 0.23 (sec) or less; wherein the content of reinforcing fiber contained in (A) is 20-60 wt % relative to the total amount of the fiber-reinforced resin composition.