Transparent Polyamide Composition Balancing Modulus and Haze
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Solution Overview
Problem
Existing transparent polyamide compositions for sports and electronics applications lack a combination of high modulus, high transmittance, low haze, and good impact/fatigue strength, as well as adequate sebum resistance.
Innovation Solution
A transparent molding composition comprising a specific blend of semi-crystalline aliphatic polyamide, amorphous polyamide, short glass fibers, and impact modifiers, with a refractive index between 1.500 and 1.540, and optionally prepolymer, without polyether block amides, achieving a modulus over 1700 MPa and improved impact and fatigue strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent polyamide compositions are used to achieve high transmittance, then transmittance is improved, but modulus and impact strength deteriorate
Solution Approach 1:
The patent uses a composite material system combining amorphous polyamide (for transparency), semi-crystalline polyamide (for modulus), glass fibers (for reinforcement), and impact modifiers (for toughness). This multi-component composite achieves both high transmittance (>70%) and high impact strength simultaneously by leveraging the complementary properties of each material.
Solution Approach 2:
The patent optimizes specific parameters including the refractive index (1.500-1.540) to reduce light scattering and improve transparency, while controlling the glass fiber content (5-20%) and polyamide ratios to achieve the desired balance between transparency, modulus (>1700 MPa), and impact strength.
2Strength
If glass fibers are added to increase modulus, then modulus is improved, but haze and transmittance deteriorate
Solution Approach 1:
The patent controls the glass fiber content within 5-20% and optimizes the refractive index of all components (polyamide, glass fiber, impact modifier) to fall within 1.500-1.540. This parameter optimization minimizes refractive index differences that cause light scattering, thereby reducing haze while maintaining the modulus enhancement from glass fiber reinforcement.
3Strength
If impact modifiers are added to improve impact strength, then impact strength is improved, but transmittance and haze control become more difficult
Solution Approach 1:
The patent selects impact modifiers with refractive indices within the 1.500-1.540 range and controls their content at 5-20%. This parameter control ensures that the impact modifier does not significantly scatter light, maintaining transmittance above 70% while achieving the desired impact strength improvement.
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 a high modulus of over 1700 MPa, transmittance greater than 70%, and low haze, along with good impact and fatigue strength, meeting the requirements of both sports and electronics markets.
Implementation Method 1
the index of refraction of each constituent (A), (B), (C) and (D) being included between 1.500 and 1.540
Implementation Method 2
a transmittance of at least 70% on a 2 mm wafer, and in particular for the sports market a good fatigue resistance
Data Source
AI summary
A transparent molding composition including, by weight (with a total of 100%): (A) 35 to 84% of a polyamide mixture including: 10 to 95% by weight of at least one semi-crystalline aliphatic polyamide, whose average number of carbon atoms relative to nitrogen atoms is greater than or equal to 8; 90 to 5% by weight of at least one amorphous polyamide; (B) from over 10 to 30% of at least one impact modifier; (C) from 6 to 20% of short glass fibers; (D) 0 to 10% of at least one prepolymer; and (E) 0 to 5% of at least one additive selected from stabilizers, dyes, plasticizers, processing aids or a mixture thereof, the index of refraction of each constituent (A), (B), (C) and (D) being included between 1.500 and 1.540, and wherein said composition has no PEBA and has a dry-measured modulus at 23° C. over 1700 MPa.