Polyamide Mixture for Eyeglass Frames
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Solution Overview
Problem
Polyamides based on bis(4-aminocyclohexyl)methane (PACM) exhibit high solvent and stress crack resistance but lack sufficient puncture resistance and processing ease, particularly in applications like eyeglass frames and lenses, where high impact strength and transparency are required, and their high melt viscosity complicates production of delicate components.
Innovation Solution
A shaped object made from a mixture comprising at least 50% by weight of a polyamide blend of 70 to 95 parts by weight of PA PACMX (derived from PACM and linear dicarboxylic acids) and 30 to 5 parts by weight of a linear aliphatic polyamide with 8 to 12 carbon atoms, processed into molded parts using methods like injection molding or extrusion, which can include additives to enhance properties without impairing transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the molecular weight of PACM-based polyamide is reduced to lower melt viscosity, then processability improves, but mechanical properties (impact strength, puncture resistance, elongation at break, aging resistance) deteriorate
Solution Approach 1:
The patent creates a composite material system by blending PACM-based polyamide with a second polyamide component having different molecular weight or structural characteristics. This composite approach allows the mixture to exhibit improved melt flow behavior for processing while the synergistic combination maintains or enhances mechanical properties including impact strength, puncture resistance, and aging resistance that would not be achievable with a single polyamide component.
2Illumination intensity
If PACM-based polyamide is used to achieve high transparency and solvent resistance, then optical properties improve, but puncture resistance remains insufficient
Solution Approach 1:
The patent employs a composite material strategy by formulating a polyamide mixture that combines PACM-based polyamide (providing transparency and solvent resistance) with a second polyamide component that contributes enhanced mechanical strength and puncture resistance. The synergistic interaction between the two components enables the final material to simultaneously achieve high optical clarity and improved puncture resistance, overcoming the limitations of using PACM-based polyamide alone.
Data Source
AI summary
A mixture consisting of at least 50 wt.% of a polyamide component comprising a) 50 to 95 wt. parts PA PACMX (with X = 8 to 18) and b) 50 to 5 wt. parts of a linear aliphatic polyamide with an average of 8 to 12 C atoms in the monomer units, where the sum of the wt. parts is 100, can be processed into a shaped object characterized by a combination of high transparency, high toughness and high resistance to chemicals, solvents and stress cracking.