Semi-Aromatic Polyamide Composition for Extrusion
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Solution Overview
Problem
Current semi-aromatic polyamide compositions face challenges in achieving a balance between high thermomechanical properties, cold impact resistance, and processability, particularly in extrusion processes, where high plasticizer content reduces flexural modulus and cold impact resistance, and high crosslinked polyolefin content leads to phase inversion and irregular surface morphology.
Innovation Solution
A composition comprising 33-40% crosslinked polyolefin, 3-10% plasticizer, and a balance of semi-aromatic polyamide, with specific weight ratios of unsaturated epoxide and carboxylic acid anhydride components, optimizing thermomechanical properties and flexibility while preventing surface irregularities and fume formation during extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the content by weight of plasticizer increases in the semi-aromatic polyamide composition, then the flexural modulus decreases, but the cold impact resistance properties decrease
Solution Approach 1:
The patent uses a composite system combining semi-aromatic polyamide, plasticizer, and crosslinked polyolefin to achieve a balance between flexibility and cold impact resistance. The crosslinked polyolefin acts as a reinforcing phase that maintains impact resistance while the plasticizer provides flexibility, creating a synergistic composite material that resolves the contradiction between these two properties.
Solution Approach 2:
The patent optimizes the weight ratio parameters of the components, specifically maintaining crosslinked polyolefin at 4-35 parts by weight per 100 parts of semi-aromatic polyamide and plasticizer at 3-20 parts by weight per 100 parts of semi-aromatic polyamide. This parameter optimization allows achieving flexural modulus ≤800 MPa while maintaining Charpy impact ≥7 kJ/m at -40°C.
2Adaptability or versatility
If the content by weight of crosslinked polyolefin increases to achieve flexural modulus of 600-700 MPa, then the flexural modulus decreases, but the morphology becomes non-nodular (phase inversion) which is prohibitive for extrusion
Solution Approach 1:
The patent precisely controls the weight ratio of crosslinked polyolefin to be 4-35 parts per 100 parts of semi-aromatic polyamide, and plasticizer to be 3-20 parts per 100 parts of semi-aromatic polyamide. This parameter optimization ensures the formation of a nodular alloy morphology that is suitable for extrusion while achieving the desired flexural modulus of 600-700 MPa.
Solution Approach 2:
The patent creates a specific nodular morphology where crosslinked polyolefin forms discrete nodules distributed in the semi-aromatic polyamide matrix. This local structural arrangement maintains processability during extrusion while providing the required mechanical properties, avoiding phase inversion.
3Adaptability or versatility
If high plasticizer content is used to lower flexural modulus, then the flexural modulus decreases, but fume formation increases during extrusion
Solution Approach 1:
The patent employs a composite system where crosslinked polyolefin serves as a stabilizing phase that reduces fume formation during extrusion. The synergistic interaction between the crosslinked polyolefin and plasticizer allows using plasticizer at 3-20 parts per 100 parts of polyamide to achieve flexural modulus ≤800 MPa while minimizing fume generation through the stabilizing effect of the crosslinked network.
4Strength
If aliphatic polyamide is added to improve cold impact resistance, then the Charpy impact value increases, but the material becomes stiffer which may affect flexibility
Solution Approach 1:
The patent uses a composite system combining semi-aromatic polyamide, crosslinked polyolefin, and plasticizer where the crosslinked polyolefin provides cold impact resistance enhancement without the stiffening effect of aliphatic polyamides. The plasticizer component maintains flexibility while the crosslinked polyolefin reinforces the structure, achieving Charpy impact ≥7 kJ/m at -40°C while preserving flexibility.
Data Source
AI summary
The present invention relates to a composition comprising: from 33 to 40% by weight of at least one crosslinked polyolefin obtained from at least one product (A) comprising an unsaturated epoxide and from at least one product (B) comprising an unsaturated carboxylic acid anhydride, from 3 to 10% by weight of at least one plasticizer, the rest being made up of at least one semi-aromatic polyamide, wherein the weight contents of (A) and (B), denoted respectively [A] and [B], are such that the [B]/[A] ratio is between 3 and 14. The present invention also relates to a process for preparing such a composition and also to the uses thereof.