Long-Fiber Polyester Flame Retardancy via Phosphinate Synergy
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Solution Overview
Problem
Thermoplastic polyester molding compositions used in the household equipment sector often fail to meet the requirements of halogen-free flame retardancy and high glow wire resistance, particularly in the IEC 60695-2-13 glow-wire test, with many compositions not passing this test.
Innovation Solution
Long-glass-fiber-reinforced polyester molding compositions are developed using phosphinates and nitrogen-containing synergists, specifically incorporating polyalkylene terephthalates, phosphinic salts, and melamine cyanurate, which provide high flame retardancy and improved notched-impact resistance without the use of halogens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If halogen-free flame retardant additives (phosphinates and nitrogen-containing synergists) are used in thermoplastic polyester molding compositions, then flame retardancy is improved, but glow wire resistance deteriorates (many compositions fail the IEC 60695-2-13 test)
Solution Approach 1:
The patent applies composite materials by combining phosphinate flame retardants with nitrogen-containing synergists (such as melamine cyanurate or melamine polyphosphate) in specific weight ratios. This composite additive system creates a synergistic effect that simultaneously achieves both flame retardancy (passing UL 94-V tests) and glow wire resistance (passing IEC 60695-2-13 tests), resolving the contradiction between these two fire safety requirements in halogen-free polyester molding compositions.
2Strength
If long-fiber reinforcing materials are incorporated into polyester molding compositions, then mechanical strength is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the long fibers (2-25 mm length) with a coupling agent before incorporating them into the polyester molding composition. This pre-treatment ensures proper dispersion and bonding of the long fibers in the polymer matrix, maintaining high mechanical strength while simplifying the subsequent processing steps and avoiding complications that would arise from adding uncoated long fibers.
Data Source
AI summary
Thermoplastic molding compositions comprisingA) from 10 to 93% by weight of a thermoplastic polyesterB) from 1 to 20% by weight of a phosphinic saltC) from 1 to 20% by weight of a nitrogen-containing flame retardantD) from 5 to 50% by weight of a long-fiber reinforcing material with fiber length from 2 to 25 mm and L/D ratio from 500 to 4000E) from 0 to 50% by weight of other additives,where the total of the percentages by weight of components A) to E) is 100%.