Polycarbonate Polysiloxane Copolymer Laminates Low Smoke
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Solution Overview
Problem
There is a need for polycarbonate resin compositions that include impact modifiers but do not produce excessive smoke when burned, while maintaining good processability and mechanical properties, which is not met by existing materials used in transportation and construction applications.
Innovation Solution
A laminate comprising a thermoplastic composition with a polycarbonate, polycarbonate-polysiloxane copolymer, and polyetherimide, where the polycarbonate constitutes greater than 50% of the composition by weight, and a 3.2 mm thick, 7.6 cm square sample produces a smoke density of less than 275 after a 4-minute burn, as measured by ASTM E 662-03.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonate blends with impact modifiers are used to achieve good impact strength and processability, then mechanical properties and ease of manufacture are improved, but smoke generation increases excessively
Solution Approach 1:
The patent creates a composite material system combining polycarbonate (50-95 wt%), polyetherimide (5-30 wt%), and impact modifiers (5-20 wt%). This composite approach allows the material to achieve low smoke generation (Ds < 275) while maintaining good impact strength and processability, resolving the contradiction between mechanical properties and smoke generation.
2Object-generated harmful factors
If polyimides and polyetherimides are used to achieve low smoke generation and flame retardance, then smoke generation is reduced, but impact strength and processability deteriorate
Solution Approach 1:
The patent optimizes the compositional parameters by limiting polyetherimide to 5-30 wt% and incorporating 50-95 wt% polycarbonate with impact modifiers. This parameter optimization maintains low smoke generation (Ds < 275) while significantly improving impact strength and processability compared to pure polyetherimide systems.
3Ease of manufacture
If polycarbonate blends are used to achieve good processability and mechanical properties, then ease of manufacture is improved, but flame retardance and smoke generation worsen
Solution Approach 1:
The patent develops a composite formulation combining polycarbonate (50-95 wt%), polyetherimide (5-30 wt%), and impact modifiers (5-20 wt%). This composite maintains excellent processability and mechanical properties while achieving low smoke generation (Ds < 275), resolving the contradiction between ease of manufacture and smoke generation.
Data Source
AI summary
A laminate contains a first layer and a second layer. The first layer contains a first composition that contains polycarbonate, polycarbonate-polysiloxane copolymer, impact modifier and polyetherimide, wherein the polycarbonate constitutes at least about 50% by weight of the composition and a 3.2 millimeter thick, 7.6 centimeter square sample of the first composition produces a smoke density (Ds) of less than 275 after a 4-minute burn, measured according to ASTM E 662-03. The first composition may contain about 50 wt. % to about 97 wt. % polycarbonate, about 0.5 wt. % to about 25 wt. % polycarbonate-polysiloxane copolymer, about 0.5 wt. % to about 20 wt. % impact modifier, and about 2 wt. % to about 15 wt. % polyetherimide, by weight. An article may contain a sheet or film made from such a composition. A laminate or article may be made to include a first layer or sheet that includes such a composition.