Multilayered Impact Modifier for Transparent Thermoplastic Polyester
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Solution Overview
Problem
Existing thermoplastic polyester resin compositions face challenges in simultaneously improving impact strength and maintaining transparency, as increasing impact strength often compromises transparency and vice versa, due to issues with rubber latex content, glass transition temperature, particle diameter ratio, and refraction index differences.
Innovation Solution
A thermoplastic polyester resin composition is developed with a multi-layered impact strength modifier prepared by graft polymerization of 20-80 weight % multilayered rubber latex, where the particle diameter ratio of inner to outer layers is 1.05-1.5 and glass transition temperature is up to −30° C., along with 20-80 weight % vinyl monomer, to regulate refraction index and enhance compatibility, thereby improving both impact strength and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If butadiene-based core-shell type polymer is added to improve impact strength, then impact strength is improved, but transparency is damaged
Solution Approach 1:
The patent changes the refraction index parameter of the impact modifier to match that of the polyester resin (both set to 1.54). This parameter matching eliminates light scattering at interfaces, thereby maintaining transparency while the core-shell structure provides impact strength improvement.
Solution Approach 2:
The patent uses a core-shell type graft copolymer as a composite material where the core provides toughness for impact strength and the shell provides compatibility and refraction index matching with the polyester resin matrix, thereby achieving both improved impact strength and maintained transparency.
2Illumination intensity
If impact modifier with styrene copolymer shell is added to preserve transparency, then transparency is preserved, but impact strength is not improved satisfactorily
Solution Approach 1:
The patent optimizes the refraction index of the shell polymer to match the polyester resin (1.54), ensuring transparency is preserved. Simultaneously, the core composition is designed to provide sufficient toughness for impact strength improvement.
Solution Approach 2:
The patent applies local quality by designing different regions of the impact modifier with different functions: the core provides impact absorption capability while the shell provides optical matching and compatibility with the matrix, thereby achieving both transparency preservation and impact strength improvement.
3Strength
If multi-layered rubber latex is used to improve impact strength, then impact strength is improved, but transparency is decreased due to refraction index difference
Solution Approach 1:
The patent changes the refraction index parameter of the multi-layered rubber latex to match that of the polyester resin (1.54). This parameter matching eliminates light scattering effects, thereby maintaining transparency while the multi-layered structure provides impact strength improvement through controlled morphology.
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 significant improvements in impact strength and retains excellent transparency by regulating the refraction index difference between the thermoplastic graft copolymer and polyester resin to ≤0.005, ensuring effective dispersibility and mechanical properties.
Implementation Method 1
prepared by graft polymerization of a) 20-80 weight % of multilayered rubber latex in which the ratio of particle diameter (Pb/Pa) of an inner layer (Pa) to an outer layer (Pb) is 1.05-1.5
Implementation Method 2
regulating the refraction index difference between the thermoplastic graft copolymer and polyester resin to ≤0.005, ensuring effective dispersibility and mechanical properties
Implementation Method 3
glass transition temperature of the inner layer or the outer layer is up to −30° C.
Data Source
AI summary
The present invention relates to an impact strength modifier for thermoplastic polyester resin and a thermoplastic polyester resin composition containing the same, more precisely an impact strength modifier for thermoplastic polyester resin prepared by graft-polymerization of a) 20-80 weight % of multilayered rubber latex in which the ratio of particle diameter (Pb/Pa) of an inner layer (Pa) to outer layer is 1.05-1.5, and glass transition temperature of the inner layer or the outer layer is up to −30° C.; and b) 20-80 weight % of vinyl monomer. According to the present invention, a thermoplastic polyester resin composition having excellent transparency and improved impact strength can be provided by containing an impact strength modifier for thermoplastic polyester resin having multilayered structure in which content of rubber latex, glass transition temperature, particle diameter and refraction index are regulated.