Silicone-Acrylic Impact Modifier Multi-Layer Structure
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Solution Overview
Problem
Thermoplastic resin compositions with conventional silicone-acrylic impact modifiers suffer from poor pigment-colorability, limiting their industrial applications despite having satisfactory low-temperature impact strength and weather resistance.
Innovation Solution
A silicone-acrylic impact modifier with a multi-layer structure is developed, comprising a silicone rubber seed, an acrylic rubber core, and a shell of vinyl copolymers with high glass transition temperature, which enhances impact resistance, chemical resistance, and colorability by regulating the particle size and composition of the seed, core, and shell through specific polymerization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicone rubber component is used in impact modifier, then impact resistance is improved, but pigment-colorability deteriorates
Solution Approach 1:
The impact modifier is divided into multiple functional layers: a silicone rubber seed layer (providing impact resistance), an acrylic rubber core layer (improving colorability), and a vinyl copolymer shell layer (enhancing dispersion). This segmentation allows each layer to perform its specific function without interfering with others, resolving the contradiction between impact resistance and colorability
Solution Approach 2:
The patent employs a nested structure where the silicone rubber seed is embedded within the acrylic rubber core, which is in turn surrounded by the vinyl copolymer shell. This nested configuration enables the inner silicone rubber layer to provide impact resistance while the outer layers facilitate pigment absorption and dispersion, simultaneously achieving both improved impact resistance and colorability
2Strength
If silicone-acrylic impact modifier is added to thermoplastic resin, then low-temperature impact strength is improved, but colorability deteriorates
Solution Approach 1:
Different regions of the impact modifier particle are assigned different properties: the silicone rubber seed region provides low-temperature impact strength, while the acrylic rubber core and vinyl copolymer shell regions provide colorability. This local differentiation of properties allows the material to simultaneously achieve both low-temperature impact strength and good colorability
3Ease of manufacture
If conventional impact modifier is used, then manufacturing process is simple, but weather resistance and chemical resistance are insufficient
Solution Approach 1:
The patent creates a composite impact modifier combining silicone rubber, acrylic rubber, and vinyl copolymers in a multi-layer structure. This composite material integrates the advantages of each component: silicone rubber provides weather and chemical resistance, acrylic rubber improves colorability, and vinyl copolymers enhance dispersion. The composite structure achieves superior overall performance while maintaining reasonable manufacturing complexity
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 multi-layer structure silicone-acrylic impact modifier significantly improves the colorability and impact resistance of thermoplastic resins like polycarbonate and PC/PBT alloy resins, maintaining excellent chemical resistance while allowing for proper molding and forming.
Implementation Method 1
grafting aromatic monomer, cyan monomer or alkyl(metha)acrylate monomer onto the above produced polymer
Implementation Method 2
a silicone impact modifier has been developed, which seems to have improved impact resistance resulted from the very low glass transition temperature of −120° C.
Implementation Method 3
dispersibility of the resin is improved, resulting in the enhancement of weather resistance and impact resistance
Data Source
AI summary
The present invention relates to a silicone-acrylic impact modifier having multi-layer structure and a thermoplastic resin composition containing the same, more precisely a silicone-acrylic impact modifier which is composed of i) silicone rubber seed containing one or more vinyl copolymers; ii) acrylic rubber core covering the seed; and iii) a shell containing one or more vinyl copolymers covering the acrylic rubber core, and a thermoplastic resin composition containing the same. The thermoplastic resin having the silicone-acrylic impact modifier of the present invention has improved impact resistance and colorability.