Agglomerated ABS Copolymers for Impact Strength and Gloss
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Solution Overview
Problem
Current ABS polymers produced with rubber latices of small particle sizes exhibit low toughness and inadequate mechanical and optical properties, such as Charpy impact strength and surface gloss, which can be improved by using larger rubber particles in graft polymerization.
Innovation Solution
A process involving the agglomeration of graft copolymers with a bimodal particle size distribution is developed, where an agglomerated graft base is formed by polymerizing ethylenically unsaturated monomers and then reacted with an agglomerating copolymer to create a graft shell, using ethyl acrylate and methacrylamide, resulting in a copolymer with improved physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rubber latices with small particle sizes are used in graft polymerization, then the production process is simpler, but the toughness and mechanical properties of the ABS polymers are poor
Solution Approach 1:
The patent applies segmentation by creating a bimodal particle size distribution with two distinct populations: primary particles (0.05-0.6 μm) and secondary agglomerated particles (0.5-5.0 μm). This segmentation allows the system to maintain simple processing of small particles while incorporating large particles to improve toughness and mechanical properties of the final ABS polymer
Solution Approach 2:
The patent employs the nested doll principle by forming secondary particles that consist of multiple primary particles agglomerated together. The small primary particles are nested within larger secondary particle structures, creating a hierarchical organization that combines the advantages of both small and large particle sizes in the final product
2Strength
If rubber latices with larger particle sizes are used in graft polymerization, then the toughness and mechanical properties are improved, but the particle size distribution becomes broader and harder to control
Solution Approach 1:
The patent segments the particle size distribution into two controlled populations: primary particles with narrow size distribution (0.05-0.6 μm) and secondary agglomerated particles with controlled larger size (0.5-5.0 μm). This segmentation enables precise control over the overall particle size distribution while maintaining the toughness benefits of larger particles
Solution Approach 2:
The patent applies parameter changes by controlling the agglomeration process parameters to achieve a specific bimodal distribution. By adjusting agglomeration conditions, the patent optimizes the ratio and size of primary versus secondary particles, thereby controlling the overall particle size distribution while improving mechanical properties
3Length of stationary object
If conventional agglomeration methods are used, then particle enlargement is achieved, but the non-uniformity of particle size distribution increases
Solution Approach 1:
The patent segments the agglomeration process into controlled stages, creating distinct primary and secondary particle populations with各自 controlled size ranges. This segmentation prevents uncontrolled agglomeration and maintains narrow size distributions within each population, reducing overall non-uniformity
Solution Approach 2:
The patent applies parameter changes by optimizing agglomeration conditions to achieve controlled particle enlargement. By carefully controlling agglomeration parameters, the patent enlarges particles to the desired size range (0.5-5.0 μm for secondary particles) while maintaining low non-uniformity (U ≤ 0.7) within the agglomerated fraction
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 process enhances the mechanical properties like Charpy impact strength and optical properties like surface gloss of the resulting thermoplastic molding compounds, achieving higher agglomeration yield and improved particle size distribution.
Implementation Method 1
the particles of a rubber produced in emulsion or brought into emulsion after its production can be enlarged (agglomeration) by adding a second suitable rubber dispersion
Implementation Method 2
ABS polymers made using such rubbers generally exhibit low toughness. It is known that acrylonitrile-butadiene-styrene copolymers with more favorable properties can be obtained if rubber latices with larger particles are used in graft polymerization to produce the ABS polymers
Data Source
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AI summary
The invention relates to graft copolymers (B) composed of an agglomerated graft core (B1) and at least one graft shell (B2), as well as to copolymers (C) having an agglomerating effect, a method for producing said graft copolymers (B), thermoplastic molding compounds, and the use of the thermoplastic molding compounds.