Core-Shell Acrylic Processing Aid for Vinyl Chloride Resin
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Solution Overview
Problem
Vinyl chloride resin processing is hindered by narrow formable temperature range, high melting viscosity, low fluidity, and adhesion issues with metal surfaces, leading to surface defects like air marks, flow marks, and fish eyes during processing, while existing additives either fail to address adhesion or compromise transparency.
Innovation Solution
A core-shell structured acrylic processing aid is developed, comprising an acrylic-silicone block copolymer with a silicone-azo macroinitiator and C12 to C18 alkyl methacrylate monomers, which enhances adhesion resistance and heat stability while maintaining transparency by controlling specific viscosity and monomer ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a processing aid and lubricant are added in large quantities to reduce adhesion with metals and resolve surface defects, then adhesion resistance and surface quality improve, but transparency decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the processing aid by incorporating specific functional groups (silane, epoxy, isocyanate) in controlled ratios. This allows achieving adequate adhesion resistance with smaller additive quantities, thereby maintaining transparency. The precise parameter control of functional group content resolves the contradiction between adhesion resistance and transparency.
Solution Approach 2:
The patent creates a composite processing aid system combining multiple functional components (silane-modified polymers, epoxy compounds, isocyanate-containing additives) working synergistically. This composite approach provides enhanced adhesion resistance through multiple mechanisms while requiring lower overall additive concentrations, thus preserving the transparency of the vinyl chloride resin product.
2Reliability
If existing additives are used to address adhesion issues, then adhesion resistance improves, but surface defects like air marks and flow marks occur
Solution Approach 1:
The patent modifies the molecular structure parameters of the processing aid by introducing specific functional groups (silane, epoxy, isocyanate) that provide balanced adhesion and release properties. This prevents both excessive adhesion (causing carbide formation) and insufficient adhesion (causing surface defects), thereby resolving the contradiction between adhesion resistance and surface quality.
Solution Approach 2:
The patent introduces functional group-containing compounds as intermediary substances between the vinyl chloride resin and metal processing surfaces. These intermediaries provide controlled interaction - sufficient adhesion during processing to prevent surface defects, but adequate release afterward to prevent carbide formation. The intermediary role of these functional additives resolves the contradiction between adhesion resistance and surface quality.
Data Source
AI summary
The present disclosure relates to an acrylic processing aid and a vinyl chloride resin composition including the same, and in particular, to a core-shell-structured acrylic processing aid preparing a core using a silicone-azo macroinitiator and preparing a shell using C12 to C18 alkyl methacrylate as a co-monomer, and a vinyl chloride resin composition including the same.The acrylic processing aid is used for sheet forming of the vinyl chloride resin, and facilitates manufacture of a high-quality vinyl chloride resin formed article having excellent transparency, adhesion resistance and heat stability, having no non-dispersed melt (fish-eye) production, and having significantly reduced air mark and flow mark occurrences.