Polyester-Graft-Poly(Meth)acrylate Copolymers Without Styrene
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Solution Overview
Problem
Existing methods for synthesizing polyester-graft-poly(meth)acrylate copolymers often result in ungelled products, but they require the use of styrene or styrene-like derivatives, which can lead to crosslinking and poor processability, and are not suitable for applications where residual aromatic monomers are undesirable.
Innovation Solution
A free radical polymerization process that forms graft copolymers without the need for styrene or styrene derivatives by using itaconic acid as a monomer in the polyester, allowing for the targeted activation of itaconate repeat units to form reactive centers for radical polymerization of acrylates or methacrylates, thereby producing compatible polyester-graft-poly(meth)acrylate copolymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If styrene or styrene-like derivatives are used to enable radical polymerization of (meth)acrylates onto polyester olefinic groups, then grafting can be carried out successfully, but crosslinking reactions occur leading to gelled products with poor processability
Solution Approach 1:
The invention extracts and removes styrene or styrene-like derivatives from the polymerization system, replacing them with itaconate repeat units that are already incorporated into the polyester backbone. This eliminates the harmful crosslinking reactions associated with styrene while maintaining the ability to achieve successful grafting of (meth)acrylates onto the polyester chains.
Solution Approach 2:
The invention changes the chemical parameter of the polyester by incorporating itaconate repeat units with specific double bond characteristics that are suitable for radical polymerization. By controlling the itaconate content within specific ranges (0.1-20 mol%, preferably 1-10 mol%), the invention optimizes the balance between grafting efficiency and prevention of excessive crosslinking, thereby avoiding gelled products.
2Productivity
If itaconate content in polyester is increased to provide more reactive sites for grafting, then proportion of graft copolymers increases, but crosslinking reactions occur leading to gelled products
Solution Approach 1:
The invention optimizes the itaconate content parameter within specific ranges (0.1-20 mol%, preferably 1-10 mol%) to achieve the desired balance. This controlled parameter change ensures sufficient reactive sites for high graft copolymer production while preventing excessive crosslinking that would lead to gelled products, thereby resolving the contradiction between productivity and harmful crosslinking.
Solution Approach 2:
The invention implements a feedback mechanism by carefully controlling the itaconate content based on its dual role: providing reactive sites for grafting (desired effect) and potentially causing crosslinking (undesired effect). By monitoring and adjusting the itaconate content within optimal ranges, the process achieves high graft copolymer yield while preventing gelation through negative feedback control of the crosslinking tendency.
3Object-generated harmful factors
If itaconate content in polyester is decreased to reduce crosslinking, then proportion of graft copolymers formed is too low
Solution Approach 1:
The invention establishes optimal parameter ranges for itaconate content (0.1-20 mol%, preferably 1-10 mol%) that simultaneously satisfy two opposing requirements: minimizing crosslinking reactions and maximizing graft copolymer formation. This optimized parameter setting ensures sufficient reactive sites for high productivity while keeping crosslinking at acceptable levels.
4Ease of manufacture
If styrene is copolymerized to enable grafting onto maleic acid or fumaric acid repeat units, then grafting can proceed, but residual aromatic monomers are present which are undesirable for food contact applications
Solution Approach 1:
The invention extracts and eliminates styrene from the polymerization system, replacing it with itaconate-based reactive sites. This removal of styrene eliminates the source of residual aromatic monomers that are harmful for food contact applications, while maintaining the essential grafting capability through the itaconate double bonds that can undergo radical polymerization with (meth)acrylates.
Solution Approach 2:
The invention replaces the problematic styrene intermediate with a built-in polyester component (itaconate repeat units) that serves the same functional purpose but without the harmful residual monomer issue. The itaconate units are permanently incorporated into the polyester backbone and do not leave residual aromatic monomers, effectively substituting a harmful temporary component with a safe permanent one.
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
This method enables the production of ungelled, compatible polyester-graft-poly(meth)acrylate copolymers that serve as excellent compatibilizers, improving material properties for applications such as coating formulations and heat sealing lacquers, while avoiding the drawbacks of styrene-based synthesis.
Implementation Method 1
The novelty of the present invention lies in the targeted activation of itaconate repeat units in polyesters to form multifunctional initiators for the radical polymerization of acrylates, methacrylates or mixtures thereof
Data Source
AI summary
The present invention relates to a novel synthesis of (meth)acrylate-grafted polyesters and their action as compatibilizers.