Crosslinked Polymer Production via Radical Polymerization
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Solution Overview
Problem
Existing methods for producing crosslinked polymers via radical polymerization face challenges in achieving high solid content without gelation, leading to inefficient production and increased costs, particularly in solution polymerization, and result in resins with insufficient weatherability and molecular weight for coating applications.
Innovation Solution
A method involving radical polymerization of a monomer composition comprising 2-30% polyfunctional methacrylate with 2-4 functional groups and 70-98% monofunctional monomers in an organic solvent, with a radical polymerization initiator having a half-life of 4-18 minutes, allowing for continuous addition and achieving a crosslinked polymer with a weight average molecular weight of 15000-200000 and a solid content of 45% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solution polymerization is used to prepare crosslinked polymer, then the polymer can be obtained in solution form, but the solid content cannot be increased due to gelation occurrence
Solution Approach 1:
The monomer composition is segmented into multiple components (polyfunctional methacrylate, monofunctional monomers, organic solvent) with controlled ratios. The polyfunctional monomer content is limited to 2-30% by weight to prevent excessive crosslinking that would cause gelation, while still achieving high solid content crosslinked polymer solution (45% or more).
Solution Approach 2:
The invention changes key parameters including: (1) controlling the half-life of radical polymerization initiator to 4-18 minutes at reaction temperature, (2) limiting polyfunctional monomer content to 2-30% by weight, (3) maintaining monofunctional monomer content at 70-98% by weight, and (4) controlling solid content to 45% or more. These parameter changes enable high solid content without gelation.
2Quantity of substance
If pulse addition method is used to increase solid content, then higher solid content can be achieved, but production efficiency decreases due to intermittent addition process
Solution Approach 1:
The invention enables continuous addition of monomer composition during polymerization by optimizing the formulation parameters. The controlled composition (polyfunctional monomer 2-30%, monofunctional monomer 70-98%, organic solvent) allows the reaction to proceed continuously without the need for intermittent stopping and starting required by pulse addition methods, thereby maintaining high production efficiency while achieving high solid content.
3Productivity
If reaction is conducted at high temperature to increase polymerization rate, then productivity improves, but molecular weight decreases due to short initiator half-life
Solution Approach 1:
The invention optimizes the initiator half-life parameter to 4-18 minutes at the reaction temperature. This specific range allows the reaction to proceed at high temperature (improving polymerization rate and productivity) while the initiator remains active long enough to build sufficient molecular weight (15000-200000). The monomer composition parameters are also optimized to support this balance.
4Reliability
If resin with high molecular weight is obtained, then weatherability improves, but production becomes difficult within short initiator half-life temperature region
Solution Approach 1:
The invention changes multiple parameters simultaneously: (1) initiator half-life controlled at 4-18 minutes, (2) polyfunctional monomer at 2-30%, (3) monofunctional monomer at 70-98%, and (4) solid content at 45% or more. This coordinated parameter change enables the production of high molecular weight crosslinked polymer (15000-200000) within the short half-life temperature region, achieving both good weatherability and production feasibility.
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 approach enables the production of crosslinked polymers with high solid content and molecular weight, improving storage, handling, and application properties, such as adhesion, water resistance, and curability, while reducing production costs and environmental solvent usage.
Implementation Method 1
conducting polymerization of a monomer composition comprising 2 to 30% by weight of a polyfunctional methacrylate having 2 to 4 functional groups (a) and 98 to 70% by weight of one or more polymerizable monomers selected from the group consisting of monofunctional (meth)acrylates, (meth)acrylic acid, and monofunctional vinyl aromatic compounds (b) in an organic solvent in the presence of a radical polymerization initiator
Data Source
AI summary
The object of the present disclosure is to provide a method for producing a crosslinked polymer by radical polymerization of a monomer composition, by which method a desired crosslinked polymer can be produced in a high solid content with good productivity (also at a low production cost), and a crosslinked polymer obtained by the production method and a coating composition containing the same.A method for producing a crosslinked polymer having a weight average molecular weight of 15000 to 200000, the method comprising step [I] of obtaining a crosslinked polymer (A) by conducting polymerization of a monomer composition comprising 2 to 30% by weight of a polyfunctional methacrylate having 2 to 4 functional groups (a) and 98 to 70% by weight of one or more polymerizable monomers selected from the group consisting of monofunctional (meth)acrylates, (meth)acrylic acid, and monofunctional vinyl aromatic compounds (b) in an organic solvent in the presence of a radical polymerization initiator in a temperature region where the radical polymerization initiator comes to have a half-life of 4 to 18 minutes.