Polyolefin-Grafted Polyacrylate Copolymers for Solvent-Free Coatings
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Solution Overview
Problem
Existing methods for incorporating hydrophobic polyolefin components into acrylic polymers and coatings are limited in enhancing hydrophobicity and crosslink stability, as they either reduce crosslink density or fail to mix well with polyacrylics, and struggle with dispersing olefin monomers in emulsion polymerization.
Innovation Solution
The development of a copolymer comprising polyolefin-grafted-polyacrylate structures formed by combining vinyl-terminated or vinylidene-terminated polyolefins with aryl acrylate monomers through alkylation, creating a comb structure that enhances processability and hydrophobicity in solvent-free coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If C18-C22 fatty acid derivatives are used as di-acid chain extenders to enhance hydrophobicity, then hydrophobicity is improved slightly, but crosslink density is reduced
Solution Approach 1:
The patent creates a composite structure by grafting polyolefin chains onto the polyacrylate backbone, forming polyolefin-graft-polyacrylate copolymers. This composite approach allows simultaneous achievement of hydrophobicity (from polyolefin side chains) and crosslink density (from polyacrylate backbone with hydroxyl groups), resolving the contradiction between these two properties.
Solution Approach 2:
The patent segments the polymer structure into distinct functional domains: hydrophobic polyolefin side chains for water resistance and hydrophilic polyacrylate backbone for crosslinking. This segmentation allows each component to fulfill its specific function without compromising the other, enabling both high hydrophobicity and maintained crosslink density.
2Object-affected harmful factors
If polyolefin latex is incorporated into acrylic coating formulation to enhance hydrophobicity, then hydrophobicity is improved, but blendability with polyacrylics deteriorates and surfactant coalescence is affected
Solution Approach 1:
The patent merges polyolefin and polyacrylate into a single copolymer molecule through grafting, where polyolefin chains are attached to the polyacrylate backbone. This molecular-level merging ensures perfect compatibility and blendability while maintaining the hydrophobic properties of polyolefin, eliminating the phase separation and surfactant issues associated with physical blending of separate latexes.
Solution Approach 2:
The graft copolymer structure creates an intrinsic composite material where hydrophobic polyolefin segments and hydrophilic polyacrylate segments are covalently bonded, ensuring uniform distribution and compatibility throughout the coating formulation without requiring external surfactants.
3Object-affected harmful factors
If olefin monomers are dispersed in water for emulsion polymerization to incorporate hydrophobicity, then hydrophobicity is improved, but dispersibility and emulsification deteriorate
Solution Approach 1:
The patent uses aryl acrylate monomers as intermediaries that contain both hydrophobic character and polymerizable vinyl groups. These intermediaries act as bridges, allowing hydrophobic polyolefin chains to be incorporated into the polyacrylate backbone through alkylation reactions, thereby achieving hydrophobicity without the need to disperse immiscible olefin monomers in water.
Solution Approach 2:
The patent changes the chemical parameters of the monomer system by using aryl acrylates with pendant aromatic rings that can undergo alkylation. This parameter change allows the incorporation of hydrophobic polyolefin chains through chemical reaction rather than physical dispersion, solving the dispersibility problem while maintaining hydrophobicity.
4Stability of the object's composition
If controlled radical polymerization is used to copolymerize olefin monomers with acrylics, then copolymerization is achieved, but radical lifetime limitations prevent polymerization of linear alpha-olefins
Solution Approach 1:
The patent performs preliminary action by first synthesizing the polyacrylate backbone with pendant aromatic groups, then subsequently grafting polyolefin chains onto this pre-formed backbone through alkylation. This two-step approach bypasses the radical lifetime limitation by avoiding the need for simultaneous copolymerization of alpha-olefins with acrylic monomers.
Solution Approach 2:
The patent substitutes the radical polymerization mechanism with an alkylation reaction mechanism for incorporating polyolefin chains. This mechanism substitution eliminates the radical lifetime constraint by using a different chemical reaction pathway that does not depend on radical stability, enabling successful incorporation of linear alpha-olefin-derived polyolefin chains.
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 effectively increases the hydrophobicity and mechanical toughness of coatings while maintaining crosslink stability, allowing for the formation of water-based coatings substantially free of volatile solvents.
Implementation Method 1
combining the polymer backbone with a vinyl-terminated polyolefin or a vinylidene-terminated polyolefin, each having a number average molecular weight of at least 300 g/mole, under alkylation conditions to form the copolymer
Data Source
AI summary
A polyacrylate-polyolefin copolymer and composition for volatile solvent-free coating comprising such compounds having the following structure:wherein “PO” is a polyolefin having a number average molecular weight of at least 300 g/mole, and “Ar” is selected from the group consisting of C6 to C20 aryls, a C7 to C32 alkylaryls, a C6 to C20 aryloxys, and halogen substituted C6 to C20 aryls and C7 to C32 alkylaryls, while the other variables are as described herein. The copolymers can be produced in an alkylation reaction between the desired polyacrylate and a vinyl/vinylidene-terminated polyolefin.