Vinyl Acetate Copolymer Dispersion for Paper Coating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current copolymers used in paper coating slips lack optimal performance characteristics, particularly in terms of binding force, dry pick resistance, and wet pick resistance, which are essential for achieving good surface strength in coated papers.
Innovation Solution
A process for preparing an aqueous dispersion of a polymer comprising vinyl acetate, at least one acrylate monomer, an α,β-ethylenically unsaturated C3-C6 carboxylic acid, glycidyl methacrylate or glycidyl acrylate, and ethylenically unsaturated sulfonic acid, with specific weight ratios, emulsified and polymerized in the presence of a free-radical initiator, to create a binder with improved surface strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If copolymers based on vinylaromatic monomers (e.g., styrene) are used as binders, then binding force is improved, but dry pick resistance and wet pick resistance deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the copolymer by using vinyl acetate as the main monomer instead of vinylaromatic monomers, and by incorporating specific comonomers (carboxylic acid, sulfonic acid, and glycidyl ester) in controlled amounts to achieve the desired balance of binding force and surface strength
Solution Approach 2:
The patent creates a composite copolymer system combining vinyl acetate with multiple functional comonomers (carboxylic acid for binding, sulfonic acid for surface properties, and glycidyl ester for crosslinking) to achieve synergistic effects that simultaneously provide binding force and surface strength
2Reliability
If copolymers with high vinyl acetate content are used, then surface strength is improved, but binding force deteriorates
Solution Approach 1:
The patent optimizes the compositional parameters by maintaining vinyl acetate as the main monomer (70-90 wt.%) for surface strength while precisely controlling the content of binding-functional comonomers (carboxylic acid 1-20 wt.%, sulfonic acid 1-10 wt.%, glycidyl ester 1-10 wt.%) to ensure adequate binding force
Solution Approach 2:
The patent designs a multi-component copolymer system where vinyl acetate provides the matrix for surface strength, carboxylic acid groups provide binding sites, sulfonic acid groups enhance surface properties, and glycidyl ester groups enable crosslinking to reinforce both binding and surface strength
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 resulting polymer dispersion enhances the surface strength of coated papers by achieving a favorable balance of dry pick resistance, wet pick resistance, and offset test results, making the coated papers suitable for various printing processes.
Implementation Method 1
emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers
Data Source
AI summary
The invention relates to a process for preparing an aqueous dispersion of a polymer P, which comprises the emulsion polymerization of vinyl acetate, an acrylate monomer, which is a C1-C10 alkyl acrylate or a C1-C10 methacrylate, an α,β-ethlyenically unsaturated C3-C8 carboxylic acid, glycidyl methacrylate or glycidyl acrylate, optionally an ethylenically unsaturated sulfonic acid and optionally an ethylenically unsaturated other monomer. Furthermore, the aqueous polymer dispersion obtainable from this process and a powder form thereof are disclosed. They are useful for a paper coating slip containing one of the aforementioned forms. A paper or a cardboard, which is coated with the paper coating slip, shows surface strength, which is expressed by a good dry pick resistance, a good wet pick resistance or good offset test results. The aqueous polymer dispersion or the powder form thereof is furthermore useful as a binder.