PVA-Stabilized Emulsion for Water-Resistant Adhesive Films
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Solution Overview
Problem
Existing aqueous synthetic resin emulsions face challenges with long-term stability, particularly when used as adhesives for wood parts, requiring improved water resistance, warm-water resistance, boiling resistance, and durability, which current technologies do not adequately address.
Innovation Solution
An aqueous synthetic resin emulsion stabilized with a PVA-based resin containing a 1,2-diol bond in its side chain, using a styrene-based monomer with low water solubility, and incorporating specific functional monomers to enhance film properties, along with a re-emulsifiable powder form for improved handling and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PVA is used as a protective colloid to improve mechanical stability and freezing stability, then mechanical stability and freezing stability are improved, but polymerization stability becomes insufficient and long-term stability decreases
Solution Approach 1:
The patent modifies the PVA structure by introducing specific functional groups (carboxyl groups from itaconic acid grafting) and controlling the degree of substitution to achieve both mechanical stability and polymerization stability simultaneously. This parameter change transforms the protective colloid's properties to resolve the contradiction.
Solution Approach 2:
The patent creates a composite protective colloid system by grafting itaconic acid onto PVA backbone, forming a composite structure that combines the mechanical stability of PVA with the polymerization stability provided by the grafted itaconic acid groups.
2Productivity
If the nonvolatile content of emulsion is increased to above 50% by weight to improve productivity, then productivity is improved, but polymerization stability becomes insufficient and long-term stability decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the protective colloid by incorporating itaconic acid grafts with specific carboxyl group content, enabling the emulsion to achieve high nonvolatile content (above 50%) while maintaining polymerization stability and long-term stability.
3Device complexity
If conventional PVA-based resins are used to simplify the formulation, then formulation complexity is reduced, but water resistance, warm-water resistance, and boiling resistance become insufficient
Solution Approach 1:
The patent develops a composite protective colloid by grafting itaconic acid onto PVA, creating a material with enhanced water resistance, warm-water resistance, and boiling resistance while maintaining relative formulation simplicity through a single modified polymer component.
Solution Approach 2:
The patent introduces specific functional groups (carboxyl groups from itaconic acid) at specific locations on the polymer chain to provide localized water resistance and thermal stability properties where needed, while the rest of the PVA backbone maintains mechanical stability.
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 solution provides a film with excellent water resistance, warm-water resistance, boiling resistance, toughness, and long-term durability, making it suitable for various applications including adhesives for wood parts and hydraulic materials.
Implementation Method 1
a PVA-based resin (a) having a 1,2-diol bond in a side chain thereof is used as a protective colloid
Implementation Method 2
the synthetic resin has a glass transition temperature of from -20 to +30°C, which enables proper film formation and adhesion properties
Data Source
AI summary
Provided are an aqueous synthetic resin emulsion, a re-emulsifiable emulsion powder, and an aqueous synthetic resin emulsion obtained by re-emulsifying the re-emulsifiable emulsion powder, the emulsions and the powder being capable of forming a film excellent in water resistance, warm-water resistance, boiling resistance, toughness, and durability. Also provided is an adhesive composition. They are an aqueous synthetic resin emulsion containing a synthetic resin dispersed and stabilized with a polyvinyl alcohol-based resin (a) having a 1,2-diol bond in a side chain thereof, wherein the synthetic resin comprises, as a polymerizable monomer which constitutes the synthetic resin, a hydrophobic monomer having a solubility in water at 20°C of 0.1% or less in an amount of 30% by weight or more based on all polymerizable monomers, the hydrophobic monomers comprising a styrene-based monomer; a re-emulsifiable emulsion powder; and an aqueous synthetic resin emulsion obtained by re-emulsifying the re-emulsifiable emulsion powder.