Modified Colloidal Silica Adhesive Composition
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Solution Overview
Problem
Existing adhesive compositions based on latexes, such as polyvinyl acetate, face challenges in achieving strong, stable, and water-resistant properties while maintaining storage stability and shelf-life, with current methods of incorporating nanocomposite particles showing limitations in improving these characteristics.
Innovation Solution
A method involving the use of modified colloidal silica particles with surface-bound hydrophilic organosilane moieties or additional elements that can adopt a +3 or +4 oxidation state, integrated into the polymerization process of aqueous polymeric dispersions, where the colloidal silica chemically interacts with the protective colloid, enhancing the adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic nanocomposite particles are added to latex adhesive formulations, then adhesive strength and water resistance are improved, but storage stability and shelf-life are compromised
Solution Approach 1:
The patent employs surface-modified inorganic nanoparticles with hydrophilic organosilane coatings as intermediaries between the hydrophobic inorganic core and the aqueous latex phase. This modification prevents direct interaction between unmodified silica surfaces and the latex polymer, eliminating aggregation and stabilisation issues while maintaining the adhesive-enhancing properties of the inorganic particles
Solution Approach 2:
The patent systematically varies parameters including nanoparticle size (5-100 nm), surface modification chemistry (different organosilane groups), and concentration (0.1-5 wt%) to optimise the balance between adhesive performance and storage stability. By controlling these parameters, the formulation achieves both improved adhesive strength and extended shelf-life
2Strength
If modified colloidal silica is incorporated during polymerisation, then inter-polymer particle bonding is enhanced, but formulation complexity increases
Solution Approach 1:
The patent combines the nanoparticle modification step with the polymerisation process itself, incorporating surface-modified inorganic particles into the latex formulation during monomer polymerisation. This merging of steps allows the nanoparticles to become integrated into the polymer matrix structure, enhancing inter-particle bonding while avoiding separate, complex formulation steps
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 approach results in improved adhesive strength, both dry and wet, and extended shelf-life, with the modified colloidal silica particles contributing to better inter-polymer particle bonding and stability, outperforming unmodified silica compositions in terms of durability and storage stability.
Implementation Method 1
polymerisation of the one or more monomers occurs to form a polymeric dispersion
Implementation Method 2
at least a portion of the colloidal silica particles chemically interact with the protective colloid
Implementation Method 3
the modified colloidal silica comprises colloidal silica particles with at least one surface-bound hydrophilic organosilane moiety
Data Source
AI summary
The disclosure is directed to a method for preparing an adhesive composition, in which an aqueous phase comprising a modified colloidal silica is mixed with an organic phase comprising one or more monomers in the presence of an initiator, wherein conditions are maintained such that polymerisation of the one or more monomers occurs to form an aqueous polymeric dispersion, wherein;(i) the aqueous polymeric dispersion comprises polymer particles with protective colloid on their surface;(ii) the modified colloidal silica comprises colloidal silica particles with at least one surface-bound hydrophilic organosilane moiety and/or comprises colloidal silica particles with at least one additional element on its surface, the element being able formally to adopt a +3 or +4 oxidation state; and(iii) the initiator is at least partially soluble in water.