Dimer Acid Monomers with Ring-Opening Groups for Low Shrinkage
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Solution Overview
Problem
Dental materials face issues with polymerization shrinkage, leading to shrinkage stresses, marginal gaps, reduced substrate adhesion, and impaired dimensional stability, which conventional monomers like Bis-GMA and UDMA cannot adequately address due to high viscosity and reactivity limitations.
Innovation Solution
Development of radically polymerizable monomers with ring-opening polymerizable groups derived from hydrogenated dimer acids, which exhibit low polymerization shrinkage and maintain mechanical properties and reactivity comparable to methacrylates, formulated as monomers of specific structural configurations to enhance dental material performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional monomers like Bis-GMA and UDMA are used to reduce polymerization shrinkage, then shrinkage stresses and dimensional stability are improved, but viscosity becomes excessively high
Solution Approach 1:
The patent changes the molecular structure parameters of the monomer by introducing ring-opening polymerizable groups (cyclic carbonate, cyclic carboxylate, or cyclic silicate groups) into the monomer molecule. This structural modification enables low shrinkage polymerization while maintaining acceptable viscosity levels, resolving the contradiction between shrinkage control and ease of operation.
2Manufacturing precision
If cyclic monomers are used to reduce polymerization shrinkage, then shrinkage stresses are reduced, but reactivity is considerably reduced
Solution Approach 1:
The patent creates a composite functional group within the monomer molecule, combining ring-opening polymerizable groups (providing low shrinkage) with vinyl or (meth)acrylate groups (providing high reactivity). This composite structure allows the monomer to simultaneously achieve low polymerization shrinkage and high reactivity, resolving the contradiction between manufacturing precision and productivity.
3Manufacturing precision
If dimer acid derivatives are used to achieve low shrinkage, then polymerization shrinkage is reduced, but mechanical properties and reactivity become insufficient
Solution Approach 1:
The patent applies local quality modification by introducing specific functional groups (vinyl or (meth)acrylate groups) at particular positions within the monomer structure. These localized reactive groups provide high reactivity and good mechanical properties, while the overall monomer structure maintains low polymerization shrinkage, thus resolving the contradiction between manufacturing precision and 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 monomers achieve extremely low polymerization shrinkage and provide dental materials with excellent mechanical properties and high reactivity, suitable for radical photopolymerization, effectively addressing the limitations of conventional dental materials.
Implementation Method 1
radically polymerizable monomers with ring-opening polymerizable groups derived from hydrogenated dimer acids, which exhibit low polymerization shrinkage
Data Source
AI summary
The invention relates to a radically polymerizable monomer of formula (I)whereinW1 and W2 in each case independently represent H or X—R—Y—PG, wherein at least one of W1 and W2 represents X—R—Y—PG,X in each case independently is missing or represents an ether, ester, amide, urethane or urea group,Y in each case independently is missing or represents an ether, ester, amide, urethane or urea group,R in each case independently is missing or represents a C1-C16 alkylene radical which can be interrupted by one or more O atoms, wherein R can be missing only if X and/or Y is simultaneously also missing, andPG in each case independently represents a cyclic, ring-opening polymerizable group,a, b, c and d independently of each other can take the values 3 to 10.The invention also relates to polymerizable compositions which comprise the monomers according to the invention, as well as their use as dental materials and for the preparation of dental materials, in particular composites, cements, adhesives or coatings.