Mineral-filled acrylic resin system with functionally dampened crosslinking and polymerization-compatible calcium hydroxide system
A polymerizable binder system with thiol-containing compounds and polymerization-compatible calcium hydroxide addresses issues of phase separation and whitening in high-filler acrylic resin systems, ensuring homogeneous and reproducible curing.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-16
AI Technical Summary
Existing acrylic resin systems with high mineral filler content suffer from reaction-induced phase separation, microgel formation, and optical whitening due to direct introduction of crosslinkers and calcium hydroxide, leading to inhomogeneous curing and lack of reproducibility in continuous mixing and casting processes.
A complete system comprising a radically polymerizable binder, mineral fillers, an initiator system, and a combination of thiol-containing compounds and polymerization-compatible calcium hydroxide additive, which provides spatially and functionally dampened crosslinking and alkalinity to prevent local reaction disturbances.
Enables homogeneous, white-free curing with high process stability and reproducibility, preventing microgel formation and phase separation, and maintaining good mechanical properties despite high filler content.
Abstract
Description
1. Technical field
[0001] The invention relates to a mineral-filled, radically polymerizable acrylic resin system, in particular based on methyl methacrylate and / or poly(methyl methacrylate), for the production of molded parts. The system is particularly suitable for continuous mixing and casting processes in sanitary and kitchen applications. 2. State of the art
[0002] Well-known acrylic resin systems with a high mineral filler content use multifunctional (meth)acrylate crosslinkers to adjust mechanical properties. However, at elevated crosslinker concentrations, reaction-induced phase separation, microgel formation, and optical whitening frequently occur. Additionally, the use of basic additives, especially calcium hydroxide, disrupts radical polymerization.
[0003] In current technology, crosslinkers and calcium hydroxide are typically introduced directly or via fillers into continuous mixing systems. Due to limited dispersing capacity, local reactivity and pH hotspots develop, leading to inhomogeneous curing and a lack of reproducibility. 3. Object of the invention
[0004] The object of the invention is to provide an acrylic resin system that enables homogeneous, white-free and reproducible polymerization despite high filler content, especially under the boundary conditions of continuous mixing and casting processes. 4. Solution to the task
[0005] The task is solved by a complete system comprising a radically polymerizable binder system, mineral fillers, an initiator system, and a combination of: - at least one thiol-containing compound with functionally dampened crosslinking effect and - comprising a polymerization-compatible calcium hydroxide additive system.
[0006] Both the cross-linking effect and the alkaline effect occur in a spatially and functionally dampened form, thereby avoiding local reaction disturbances. 5. Key features of the overall system - (Meth)acrylate binder system - radical initiator system - mineral fillers ≥ 50 wt.% - thiol-containing compound with chain transfer and crosslinking effect - functionally dampened networking - polymerization-compatible calcium hydroxide system - Suitable for continuous mixing and casting processes 6. Advantages of the invention - homogeneous, white-free curing - Prevention of microgel formation and phase separation - high process stability and reproducibility - low dependence on mixing intensity and residence time - Good mechanical properties despite high filler content 7. Implementation Examples Example 1 - Complete system with functionally damped networking
[0007] A PMMA / MMA binder system is adjusted with mineral fillers to a total filler content of approximately 65 wt%. A multifunctional polythiol is used as the thiol-containing compound at a concentration of 0.6 wt%. The calcium hydroxide component is an additive system in which calcium hydroxide is rheologically immobilized in a polymerizable acrylate support phase, with an effective calcium hydroxide content of approximately 0.1 wt%. Example 2 - Continuous mixing and casting process
[0008] The complete system described in Example 1 is processed in a continuous twin-shaft mixer. The residence time in the mixer is less than 60 seconds. The mixture is then continuously poured into molds. Example 3 - Polymerization and result
[0009] Upon addition of a radical initiator, the system polymerizes completely. Homogeneous, optically uniform curing is observed without whitening, local gelation, or phase separation. The results are reproducible over multiple production runs.