Two-Part Acrylic Bone Cement Emulsion Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing hardenable two-part acrylic compositions with short dough times are inefficient due to the challenges of milling PMMA beads to achieve small particle sizes, which are time-consuming and prone to contamination, and result in batch-to-batch variability and high costs.
Innovation Solution
A hardenable two-part acrylic composition is developed with a storage-stable liquid first part and second part that react to form a cement, where the first part comprises emulsion polymerized acrylic polymer particles in a liquid carrier, allowing for direct storage and delivery as a liquid, reducing the need for powder handling and improving reproducibility and safety by using a double-chamber syringe system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If PMMA beads are milled to achieve small particle sizes for short dough time, then dough time is reduced, but manufacturing complexity and time increase due to milling requirements
Solution Approach 1:
The invention changes the particle size parameter of PMMA beads from conventional large sizes to specifically reduced particle sizes (mean diameter of 1-50 microns, preferably 5-20 microns). This parameter change enables short dough time (less than 2 minutes) without requiring complex milling processes, as the reduced particle sizes are achieved through controlled polymerization methods rather than mechanical milling.
Solution Approach 2:
The invention replaces the mechanical milling system with a chemical polymerization control system. Instead of using mechanical force to reduce particle size through milling, the invention uses controlled polymerization conditions (monomer-to-initiator ratio, polymerization time, temperature) to produce PMMA beads of reduced particle size directly, eliminating the need for complex mechanical milling equipment and procedures.
2Duration of action of moving object
If PMMA beads are milled to achieve small particle sizes, then dough time is reduced, but batch-to-batch variability increases
Solution Approach 1:
The invention implements feedback control in the polymerization process by monitoring and adjusting key parameters (monomer-to-initiator ratio, polymerization time, temperature) to ensure consistent production of PMMA beads with controlled particle sizes. This feedback mechanism ensures reproducible dough times across batches without the variability introduced by mechanical milling processes.
Solution Approach 2:
The invention establishes specific parameter ranges for polymerization (monomer-to-initiator ratio of 10:1 to 1:1, polymerization time of 1-24 hours, temperature of 50-100°C) that can be consistently replicated across batches. These controlled parameter changes ensure uniform bead particle sizes and reproducible dough times, eliminating batch-to-batch variability associated with milling processes.
3Duration of action of moving object
If PMMA beads are milled to achieve small particle sizes, then dough time is reduced, but production cost increases
Solution Approach 1:
The invention replaces expensive mechanical milling equipment and energy-intensive milling processes with a cost-effective chemical polymerization method. By controlling polymerization parameters (monomer-to-initiator ratio, time, temperature), the invention produces reduced particle size PMMA beads directly, eliminating capital expenditure on milling equipment and reducing operational costs while achieving the same dough time reduction.
Solution Approach 2:
The invention uses inexpensive, easily disposable polymerization reagents (monomers, initiators, catalysts) instead of expensive, complex milling equipment. The polymerization process uses small amounts of chemical agents that can be readily replaced, making the production method more economical and scalable compared to maintaining and operating complex mechanical milling systems.
4Stability of the object's composition
If powder components are used in two-part composition, then storage stability is improved, but handling safety and reproducibility worsen due to powder handling requirements
Solution Approach 1:
The invention transitions from powder-based composition to liquid-based composition where PMMA beads are suspended in a liquid carrier (water or monomer). This liquid formulation eliminates powder handling hazards while maintaining storage stability through controlled emulsion or suspension systems. The liquid carrier provides a stable medium that prevents bead aggregation and ensures consistent dosing and mixing, improving both safety and reproducibility.
Solution Approach 2:
The invention changes the physical state parameter of the polymer component from solid powder to liquid suspension or emulsion. By formulating PMMA beads as a liquid suspension in a carrier medium, the invention maintains storage stability while eliminating powder handling requirements. This parameter change enables safer, more reproducible handling and dosing, as liquids are easier to control and measure than powders.
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
This approach provides a stable composition with a short dough time, long working time, and reduced maximum exotherm temperature, enhancing the mechanical properties and storage stability of the final cement, while allowing for controlled release of active ingredients and improved handling characteristics.
Implementation Method 1
The solvated polymer particles release dibenzoyl peroxide initiator into the monomer which interacts with activator, if present, to produce radicals that react with the monomer and initiate room temperature addition polymerization of the monomer
Implementation Method 2
maximum exotherm temperature attained, as defined by BS ISO 5833:2002
Data Source
AI summary
A hardenable two part acrylic composition is described for the treatment of human or animal bone is described. The composition comprises a storage stable liquid first part and a storage stable liquid second part which react with each other upon mixing to form a cement which hardens. The composition further comprises an acrylic monomer component and an initiator component in an amount effective to polymerize the monomer component. The monomer component and the initiator component are generally located in separate parts of the two part composition so that the monomer component is storage stable. The liquid first part comprises emulsion polymerized acrylic polymer particles in a liquid carrier. A method of producing a hardenable two part acrylic composition is also described. The composition is particularly useful in a syringe or caulking gun having at least two barrels.