Poly(1,4-dioxanone) Molding Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing molding processes for poly(dioxanone) result in medical devices with mediocre mechanical properties that deteriorate over time, becoming brittle and friable within a month, making them unsuitable for long-term use as bioresorbable implants.
Innovation Solution
A process involving heating poly(1,4-dioxanone) to a bulk temperature of 145°C to 165°C, followed by injection molding into a cooler mold, and controlled cooling to achieve high crystallinity and maintain mechanical integrity, with specific temperature ranges and durations optimizing the rigidity or flexibility of the final product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polydioxanone is molded at low temperature (close to melting point) as recommended in prior art, then mechanical properties are satisfactory at demoulding, but the properties deteriorate over time and the material becomes brittle and friable
Solution Approach 1:
The patent applies parameter changes by raising the molding temperature from the conventional range (110-140°C) to a higher range (145-165°C). This temperature parameter change fundamentally alters the crystallization behavior of polydioxanone, producing a crystalline structure that maintains mechanical strength over extended storage periods, thereby resolving the contradiction between initial mechanical properties and long-term durability
Solution Approach 2:
The patent inverts the conventional molding approach by using high temperature molding instead of low temperature molding. While prior art recommended molding close to the melting point to ensure mechanical strength, this patent demonstrates that molding at temperatures significantly higher than previously used (145-165°C vs. 110-140°C) produces superior long-term mechanical stability, effectively applying the 'other way round' principle
2Reliability
If polydioxanone is molded at high temperature (145-165°C) as disclosed in the invention, then mechanical properties are maintained over time, but energy consumption increases
Solution Approach 1:
The patent maintains continuous heating at high temperature (145-165°C) throughout the molding process to ensure complete melting and proper crystallization. This continuous energy input at elevated temperature creates a stable crystalline structure that ensures long-term mechanical reliability, accepting increased energy consumption as necessary for achieving dependable medical implants
3Ease of manufacture
If polydioxanone is molded at conventional temperature ranges, then the process is energy-efficient, but the molded parts become brittle after one month of storage
Solution Approach 1:
The patent changes the temperature parameter from conventional ranges to 145-165°C, which fundamentally improves the reliability of molded parts for long-term storage. This parameter change ensures the material maintains its mechanical properties for several months, making it suitable for medical implant applications where reliability is critical
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 process produces bioresorbable medical devices with stable mechanical properties that retain their strength and flexibility for several months, allowing for extended storage and potential industrial-scale application without brittleness.
Implementation Method 1
heating a poly(1,4-dioxanone), in the absence of any solvent for this polymer, to a bulk temperature of between 145°C and 165°C
Implementation Method 2
cooling of the mold until solidification of the mass of poly(1,4-dioxanone)
Implementation Method 3
controlled cooling to achieve high crystallinity and maintain mechanical integrity
Data Source
AI summary
The invention relates to a method for moulding a bio-resorptive polymer for making a bio-resorptive medical device that comprises the following consecutive steps: (a) heating a poly(1,4-dioxanone) in the absence of any solvent in said polymer to a mass temperature of 145°C to 165°C; (b) injection-moulding the molten mass obtained in step (a) in a mould at a temperature that is lower than that of the poly(1,4-dioxanone) mass by 80°C to 115°C; (c) cooling down the mould until the solidification of the poly(1,4-dioxanone) mass; and (d) releasing the part thus obtained. The invention also relates to a moulded part that can be obtained by said method, and to a medical device containing such a part.