Microstructured Composite Particles for Medical Laser Sintering

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Solution Overview

Problem

Conventional polymers, particularly thermoplastics and resorbable polymers like polyamides and polyesters, face challenges in achieving optimal mechanical properties, medical application suitability, and homogeneous dispersion of calcium salts, especially in reducing particle sizes for medical applications like laser sintering, while also requiring easy processing and visibility for treatment progress monitoring.

Innovation Solution

Microstructured composite particles are created by combining large polymer particles with small calcium salt particles, such as precipitated calcium carbonate, where the small particles are arranged on the surface or inhomogeneously within the large particles, enhancing mechanical properties and pH stabilization, and allowing for easy processing and visibility under X-rays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional polymers are used with standard particle sizes, then processing is straightforward, but mechanical properties and medical application suitability are insufficient

Engineering Contradiction:
Improvemechanical propertiesVSAvoidprocessing ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent creates composite particles by combining polymer particles with calcium salt particles (particularly calcium carbonate). This composite structure enhances mechanical properties, biocompatibility, and pH stabilization while maintaining processability. The calcium salt component provides rigidity and structural support, while the polymer matrix ensures flexibility and ease of processing.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention segments the particle system into two distinct size classes: large polymer particles (0.1-10 mm) and small calcium salt particles (at most 1/10 of the large particle diameter). This segmentation allows each component to contribute its optimal properties - the large particles provide structural integrity and ease of handling, while the small particles enhance mechanical strength and pH buffering capacity.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If particle size is reduced for medical applications like laser sintering, then application suitability improves, but dust formation increases and processing becomes difficult

Engineering Contradiction:
Improvemedical application suitabilityVSAvoiddust formation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The composite structure with calcium salt particles embedded in or attached to polymer particles reduces dust formation during processing. The calcium carbonate component acts as a dust suppressant and binds fine particles together, reducing airborne dust while enabling the use of smaller particle sizes suitable for laser sintering and other medical applications.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The calcium salt particles serve as an intermediary substance that mediates between the polymer particles and the processing environment. They reduce the harmful dust effect by acting as binding agents and surface modifiers, allowing smaller particles to be handled without excessive dust generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If calcium salts are dispersed in polymers, then pH stabilization is achieved, but homogeneous dispersion at reduced particle sizes is difficult

Engineering Contradiction:
ImprovepH stabilizationVSAvoidhomogeneous dispersion
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent segments the calcium salt into very fine particles (at most 1/10 of the polymer particle diameter), which facilitates homogeneous dispersion throughout the polymer matrix. This size segmentation ensures uniform distribution while maintaining adequate pH buffering capacity throughout the material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by positioning calcium salt particles specifically within or on the surface of polymer particles. This localized arrangement ensures that pH stabilization occurs at multiple discrete points throughout the material, creating a distributed buffering system that achieves homogeneous pH control throughout the bulk material.

Inventive Principle:
Principle #3Local quality

4Reliability

If implant materials are used for medical applications, then treatment progress monitoring is needed, but visibility under X-rays is insufficient

Engineering Contradiction:
Improvetreatment progress monitoringVSAvoidvisibility for monitoring
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The composite particles combining polymer and calcium salt materials provide inherent X-ray visibility. The calcium carbonate component has sufficient density and atomic number to be visible under X-ray imaging, allowing non-invasive monitoring of implant placement and treatment progress while maintaining biocompatibility and mechanical performance.

Inventive Principle:
Principle #40Composite materials

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 composite particles improve mechanical properties, absorbability, and processing ease, enabling their use in medical applications, including laser sintering, with reduced dust formation and improved visibility for treatment monitoring.

Implementation Method 1

repeatedly subjected to mechanical forces, particularly impact forces, compression forces, frictional forces and shearing forces

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 2

repeatedly subjected to mechanical forces, particularly impact forces, compression forces, frictional forces and shearing forces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

allowing for easy processing and visibility under X-rays

Methodology Applied
Scientific EffectX-ray: X-Ray

Data Source

PatentEP3524279A1Microstructured particles
Publication Date: 2019.08.14 SCHAEFER KALK
  • EP3524279A1 patent drawingFigure 1a~4a
  • EP3524279A1 patent drawingFigure 4b
  • EP3524279A1 patent drawing

AI summary

Microstructured composite particles obtainable by a process in which large particles are combined with small particles, wherein: - the large particles have a mean particle diameter in the range of 0.1 µm to 10 mm, - the mean particle diameter of the small particles is at most 1/10 of the mean particle diameter of the large particles, - the large particles comprise at least one polymer, - the small particles comprise at least one calcium salt, - the small particles are arranged on the surface of the large particles and/or inhomogeneously distributed within the large particles, characterized in that the large particles comprise at least one resorbable polyester with a number-average molecular weight in the range of 500 g/mol to 1,000,000 g/mol.The composite particles are preferably used as an additive, in particular as a polymer additive, as an additive material or starting material for the manufacture of components, for applications in medical technology and/or in microtechnology and/or for the manufacture of foamed objects.