Cellulose Ester Composition With Low Friction and Maintained Stiffness
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Solution Overview
Problem
Cellulose ester polymers, such as cellulose acetate propionate (CAP), exhibit high coefficients of friction, making it difficult to join and separate molded plastic articles, and they lack sufficient toughness and transparency for certain applications.
Innovation Solution
Incorporation of additives like waxes and organosiloxanes to reduce friction, combined with impact modifiers to maintain toughness and stiffness, while optionally using polymeric aliphatic polyesters to enhance properties like impact toughness and clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cellulose ester polymers are used as base material, then bio-based sustainability is achieved, but coefficient of friction is too high
Solution Approach 1:
A friction modification package containing waxes and/or organosiloxanes is introduced as an intermediary substance between the cellulose ester polymer and contacting surfaces. This package reduces the coefficient of friction by providing a low-friction interface, allowing the bio-based polymer to function effectively in applications requiring repeated joining and separating of articles.
2Ease of operation
If friction is reduced by incorporating additives, then coefficient of friction decreases, but physical properties such as toughness and stiffness deteriorate
Solution Approach 1:
The composition carefully controls the quantity of friction modification package at 0.01-10 wt% and impact modifier at 1-30 wt% to optimize the balance between friction reduction and property maintenance. This parameter optimization ensures that sufficient base polymer remains to maintain toughness and stiffness while achieving the desired friction reduction.
Solution Approach 2:
The invention creates a composite material system combining cellulose ester polymer, friction modification package (waxes and/or organosiloxanes), and impact modifier. This composite structure allows simultaneous achievement of low friction and maintained mechanical properties through synergistic interaction of components.
3Strength
If impact modifiers are added to maintain toughness, then toughness is improved, but manufacturing complexity increases
Solution Approach 1:
The impact modifier quantity is optimized at 1-30 wt% to achieve sufficient toughness improvement with minimal addition. This controlled parameter approach maintains process simplicity while achieving the necessary mechanical property enhancement for the bio-based polymer composition.
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 modified cellulose ester polymers achieve a tunable frictional profile comparable to traditional engineering polymers, maintaining toughness and modulus, and can be used in injection molded toy building bricks with desired physical and mechanical properties.
Implementation Method 1
reduction of the coefficient of friction was achieved by incorporation of additives including waxes and/or organosiloxanes
Data Source
Figure 1~2
AI summary
Provided are cellulose ester compositions comprising a cellulose ester which exhibit a coefficient of friction reduction while physical properties such as heat distortion temperature (HDT) and flexural modulus, after modification, are substantially maintained compared to un-modified compositions.