Uncrosslinked Thermoplastic Shell for Blowing Agent Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing foaming methods using chemical and physical blowing agents face challenges such as volatile organic compounds (VOCs), compatibility issues, and undesirable side reactions, while expandable microspheres have limitations in VOC emissions and shelf life, and remnant hard shells affect adhesion and tackiness.
Innovation Solution
Encapsulating chemical blowing agents in uncrosslinked thermoplastic shells with high complex viscosity, which decreases foam cell size and increases density and homogeneity, and prevents VOC emissions and shell degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical blowing agents are used to form foams, then foam formation is achieved, but volatile organic compounds are emitted and side reactions occur
Solution Approach 1:
An uncrosslinked thermoplastic shell is introduced as an intermediary between the chemical blowing agent and the environment. This shell encapsulates the blowing agent, preventing VOC emissions while allowing controlled decomposition to achieve reliable foam formation. The shell acts as a mediator that separates the harmful effects from the useful function.
Solution Approach 2:
An uncrosslinked thermoplastic shell is introduced as an intermediary between the chemical blowing agent and the environment. This shell encapsulates the blowing agent, preventing VOC emissions while allowing controlled decomposition to achieve reliable foam formation. The shell acts as a mediator that separates the harmful effects from the useful function.
2Object-generated harmful factors
If expandable microspheres are used, then VOC emissions are reduced, but shelf life is limited and hard shells remain after foaming
Solution Approach 1:
The key parameter changed is the crosslinking state of the thermoplastic shell. By using an uncrosslinked thermoplastic material instead of a crosslinked one, the shell maintains flexibility and processability throughout storage and processing. The uncrosslinked state prevents premature degradation and shell brittleness, thereby extending shelf life while still providing VOC emission reduction.
3Strength
If hard shells remain after foaming, then structural integrity is maintained, but adhesion and tackiness are reduced
Solution Approach 1:
The crosslinking state parameter is changed from crosslinked to uncrosslinked. This transformation allows the shell to maintain structural integrity through its thermoplastic nature while providing uncured reactive groups that enable post-foaming crosslinking. This sequential approach preserves adhesion and tackiness during processing while achieving structural strength in the final product.
Solution Approach 2:
The shell is prepared in an uncrosslinked state before foaming, allowing it to maintain flexibility and adhesion properties during processing. The crosslinking action is postponed until after foaming, when structural integrity is needed. This preliminary uncrosslinked state enables better adhesion and tackiness during handling and processing.
4Device complexity
If chemical blowing agents are not encapsulated, then simpler processing is achieved, but foam cell size is larger and homogeneity is reduced
Solution Approach 1:
The chemical blowing agent is segmented into individual encapsulated particles rather than being used as bulk material. Each encapsulated particle acts as a discrete foam cell nucleation site, leading to more uniform cell size distribution and improved homogeneity. The segmentation of the blowing agent into controlled-release units enhances manufacturing precision without significantly complicating the overall processing.
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 encapsulation of chemical blowing agents in uncrosslinked thermoplastic shells results in foams with smaller, denser, and more homogeneous cells, reducing VOC emissions and extending shelf life, while maintaining compatibility and adhesion properties.
Implementation Method 1
The uncrosslinked thermoplastic material exhibits a complex viscosity of 3,700 Pascal seconds (Pa·s) or greater at a decomposition temperature of the chemical blowing agent particle
Implementation Method 2
chemical blowing agent particle encapsulated within a shell including an uncrosslinked thermoplastic material... at a decomposition temperature of the chemical blowing agent particle
Data Source
AI summary
Composite particles are provided including a chemical blowing agent particle encapsulated within a shell including an uncrosslinked thermoplastic material. The uncrosslinked thermoplastic material exhibits at least a certain minimum complex viscosity at a decomposition temperature of the chemical blowing agent particle. Also described are compositions and foam compositions containing the composite particles. Further, articles are provided including the foam compositions, such as a sheet, tape, or hearing protection article. Methods of making and using the foam compositions are additionally described herein.