Polyguanidine Thermoplastic Compounds Non-Leaching
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Solution Overview
Problem
Existing antimicrobial thermoplastic molding compositions, particularly those based on styrene-acrylonitrile copolymers, face issues with bleeding of antimicrobial agents when exposed to liquid media, leading to reduced effectiveness and potential discoloration, and current solutions either fail to adequately bond the antimicrobial agents to the polymer matrix or require complex processes.
Innovation Solution
A thermoplastic molding composition comprising polyguanidine as an antimicrobially active component covalently bonded to a polymer with functional groups, such as maleic anhydride-containing copolymers, which reacts during compounding to form a stable and effective antimicrobial material with reduced bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic antimicrobial additives (metal ions) are used, then good antimicrobial effect is achieved, but discoloration and leaching occur
Solution Approach 1:
The patent uses polymer-bound guanidine compounds as intermediary substances that carry antimicrobial activity without the harmful effects of metal ions. The guanidine is covalently bonded to polymer chains, creating a mediator that provides antimicrobial protection while avoiding direct release of toxic metal ions into the environment.
Solution Approach 2:
The invention changes the chemical form of the antimicrobial agent from inorganic metal ions to organic polymer-bound guanidine compounds. This parameter change transforms the substance from a small inorganic ion that leaches easily to a large organic polymer that remains stable and bonded, eliminating discoloration and leaching issues.
2Reliability
If organic antimicrobial additives are used, then antimicrobial effect is achieved with small amounts, but thermal decomposition occurs during processing
Solution Approach 1:
The patent creates a composite material where guanidine is chemically bonded to a polymer matrix. This composite structure combines the antimicrobial properties of guanidine with the thermal stability of the polymer, allowing the mixture to withstand processing temperatures without decomposition while maintaining antimicrobial effectiveness.
3Reliability
If small organic antimicrobial molecules are used, then antimicrobial effect is achieved, but migration to surface and bleeding occur
Solution Approach 1:
The polymer-bound guanidine acts as an intermediary that anchors the antimicrobial agent within the plastic matrix. The polymer chain serves as a tether that prevents the small guanidine molecules from migrating to the surface and bleeding out, while still allowing them to exert their antimicrobial effect when needed.
4Reliability
If polyguanidine is added to thermoplastic molding compounds, then antimicrobial effect is achieved, but bleeding occurs in liquid media
Solution Approach 1:
The invention creates a composite material where polyguanidine is covalently bonded to polymer chains containing functional groups. This composite structure integrates the antimicrobial polyguanidine into the polymer matrix, preventing it from leaching out into liquid media while maintaining its antimicrobial effectiveness.
Solution Approach 2:
The patent changes the physical state and bonding of polyguanidine from a free-standing polymer that can bleed to a chemically bonded component within a polymer matrix. This parameter change from independent polymer to integrated functional component prevents bleeding while preserving antimicrobial activity.
5Loss of substance
If reactive extrusion process is used to bond polyguanidine to polymer, then bleeding is reduced, but process complexity increases
Solution Approach 1:
The patent uses functional groups on the polymer chains as intermediary bonding sites that react with polyguanidine during extrusion. These functional groups act as chemical mediators that facilitate the bonding process, enabling the formation of stable bonds between polyguanidine and the polymer matrix through a controlled chemical reaction during the extrusion process.
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 composition exhibits a significant antimicrobial effect while minimizing bleeding, maintaining mechanical and optical properties, and can be easily processed, even at higher polyguanidine levels without undesirable crosslinking of the polymer matrix.
Implementation Method 1
polyguanidine as an antimicrobially active component covalently bonded to a polymer with functional groups, such as maleic anhydride-containing copolymers, which reacts during compounding to form a stable and effective antimicrobial material
Data Source
AI summary
The invention relates to thermoplastic molding compounds M comprising an antimicrobially active polymer component A containing 0.2 to 25 wt% polyguanidine A1 and one or more polymers A2 which carry one or more functional groups that can react with polyguanidine A1. The present invention also relates to methods for producing an antimicrobially active thermoplastic molding compound M comprising the extrusion of a polyguanidine component and polymer A2. In addition, the invention relates to molded parts and products which contain the thermoplastic molding compound M.