Multilayer Thermoformed Sheet With Antimicrobial Sealant Layer
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Solution Overview
Problem
Current thermoformed packaging solutions fail to adequately address the need for improved antibacterial and antifungal properties while maintaining acceptable sealing properties, which is crucial for extending the shelf life of food products.
Innovation Solution
A multilayer sheet comprising a sealant layer with a propylene/ethylene copolymer composition and a core layer, both containing antimicrobial agents, is thermoformed to create a packaging device with enhanced antibacterial and antifungal properties while maintaining effective sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermoformed trays are used, then manufacturing simplicity is maintained, but antibacterial and antifungal properties are insufficient
Solution Approach 1:
The patent employs a multilayer composite structure consisting of a core layer (polypropylene homopolymer or random copolymer) and a sealant layer (propylene/ethylene copolymer with antimicrobial agents). This composite material approach integrates structural integrity from the core layer with antibacterial and antifungal properties from the sealant layer, simultaneously achieving enhanced reliability and maintaining manufacturing feasibility through established extrusion and thermoforming processes.
2Reliability
If antimicrobial agents are added to enhance food safety, then shelf life is extended, but sealing properties may be compromised
Solution Approach 1:
The patent applies local quality by concentrating antimicrobial agents specifically in the sealant layer where they contact food products, while the core layer maintains pure polypropylene composition for optimal structural strength and sealing properties. The sealant layer contains 0.02 to less than 1 percent by weight of antimicrobial agents, ensuring food safety without compromising the overall sealing performance of the packaging structure.
Solution Approach 2:
The patent utilizes parameter changes by selecting a propylene/ethylene copolymer with specific crystallinity (1-30 percent by weight) and melting point (25°C to 110°C) for the sealant layer. These parameter optimizations ensure that the sealant layer provides effective sealing at appropriate temperatures while maintaining compatibility with antimicrobial agents, thus preserving both sealing strength and food safety properties.
3Reliability
If a multilayer structure with specific polymer compositions is used, then sealing and antibacterial properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges for the propylene/ethylene copolymer in the sealant layer, including crystallinity (1-30 percent by weight) and melting point (25°C to 110°C). These parameter definitions enable manufacturers to select from commercially available polymers that meet the requirements, simplifying the manufacturing process while ensuring consistent sealing and antibacterial performance across production batches.
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 solution effectively inhibits bacterial and fungal growth while ensuring strong sealing properties, thereby extending the shelf life of food products and ensuring food safety.
Implementation Method 1
forming said multilayer sheet into an article via thermoforming process
Implementation Method 2
from 0.02 to less than 1 percent by weight of one or more antimicrobial agents... effectively inhibits bacterial and fungal growth
Data Source
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AI summary
The instant invention provides a multilayer sheet, a thermoformed article, and a method for making the same. The multilayer sheet comprises (a) at least one sealant layer comprising: less than 1 percent by weight of one or more antimicrobial agents, based on the total weight of the sealant layer; at least 20 percent by weight of a base polymer, based on the total weight of the sealant layer, wherein said base polymer comprises a propylene/ethylene copolymer composition, wherein said propylene/ethylene copolymer has a crystallinity in the range of from 1 percent by weight to 30 percent by weight, a heat of fusion in the range of from 2 Joules/gram to 50 Joules/gram), and a DSC melting point in the range of 25° C to 110° C; and less than 80 percent by weight of a secondary polymer selected from the group consisting of polypropylene homopolymer, polypropylene random copolymer, impact modified polypropylene, combinations thereof, and blends thereof; and (b) at least one core layer in contact with said at least one sealant layer, wherein said core layer comprises a core polymer