Container Closure Sealing Element for Low-Migration Food Contact
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Solution Overview
Problem
PVC-free sealing elements in vessel closures with white oil components exhibit high total migration into foodstuffs, particularly those with high fat or oil content, necessitating a solution that reduces migration while maintaining processability and low-temperature usability.
Innovation Solution
A polymer composition comprising polyalphaolefin and a second polyolefin, with specific viscosities and densities, is used in vessel closures to form a sealing element, which is applied to the carrier through adhesion or shaping, ensuring low migration and improved processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If white oil is used as a component in PVC-free sealing elements, then processability and cost are improved, but total migration into foodstuffs is significantly increased
Solution Approach 1:
The patent replaces white oil with polyalphaolefin having specific viscosity parameters (at least 4 cSt at 100°C) and controlled dropping point (no more than −10°C). This parameter change maintains the lubricity and processability benefits of white oil while eliminating its harmful migration into foodstuffs, as polyalphaolefin is food-contact approved and does not exhibit the same migration behavior.
Solution Approach 2:
The sealing element uses a composite polymer composition comprising polyalphaolefin combined with other polyolefins (such as polyethylene, polypropylene, or elastomers). This composite material approach allows optimization of both processability and migration resistance by combining materials with complementary properties, achieving low migration while maintaining manufacturability.
2Adaptability or versatility
If the sealing element is designed for low-temperature use, then usability is improved, but material selection becomes more constrained
Solution Approach 1:
The patent specifies polyalphaolefin with a dropping point of no more than −10°C, ensuring the material remains flexible and functional at low temperatures. This parameter specification directly addresses low-temperature usability while providing clear material selection criteria, reducing complexity by defining precise performance thresholds.
Solution Approach 2:
The sealing element incorporates different polyolefin components with specific properties tailored for different functional requirements. The polyalphaolefin provides low-temperature flexibility, while other polyolefins contribute to structural integrity and sealing performance. This local quality differentiation allows the sealing element to perform optimally across temperature ranges without requiring entirely different materials.
3Reliability
If the polyalphaolefin has high kinematic viscosity, then sealing integrity is improved, but processability may be affected
Solution Approach 1:
The patent defines a specific viscosity range for polyalphaolefin (at least 4 cSt at 100°C) that optimizes both sealing integrity and processability. This parameter specification ensures sufficient viscosity for reliable sealing while maintaining workability during manufacturing processes such as molding and forming, balancing the two competing requirements.
Data Source
AI summary
A vessel closure (1, 21, 41, 61) includes a sealing element (3, 23, 43, 63). The sealing element (3, 23, 43, 63) includes a polymer composition. The polymer composition includes a polysiphaolefin with kinematic viscosity, determined according to ASTM D445/ISO 3104, of at least 4 cSt, at a temperature of 100° C., and/or a dropping point, determined according to ASTM 5950, of at most −10° C., and up to 95% by weight of a second polyolefin.