Laminate Tabstock Adhesion for Low-Temperature Seal Integrity
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Solution Overview
Problem
Existing container closure systems face challenges in producing a simple and cost-effective method for including a tabstock in primary seal laminates, resulting in uneven bonding to containers and potential failure at low temperatures.
Innovation Solution
A method involving the continuous feeding of a seal laminate with a hot melt adhesive layer, a foil layer, and a top foam layer, along with a narrower tabstock and plastic film stock to a laminating station, where a polymeric adhesive is extruded between the primary substrate and plastic film stock, ensuring a uniform bond strength and tab formation within the container neck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tabstock is included in the primary seal laminate using conventional methods, then a tab is formed for seal removal, but uneven bonding is achieved with stronger bonds under the tabbed portion and potential burning of the top layer
Solution Approach 1:
The patent applies local quality by creating a tab structure with different properties than the main seal body. The tab portion has modified adhesive characteristics and thermal properties to provide localized functionality for removal while the main body maintains uniform bonding characteristics. This resolves the contradiction by allowing the tab to be optimized for removal ease without compromising overall bonding uniformity.
Solution Approach 2:
The seal laminate is segmented into distinct regions: a tab portion and a main seal portion. The tab portion is designed with specific properties (different adhesive content, thickness, or material composition) that differ from the main seal body. This segmentation allows each region to be optimized independently - the tab for easy removal and the main body for uniform bonding - thereby resolving the technical contradiction.
2Adaptability or versatility
If the seal laminate is used on containers for low temperature storage, then container closure functionality is maintained, but the bond between seal substrate and tab fails causing tab detachment
Solution Approach 1:
The patent changes the physical and chemical parameters of the adhesive and tabstock materials to ensure stability at low temperatures. This includes selecting materials with appropriate glass transition temperatures, adjusting adhesive composition to maintain flexibility and bond strength in cold conditions, and modifying the tabstock material properties. These parameter changes enable the seal to function reliably across a wide temperature range while maintaining bond stability.
Solution Approach 2:
The seal laminate uses composite materials combining different polymers and adhesives with complementary properties. The tab portion and main seal body utilize composite constructions that provide both low-temperature flexibility and strong bonding. This composite approach allows the structure to adapt to temperature variations while maintaining bond integrity, resolving the contradiction between temperature adaptability and bond stability.
3Device complexity
If a one component seal and liner system is used to avoid two separate fitting operations, then manufacturing complexity is reduced, but the seal and liner must be fitted in separate operations anyway
Solution Approach 1:
The patent merges the seal and liner into a single integrated component - a one-component seal and liner system where the liner is incorporated within or as part of the seal structure. This eliminates the need for separate fitting operations while maintaining the functionality of both seal and liner, thereby reducing device complexity and improving productivity simultaneously.
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
This method achieves a uniform bond strength around the container circumference and maintains seal integrity at various temperatures, including low temperatures, preventing tab detachment and ensuring effective seal removal.
Implementation Method 1
extruding a polymeric adhesive which is a copolymer of ethylene and an alkyl(alk)acrylate... such that the two are adhered together
Implementation Method 2
Upon induction heating, the metal foil is heated which activates the heat sensitive adhesive layer or melts the plastic layer
Data Source
AI summary
A primary laminate including a tabstock in which a seal laminate including a foil layer and a top foam layer, a tabstock and a plastic film stock are fed to a laminating station is provided herein. At the lamination station, a curtain of polymeric adhesive is extruded between the plastics film stock and the top face of the primary substrate, which is partly comprised of the top face of the tabstock and partly comprised of the top foam layer of the seal laminate. Use of primary laminates obtained by such a process to form seals for sealing a container, for food or drink stored at low temperatures, is also described.