HDPE-Elastomer Fitment for Flexible Container Seal Integrity
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Solution Overview
Problem
The existing rigid fitments for flexible containers face challenges in compatibility and seal adhesion with the pouch seal layer due to differences in melt temperatures, leading to overheating or underheating issues during the assembly process, which affects leak-proof sealing and increases production costs and time.
Innovation Solution
A polymeric composition for the fitment comprising 70-90 weight percent high density polyethylene (HDPE) with a melt temperature greater than 125°C and 30-10 weight percent olefin-based elastomer with a melt temperature less than 125°C, allowing for improved sealability and reduced production time by matching the melt window of the pouch sealant layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid fitment made from olefin-based polymer with high melt temperature is used, then fitment rigidity is improved, but seal adhesion with the pouch seal layer deteriorates due to overheating or underheating
Solution Approach 1:
The fitment is constructed from a composite material comprising a polymeric composition with multiple components: a first polymer (70-90 wt%), a second polymer (5-30 wt%), and optionally a third polymer (5-30 wt%). This composite structure combines materials with different melt temperatures to achieve both rigidity and compatible sealing behavior with the pouch seal layer.
Solution Approach 2:
The invention changes the thermal parameters of the fitment material by selecting polymers with specific melt temperature ranges. The first polymer has a melt temperature within 20-50°C of the pouch seal layer, while the second polymer has a melt temperature within 20-50°C of the first polymer, creating a gradient that enables proper sealing without overheating or underheating.
2Reliability
If the pouch seal layer is overheated to seal to the fitment, then sealing is achieved, but the pouch seal layer deforms and loses structural integrity
Solution Approach 1:
The invention changes the temperature parameters by selecting polymers with matched melt temperatures. The first polymer's melt temperature is within 20-50°C of the pouch seal layer, enabling sealing at temperatures that do not exceed the pouch seal layer's thermal tolerance, thus preventing deformation while achieving reliable seals.
3Stability of the object's composition
If the fitment is underheated during sealing, then pouch seal layer integrity is maintained, but proper leak-proof sealing cannot be achieved
Solution Approach 1:
The composite polymeric composition with multiple polymers having different melt temperatures creates a material that seals effectively at lower temperatures. The combination of polymers enables leak-proof sealing without requiring excessive heat that would compromise the pouch seal layer.
4Strength
If conventional fitment materials are used, then fitment rigidity is achieved, but production time and costs increase due to sealing difficulties
Solution Approach 1:
By changing the thermal parameters of the fitment material through polymer selection, the sealing process occurs at optimized temperatures that reduce cycle time. The matched melt temperatures enable faster, more reliable sealing without retries or adjustments, improving production efficiency.
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 proposed solution enhances seal adhesion and reduces production time and costs by ensuring proper sealing without overheating or underheating, achieving a desirable burst strength and hermetic seal integrity.
Implementation Method 1
The elastomer/ethylene-based polymer blend reduces the melt temperature of the fitment enabling sealability within a desirable melt window of the pouch sealant layer
Implementation Method 2
the film surface and the fitment surface are brought into contact by heat seal bars that impart elevated temperature and elevated pressure to the film-fitment assembly
Data Source
AI summary
The present disclosure provides a fitment. In an embodiment, a fitment is provided and includes a top portion, a base, and a channel extending through the top portion and the base for passage of a flowable material. The fitment is composed of a polymeric composition. The polymeric composition includes (i) from 70 to 90 weight percent of a high density polyethylene (HDPE) having a density from 0.940 g/cc to 0.970 g/cc, a melt temperature, Tm, greater than 125° C., and a melt index from 1 g/10 min to 50 g/10 min; and (ii) from 30 to 10 weight percent of an olefin-based elastomer having a density from 0.860 g/cc to 0.905 g/cc, a melt index from 0.2 g/10 min to 50 g/10 min, and a Tm less than 125° C.