Flow Wrap Laminate Cutouts for Fast Airtight Heat Seals
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Solution Overview
Problem
Conventional flow wrap equipment struggles to form airtight seals with laminated films containing a paper or thermally resistant outer ply due to insufficient heat transfer, requiring complex and costly equipment with extended dwell times.
Innovation Solution
A laminated film structure with cutouts in the outer ply aligned with transverse heat seal regions, allowing the sealant ply to soften and seal at lower dwell times, compatible with rotary sealing heads, enhancing seal integrity and packaging speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a paper or thermally resistant outer ply is used in flexible packaging, then mechanical strength and barrier properties are improved, but heat seal integrity deteriorates due to insufficient heat transfer through the outer ply
Solution Approach 1:
The packaging structure is segmented into distinct functional zones: the outer ply provides mechanical strength in non-sealing areas, while cutouts create localized zones where heat can directly reach the sealant ply for reliable sealing. This segmentation allows each material to perform its optimal function without compromising the other.
Solution Approach 2:
The outer ply is modified with cutouts specifically at the heat seal regions, creating local variations in thermal properties. The cutout areas have high thermal conductivity (direct heat access), while the remaining outer ply maintains its insulating and strength-providing properties in non-sealing areas.
2Strength
If the outer ply is made thicker or with higher thermal resistance, then barrier properties and mechanical strength are improved, but scaling time increases beyond the capability of conventional rotary sealing heads
Solution Approach 1:
The structure segments the thermal path by removing the outer ply material from seal regions, creating direct thermal access through cutouts. This allows the rest of the outer ply to maintain its thickness for strength while seal areas achieve rapid heating through the cutout openings.
Solution Approach 2:
The outer ply material is extracted (removed via cutouts) from specific regions where it would impede heat transfer. This extraction creates clear paths for heat to reach the sealant ply without having to conduct through the thermally resistant outer material.
3Productivity
If conventional rotary sealing heads are used with paper-containing laminations, then packaging speed is maintained, but seal integrity deteriorates due to insufficient contact time for heat transfer
Solution Approach 1:
The structure creates local quality differences by providing direct thermal access only at seal regions through cutouts. The sealant ply in cutout areas experiences immediate and intense heat exposure, ensuring rapid sealing that keeps pace with high-speed rotary sealing operations.
Solution Approach 2:
The outer ply is taken out at seal locations to eliminate the thermal barrier, allowing heat to directly contact the sealant ply. This extraction enables sufficient heat transfer in the short dwell time characteristic of rotary sealing heads.
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 film structure achieves high seal integrity and increased packaging speed while reducing the complexity and cost of equipment by allowing the sealant material to soften and seal at lower temperatures.
Implementation Method 1
the first major surface comprising a heat sealable material... adequate to melt the heat seal layers and produce an airtight seal
Implementation Method 2
melt the heat seal layers and produce an airtight seal
Data Source
AI summary
A web of sheet material is provided which can be wrapped around a product to form a pack. The sheet material comprises a sealant ply laminated to an outer ply. The sealant ply has a first major surface and a second major surface opposite the first major surface, the first major surface comprising a heat sealable material. The outer ply has a third major surface and a fourth major surface opposite the third major surface, wherein the third major surface faces the second major surface. The web of sheet material comprises a plurality of connected blanks, each blank comprising a plurality of cutouts removing a portion of the outer ply, the cutouts aligned with overlapping portions of transverse heat seal regions of the sheet material.