Multilayer Packaging Film Opacity and Weldability via Pigment Distribution
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Solution Overview
Problem
Existing packaging films face challenges in achieving high opacity, mechanical strength, and seamability while maintaining a bright white color and low caliper, as inorganic opacifying agents like titanium dioxide compromise tensile strength and film fusion during heat sealing, and reducing film thickness compromises seam integrity and opacity.
Innovation Solution
A multilayer film composition with outer skin layers of polyethylene and intermediate layers of polypropylene, incorporating titanium dioxide and non-white pigments in specific weight percentages to enhance opacity and maintain weldability, tensile strength, and caliper, with tie layers for compatibility, and a manufacturing process that balances film properties for efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If inorganic opacifying agents like titanium dioxide are included to enhance opacity, then opacity and whiteness are improved, but tensile strength and ability to fuse cleanly during heat sealing are compromised
Solution Approach 1:
The patent employs a composite material system consisting of multiple polymer layers (polyethylene, polypropylene, and their copolymers) with different properties. Each layer contributes specific characteristics: polyethylene layers provide opacity and sealability, while polypropylene layers provide tensile strength and structural integrity. This composite structure allows the film to achieve high opacity without relying solely on inorganic fillers that would compromise mechanical strength.
2Illumination intensity
If inorganic opacifying agents like titanium dioxide are included to enhance opacity, then opacity and whiteness are improved, but seamability and film fusion during heat sealing are compromised
Solution Approach 1:
The patent applies local quality by creating distinct layers with specialized functions. The polyethylene-containing layers are positioned specifically to provide opacity and heat sealability at the sealing surfaces, while other layers provide structural support. This localized functional distribution allows the film to seal effectively without the entire film structure being compromised by opacity-enhancing additives.
3Quantity of substance
If film caliper (thickness) is reduced to exercise economy in polymer material consumption, then material cost is reduced, but seam integrity, tensile strength, and opacity are decreased
Solution Approach 1:
The multilayer composite structure allows for optimized material distribution where each layer contributes specific properties. High-strength polypropylene layers provide structural integrity, while thinner polyethylene layers provide necessary opacity and sealability. This composite approach enables reduced overall caliper while maintaining mechanical strength through the synergistic combination of different polymer layers with specialized functions.
4Quantity of substance
If film caliper (thickness) is reduced to exercise economy in polymer material consumption, then material cost is reduced, but opacity is decreased
Solution Approach 1:
The patent concentrates opacity-providing materials in specific localized layers rather than distributing them throughout the entire film thickness. The polyethylene-containing layers are positioned to provide maximum opacity contribution, allowing the overall film to be thinner while maintaining adequate opacity. This localized concentration of functional properties enables reduced material consumption without sacrificing optical performance.
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 multilayer film achieves high opacity, structural integrity, and cost-effectiveness by synergistically combining titanium dioxide and non-white pigments, maintaining film weldability and tensile strength, and allowing for a thinner caliper, thus enhancing packaging film performance.
Implementation Method 1
Inclusion of inorganic opacifying and/or whitening agents... particles of titanium dioxide (TiO2)... imparting a robust appearance to the package... preventing appearance of the contents from visually interfering
Implementation Method 2
edges joined at seams via application of heat, which has caused the film to melt and fuse along the seams
Implementation Method 3
thorough fusing and sealing will occur... application of heat in such a manner that thorough fusing and sealing will occur
Data Source
AI summary
An improved multilayer polymer film is disclosed. The film may include a first skin layer, a second skin layer, and an intermediate layer between the skin layers. The first, second and intermediate layers may be formed of respective first, second and intermediate polymer compositions. Each layer may have distributed therein particles of titanium dioxide to a weight content of from 6 percent to 14 percent. One or both the second skin layer and the intermediate layer may have distributed therein non-white pigment particles to a weight content of from 0.050 percent to 0.15 percent of such layer(s). The contents and distribution among layers of the pigments may provide for relatively disproportionate improvement of opacity while preserving a neutral white color surface to receive ink-printing, enabling high conformity of printed colors with target colors, and preserving weldability of the film to itself.