Multilayer Films Removing PIB Noise and Contamination
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Solution Overview
Problem
Multilayer films used in packaging face challenges such as excessive noise when unwound, the need for aging to achieve desired cling properties, contamination of process equipment, and handling issues due to additives like polyisobutylene (PIB), as well as high costs and processing difficulties with ethylene/alpha-olefin elastomers.
Innovation Solution
The development of multilayer films comprising a cling layer with ethylene/alpha-olefin elastomers and ultra-low or very low density polyethylene, combined with a release layer made from a polyethylene composition characterized by specific properties, allowing for high cling force without the use of PIB and reducing processing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If polyisobutylene (PIB) is incorporated into the cling layer to improve tack, then cling force is improved, but the film becomes excessively noisy when unwound from film-roll
Solution Approach 1:
The patent removes PIB from the cling layer formulation entirely, extracting the problematic additive that causes noise while maintaining cling force through alternative polymer compositions (ethylene/alpha-olefin elastomers and ultra-low density polyethylene).
Solution Approach 2:
The patent changes the compositional parameters of the cling layer by specifying precise density ranges for ethylene/alpha-olefin elastomers (0.855-0.890 g/cm³) and ultra-low density polyethylene (0.910-0.930 g/cm³), replacing the PIB-based system with a polymer blend that achieves comparable tack without noise issues.
2Force
If polyisobutylene (PIB) is incorporated into the cling layer to improve tack, then cling force is improved, but the film must be aged for a period of time so that the additive migrates to the surface
Solution Approach 1:
The patent eliminates PIB from the formulation, removing the need for aging processes required for additive migration and blooming to the film surface.
Solution Approach 2:
The desired cling properties are built into the polymer composition itself through careful selection of ethylene/alpha-olefin elastomer and ultra-low density polyethylene ratios, eliminating the need for subsequent aging or blooming processes.
3Force
If polyisobutylene (PIB) is incorporated into the cling layer to improve tack, then cling force is improved, but process equipment is contaminated
Solution Approach 1:
The patent removes PIB from the cling layer, eliminating the source of contamination that adheres to process equipment during manufacturing and handling.
Solution Approach 2:
The patent uses standard polyethylene-based materials that are easier to handle and less prone to causing contamination issues compared to PIB, simplifying process equipment maintenance.
4Force
If polyisobutylene (PIB) is incorporated into the cling layer to improve tack, then cling force is improved, but handling issues occur when the additive is in liquid form and drips from process equipment
Solution Approach 1:
The patent eliminates liquid PIB from the formulation, removing the handling challenges associated with liquid additive storage, transport, and processing.
Solution Approach 2:
The patent transitions from using liquid PIB additive to a solid polymer blend system with controlled melt indices (0.1-10.0 g/10 min for ethylene/alpha-olefin elastomer, 0.5-5.0 g/10 min for ultra-low density polyethylene), improving processability and handling.
5Force
If ethylene/alpha-olefin elastomers are used at high levels to achieve higher tack, then cling force is improved, but the films become very expensive
Solution Approach 1:
The patent combines ethylene/alpha-olefin elastomer with ultra-low density polyethylene in a synergistic blend, achieving the desired cling force through the combination of materials rather than relying solely on expensive high levels of elastomer.
Solution Approach 2:
The patent optimizes the density and compositional parameters of both polymers (ethylene/alpha-olefin elastomer density: 0.855-0.890 g/cm³, ultra-low density polyethylene density: 0.910-0.930 g/cm³) to achieve cost-effective cling performance.
6Force
If ethylene/alpha-olefin elastomers are used at high levels to achieve higher tack, then cling force is improved, but the films become difficult to process using blown film techniques
Solution Approach 1:
The patent merges ethylene/alpha-olefin elastomer with ultra-low density polyethylene to create a balanced formulation that maintains processability during blown film extrusion while achieving the desired cling properties in the final product.
Solution Approach 2:
The patent controls the melt index parameters (ethylene/alpha-olefin elastomer: 0.1-10.0 g/10 min, ultra-low density polyethylene: 0.5-5.0 g/10 min) to ensure the blend remains processable using conventional blown film techniques while achieving high cling force.
Data Source
Figure 1
AI summary
Embodiments disclosed herein include multilayer films having a cling layer and a release layer, wherein the cling layer comprises (i) an ethylene/alpha-olefin elastomer, and (ii) a polyethylene polymer selected from ultra-low density polyethylene, a very low density polyethylene, or combinations thereof, and the release layer comprises a polyethylene composition.