Barrier Container Coating for Oxygen Resistance and Hot Fill
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Solution Overview
Problem
Existing food packaging materials, such as high impact polystyrene (HIPS) and polyvinylidene chloride (PVdC), pose environmental and chemical migration risks, while polyethylene terephthalate (PET) lacks sufficient oxygen barrier properties and is difficult to trim, deform under heat, and requires additives for proper performance.
Innovation Solution
A packaging structure comprising a cap layer of post-consumer resin, an alloy layer of polyethylene terephthalate and polyolefin with a compatibilizer, and a barrier coating of polyethyleneimine and polyvinyl alcohol, providing a sustainable, recyclable solution with enhanced oxygen and moisture barriers, hot fill capability, and improved trimability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PET is used as packaging material, then strength and basic barrier properties are improved, but oxygen barrier characteristics are insufficient
Solution Approach 1:
The patent applies composite materials by combining PET with a barrier coating layer containing oxygen scavengers (such as ascorbic acid, ferrous sulfate, or gallic acid) and hydrophobic polymers. This composite structure provides both the mechanical strength of PET and the enhanced oxygen barrier properties of the coating layer, resolving the contradiction between strength and oxygen barrier characteristics.
2Ease of manufacture
If PET is used for packaging, then basic packaging properties are achieved, but trimability is poor and plastic fragments may contaminate packaging
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of PET through the application of a barrier coating layer. This coating layer changes the physical and chemical parameters of the material surface, improving trimability and preventing plastic fragment contamination while maintaining the basic packaging properties of PET.
3Temperature
If conventional PET containers are heated to 180°F, then hot fill capability is achieved, but container deformation occurs
Solution Approach 1:
The patent applies beforehand cushioning by incorporating heat-resistant additives and a barrier coating layer before the hot fill process. These pre-applied protective elements cushion against thermal stress and prevent deformation when the container is heated to 180°F for hot fill applications.
4Ease of manufacture
If HIPS is used in food-contact applications, then ease of manufacture is improved, but environmental and chemical migration risks increase
Solution Approach 1:
The patent applies the taking out principle by removing HIPS from the food-contact application and replacing it with PET-based composite materials. This extraction eliminates the harmful chemical migration risks associated with HIPS while maintaining ease of manufacture through the use of food-safe PET and approved additives.
Data Source
AI summary
In an embodiment, the invention comprises a packaging structure comprising a cap layer which comprises post-consumer resin, at least one additional layer adjacent the first layer which comprises an alloy of: polyethylene terephthalate; a polyolefin; and at least one compatibilizer; a barrier coating adjacent the at least one additional layer and opposite the cap layer, wherein the barrier coating comprises a matrix of polyethyleneimine and polyvinyl alcohol and an overlacquer about the barrier coating. The methods of the invention may include co-extruding the cap layer and an alloy layer to form a co-extrudate; optionally, melt adhering the co-extrudate to another alloy layer to form a melt-adhered sheet; intermixing a solution of polyethyleneimine, polyvinyl alcohol, and water to form a coating; applying the coating to the outermost alloy layer opposite the cap layer; drying the applied coating; applying an overlacquer about the coating; and drying the overlacquer.