Moisture Barriers for Food Packaging

Sustainable, high-barrier, food-contact packaging materials and methods that replace traditional materials like HIPS and PVdC. The packaging uses a formable sheet made from a specific alloy of polymers, coated with a barrier layer containing polyethyleneimine (PEI) and polyvinyl alcohol (PVOH). The alloy layers have a composition of PET, HDPE, and a compatibilizer. The barrier coating provides oxygen and moisture barrier properties without compromising the sheet strength during forming. The coating composition and method involve intermixing PEI and PVOH with water to create a stretchable, formable gel. This gel-coated alloy sheet can be thermoformed into containers without rupturing the barrier layer. The coating composition and method avoid using HIPS and PVdC, which are banned in some jurisdictions due to environmental concerns.

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Aqueous dispersion of ethyl cellulose with plasticizer for coating substrates like paper to improve moisture barrier properties. The dispersion contains 40-90 wt% ethyl cellulose and 10-50 wt% plasticizer. Coating substrates with this dispersion provides film layers with 40-90 wt% ethyl cellulose and 10-50 wt% plasticizer. This enables high moisture barrier films on paper without solvents. The plasticizer allows ethyl cellulose dispersion coating without blocking. Coating multiple layers further improves barrier.

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Multilayer moisture barrier films for packaging applications that maintain desired moisture levels inside sealed packages without the need for metal barriers. The moisture barrier films have inner layers containing desiccant particles dispersed in a polymer matrix. The desiccant particles absorb moisture from the packaged product. The inner layers can have cavities with desiccant particles inside to further improve moisture barrier properties. The cavities provide multiple points of contact for moisture to interact with the desiccant. The desiccant-containing inner layers replace metal barriers while still maintaining moisture levels inside sealed packages.

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Flexible packaging for hot-fill and retort applications that can survive pasteurization, boiling, and retorting without compromising the integrity of the barrier layer. The packaging structure has a patterned barrier coating that avoids the cut edges and seal areas. This protects the barrier from moisture exposure during processing. The barrier coating is applied only to the interior surface of the panels, leaving those areas around the seams barrier-free. This allows the packaging to withstand high heat and moisture without delaminating or ruining the product inside. It uses a single polymer for recyclability.

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Barrier composite film with improved properties like reduced hygroscopicity, enhanced mechanical strength, and reduced aging compared to conventional barrier films. The composite film consists of layers in order: LDPE, IPN1, EVOH, IPN2, modified PVA. The IPN layers are interpenetrating polymer networks made of specific compositions. The EVOH layer is ethylene vinyl alcohol copolymer. The modified PVA layer is polyvinyl alcohol with added compatibilizer and slip agent. This composite film structure provides improved barrier properties and processing ease compared to single-layer EVOH films.

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A fresh produce packaging solution that prevents high water vapor generating produce from being prematurely desiccated, while at the same time preventing pooling of excess moisture within the package. The solution is a laminate film for packaging fresh produce that allows a limited exchange of moisture with the environment while preventing gas exchange. The film has a first layer with low moisture vapor transport and a second layer with high moisture vapor transport. Windows in the second layer allow excess moisture to escape without gas exchange. This creates a moisture-controlled environment inside the package that avoids desiccation of the produce while preventing excessive moisture buildup.

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Sustainable, high-barrier, food-contact packaging made from a formable sheet with improved oxygen and moisture barrier properties. The sheet contains a barrier coating sandwiched between alloy layers. The barrier coating is a premixed solution of polyethyleneimine and polyvinyl alcohol. The alloy layers are blends of polyethylene terephthalate, a polyolefin, and a compatibilizer. The alloy layers provide mechanical strength and formability. The barrier coating provides oxygen and moisture barrier properties. The coating composition and application method are optimized to avoid rupture during thermoforming and container filling.

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Fully biodegradable cling film with improved moisture barrier for food packaging. The film has two biodegradable cellulose outer layers sandwiched around a starch-based water absorbent layer. The outer layers have water holes on one end to allow air inlet during packaging. This allows the starch layer to absorb moisture from the food instead of condensing inside the film, preventing spoilage and extending shelf life. The entire film is fully biodegradable for environmental benefit.

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Paper-based packaging with improved oxygen and moisture barrier properties for food packaging. The packaging uses a cellulosic fiber substrate with an inner PVOH oxygen barrier layer and an outer moisture barrier layer. The inner moisture barrier can be a polyolefin or functionalized polyolefin. The PVOH layer seals against the moisture barrier to create a hermetic package. The cellulosic substrate allows recyclability. The PVOH inner layer prevents oxygen degradation, while the moisture barrier prevents spoilage. The inner moisture barrier prevents delamination between the layers.

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High-barrier packaging film for controlled atmosphere preservation that extends the shelf life and safety of packaged products like food and medicine. The film has multiple layers stacked inside-out: base layer, inner ethylene-ethanol copolymer layer, inner o-phenylphenol layer, outer polyethylene layer. This provides improved barrier properties against oxygen, moisture, and bacteria compared to single layer films. The inner layers prevent gas and moisture permeation, while the outer polyethylene layer provides strength and sealing. The stacked layers are bonded together. The film can be wrapped around a drum for production and transport, then opened by cutting the outer polyethylene layer.

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Food product containers with improved barrier properties to prevent oxygen and moisture ingress, especially for thin-walled containers like yogurt cups. The containers have a multi-layer structure with an inner barrier layer sandwiched between two outer skin layers. The barrier layer contains a specific composition of polypropylene copolymer, Ethylene Vinyl Alcohol (EVOH), and a tie additive. The EVOH provides the barrier against oxygen and moisture, while the polypropylene copolymer and tie additive improve the container's mechanical properties and processing. The tie additive is an anhydride-modified polypropylene resin.

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Multilayer packaging film for food applications that maintains transparency after sterilization and shaking. The film has three layers: a polyolefin outer layer, an inner ethylene-vinyl alcohol copolymer (EVOH) barrier layer, and another polyolefin inner layer. The EVOH barrier layer sandwiched between the polyolefin layers prevents gas and moisture permeation. The outer polyolefin layer has a higher water vapor transmission rate than the inner layer to prevent delamination. The film retains transparency after sterilization and shaking due to the EVOH barrier and balanced water vapor transmission rates.

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Modified atmosphere cling film for extended shelf life of fruits and vegetables. The film has controlled gas and water permeability to maintain ideal storage conditions for produce. The film is made by adjusting the composition of hyperbranched polyethylene, branched polyethylene, and polyethylene vinyl acetate resin. The hyperbranched polyethylene provides gas permeability and reduces crystallization. The branched polyethylene reduces crystallization further. The vinyl acetate resin forms an island structure with adjustable density to control water vapor transmission. This simultaneous gas and water permeability prevents rot and decay by allowing CO2 and O2 exchange while preventing excessive moisture buildup.

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Modified atmosphere fresh-keeping high barrier packaging film that extends shelf life and inhibits bacterial growth. The film has a base layer sandwiched between two polyethylene layers. Inside the polyethylene layers, an ethylene-ethanol copolymer layer and an o-phenylphenol layer provide freshness preservation. An outer high barrier layer made of polyethylene terephthalate film further enhances barrier properties. The layers are bonded with adhesive. The inner side of the film wraps around a drum for winding. The drum ends rotate to seal the film.

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Erectable-type food container with improved moisture resistance to prevent seepage and leaking of moisture and oil from the contents. The container has a sealed bottom and side walls adhered to the bottom using an insoluble sealing material that prevents moisture infiltration. This sealing material seals the joint between the bottom and side walls to prevent moisture seepage.

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A polyester film for maintaining freshness of packaged fruits and vegetables. The film has specific oxygen and carbon dioxide permeabilities, folding angle, and thermal shrinkage properties that allow easy resealing and extended storage life. The oxygen permeability is 50-1000 cc/m2/day, carbon dioxide permeability is 200-4950 cc/m2/day, folding holding angle is 20-80 degrees, and warm water thermal shrinkage is 0-10%. The film is made from a polyester resin containing ethylene terephthalate. The unique properties enable the film to be easily twisted and folded to reseal after opening, preventing contents from spilling out. The optimized oxygen and carbon dioxide permeabilities extend storage life by maintaining low oxygen and high carbon dioxide

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Spray coating fiber-based food packaging to improve barrier properties like oil, moisture, and vapor transmission. The coating is applied using specialized spray systems with nozzles configured to cover specific areas like bottoms and sidewalls. The coating chemistry includes additives like alkyl ketene dimer (AKD) for moisture barrier, fluorocarbon emulsions for oil barrier, and retention aids. This allows fiber containers to replace plastics in food applications without compromising performance.

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Fresh-keeping anti-fog packaging film for fruits and vegetables that extends shelf life by inhibiting decay. The film has an ink layer for printing, a barrier coating to block oxygen, a biaxially stretched polypropylene layer for strength, and an outer hydrophobic anti-fog coating. The anti-fog coating is on the inside facing the fruits/vegetables to prevent water droplets and high humidity. The barrier coating reduces oxygen levels to inhibit respiration. The film wraps the produce to protect it.

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Packaging systems for storing moisture-inducing foods like fruits, bread, cheese, and meats that release an antimicrobial agent to extend shelf life. The packaging has multilayer films with barrier layers that activate and lose barrier properties in humid environments. The active agent layer between these barrier layers is moisture-sensitive, absorbing moisture and diffusing into the food to provide antimicrobial protection. This controlled release prevents premature loss of the agent from the packaging.

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A composite food packaging film that combines freshness preservation and water vapor barrier properties. The film has three layers arranged sequentially: a barrier layer, an opaque water-absorbing layer, and an air-permeable layer. The opaque water-absorbing layer is located inside a recessed groove on the air-permeable layer. This configuration allows the opaque layer to absorb moisture from packaged food without affecting the barrier layer, while the air-permeable layer allows gas exchange. The groove prevents the opaque layer from contacting the food surface.

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