Barrier Coating for Recycled Paper Packaging
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Solution Overview
Problem
Recycled paper used in cardboard packaging often contains mineral oil residues, which evaporate and contaminate food, posing health risks, and existing barrier coatings are inadequate in preventing the passage of volatile hydrocarbons.
Innovation Solution
Aqueous polymer dispersion with a copolymer produced by emulsion polymerization, using C1 to C4 alkyl (meth)acrylates, acid monomers, and optional acrylonitrile, applied as a barrier layer on packaging to prevent the migration of volatile mineral oil components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If barrier coatings based on water-based polymer compositions are applied to paper and cardboard, then good barrier properties against liquid fatty substances are achieved, but insufficient protection against gaseous mineral oil components is provided
Solution Approach 1:
The patent modifies the chemical composition parameters of the barrier coating by incorporating specific polymer resins with controlled molecular weight, functional groups, and crosslinking density. These parameter changes enable the coating to effectively block gaseous mineral oil components while maintaining barrier properties against liquid fats and oils.
Solution Approach 2:
The invention creates a composite barrier coating system combining water-based polymer compositions with additional functional components such as crosslinking agents, adhesion promoters, and potentially nanomaterials. This composite structure provides multi-mechanism protection against both liquid and gaseous mineral oil contaminants.
2Ease of manufacture
If recycled paper is used for cardboard packaging, then ecological benefits and cost savings are achieved, but mineral oil residues from printing inks contaminate food
Solution Approach 1:
The barrier coating acts as an intermediary layer between the recycled paper containing mineral oil residues and the food being packaged. This intermediate barrier prevents the migration of volatile mineral oil components from the paper to the food, enabling the use of recycled materials while ensuring food safety.
Solution Approach 2:
The invention effectively extracts or removes the harmful mineral oil contamination pathway by applying a barrier coating that selectively blocks volatile hydrocarbons while allowing the recycled paper to maintain its ecological and economic benefits.
3Object-generated harmful factors
If mineral oils are avoided in newspaper printing inks, then food safety is improved, but wiping resistance of the print deteriorates
Solution Approach 1:
The invention converts the potential harm of mineral oil residues in recycled paper into a benefit by using the same mineral oils in printing inks (which provide good wiping resistance) while then using the barrier coating to prevent any migration to food. This approach maintains print quality while ensuring food safety through the barrier layer.
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 solution effectively reduces the risk of food contamination by creating a barrier that limits the permeation of volatile mineral oil components, ensuring safer packaging for food products.
Implementation Method 1
The solution effectively reduces the risk of food contamination by creating a barrier that limits the permeation of volatile mineral oil components
Data Source
AI summary
A description is given of paper or cardboard packaging made from recycled paper with mineral oil contamination, the packaging having a barrier layer which can be produced by applying an aqueous polymer dispersion comprising a copolymer which is preparable by emulsion polymerization of C1 to C4 alkyl (meth)acrylates, acid monomers, such as acrylic acid or methacrylic acid for example, 0-20% by weight of acrylonitrile and 0% to 10% by weight of further monomers, the glass transition temperature of the copolymer being situated in the range from +10 to +45°C. The barrier layer may be located on one of the packaging surfaces, or may form one of a plurality of layers in a multi-layer packaging coating, or may be located as a coating on one side of an inner pouch situated within the packaging.