Deinkable Light-Blocking Coatings for Transparent Containers
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Solution Overview
Problem
Conventional light-blocking solutions for light-sensitive products, such as colored containers, are challenging to recycle due to cross-contamination issues, which are exacerbated by environmental concerns and recycling regulations.
Innovation Solution
A composition comprising a blend of pigments and fillers, binders, and optional additives that provide light-blocking properties while being deinkable, allowing for recyclability by dissolving in an alkaline aqueous medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If colored containers or colored films are used to block light, then light-blocking properties are improved, but recyclability deteriorates due to cross-contamination
Solution Approach 1:
The invention separates the light-blocking function from the container structure by applying a removable colored coating layer on top of a clear container. This segmentation allows the light-blocking property to be provided temporarily during storage, while the base container remains clear and recyclable. The coating can be removed before recycling, preventing cross-contamination of recycling streams.
Solution Approach 2:
The coating composition uses specific binder components (nitrocellulose, polyurethane, maleic resin, or acrylic resin) that change their solubility properties when exposed to alkaline aqueous media. This parameter change allows the coating to be permanently attached during use but easily removed during recycling by dissolving in alkaline solution, thus resolving the contradiction between adhesion and removability.
2Object-affected harmful factors
If conventional colored substrates are used, then light-blocking is achieved, but sortation complexity increases to avoid cross-contamination
Solution Approach 1:
The invention extracts the colored light-blocking property from the container substrate itself and places it in a separate removable coating layer. This allows the container to maintain its original clear color for recycling purposes while still providing light-blocking functionality when needed. The colored coating can be easily removed and discarded, simplifying the recycling sortation process.
3Object-affected harmful factors
If colored films are applied to clear containers, then light-blocking properties are improved, but deinking difficulty increases
Solution Approach 1:
The coating formulation uses binders with specific chemical properties that respond to alkaline conditions. The nitrocellulose, polyurethane, maleic resin, or acrylic resin binders are selected for their solubility characteristics in alkaline aqueous media, enabling easy removal through deinking processes. This parameter change in chemical solubility makes the coating readily removable without complex deinking procedures.
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 composition effectively blocks UV/VIS light transmission by 95-99.9% and can be readily removed from transparent substrates, enabling efficient recycling of containers and substrates.
Implementation Method 1
a layer manufactured from the composition of the present invention can be removed in an alkaline aqueous medium having a pH value from more than 7 to 14
Implementation Method 2
said composition comprising 10-50 wt.-% a blend of a pigment and a filler... capable of at least partially blocking light in the UV/VIS region
Implementation Method 3
Transmittance can be prevented by the effects of absorption or reflectance (scattering)
Data Source
AI summary
The present invention is related to a composition for manufacturing a layer (4a, 4b, 4c) that is capable of at least partially blocking light in the UV/VIS region and is deinkable, said composition comprising a blend of a pigment and a filler. The present invention is also related to a printed article, comprising a transparent substrate (3) and on said transparent substrate (3) at least one ink layer (4a, 4b, 4c) being made from said composition. The present invention is furthermore related to a container for storing a product, preferably a food product, wherein said container comprises a transparent substrate (2) containing on its outer surface said printed article, and to a method for deinking said container.