Cellulosic Barrier Coating with Polyolefin Dispersion for Recyclable Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current recyclable cellulosic structures for packaging lack effective barrier functionalities, such as resistance to oil, grease, and moisture vapor, while also facing issues like stickies and roll blocking during the recycling process, which hinders their sustainability and performance.
Innovation Solution
A cellulosic structure comprising a cellulosic substrate with a single polyolefin aqueous polymer dispersion barrier layer and at least one non-polyolefin aqueous polymer dispersion coating layer, utilizing clay as the primary pigment and minimal calcium carbonate to enhance barrier properties and maintain repulpability and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paper or paperboard is laminated with aluminum foil, plastic film, or extrusion polymer to achieve barrier functionality, then barrier performance is improved, but recyclability and repulpability deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters of the coating layer by using aqueous polymer dispersions with specific polymer types, binder contents, and pigment compositions. This allows the coating to provide high barrier performance while maintaining water solubility and repulpability, enabling recyclability without sacrificing barrier functionality
Solution Approach 2:
The invention creates a composite coating system combining multiple polymer types (polyolefin and non-polyolefin aqueous polymer dispersions) with pigments like clay and calcium carbonate. This composite structure provides enhanced barrier properties while the aqueous nature of the polymers maintains repulpability and recyclability
2Ease of manufacture
If aqueous coated paper or paperboard is used to maintain recyclability, then repulpability is improved, but barrier performance deteriorates
Solution Approach 1:
The invention optimizes parameters including polymer selection (polyolefin and non-polyolefin aqueous dispersions), binder content (5-50% of coating weight), and pigment composition (clay and calcium carbonate ratios) to achieve both high barrier performance and maintained repulpability through controlled coating formulation
3Reliability
If high barrier aqueous coatings with high polymer binder level are used to improve barrier performance, then barrier functionality is improved, but roll blocking occurs
Solution Approach 1:
The invention adjusts the polymer binder content to an optimized range (5-50% of coating weight) and selects specific polymer types with appropriate glass transition temperatures and molecular weights. This parameter optimization provides high barrier functionality while controlling tackiness and preventing roll blocking during processing
Solution Approach 2:
The invention creates different functional zones within the coating layer by incorporating specific polymer types and pigments in controlled distributions. The polyolefin provides barrier function while the non-polyolefin aqueous polymer and pigment composition control surface properties to prevent blocking, achieving localized functional optimization
4Adaptability or versatility
If heat-sealable coatings are applied to cellulosic substrate to improve heat-seal functionality, then heat-sealability is improved, but roll blocking increases due to hot-tack requirement
Solution Approach 1:
The invention selects polymer dispersions with specific glass transition temperatures and molecular weight distributions that enable heat-seal functionality at lower temperatures. The optimized binder content and pigment composition reduce hot-tack formation, allowing heat-sealability while minimizing roll blocking during processing
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 provides a sustainable packaging material with barrier properties comparable to laminated or extrusion polymer-coated paperboard, preventing roll blocking and ensuring effective recyclability without stickies, while maintaining heat-sealability and repulpability.
Implementation Method 1
a single polyolefin aqueous polymer dispersion barrier layer on the first major side of the cellulosic substrate
Implementation Method 2
a single polyolefin aqueous polymer dispersion barrier layer on the first major side of the cellulosic substrate; and at least one non-polyolefin aqueous polymer dispersion coating layer between the single polyolefin aqueous polymer dispersion barrier layer and the first major side of the cellulosic substrate
Data Source
AI summary
A cellulosic substrate includes a first major side and a second major side opposed from the first major side, a single polyolefin aqueous polymer dispersion barrier layer on the first major side of the cellulosic substrate, and at least one non-polyolefin aqueous polymer dispersion coating layer between the single polyolefin aqueous polymer dispersion barrier layer and the first major side of the cellulosic substrate.