Biodegradable Lamination Film for Adhesion and Home Compostability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing biodegradable composite films do not meet the requirements for flexible packaging in terms of biodegradability, adhesion to substrates, and mechanical and barrier properties, particularly failing to be home compostable and suitable for all applications.
Innovation Solution
A laminating film with a 0.5 to 7 µm thick adhesive layer containing polyurethane or acrylate and a 5 to 150 µm thick layer B comprising aliphatic or aliphatic-aromatic polyester, optionally with lubricants, providing excellent adhesion to substrates like paper or cardboard and enhanced biodegradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional biodegradable polymers are used for coating paper, then biodegradability is improved, but adhesion to paper and mechanical properties deteriorate
Solution Approach 1:
The coating is divided into multiple functional layers: a bottom layer containing biodegradable polyester (providing adhesion and structural support) and a top layer containing the biodegradable polymer (providing biodegradability and surface properties). This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The invention uses a composite film structure combining biodegradable polyester with other biodegradable polymers in a multi-layer configuration. The polyester layer acts as an adhesive base while the top layer provides the required biodegradability and surface characteristics, creating a composite material that achieves both strong adhesion and high biodegradability.
2Strength
If adhesive layers are added to improve bonding, then adhesion is improved, but biodegradability deteriorates
Solution Approach 1:
The adhesive layer uses polyester with specifically controlled parameters (molecular weight, composition, and crystallinity) to achieve optimal balance between adhesion strength and biodegradability. The polyester is formulated to provide sufficient bonding while maintaining susceptibility to biodegradation under composting conditions.
Solution Approach 2:
Different regions of the coating have different properties: the bottom layer (adhesive layer) is formulated with polyester optimized for bonding to paper, while the top layer is formulated with biodegradable polymers optimized for surface properties and degradation. This local differentiation allows each region to perform its specific function optimally.
3Ease of manufacture
If lubricants are added to improve processing, then ease of manufacture is improved, but adhesion deteriorates
Solution Approach 1:
The lubricant is extracted or removed before the lamination process. The coating is applied and dried to remove volatile components including lubricants, ensuring that no substances remain to interfere with the adhesion between the coating and the paper substrate.
Solution Approach 2:
The coating is dried and prepared in advance before lamination, removing lubricants and other volatile components beforehand. This preliminary action ensures that the adhesion process occurs without interference from lubricant residues.
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 laminating film achieves high adhesion and biodegradability, making it suitable for home composting and meeting the stringent requirements of flexible packaging, including mechanical and barrier properties.
Implementation Method 1
Layer A, also known as the adhesive layer, bonds layer B to the substrate. Layer A has a thickness of 0.5 to 7 μm and contains a polyurethane or acrylate adhesive.
Implementation Method 2
The composite films described in WO 2012/013506 do not sufficiently meet this criterion [home compostability]... The laminating films described at the beginning meet these criteria... are preferably home compostable
Data Source
AI summary
The present invention relates to a biodegradable laminating film having the layer structure A/B, wherein the 0.5 to 7 μm thick layer A comprises a polyurethane adhesive or acrylate adhesive; and wherein the 5 to 150 μm thick layer B comprises an aliphatic polyester and/or aliphatic-aromatic polyester, wherein the aliphatic-aromatic polyester is composed as follows: b1-i) 30 to 70 mol %, based on components b1-i and b1-ii, of a C6-C18- dicarboxylic acid; b1-ii) 30 to 70 mol %, based on components b1-i and b1-ii, of terephthalic acid; b1-iii) 98 to 100 mol %, based on components b1-i and b1-ii, of 1,3-propanediol or 1,4-butanediol; b1-iv) 0 to 2 wt.%, based on the components b1-i and b1-iii, of a chain extender and/or branching agent.