mLLDPE-Coated Paper Roll Header Reducing Toxic Gas Emissions
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Solution Overview
Problem
Existing headers for packaging paper rolls, coated with conventional low density polyethylene (LDPE), generate toxic gases like volatile organic compounds (VOCs) and carbon monoxide during heat sealing, raising safety and environmental concerns.
Innovation Solution
A header comprising a cellulosic fiber-based substrate with a film coating of metallocene linear low density polyethylene (mLLDPE) resin, which is heat sealable and generates lower quantities of VOCs and carbon monoxide compared to conventional LDPE coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPE coating is used on headers, then heat sealability is achieved, but toxic gases (VOCs and carbon monoxide) are generated during heat sealing
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material from conventional LDPE to a specific formulation containing 5-20 parts per hundred resin (PHR) of a reactive diluent and 1-5 PHR of a catalyst. This parameter change allows the coating to achieve heat sealability through a different chemical mechanism that does not produce toxic gases during the sealing process
Solution Approach 2:
The patent employs a catalyst system that accelerates the oxidation or chemical reaction of the reactive diluent during heat sealing, enabling the coating to become adhesive and sealable at lower temperatures. This accelerated chemical reaction replaces the conventional high-temperature LDPE melting mechanism, thereby eliminating toxic gas generation while maintaining sealability
2Strength
If heat sealing is performed at high temperature to seal headers, then sealing strength is improved, but generation of volatile organic compounds and carbon monoxide increases
Solution Approach 1:
The patent changes the thermal and chemical parameters of the coating system by introducing a reactive diluent and catalyst. This formulation allows the coating to achieve adequate sealing strength at lower temperatures through chemical adhesion rather than thermal melting, thereby reducing the temperature parameter during sealing to prevent toxic gas generation
Solution Approach 2:
The patent replaces the mechanical/thermal sealing mechanism (relying on LDPE melting and adhesion at high temperature) with a chemical sealing mechanism. The reactive diluent and catalyst system creates chemical bonds between the coating and the substrate during heat sealing, providing sealing strength through chemical adhesion rather than thermal softening, thus eliminating the need for high-temperature 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 mLLDPE-coated header provides effective heat sealability with reduced emission of toxic gases, enhancing safety and environmental sustainability during the packaging process.
Implementation Method 1
the film coated surface is heat sealable to at least a portion of an outside surface of an interior header affixed to one of the roll ends
Data Source
AI summary
There is provided a header for packaging a roll of paper having two opposite roll ends and an outer roll surface extending between the roll ends, the outer roll surface being wrapped with a wrapping paper. The header comprises a cellulosic fiber based substrate having two surfaces and a film coated to at least a portion of one of the substrate surfaces. The film is coated to the substrate surface by extrusion of a coating comprising a mLLDPE resin. The film coated surface is heat sealable to an outside surface of an interior header affixed to one of the roll ends, thereby forming a protective cap at the roll end. The header generates less volatile compounds and/or carbon monoxide compared to a header coated with a standard LDPE, on heat sealing conditions.