Biodegradable Polymer Coating for Cellulosic Fiber Food Service Items
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Solution Overview
Problem
Conventional disposable food service items coated with non-biodegradable polymers like polyethylene, polypropylene, or polyethylene terephthalate do not degrade in landfills, leading to long-term environmental issues despite improved water and grease resistance.
Innovation Solution
A biodegradable food service item featuring a substrate made from cellulosic fibers coated with a mixture containing 25 to 60 weight percent of biodegradable polymers such as polyhydroxyalkanoates, polylactic acid, or polycaprolactone, along with water and additives like surfactants and biocides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-biodegradable polymers (polyethylene, polypropylene, polyethylene terephthalate) are used to coat paperboard food service items, then water and grease resistance is significantly improved, but the items do not degrade in landfills and subsist for centuries
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by using biodegradable polymers (polyhydroxyalkanoates, polylactic acid, polycaprolactone) instead of conventional non-biodegradable polymers. This parameter change maintains the protective function (water and grease resistance) while enabling biodegradation, thus resolving the contradiction between reliability and environmental harm.
Solution Approach 2:
The patent creates a composite coating system combining biodegradable polymers with water and various additives (surfactants, biocides, rheology modifiers) to achieve both protective performance and biodegradability. The composite nature allows optimization of both functional properties and environmental compatibility.
2Duration of action of stationary object
If paperboard is used as a substrate for food service items, then the item is biodegradable and decomposes quickly after landfill disposal, but the paperboard rapidly soaks up water and grease which compromises its strength
Solution Approach 1:
The patent applies a thin film coating of biodegradable polymer over the paperboard substrate. This thin film acts as a protective barrier that prevents water and grease penetration while maintaining the underlying paperboard's biodegradability. The coating provides the necessary mechanical protection without compromising the environmental benefits.
Solution Approach 2:
The patent creates a composite structure combining paperboard substrate with a biodegradable polymer coating. This composite material integrates the biodegradability of paperboard with the water and grease resistance of the polymer coating, achieving both rapid decomposition and maintained strength when wet.
3Object-generated harmful factors
If a biodegradable coating is applied to maintain environmental friendliness, then the item degrades over time, but achieving good water and grease resistance comparable to non-biodegradable coatings is challenging
Solution Approach 1:
The patent optimizes multiple parameters of the biodegradable coating including polymer selection (polyhydroxyalkanoates, polylactic acid, polycaprolactone), molecular weight (50,000 to 2.5 million Daltons), coating weight (5 to 50 grams per square meter), and formulation composition (25 to 60 weight percent polymer, 40 to 75 weight percent water). These parameter changes enable the coating to achieve both biodegradability and performance comparable to conventional coatings.
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 biodegradable coating provides water and grease resistance comparable to non-biodegradable coatings while ensuring the entire food service item degrades over time, reducing environmental impact.
Implementation Method 1
the coating provides water and grease resistance comparable to that provided by conventional, nonbiodegradable coatings
Implementation Method 2
The coating, prior to curing or drying, is made up of from about 25 to about 60 weight percent of at least one biodegradable polymer and typically from about 40 to about 75 weight percent water
Data Source
AI summary
A biodegradable food service item is disclosed, which includes a biodegradable substrate having at least one food contact surface. This substrate is made of cellulosic fibers. The food service item also includes a coating applied over the at least one food contact surface. This coating is made up of from about 25 to about 60 weight percent of at least one biodegradable polymer, such as polyhydroxyalkanoates. A method for making the biodegradable food service item is also disclosed.