Coating Material for Food Packaging Resists Yellowing
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Solution Overview
Problem
Current food packaging paper materials lack sufficient safety standards, particularly in terms of water resistance, oil resistance, weatherability, and heat-sealing properties, and often suffer from yellowing and poor recycling characteristics.
Innovation Solution
A coating material comprising an aqueous emulsion polymerized with a polymerizable unsaturated monomer composed mainly of (meth)acrylic acid esters, blended with a copolymer having a carboxyl group, which enhances water resistance, oil resistance, heat-sealing properties, and weatherability while being safe for human use and the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluorine-based resin is used as an oilproof agent, then oil resistance is improved, but harmful factors increase due to inert gas generation and accumulative components
Solution Approach 1:
The invention changes the chemical composition parameters by using a copolymer with specific acid value (100-300 mgKOH/g) and controlled functional groups instead of fluorine-based resin, achieving oil resistance through different chemical mechanisms that don't produce harmful byproducts
Solution Approach 2:
The invention uses a composite coating system combining copolymer with carboxyl group, polyvinyl alcohol, and specific additives to achieve oil resistance without fluorine-based resin, creating a multi-component material system that provides protection without harmful effects
2Reliability
If a synthetic resin emulsion is applied to achieve oil resistance, then oil resistance is improved, but blocking occurs during winding
Solution Approach 1:
The invention controls the glass transition temperature of the polymer at 30°C or lower, which maintains the coating's flexibility and prevents blocking during winding while preserving oil resistance properties
3Reliability
If a barrier composition is applied to improve water and oil resistance, then water resistance and oil resistance are improved, but weatherability deteriorates causing yellowing
Solution Approach 1:
The invention uses specific monomer compositions ((meth)acrylic acid ester with controlled Tg) and copolymer ratios to achieve a balance between barrier properties and weatherability, preventing yellowing while maintaining water and oil resistance
Solution Approach 2:
The invention employs a composite system including copolymer, polyvinyl alcohol, and specific additives that work synergistically to provide both barrier properties and improved weatherability, preventing the yellowing issue
4Reliability
If the application amount of substitute resin is increased to replace fluorine-based resin, then oil resistance is maintained, but cost performance deteriorates
Solution Approach 1:
The invention optimizes the acid value of the copolymer (100-300 mgKOH/g) and the ratio of components to achieve effective oil resistance at lower application amounts, improving cost performance while maintaining protection
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 coating material significantly improves the safety and performance of food packaging materials by providing excellent water resistance, oil resistance, and heat-sealing properties without yellowing, making them suitable for food packaging containers and ensuring compliance with FDA standards.
Implementation Method 1
an aqueous emulsion obtainable by polymerizing a polymerizable unsaturated monomer in the presence of a copolymer having a carboxyl group
Implementation Method 2
the copolymer having a carboxyl group is blended in an amount of 10 to 50 parts by mass based on 100 parts by mass of the total mass of the polymerizable unsaturated monomer
Implementation Method 3
excellent water resistance, oil resistance, heat-sealing properties and weatherability
Implementation Method 4
heat-sealing properties at a level required in the food industry
Implementation Method 5
the end of the paper cup is formed by heating after applying the barrier composition
Implementation Method 6
excellent water resistance, oil resistance, weatherability and heat-sealing properties
Implementation Method 7
poor weatherability and sometimes underwent yellowing after being applied on a paper container
Data Source
AI summary
Disclosed is a coating material comprising (B) an aqueous emulsion obtainable by polymerizing (b) a polymerizable unsaturated monomer in the presence of (A) a copolymer having a carboxyl group, wherein the polymerizable unsaturated monomer (b) comprises (b1) a (meth)acrylic acid ester, and the content of the (meth)acrylic acid ester (b1) is more than 95 parts by mass based on 100 parts by mass of the total mass of the polymerizable unsaturated monomer (b).