Lamination Ionomer Composition for Hot Tack and Thin Sealant Layers
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Solution Overview
Problem
Conventional ethylene-based ionomers with multi-branched molecular structures lack strength and exhibit poor heat-sealing properties, particularly in hot tack strength, limiting packaging speed and processability.
Innovation Solution
A polymer resin composition using a novel ethylene-based ionomer with a substantially linear molecular structure, converted into a metal-containing carboxylic acid salt, which includes structural units derived from ethylene, α-olefins, and monomers with carboxyl or dicarboxylic anhydride groups, enhancing heat-sealing properties and hot tack strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional high-pressure radical polymerization method is used to produce polar group-containing olefin copolymer, then polymerization is possible at low cost and with flexible monomer selection, but the molecular structure becomes multi-branched type with many long-chain and short-chain branches resulting in insufficient strength
Solution Approach 1:
The patent changes the polymerization parameters by introducing a chain transfer agent with a specific structure (formula 1) that has a carbon-carbon double bond and a leaving group. This chain transfer agent modifies the polymerization mechanism to produce copolymers with controlled branching, transforming the molecular structure from multi-branched to substantially linear while maintaining the ease of manufacture through the same high-pressure radical polymerization process
Solution Approach 2:
The chain transfer agent acts as an intermediary substance during polymerization. It temporarily incorporates into the polymer chain and then eliminates through beta-elimination, facilitating the formation of linear molecular structures. This intermediary enables the transformation of the polymerization outcome without changing the fundamental polymerization method
2Ease of operation
If ethylene-based ionomer with multi-branched molecular structure is used, then it provides toughness, high elasticity, flexibility, and wear resistance, but it lacks strength and has poor heat-sealing properties particularly in hot tack strength
Solution Approach 1:
The patent changes the molecular structure parameter from multi-branched to substantially linear by using a specific chain transfer agent during polymerization. This structural change fundamentally alters the material properties, providing both the desired flexibility and the improved strength and heat-sealing properties simultaneously
3Productivity
If sealant layer is made thinner to increase packaging speed, then packaging efficiency improves, but heat-sealing strength and hot tack strength decrease
Solution Approach 1:
The patent changes the molecular structure parameter of the sealant layer material from multi-branched to substantially linear, which fundamentally improves the material's strength characteristics. This allows the sealant layer to maintain high heat-sealing strength even at reduced thickness, thereby enabling increased packaging speed without sacrificing sealing quality
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 composition achieves improved heat-sealing properties and hot tack strength, allowing for increased packaging speed and reduced sealant layer thickness, thereby enhancing the properties of packaging materials.
Implementation Method 1
it has a capability of undergoing beta-elimination to form a carbon-carbon double bond and eliminate a leaving group
Implementation Method 2
a polar group-containing olefin copolymer in which a polar group-containing monomer such as ethylene and an unsaturated carboxylic acid, etc., are polymerized by the high-pressure radical polymerization method
Data Source
AI summary
A polymer composition for lamination characterized in that the composition consists of (X1) 100 to 60% by weight of an ionomer characterized in that at least a part of a carboxyl group and/or a dicarboxylic anhydride group in a copolymer (P) containing a structural unit (A) derived from ethylene and/or an α-olefin having 3 to 20 carbon atoms and a structural unit (B) derived from a monomer having a carboxyl group and/or a dicarboxylic anhydride group as essential constitutional units being converted into a metal-containing carboxylic acid salt containing at least one kind of a metal ion(s) selected from Group 1, Group 2 or Group 12 of the periodic table, and a phase angle δ of the ionomer at an absolute value G*=0.1 MPa of a complex modulus of elasticity measured by a rotary rheometer is a range of 50 degrees to 75 degrees, and (X2) 40 to 0% by weight of an ethylene-based copolymer.