Metallocene Polyolefin Adhesive Creep Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current stretch film lamination adhesives for personal care garments face challenges with creep resistance and bleed-through at elevated temperatures, particularly due to the use of styrene block copolymers and low molecular weight plasticizers, which compromise elasticity and adhesion over time.
Innovation Solution
A stretch film lamination adhesive comprising a metallocene catalyzed polyolefin copolymer with a density greater than 0.870 g/cm³ and a peak melting point above 100°C, combined with a plasticizer of molecular weight greater than 1000 g/mol and a tackifier with a softening point above 110°C, while being essentially free of low molecular weight plasticizers, to achieve high creep resistance and minimal bleed-through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If styrene block copolymers are used as elastomeric adhesives, then good elasticity and adhesion are achieved, but creep resistance deteriorates at elevated temperatures
Solution Approach 1:
The patent changes the chemical composition parameters by replacing styrene block copolymers with metallocene-catalyzed polyolefin copolymers having specific density (≥0.870 g/cm³) and melting point (>100°C) parameters. This parameter transformation resolves the contradiction by achieving both adhesion and creep resistance through fundamentally different material properties.
Solution Approach 2:
The patent creates a composite adhesive formulation combining metallocene-catalyzed polyolefin copolymer with high molecular weight plasticizers (MW >1000 g/mol) and tackifiers (softening point >110°C). This composite approach achieves synergistic effects where each component contributes to both adhesion and high-temperature creep resistance.
2Ease of operation
If low molecular weight plasticizers are added to elastomeric adhesives, then flexibility and adhesion are improved, but bleed-through increases at high temperatures
Solution Approach 1:
The patent fundamentally changes the molecular weight parameter of the plasticizer from low (conventional) to high (>1000 g/mol). This parameter change eliminates bleed-through by preventing low molecular weight species diffusion while maintaining flexibility through the high molecular weight plasticizer's viscoelastic properties.
3Quantity of substance
If the amount of styrene block copolymer is reduced, then raw material cost decreases, but creep resistance deteriorates
Solution Approach 1:
The patent extracts and eliminates styrene block copolymer from the adhesive formulation, replacing it with metallocene-catalyzed polyolefin copolymer. This extraction removes the source of high raw material cost while the replacement material provides equal or superior creep resistance at lower cost.
4Ease of manufacture
If conventional olefin-based adhesives are used, then manufacturing simplicity is maintained, but creep resistance at high temperatures is insufficient
Solution Approach 1:
The patent changes the melting point parameter of the polyolefin copolymer to >100°C and density to ≥0.870 g/cm³, which fundamentally improves high-temperature creep resistance while maintaining conventional hot-melt adhesive manufacturing processes and simplicity.
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 adhesive exhibits a creep recovery of over 60% at 2 psi shear stress at 38°C and low plasticizer migration, maintaining performance and adhesion integrity even after aging at moderate to high temperatures.
Implementation Method 1
the invention relates to adhesives that exhibit desirable viscoelastic properties and are suitable for bonding elastic attachments
Implementation Method 2
the adhesive must exhibit high resistance to creep: not move substantially under a fixed stress
Implementation Method 3
the diffusion of low molecular weight species in the adhesive
Data Source
Figure 1~2
Figure 3
AI summary
The invention provides stretch film laminant adhesives, methods of using the adhesives to bond substrates together, and to articles of manufacture comprising the adhesives. It has been discovered that a stretch film lamination adhesive, which comprises a metallocene catalyzed polyolefin copolymer with a density greater or equal to 0.870g/cm and a peak melting point greater than 100°C, a plasticizer having a number average molecular weight greater than 1,000 g/mol, and a tackifier with a softening point greater than 110°C, has high creep resistance and low plasticizer migration and bleed-through making them particularly well suited for disposable personal care garments.