Hot Melt Adhesive Block Composite Compatibilizer
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Solution Overview
Problem
Hot melt adhesives (HMAs) based on high flow, low crystallinity polyethylene polymers face challenges in niche applications requiring improved performance at high temperatures, such as cardboard box packaging and insulation coatings, due to poor fiber tear, peel adhesion, and increased set time when polyethylene or propylene-based polymers are blended, resulting in undesirable properties.
Innovation Solution
A HMA composition incorporating a block composite compatibilizer (BCC) comprising a hard propylene polymer, a soft ethylene polymer, and a block copolymer with specific ethylene and propylene content ratios, combined with a tackifier and wax/oil, to enhance adhesive properties and reduce set time under stress conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyethylene polymer or wax and propylene-based polymer or wax are added to improve high temperature performance, then high temperature resistance is improved, but blending compatibility deteriorates resulting in poor fiber tear, poor peel adhesion, and increased set time
Solution Approach 1:
The patent introduces a block copolymer as a compatibilizer that contains both propylene and ethylene segments. This block copolymer acts as an intermediary between the incompatible polyethylene/wax and propylene-based polymer/wax phases, enabling them to blend properly while maintaining high temperature resistance. The block copolymer's dual composition allows it to interact with both polymer types, resolving the compatibility issue.
Solution Approach 2:
The patent creates a composite adhesive formulation that combines polyethylene-based components (for high temperature resistance), propylene-based components (for processability), and a block copolymer compatibilizer. This composite approach allows the system to achieve properties from both polymer types while avoiding their incompatibility through the structured blend design.
2Temperature
If polyethylene polymer or wax and propylene-based polymer or wax are blended to achieve desired properties, then high temperature performance is improved, but set time increases
Solution Approach 1:
The patent modifies the compositional parameters of the adhesive by incorporating a block copolymer with specific propylene and ethylene content ratios. This parameter change in the blend composition accelerates the crystallization kinetics and reduces set time while preserving the high temperature performance achieved through the polyethylene/propylene combination.
Solution Approach 2:
The block copolymer compatibilizer mediates the interaction between polyethylene and propylene phases, facilitating faster phase integration and crystallization. This intermediary action reduces the time required for the adhesive to set while maintaining the thermal properties provided by the combined polymer system.
3Temperature
If polyethylene polymer or wax and propylene-based polymer or wax are blended to improve high temperature performance, then thermal resistance is improved, but adhesive strength deteriorates
Solution Approach 1:
The block copolymer compatibilizer acts as an intermediary that enhances interfacial adhesion between the polyethylene and propylene phases. By improving the compatibility and interfacial bonding between these phases, the block copolymer ensures that the adhesive maintains strong peel adhesion properties while benefiting from the high temperature resistance of both polymer systems.
Solution Approach 2:
The patent designs a composite adhesive system where the block copolymer creates a synergistic effect between polyethylene and propylene components. This composite structure ensures that the adhesive strength is enhanced or maintained through improved phase compatibility, while the high temperature performance is achieved through the combined thermal resistance of both polymer types.
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 HMA composition exhibits improved adhesive properties, including enhanced fiber tear, peel adhesion, and reduced set time at elevated temperatures, addressing the limitations of traditional HMA blends by optimizing the compatibility and crystallization of the polymer phases.
Implementation Method 1
The HMA composition exhibits improved adhesive properties, including enhanced fiber tear, peel adhesion, and reduced set time at elevated temperatures, addressing the limitations of traditional HMA blends by optimizing the compatibility and crystallization of the polymer phases.
Data Source
AI summary
A hot melt adhesive (HMA) composition includes (A) from 1-60 wt% of a block composite compatibilizer comprising (i) a hard polymer that includes propylene, (ii) a soft polymer that includes ethylene, and (iii) a block copolymer having a soft block and a hard block, the hard block of the block copolymer having the same composition as the hard polymer of the block composite compatibilizer and the soft block of the block copolymer having the same composition as the soft polymer of the block composite compatibilizer; (B) from 1-70 wt% of a tackifier; (C) from 1-40 wt% of at least one selected from the group of a wax and an oil; and (D) Optionally, from greater than zero to 97 wt% of a polymer component that includes an ethylene-based polymer and/or a propylene-based polymer.