Propylene-Based Polymer Hot Melt Adhesive Heat Creep
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Solution Overview
Problem
Conventional hot melt adhesives face challenges in achieving a balance between heat creep resistance and open time, with increased additives affecting cohesive force and flexibility, and existing solutions either compromise on heat resistance or open time.
Innovation Solution
A propylene-based polymer with specific molecular weight and pentad fraction ranges is used as a modifier in combination with an ethylene-based polymer, along with tackifier resin and wax, to create a hot melt adhesive with improved heat creep resistance and moderate open time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the amount of plasticizer or other additives is increased to prolong the open time, then the open time is improved, but the cohesive force is decreased
Solution Approach 1:
The invention changes the chemical composition parameters by introducing a specific propylene-based polymer with controlled microstructure (mmmm 20-80 mol%, Mw 1,000-150,000, Mw/Mn ≤ 3.0) to achieve the desired balance between open time and cohesive force without relying on excessive additives
Solution Approach 2:
The invention creates a composite adhesive system combining the propylene-based polymer with ethylene-based polymer, tackifier resin, and wax in specific proportions (1-30 parts propylene-based polymer per 100 parts ethylene-based polymer) to achieve synergistic effects that resolve the contradiction between open time and cohesive force
2Strength
If the amount of tackifier resin is increased to improve the cohesive force or heat resistance, then the cohesive force is improved, but the flexibility is decreased
Solution Approach 1:
The invention changes the polymer microstructure parameters (mmmm, Mw, Mw/Mn) to achieve the desired balance between cohesive force and flexibility, reducing the need for excessive tackifier resin addition
Solution Approach 2:
The composite system combines propylene-based polymer with ethylene-based polymer and other additives in optimized ratios, where the propylene-based polymer provides cohesive force while the ethylene-based polymer maintains flexibility
3Ease of manufacture
If a conventional hot melt adhesive formulation is used, then the adhesive can be manufactured easily, but the balance between heat creep resistance and open time is insufficient
Solution Approach 1:
The invention specifies precise parameter ranges for the propylene-based polymer (mmmm 20-80 mol%, Mw 1,000-150,000, Mw/Mn ≤ 3.0) to achieve both heat creep resistance and adequate open time while maintaining ease of manufacture through standard polymerization processes
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 resulting adhesive exhibits an excellent balance between heat creep resistance and open time, enhancing its applicability in various temperature conditions and bonding scenarios.
Implementation Method 1
a hot melt adhesive which is melted by heating and coated onto an adherend, followed by cooling to solidify the adhesive
Data Source
AI summary
A propylene-based polymer which satisfies the following (a1) to (d1): (a1) [mmmm]=60 to 80 mol %; (b1) weight-average molecular weight (Mw)=10,000 to 55,000; (c1) Mw/Mn≦2.5; and (d1) [rmrm]≦2.5 mol %.