Hot Melt Adhesive Composition for Wet Peel Strength After Aging
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Solution Overview
Problem
Hot melt adhesives used in nonwoven applications experience significant loss of adhesiveness after aging, particularly in wet conditions, leading to product failure in disposable hygiene and medical products.
Innovation Solution
A hot melt adhesive composition comprising non-amorphous single-site catalyzed polyolefins, amorphous polyolefins, and waxes, which are combined to enhance both dry and wet peel strength after aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hot melt adhesives are used, then initial adhesion is achieved, but adhesion strength decreases significantly after aging and exposure to moisture
Solution Approach 1:
The patent employs a composite adhesive formulation consisting of multiple polyolefin components with different molecular weights and crystallinities, combined with specific additives. This composite structure allows the adhesive to maintain both initial bonding strength and long-term stability after aging, as the different components work synergistically to resist degradation from moisture and time.
Solution Approach 2:
The patent optimizes specific parameters including the molecular weight distribution of polyolefins, the ratio of crystalline to amorphous phases, and the concentration of additives. By carefully controlling these parameters, the adhesive achieves a balance between initial adhesion and aged adhesion performance, particularly improving resistance to moisture-induced degradation.
2Strength
If hot melt adhesive is applied, then substrates are bonded together, but the adhesive joint fails under wet conditions after storage
Solution Approach 1:
The patent incorporates hydrophobic additives and optimizes the polyolefin composition to specifically counteract the harmful effects of moisture. The formulation converts the potential harm of moisture exposure into an opportunity to demonstrate the adhesive's superior water resistance, maintaining bond strength even after prolonged storage in humid conditions.
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating specific ratios of polyolefins with different properties and adding hydrophobic agents. These parameter changes enhance the adhesive's resistance to moisture penetration and hydrolysis, thereby preserving wet peel strength after aging.
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 maintains excellent adhesiveness, both dry and wet, even after long-term storage or exposure to moisture, ensuring the integrity of nonwoven products.
Implementation Method 1
heating the hot melt adhesive composition according to the invention, e.g. at a temperature comprised between 130°C and 180°C, for at least a period of time long enough to render said composition liquid enough to be applied on a substrate
Implementation Method 2
They are applied in the molten state after heating to a temperature most often comprised between 130°C and 180°C, and solidify during cooling, thus forming a seal (or adhesive joint)
Data Source
AI summary
The invention relates to a hot melt adhesive composition comprising: a first non-amorphous single-site catalyzed polyolefin (PO1), a second non-amorphous single-site catalyzed polyolefin (PO2) having a number average molecular weight higher than PO1, an amorphous poly(alpha-olefin) and a wax. The invention also relates to the use of the hot melt adhesive composition according to the invention. Furthermore, the invention relates to a method for bonding substrates implementing the hot melt adhesive composition according to the invention. Finally, the invention relates to an article comprising the hot melt adhesive composition according to the invention.