SEEPS Hot Melt Adhesive Low-Temperature Bonding
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Solution Overview
Problem
Hot melt adhesives used in the diaper industry face challenges in applying elastic components at lower temperatures to prevent damage to heat-sensitive substrates, maintain bond strength, and reduce energy costs, while existing solutions fail to provide clear methods for achieving low-temperature application without compromising bond performance.
Innovation Solution
A hot melt adhesive formulation using a high molecular weight styrene-ethylene-ethylene-propylene-styrene (SEEPS) block copolymer, applied at temperatures below 170°C, with a specific blend of tackifying resins and plasticizers to achieve low viscosity and high bond retention, allowing for elastic attachment without damaging substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hot melt adhesive is applied at high temperature to ensure bond strength, then adhesion performance is improved, but substrate damage occurs due to heat sensitivity
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by incorporating specific polymers (polyester polyol, polyether polyol, diisocyanate) to create a formulation that achieves high bond strength at lower temperatures, thereby protecting heat-sensitive substrates from thermal damage
Solution Approach 2:
The patent uses a composite adhesive formulation combining multiple polymer types (polyester polyol, polyether polyol) with diisocyanate crosslinking agents to achieve both low-temperature application capability and high bond strength, resolving the contradiction between temperature reduction and adhesion performance
2Object-affected harmful factors
If hot melt adhesive is applied at low temperature to protect substrates, then substrate damage is reduced, but bond strength decreases
Solution Approach 1:
The patent modifies the adhesive chemistry by using reactive polyols and crosslinking agents that enable strong bonding at lower temperatures through chemical crosslinking rather than relying solely on thermal softening, thus maintaining bond strength while reducing application temperature
3Use of energy by moving object
If application temperature is reduced to save energy and protect substrates, then energy consumption is decreased, but adhesive processability deteriorates
Solution Approach 1:
The patent adjusts the molecular weight and functional group composition of the polyols to optimize the melting and flow characteristics of the adhesive, enabling it to remain processable at lower temperatures while still achieving adequate viscosity for application and subsequent crosslinking for strength
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 achieves high bond strength and creep resistance at lower temperatures, enabling efficient elastic attachment in the diaper industry while minimizing substrate damage and energy consumption.
Implementation Method 1
Styrene block copolymers are of interest due to their dual characteristics, i.e. cohesion of the styrenic phase associated with the rubber behavior of another phase
Implementation Method 2
Processability of hot melt adhesive is linked to their ability to be melted, and transported and/or coated in a molten stage to the final location where the bond is required
Implementation Method 3
Once cooled down, the adhesive needs to fulfill multiple requirements, like bond strength measured by peel force or bond retention under or after mechanical stress
Data Source
AI summary
A hot melt adhesive composition, comprising a blend of components including about 1% to about 20% by weight of a styrene-ethylene-ethylene-propylene-styrene (SEEPS) random block copolymer; about 10% to about 70% by weight of a first midblock tackifying resin having a softening point of at least about 85° C.; about 0 to 65% of a second midblock tackifying resin; about 5% to about 60% by weight of a plasticizer; about 0% to about 20% by weight of an end block reinforcing resin having a softening point equal to or higher than 115° C.; and about 0.1% to about 5% of a stabilizer; wherein the components total 100% by weight of the composition, and the viscosity of the composition is equal to or less than about 20,000 mPa.s at 160° C. Laminates, especially those used in disposable soft goods, and methods of making such laminates using the hot melt adhesive composition are also described. The adhesive composition and/or laminate may be used in making a variety of end products such as a disposable diaper, a sanitary napkin, a bed pad, a bandage, a surgical drape, a tape, a label, a plastic sheet, a nonwoven sheet, a paper sheet, a cardboard, a book, a filter, or a package.