Amorphous Poly-α-Olefin Adhesive Low Temperature Application
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Solution Overview
Problem
Conventional hot melt adhesives require high processing temperatures, leading to polymer degradation, increased energy costs, and reduced mechanical strength when applied to nonwoven articles, especially in the production of disposable absorbent products, due to high viscosity and the need for large quantities of low molecular weight diluents which compromise adhesive strength and appearance.
Innovation Solution
Development of a low application temperature hot melt adhesive using an amorphous poly-α-olefin copolymer with a softening point of 70 to 105°C and viscosity less than 1900 cP at 190°C, specifically an amorphous polybutene copolymer, which maintains mechanical strength and resistance to flow, allowing for application below 150°C without significant diluent addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high molecular weight polymer or high polymer content is used to promote cohesive strength and adhesion, then mechanical strength is improved, but melt viscosity increases significantly
Solution Approach 1:
The invention changes the molecular weight parameters of the polymer components. Specifically, it uses a mid-range molecular weight polyolefin (10,000-100,000 g/mol) instead of high molecular weight polymer, and combines it with a low molecular weight polyolefin (100-10,000 g/mol). This parameter optimization achieves adequate cohesive strength while maintaining lower melt viscosity that allows processing at reduced temperatures below 150°C.
2Ease of operation
If high processing temperature is used to reduce adhesive viscosity, then ease of application is improved, but polymer degradation and loss of adhesion occur
Solution Approach 1:
The invention changes the viscosity parameters through optimized polymer molecular weight selection and blending ratio. The specific combination of mid-range and low molecular weight polyolefins creates an adhesive composition with reduced melt viscosity that can be applied at lower temperatures (below 150°C), eliminating the need for high temperature processing that causes polymer degradation.
3Temperature
If large quantities of low molecular weight diluents are added to lower adhesive viscosity, then ease of application is improved, but mechanical strength decreases
Solution Approach 1:
The invention replaces traditional low molecular weight diluents (tackifiers and waxes) with low molecular weight polyolefin (100-10,000 g/mol) as the viscosity-modifying component. This substitution maintains low application temperature capability while preserving mechanical strength, as the polyolefin diluent does not compromise the adhesive's structural integrity or resistance to flow at body temperature.
4Ease of operation
If large quantities of low molecular weight diluents are added to lower adhesive viscosity, then ease of application is improved, but resistance to flow at body temperature is reduced
Solution Approach 1:
The invention substitutes traditional diluents (tackifiers and waxes) with low molecular weight polyolefin (100-10,000 g/mol) blended with mid-range molecular weight polyolefin. This combination provides adequate flow characteristics for application while maintaining sufficient resistance to flow at body temperature, preventing excessive migration and separation over time.
5Temperature
If high processing temperature is used, then energy cost increases and safety hazards increase, but application temperature can be reduced with optimized polymer composition
Solution Approach 1:
The invention changes the thermal parameters through optimized polymer molecular weight selection and blending. The specific combination of mid-range (10,000-100,000 g/mol) and low (100-10,000 g/mol) molecular weight polyolefins creates an adhesive with reduced melting point and viscosity, enabling application at temperatures below 150°C. This directly reduces energy consumption and eliminates safety hazards associated with high temperature processing.
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 peel strength, reduced energy costs, and minimized substrate deformation, with the ability to be sprayed at lower temperatures, providing a cost-effective solution for manufacturing disposable absorbent articles like diapers and sanitary napkins with improved durability and appearance.
Implementation Method 1
amorphous poly-α-olefin copolymer that has a softening point of from about 70 to about 105°C
Implementation Method 2
viscosity of less than about 1,900 cP at 190°C
Data Source
AI summary
It has been discovered that amorphous polybutene copolymers that have a softening point of from about 70 to about 105° C. and viscosity of less than about 1,900 cP at 190° C. possesses desirable properties and may be used to make a low application temperature hot melt adhesive for disposable absorbent articles.