Polyolefin Adhesive Heat Stability via Molecular Weight Control
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Solution Overview
Problem
There is a need for adhesives that are heat stable and low in color, with high and low temperature performance capabilities.
Innovation Solution
The development of adhesives comprising functionalized components and olefin polymers with specific properties, such as a Dot T-Peel of 1 Newton or more on Kraft paper, a branching index of 0.95 or less, a weight average molecular weight of 10,000 to 100,000, and a heat of fusion of 1 to 70 J/g, where the Gardner color remains unchanged by more than 7 units after heat aging at 180°C for 48 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesives are used to achieve adequate bonding strength, then they provide basic adhesive performance, but they exhibit poor heat stability and significant color change when heat aged
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight (Mw of 10,000 to 100,000), branching index (g' of 0.95 or less), and heat of fusion (1 to 70 J/g) of the olefin polymer, along with using a functionalized component with specific functional group content (0.1 to 10 weight %). These parameter optimizations enable the adhesive to maintain color stability (Gardner color change of 7 units or less) while achieving heat stability when heat aged at 180° C. for 48 hours.
Solution Approach 2:
The patent uses composite materials by combining the olefin polymer (comprising C3 to C40 olefins) with a functionalized component (selected from functionalized polymers, functionalized oligomers, or beta nucleating agents). This composite structure integrates the heat resistance of the olefin polymer with the adhesive functionality of the functionalized component, achieving both heat stability and color retention while providing bonding strength of 1 Newton or more on Kraft paper.
2Object-generated harmful factors
If adhesive formulations are optimized for low color intensity, then they maintain low Gardner color values, but they may compromise bonding strength or heat resistance
Solution Approach 1:
The patent optimizes the molecular weight parameter (Mw of 10,000 to 100,000) and branching index (g' of 0.95 or less) of the olefin polymer to achieve a balance between color stability and bonding strength. The controlled heat of fusion (1 to 70 J/g) further ensures that the adhesive maintains low color intensity while providing adequate bonding strength of 1 Newton or more on Kraft paper.
3Strength
If the molecular weight of the olefin polymer is increased to improve bonding strength, then higher adhesive strength is achieved, but the heat of fusion increases leading to poorer heat stability
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight (Mw) within the range of 10,000 to 100,000 and the heat of fusion within 1 to 70 J/g. This optimized parameter range enables the adhesive to achieve bonding strength of 1 Newton or more on Kraft paper while maintaining heat stability, as evidenced by Gardner color change of 7 units or less when heat aged at 180° C. for 48 hours.
Data Source
AI summary
Embodiments of the present invention relate to article comprising 1) a functionalized component, 2) tackifier, and 3) an olefin polymer comprising one or more C3 to C40 olefins, optionally one or more diolefins, and less than 5 mole % of ethylene having a Dot T-Peel of 1 Newton or more, a branching index (g′) of 0.95 or less measured at the Mz of the polymer; and an Mw of 100,000 or less; where the functional component is selected from the group consisting of functionalized polymers, functionalized oligomers and beta nucleating agents; and where the Gardner color of the adhesive does not change by more than 7 Gardner units when the adhesive has been heat aged at 180° C. for 48 hours as compared to the Gardner color of the unaged composition.