Polyolefin Hot Melt Adhesive Viscosity Control
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Solution Overview
Problem
Hot melt adhesive compositions containing polybutene-1 visbroken with peroxides often exhibit unpleasant odors and high yellow indices, limiting their use in applications like food packaging due to peroxidic degradation and viscosity issues.
Innovation Solution
A hot melt adhesive composition comprising 25-75 wt.% of a butene-1 copolymer with ethylene, propylene, or C5-C10 alpha-olefins, and 75-25 wt.% of waxes, resins, or additional polymers, tailored to achieve specific melt flow rates and viscosity profiles, avoiding peroxidic degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If peroxides are used to visbreak polybutene-1 to achieve low viscosity values, then viscosity is reduced, but unpleasant odor and high yellow index occur due to peroxidic degradation
Solution Approach 1:
The patent extracts and removes peroxides from the adhesive composition formulation. Instead of using peroxides to achieve low viscosity, the invention uses a peroxide-free polybutene-1 base polymer combined with specific viscosity modifiers (waxes, resins, plasticizers) to achieve the desired rheological properties without peroxidic degradation, thereby eliminating unpleasant odor and yellowing.
Solution Approach 2:
The patent changes the chemical composition parameters by formulating an adhesive containing 25-75 wt.% polybutene-1 and 75-25 wt.% additional components (waxes, resins, plasticizers, polymers). This parameter change allows achieving low viscosity through physical blending rather than chemical degradation, avoiding peroxide-induced harmful effects while maintaining desired flow properties.
2Ease of operation
If peroxides are used to reduce viscosity, then flow properties improve, but thermal stability deteriorates due to peroxidic degradation
Solution Approach 1:
The invention removes peroxides from the formulation and replaces them with peroxide-free polybutene-1 and stabilizing additives. This extraction eliminates the source of peroxidic degradation while maintaining flow properties through alternative rheological modifiers, thereby preserving thermal stability.
Solution Approach 2:
The patent introduces intermediary substances (waxes, resins, plasticizers, and additional polymers) that mediate the viscosity control function without causing thermal degradation. These intermediaries provide the necessary flow properties while protecting the adhesive's thermal stability, acting as substitutes for the harmful peroxide system.
3Ease of operation
If peroxides are used to achieve low viscosity, then application performance improves, but color stability worsens due to high yellow index
Solution Approach 1:
The patent extracts peroxides from the formulation and replaces them with peroxide-free polybutene-1 combined with color-stable additional components. This eliminates yellowing while maintaining application performance through alternative viscosity control mechanisms.
Solution Approach 2:
The invention changes the compositional parameters to include 25-75 wt.% polybutene-1 and 75-25 wt.% additional components with specific properties. This parameter change achieves low viscosity for good application performance while selecting components that resist yellowing, thereby preserving color stability.
Data Source
AI summary
A polyolefin-based hot melt adhesive composition made from or containing(A) 25-75 wt. % of a copolymer of butene-1 with a Melt Flow Rate, measured according to ISO 1133 (190° C., 2.16 kg), higher than 1500; and(B) 75-25 wt. % of at least one additional component selected from the group consisting of waxes, resins, plasticizers, additional polymers and mixtures thereof,wherein the amounts of A) and B) are referred to the total weight of A)+B).