Hot Melt Adhesive Reducing Stringing via Composite Formulation
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Solution Overview
Problem
Hot melt adhesives face challenges with stringing, thermal stability, adhesion to various substrates, and maintaining performance across a wide temperature range, particularly on paper substrates like corrugated cardboards.
Innovation Solution
A hot melt adhesive formulation comprising a metallocene-based copolymer of ethylene with olefins, an ethylene-carboxylic acid ester copolymer, and a wax, which reduces stringing and enhances thermal stability, adhesion, and heat-resistant creep properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hot melt adhesive formulations are used, then adhesion is achieved, but stringing occurs and thermal stability is insufficient
Solution Approach 1:
The patent employs a composite adhesive formulation combining multiple polymer components: ethylene-carboxylic acid ester copolymer (2-25 mass%), olefin-based resin (30-70 mass%), and synthetic rubber (5-30 mass%). This composite structure synergistically improves thermal stability while reducing stringing, as each component contributes specific properties that collectively resolve the contradictions between adhesion, stringing, and thermal stability.
Solution Approach 2:
The patent optimizes specific parameters including the glass transition temperature of the olefin-based resin (−50°C to −10°C), the carboxylic acid ester content (2-25 mass%), and the melt flow rate (1-400 g/10 min). By precisely controlling these parameters, the adhesive achieves reduced stringing and improved thermal stability while maintaining adhesion performance.
2Reliability
If adhesive performance is improved for paper substrates, then adhesion increases, but performance consistency across temperature range deteriorates
Solution Approach 1:
The composite formulation includes olefin-based resin with specific glass transition temperature (−50°C to −10°C) and synthetic rubber (5-30 mass%), which together provide both low-temperature adhesion to paper substrates and high-temperature stability. The olefin-based resin ensures adhesion while the rubber component maintains compositional stability across temperature variations.
Solution Approach 2:
The patent specifies the glass transition temperature of the olefin-based resin as −50°C to −10°C, which is optimized for paper substrate adhesion.同时, the melt flow rate is controlled at 1-400 g/10 min to ensure consistent performance across temperature ranges, resolving the contradiction between adhesion improvement and temperature consistency.
3Object-generated harmful factors
If adhesive is made more viscous to reduce stringing, then stringing decreases, but heat-resistant creep property worsens
Solution Approach 1:
The patent uses a composite system where the olefin-based resin (30-70 mass%) provides viscosity control for reduced stringing, while the synthetic rubber (5-30 mass%) maintains heat-resistant creep property. The synergistic interaction between these components allows the adhesive to be sufficiently viscous to minimize stringing while retaining thermal stability and creep resistance.
Solution Approach 2:
The patent optimizes the balance between viscosity and thermal stability by controlling the glass transition temperature of the olefin-based resin (−50°C to −10°C) and the content of synthetic rubber (5-30 mass%). This parameter optimization enables the adhesive to achieve reduced stringing without compromising heat-resistant creep property.
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 significantly reduces stringing, exhibits excellent thermal stability and adhesion to paper substrates, and maintains performance without deformation even when stored at high temperatures or in piles, ensuring effective application and durability.
Implementation Method 1
a hot melt adhesive is heated to about 120 to 190° C. and discharged from a tip of the nozzle
Implementation Method 2
subsequently cooled to solidify
Data Source
AI summary
Disclosed is a hot melt adhesive, comprising: (A) a copolymer of ethylene with an olefin having 3 to 20 carbon atoms; (B) an ethylene-carboxylic acid ester copolymer; and (C) a wax, wherein the (A) copolymer of ethylene with an olefin having 3 to 20 carbon atoms comprises (A1) a metallocene-based copolymer of ethylene with propylene, and the (B) ethylene-carboxylic acid ester copolymer comprises (B1) an ethylene-carboxylic acid ester copolymer which has a structural unit derived from the carboxylic acid ester in an amount of 2% by mass or more and less than 25% by mass, and a melt flow rate of 1 to 400 g/10 min.