Solventless Adhesive Multilayer Film for Bubble-Free Lamination
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Solution Overview
Problem
Multilayer films using solventless adhesives are prone to air bubble generation and winding misalignment due to positional misalignment during the curing process, especially in films with multiple layers or vapor deposition layers.
Innovation Solution
A multilayer film with solventless adhesive layers containing a polyester-based resin and an aliphatic isocyanate curing agent, with a viscosity of 600 to 1400 mPa·s at 80°C, is used, and the adhesive is applied between a vapor deposition layer and an adjacent resin film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a solventless adhesive with low viscosity is used to ensure easy application and rapid curing, then productivity is improved, but air bubbles are generated in the adhesive layer and winding misalignment occurs
Solution Approach 1:
The patent changes the viscosity parameter of the solventless adhesive to a specific range (600-1400 mPa·s at 80°C) to resolve the contradiction. This optimized viscosity range provides enough fluidity for easy application and air bubble escape while maintaining sufficient stability to prevent winding misalignment during the curing process.
2Manufacturing precision
If the adhesive viscosity is increased to suppress air bubble generation and winding misalignment, then manufacturing precision is improved, but application difficulty increases and curing efficiency decreases
Solution Approach 1:
The patent optimizes the adhesive viscosity to a balanced range (600-1400 mPa·s at 80°C) that simultaneously ensures easy application and high lamination precision, avoiding the need to choose between the two opposing requirements.
3Object-affected harmful factors
If a solventless adhesive is used to reduce environmental impact, then harmful factors are reduced, but air bubble generation and winding misalignment occur during curing
Solution Approach 1:
The patent modifies the viscosity parameter of the solventless adhesive to a specific range that eliminates the harmful effects of air bubbles and misalignment, making the solventless adhesive system suitable for high-precision lamination applications.
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
Suppresses air bubble generation and winding misalignment in the multilayer film after lamination, ensuring stable lamination and improved impact resistance.
Implementation Method 1
an adhesive is generally used due to poor adhesion between the films
Implementation Method 2
when curing of the solventless adhesive constituting the adhesive layer is completed
Data Source
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AI summary
Provided are a multilayer film capable of suppressing generation of air bubbles in an adhesive layer and suppressing occurrence of winding misalignment when wound immediately after lamination, a method for producing the multilayer film, and a packaging container using the multilayer film. The multilayer film of the present invention is a multilayer film including a plurality of resin films and one or more adhesive layers, and is characterized that at least one of the adhesive layers is formed of a solventless adhesive; and the solventless adhesive contains a main agent made of a polyester-based resin and a curing agent made of an aliphatic isocyanate, and a viscosity of the solventless adhesive at 80°C is from 650 to 1600 mPa·s.