Solventless Laminating Adhesive Coating via Opposed Roll Inversion
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Solution Overview
Problem
Solventless laminating adhesives face issues with air bubble entrainment and stringing phenomena during coating, leading to poor film appearance and reduced productivity, while high temperature coating can damage films and worsen the working environment.
Innovation Solution
A solventless laminating adhesive with a polyisocyanate and polyol components, having an initial viscosity of 500 to 1000 mPa·s and a viscosity increase of 100% to 350% after mixing, is coated using rolls rotating in opposite directions at 40 to 80°C, allowing for high-speed coating that reduces air bubbles and stringing, thereby improving film quality and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rolls rotate in the same direction in opposed relation, then coating can be performed, but air bubbles are entrapped and stringing phenomenon occurs
Solution Approach 1:
The patent applies reverse rotation of rolls instead of same-direction rotation. The first roll rotates in one direction while the second roll rotates in the opposite direction, creating a shearing force that prevents air bubble entrapment and stringing phenomenon during coating, thereby resolving the manufacturing precision issue while maintaining ease of manufacture
2Productivity
If high temperature coating is used, then coating speed can be increased, but film damage occurs and working environment deteriorates
Solution Approach 1:
The patent changes the temperature parameter to low temperature coating (40-80°C) while compensating with optimized roll rotation parameters (opposite directions) and adhesive viscosity control (500-1000 mPa·s). This parameter change allows maintaining productivity through efficient low-temperature coating chemistry while preventing film damage and improving working environment
3Ease of operation
If adhesive viscosity is low, then coating is easier, but air bubbles are more easily entrapped
Solution Approach 1:
The patent optimizes the adhesive viscosity parameter to a specific range (500-1000 mPa·s) that balances ease of coating operation with bubble-free application. This parameter change, combined with reverse roll rotation, ensures the adhesive is viscous enough to resist bubble entrapment while remaining fluid enough for easy coating operation
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 a smooth, bubble-free coating at low temperatures, enhancing the appearance of composite films and reducing film damage, while increasing productivity and minimizing environmental deterioration.
Implementation Method 1
a solventless laminating adhesive containing a polyisocyanate component and a polyol component
Implementation Method 2
Two-part laminating adhesives composed of a base composition containing polyol and a curing agent containing polyisocyanate
Implementation Method 3
having an initial viscosity of 500 to 1000 mPa·s and a viscosity increase of 100% to 350% after mixing
Data Source
AI summary
A solventless laminating adhesive comprising a polyisocyanate component and a polyol component, both of which are free from polyol components exhibiting crystalline properties at ordinary temperatures. The adhesive exhibits an initial viscosity of 500 to 1000 mPa s three minutes after mixing of the polyisocyanate component with the polyol component and a viscosity increase of 100 to 350% based on the initial viscosity 20 minutes after the mixing. In a coater which is provided with a pair of opposed rolls and in which the rolls rotates in the directions contrary to each other at the opposition site, the adhesive is applied to a film passing between the rolls.