Undercoating Composition for Low-Temperature Ionic Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas-barrier laminated films require high-temperature processing and additional treatments like dip or spray methods to achieve sufficient ionic crosslinking, leading to poor productivity, high energy consumption, and unsatisfactory gas-barrier properties.
Innovation Solution
A coating composition for undercoating comprising a nonaqueous polyester polyol, an isocyanate compound, and an alkaline compound of a polyvalent metal, which allows for easy and quick migration of polyvalent metal ions into a polycarboxylic acid type polymer, forming a crosslinked structure at lower temperatures without the need for additional treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heating (150°C or more) is used to crosslink the gas-barrier material, then the ionic crosslinking degree is improved, but the plastic base body is seriously affected and energy consumption increases
Solution Approach 1:
The patent applies a coating containing polyvalent metal ions as undercoating before applying the polycarboxylic acid type polymer solution. This preliminary action allows metal ions to be pre-positioned on the base body surface, enabling subsequent low-temperature ionic crosslinking when the polymer solution is applied, thus avoiding high-temperature damage to the plastic base body while achieving sufficient crosslinking degree
Solution Approach 2:
The patent introduces a coating composition as an intermediary layer between the plastic base body and the polycarboxylic acid type polymer solution. This coating contains polyvalent metal ions that serve as a mediator to facilitate ionic crosslinking at lower temperatures, preventing direct high-temperature exposure to the plastic base body while enabling effective crosslinking of the polymer layer
2Reliability
If dip treatment or spray treatment is used to achieve ionic crosslinking, then the gas-barrier property is improved, but productivity decreases and water consumption increases
Solution Approach 1:
The patent combines the application of polycarboxylic acid type polymer solution and the achievement of ionic crosslinking into a single integrated process. By pre-applying the coating containing metal ions and then applying the polymer solution, both steps are merged, eliminating the need for separate dip or spray treatments and achieving high productivity with satisfactory gas-barrier properties
Solution Approach 2:
The coating composition is designed to automatically provide metal ions that migrate into the polycarboxylic acid type polymer solution upon application, enabling self-crosslinking without requiring additional dip or spray treatments. This self-service mechanism improves productivity while maintaining gas-barrier properties
3Device complexity
If the coating solution (B) containing water-soluble polyvalent metal salt is applied after the polycarboxylic acid type polymer is fixed, then the layer structure is simplified, but the ionic crosslinking ratio is insufficient
Solution Approach 1:
The patent inverts the conventional sequence by applying the coating containing metal ions first, then applying the polycarboxylic acid type polymer solution. This reversal allows metal ions to be present before polymer fixation, enabling sufficient ionic crosslinking to occur during the drying process rather than requiring subsequent treatments
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
This solution enables the formation of a gas-barrier layer with high ionic crosslinking ratio, improving gas-barrier properties, productivity, and interlayer adhesion, while reducing energy consumption and processing time.
Implementation Method 1
forming a crosslinked structure of a polycarboxylic acid type polymer and polyvalent metal ions
Implementation Method 2
permits polyvalent metal ions to be easily and quickly fed into the polycarboxylic acid type polymer
Implementation Method 3
an isocyanate compound having at least two isocyanate groups in a molecule thereof
Data Source
AI summary
To provide a coating composition for undercoating which, in forming a gas-barrier layer having a crosslinked structure between a polycarboxylic acid type polymer and polyvalent metal ions by the heating at a low temperature for a short period of time, permits polyvalent metal ions to be easily and quickly fed into the polycarboxylic acid type polymer and, besides, into the whole gas-barrier layer. A coating composition containing, as chief components, a nonaqueous polyester polyol, an isocyanate compound, and an alkaline compound of a polyvalent metal that serves as an ion source for forming the crosslinked structure, wherein the nonaqueous polyester polyol contains a nonaqueous polyester polyol which contains a metal element in the resin skeleton thereof as an essential component, and the alkaline compound of the polyvalent metal has an average primary particle size in a range of 0.005 to 0.5 μm.