Inkjet Recording Medium with Temperature-Dependent Gelation
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Solution Overview
Problem
The ink jet recording medium's ink receiving layer tends to color over time and lacks sufficient water resistance, especially under harsh conditions, and the existing crosslinkable systems have a short pot life due to high gelation rates at ambient temperature, leading to non-uniform mixing and characteristics.
Innovation Solution
An ink jet recording medium using an acetoacetic ester group-containing polyvinyl alcohol resin (AA-PVA-based resin) crosslinked by glyoxylates, with a coating solution containing AA-PVA-based resin, glyoxylate, and water, which exhibits a significant difference in gelation rate between ambient temperature and heating, allowing for stable storage and rapid gelling when heated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a crosslinking agent with high gelation rate at ambient temperature is used, then gelling occurs rapidly, but the coating solution has short pot life and cannot be uniformly mixed
Solution Approach 1:
The patent uses a modified PVA resin with keto groups that changes its gelation behavior based on temperature parameters. At ambient temperature, the gelation rate is slow allowing long pot life and uniform mixing. When heated, the gelation rate accelerates rapidly to achieve quick gelling and eliminate fluidity. This parameter-based control resolves the contradiction between rapid gelling and long pot life.
2Quantity of substance
If the ink receiving layer is made relatively thick to improve ink absorptivity, then ink absorption increases, but drying time increases and surface defects occur
Solution Approach 1:
The patent applies preliminary gelling action before the drying process. By gelling the coating layer first (either at ambient temperature or under heating), the fluidity is eliminated in advance, preventing wind ripple patterns and surface defects during subsequent drying. This allows the use of thicker coating for better ink absorptivity without suffering from extended drying time penalties, as the gelling step prepares the layer for faster, defect-free drying.
3Stability of the object's composition
If cooling is applied to gel the PVA resin with boric acid, then gelling occurs, but productivity decreases and production cost increases
Solution Approach 1:
Instead of using cooling to achieve gelling (as with boric acid crosslinking), the patent inverts the approach by using heating to accelerate gelation. The modified PVA resin with keto groups gels slowly at ambient temperature but gels rapidly when heated. This eliminates the need for cooling steps, thereby maintaining high productivity and reducing production costs while achieving the desired gelling and stability.
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 solution provides an ink jet recording medium with excellent coloration resistance and water resistance, long pot life of the coating solution, and enhanced uniformity, enabling efficient production with improved productivity and reduced production costs.
Implementation Method 1
an ink receiving layer containing an acetoacetic ester group-containing polyvinyl alcohol resin crosslinked by a glyoxylate
Implementation Method 2
the coating solution applied on a supporting base is gelled and then dried
Implementation Method 3
a modified PVA resin having a keto group is used as a crosslinkable system allowing for progress of gelling at ambient temperature or under heating
Implementation Method 4
drying the coating by heating to remove water
Data Source
Figure 1~2
Figure 3(a)~3(b)
AI summary
The present invention provides an ink jet recording medium having an ink receiving layer excellent in the coloration resistance and water resistance; and a coating solution for forming an ink receiving layer, which exhibits a large difference in the gelation rate between at ambient temperature and under heating, and is stable at ambient temperature and swiftly gelled when heated. The present invention relates to an ink jet recording medium comprising an ink receiving layer containing an acetoacetic ester group-containing polyvinyl alcohol resin crosslinked by a glyoxylate on a supporting base; and a coating solution for forming an ink receiving layer containing an acetoacetic ester group-containing polymer compound, a glyoxylate and water.