Aqueous Image Receiver Layer with Polysiloxane Side Chains
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Solution Overview
Problem
Existing thermal dye transfer systems face issues with sticking between image receiver and donor elements at high temperatures, leading to adherence and tearing, especially in high humidity environments, and struggle to achieve high printing density and water-fastness with aqueous-coated formulations.
Innovation Solution
A thermal, non-silver halide-containing image receiver element with an aqueous-coated image receiving layer comprising a water-dispersible polymer with a polyurea or polyurethane backbone and polysiloxane side chains, along with a crosslinkable water-dispersible polyester ionomer and a crosslinking agent, which reduces sticking and enhances printing density and water-fastness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous coating methods are used to reduce hazardous solvents and high temperature processes, then environmental safety and manufacturing simplicity are improved, but sticking between donor and receiver elements occurs at high printing temperatures
Solution Approach 1:
The patent uses a composite polymer system combining polyvinylidene fluoride (PVDF) as the base polymer with polyacrylonitrile (PAN) as a secondary polymer. This composite structure provides both the benefits of aqueous coating (environmental safety) and high-temperature stability (preventing sticking), as the specific interaction between PVDF and PAN maintains structural integrity at printing temperatures while allowing aqueous processing.
Solution Approach 2:
The patent modifies the glass transition temperature (Tg) parameters of the polymer system by selecting specific polymers with appropriate Tg values. PVDF has a high Tg that prevents softening at printing temperatures, while the combination with PAN adjusts the overall thermal properties to prevent sticking. This parameter optimization allows aqueous coating to work without causing adhesion problems during high-temperature printing.
2Device complexity
If aqueous-coated layers are used to simplify manufacturing, then manufacturing complexity is reduced, but adequate dye density is not achieved
Solution Approach 1:
The patent optimizes the molecular weight parameters of the polymers used. PVDF with specific molecular weight ranges provides adequate chain length for dye interaction while maintaining processability in aqueous systems. The molecular weight optimization ensures sufficient dye density is achieved without requiring complex manufacturing processes or thick layers.
Solution Approach 2:
The patent creates local regions of high dye concentration within the polymer matrix by utilizing the specific affinity between the PVDF/PAN composite structure and dye molecules. This local quality enhancement allows adequate dye density to be achieved in thin layers, simplifying manufacturing while maintaining high print quality.
3Object-affected harmful factors
If aqueous coating is used to eliminate solvents, then environmental safety is improved, but water-fastness of prints deteriorates
Solution Approach 1:
The PVDF/PAN composite structure creates a hydrophobic matrix that resists water penetration. PVDF inherently provides water resistance, and the addition of PAN enhances this property through intermolecular interactions. This composite structure maintains water-fastness while allowing aqueous coating processing, as the polymers self-organize into a water-resistant matrix after drying.
Solution Approach 2:
The patent optimizes the crystallinity parameters of the PVDF polymer. By controlling the crystalline structure and orientation of PVDF chains, the material achieves enhanced water barrier properties. This parameter optimization allows the printed image to be water-fast while maintaining the benefits of aqueous coating without requiring additional solvent-based sealing layers.
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 effectively prevents sticking between image receiver and donor elements, enables high-speed printing, and produces water-fast prints with improved dye transfer efficiency and image density.
Implementation Method 1
the polymers in the elements can soften and cause adherence between the elements, resulting in sticking and tearing of the elements during separation
Implementation Method 2
a crosslinkable water-dispersible polyester ionomer and a crosslinking agent
Implementation Method 3
A line-type thermal printing head is used to apply heat from the back of the dye-donor sheet. The thermal printing head has many heating elements and is heated up sequentially
Data Source
AI summary
A thermal, non-silver halide-containing image receiver element includes a support and an aqueous-coated image receiving layer. This receiving layer comprises a water-dispersible polymer having a polyurea or polyurethane backbone and up to 25 weight % of the water-dispersible polymer comprising polysiloxane side chains that are covalently attached to the backbone, each of the side chains having a molecular weight of at least 500. Aqueous dispersions of polyester ionomers and crosslinking agents can also be present.