White Ink Composition Balancing Opacity and Preservation Stability
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Solution Overview
Problem
Inkjet printing on transparent flexible packaging often results in insufficient opacity and visibility of printed images due to the transparency of the medium, and challenges arise when printing on surfaces with projections and recesses, requiring high whiteness, opacity, surface smoothness, and glossiness, while maintaining preservation stability.
Innovation Solution
A white ink formulation containing a specific blend of anatase-type and rutile-type titanium oxide particles with controlled particle diameters and aspect ratios, along with an aqueous medium, pigment dispersion resin, and binder resin, optimized for non-permeable recording media like flexible packaging, ensuring high whiteness, opacity, glossiness, and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white ink containing titanium oxide particles is used to print on transparent flexible packaging, then opacity and whiteness of the printed image are improved, but preservation stability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution (number average primary particle diameter 140-340 nm) and composition ratio (anatase 17.50-37.50%, rutile 72.50-82.50%) of titanium oxide particles. This optimization resolves the contradiction by finding the optimal parameter range that simultaneously achieves high opacity and maintains preservation stability, preventing both yellowing and aggregation.
Solution Approach 2:
The patent uses composite materials by combining two crystal forms of titanium oxide (anatase and rutile) in specific proportions. This composite approach leverages the complementary properties of each crystal form: anatase provides high scattering power for opacity, while rutile contributes to stability and resistance against yellowing, thereby resolving the contradiction between opacity and preservation stability.
2Illumination intensity
If white ink is used to form images with high glossiness, then glossiness is improved, but surface smoothness deteriorates when printing on surfaces with projections and recesses
Solution Approach 1:
The patent applies local quality by ensuring the titanium oxide particles have uniform size distribution (140-340 nm) and consistent aspect ratios (2-17), creating homogeneous local properties throughout the ink formulation. This uniformity allows the ink to adapt to surface variations and fill projections and recesses evenly, achieving both glossiness and surface smoothness.
Solution Approach 2:
The patent uses parameter changes by optimizing the particle size range (140-340 nm) and aspect ratio (2-17) of titanium oxide particles. These parameter optimizations enable the particles to effectively fill surface irregularities while maintaining a smooth top layer that reflects light uniformly, thereby achieving both surface smoothness and glossiness simultaneously.
3Illumination intensity
If titanium oxide particles with high scattering power are used to improve whiteness, then whiteness is improved, but preservation stability deteriorates due to yellowing
Solution Approach 1:
The patent uses composite materials by formulating a mixture of anatase-type (17.50-37.50%) and rutile-type (72.50-82.50%) titanium oxide particles. This composite structure resolves the contradiction by combining the high scattering power of anatase (which provides whiteness) with the superior stability and yellowing resistance of rutile, achieving both whiteness and preservation stability.
Solution Approach 2:
The patent applies parameter changes by optimizing the crystal phase composition ratio and particle size distribution of titanium oxide. This parameter optimization balances the scattering efficiency (for whiteness) and chemical stability (for preservation), preventing yellowing while maintaining high whiteness in the printed images.
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 ink achieves images with high lightness, opacity, and glossiness, reduces yellowness, and maintains excellent preservation stability, suitable for both front and reverse printing on transparent and glossy recording media.
Implementation Method 1
the white ink for inkjet printing is required to be capable of forming images with high whiteness and opacity
Implementation Method 2
the white ink for inkjet printing is required to be capable of forming images with high whiteness and opacity
Implementation Method 3
the white ink for inkjet printing is further required to have excellent preservation stability
Data Source
AI summary
A white ink for inkjet printing contains titanium oxide particles and an aqueous medium. The titanium oxide particles include anatase-type titanium oxide particles and rutile-type titanium oxide particles. The anatase-type titanium oxide particles have a percentage content of at least 17.50% by mass and no greater than 37.50% by mass in the titanium oxide particles. The rutile-type titanium oxide particles have a percentage content of at least 72.50% by mass and no greater than 82.50% by mass in the titanium oxide particles. Both the anatase-type titanium oxide particles and the rutile-type titanium oxide particles have a number average primary particle diameter of at least 140 nm and no greater than 340 nm.