Non-aqueous Ink Composition with High-Mass Cellulose Binder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ink compositions for continuous deflected ink jet printing are limited by the viscosity and molecular mass of resins and polymers, which restrict the range of viscosities and molecular masses suitable for printing, leading to unsatisfactory print quality and limitations in formulation possibilities.
Innovation Solution
A non-aqueous ink composition using a cellulose derivative as a binder with an average molecular mass greater than 120 kDa and a pigment/dye/binder mass ratio less than 1.5, combined with organic solvent compounds, allowing for higher viscosities and molecular masses suitable for deviated continuous ink jet printing without the 'bead on string' phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the viscosity of ink is increased to expand formulation possibilities, then the range of suitable viscosities for printing is improved, but the pressure required for jetting increases and drop formation rate decreases
Solution Approach 1:
The patent applies parameter changes by utilizing the shear-dependent viscosity characteristics of pseudoplastic fluids. The ink formulation is designed to exhibit high viscosity at low shear rates (expanding formulation possibilities) while showing reduced viscosity at high shear rates (during jetting through the nozzle). This allows the system to achieve both high adaptability in formulation and acceptable jetting pressure by exploiting the non-Newtonian flow behavior where viscosity is not a fixed parameter but changes with the applied shear rate.
2Adaptability or versatility
If the molecular mass of resins and polymers is increased to expand formulation possibilities, then the binder properties are improved, but the ink jetting performance deteriorates due to clogging and poor sprayability
Solution Approach 1:
The patent resolves this contradiction by changing the rheological parameters of the ink system. By formulating pseudoplastic inks where viscosity decreases with increasing shear rate, high molecular mass resins and polymers (up to 100,000 g/mol or higher) can be used to achieve desired binder properties and formulation versatility. During normal handling and storage, the ink maintains high viscosity for stability, but during jetting when high shear rates are applied, the viscosity drops sufficiently to allow reliable jetting of high molecular mass components without clogging or sprayability issues.
Solution Approach 2:
The patent applies dynamics by introducing time-dependent and shear-rate-dependent viscosity characteristics to the ink system. The pseudoplastic behavior creates a dynamic viscosity profile that adapts to the operating conditions: high viscosity during storage and handling (low shear) ensures formulation stability and prevents settling, while low viscosity during jetting (high shear) ensures reliable delivery of high molecular mass resins and polymers. This dynamic parameter adjustment resolves the static contradiction between formulation possibilities and jetting reliability.
3Adaptability or versatility
If the viscosity of ink is increased above 10 mPa.s, then formulation possibilities are expanded, but the drop formation rate and jet orientation stability deteriorate
Solution Approach 1:
The patent resolves this contradiction by changing the viscosity parameter from a static to a dynamic characteristic. The pseudoplastic ink formulation allows the viscosity to be higher than 10 mPa.s at low shear rates (providing expanded formulation possibilities and better stability), while automatically reducing to below 10 mPa.s at the high shear rates encountered during drop formation and jetting. This shear-thinning behavior ensures that the manufacturing precision parameters (drop formation rate and jet orientation stability) are maintained despite using higher viscosity formulations.
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 composition exhibits pseudoplastic shear thinning behavior, enabling jetting at lower pressures and maintaining print quality, overcoming the limitations of traditional ink compositions by allowing higher viscosities and molecular masses, thus expanding formulation possibilities for continuous deflected ink jet printing.
Implementation Method 1
The ink composition exhibits pseudoplastic shear thinning behavior, enabling jetting at lower pressures and maintaining print quality
Implementation Method 2
The piezoelectric crystal, vibrating at a determined frequency, provokes pressure disturbances in the ink jet, that oscillates and gradually breaks up into spherical droplets
Implementation Method 3
The piezoelectric crystal, vibrating at a determined frequency, provokes pressure disturbances in the ink jet
Implementation Method 4
An electrode called the 'charging electrode' placed on the path of the jet at the location at which it breaks, applies an electrostatic charge to these drops if the ink is conductive
Implementation Method 5
The dropplets thus charged and deflected and deviated in an electric field to enable printing
Implementation Method 6
In the case of a bubble ink jet, ink is vaporised close to the nozzle and this vaporisation causes the ejection of a small quantity of ink located between the resistor that vaporises the ink and the nozzle
Implementation Method 7
In the case of a bubble ink jet, ink is vaporised close to the nozzle and this vaporisation causes the ejection of a small quantity of ink
Implementation Method 8
a vehicle comprising one or several organic solvent compound(s) that is (are) liquid at ambient temperature
Data Source
Figure 1
AI summary
Non-aqueous ink composition for continuous deflected ink jet printing comprising: - a vehicle comprising one or several organic solvent compound(s) that is (are) liquid at ambient temperature; - one or several dye(s), preferably soluble, and/or pigment(s); - a binder, comprising at least one binding resin consisting of a cellulose derivative chosen from among cellulose ethers with an average molecular mass by weight Mw greater than or equal to 120 kDa; in which the pigment(s) and/or dye(s)/binder mass ratio is less than 1.5, and preferably less than 1. Method of marking a substrate, by spraying said ink composition onto this substrate, using a liquid jet printing technique. Substrate with marking obtained by drying and/or absorption of said ink composition.