THERMOCHROMIC Screen Ink (Water Based)

Temperature Reactive Color Changing Materials

Technical Data Sheet

Description

Water based Thermochromic ink for absorbent paper and board substrates. Thermochromic Water Based Screen Ink is supplied as an easily mixed 2 part ink system to give optimum shelf life and on press flexibility for control of color intensity, opacity and press performance.

Screen printing ink ideally suited to flat bed screen printing processes onto absorbent paper and board substrates for applications such as labels, tags, tickets and boards. As with all Thermochromic inks the printed effect is dependent upon several factors including press speed, substrate, drying time/temperature and mesh count. The prints exhibit a matte finish. Therefore, it is always recommended that over laminate or spot varnish is used to give a glossy aspect.


Colors and Activations Temperatures

The activation temperature is defined as the temperature above which the ink has almost achieved its final clear or light color end point. The color starts to fade at approximately 4°C below the activation temperature and will be in between colors within the activation temperature range. The color change is “reversible,” i.e., the original color will be restored upon cooling.


Standard Colors: Black, Blue, Magenta, Green, Orange & Red.

Custom Colors: Purple, Brown & Turquoise


Standard Activation Temperatures: 15°C, 31°C & 47°C

Custom Activation Temperatures: -10°C to 69°C


Product Properties

Adhesion

Thermochromic Water Based Screen Ink is suitable for absorbent paper and boards. Due to the wide variety of substrates it is recommended that this ink is evaluated fully prior to any commercial use.


Rub Resistance

An over varnish or laminate is necessary if any resistance to abrasion is required as resistance to pressure is low.


Overprintability/Lamination Properties

Hot laminates can be used with Thermochromic WB Screen Inks. Thermochromic WB Screen Inks can be also overprinted with UV offset, UV flexo and UV screen varnish. However an evaluation for compatibility should always be carried out prior to commercial use.


When Thermochromic Water Based Screen Ink is intended for use on overprinting onto a surface pre-printed with offset inks, it is recommended that the offset inks are wax free. For applications that use a Thermochromic ink activated at cold temperatures (less than 20°C/68°F) we would recommend the use of a matte laminate for optimum effect. For warm and hot temperatures activation inks (20°C/ 68°F and above), we would recommend a gloss laminate.


Light fastness

Thermochromic inks are inherently susceptible to damage by UV light. They are only recommended for use in applications with minimal exposure to UV light. UV protective varnish should be used to slow degradation caused by UV light.


Light fastness properties of supplied thermochromic ink colors are as follows:*

Green 1

Red, Orange & Magenta 1-2

Yellow, Blue, Purple 2

Turquoise 3


*Rating according to measurement on Blue Wool Scale


Heat Behavior

Reversible Thermochromics are showing thermal Hysteresis. This means temperature against color curves on the heating cycle does not match the cooling cycle curve. Thermochromic prints can experience far more than 1000 heating/cooling cycles above their activation temperature. Thermochromics consistently heated up at temperatures above 50°C (122°F) will slowly lose color intensity below the activation temperature.


Technical Specifications

Pigment Content: 24% +/- 1.5%

Particle Size: <6 microns (95%)

Solid Content: 50% +/- 2.0%

Solvent: Water

Supplied Viscosity: 1700 – 2000 cps

Recommended Printing Parameters

Screen Configuration

The optimum screen configuration depends on several factors, the most important of which is the desired opacity and color of the finished product. The theoretical ink volume of the screen is crucial for the desired effect. Using a higher theoretical ink volume will increase the intensity of color of the product when below its activation point and also the level of residual color when above its activation point.


                                       Activated Below 20°C          Activated Above 20°C

                                                 Metric / US                        Metric / US

Recommended Mesh Size          120 / 310                            70 / 195

Minimum Mesh Size                    150 / 379                          150 / 379


Do not allow the ink to sit dormant on the screen as this will cause ‘drying in’ on the screen and affect print definition and quality.


Ink Consumption

Typical ink consumption for Thermochromic Water Based Screen Ink on a 195 mesh is approx 10 – 15gms per sq f. When obliterating an image, 2 passes may be required.


Dilution

The printing ink is supplied in a format that once mixed is at printing viscosity. Should the ink need to be thinned to suit application then only water should be used. No alternative thinners should be used as these will affect both the performance of the ink and Thermochromic function. No more than 15% water should be added to the ink system.


Drying

The ink should be dried using hot air dryers or IR lamps set to a maximum temperature of 70°C/158°F. Care should be taken when stacking the finished product as if too much pressure is applied to uncoated ink (not varnished or laminated) offsetting of the print can occur.


Mixing Instructions:

Recommended Mixing Ratio:            1 Part Binder to 1 Part Pigment


It is recommended that a mechanical stirrer or similar device be used to blend binder and pigment effectively. Never use bead or ball mills to blend the ink parts together. The ratio of pigment to binder can be increased or decreased depending upon the effect required. If the ratio of binder to pigment is altered this ink must be evaluated fully prior to any commercial use. Do not mix with other ink systems.


Cleaning recommendations

Thermochromic Water Based Screen Ink should be cleaned on screen using water only. Glycol based cleaners should not be used as these will damage the function of the ink. After use screens can be cleaned with water. A high powered water jet may be required to remove all ink remnants.

Use a clean screen free of solvents when printing Thermochromic Water based Screen Ink since the Thermochromic effect can be affected by traces of solvents.


Storage and Handling

Thermochromic Water Based Screen Inks are a 2 part ink system that will remain stable if both parts are kept in separate containers and stored in the correct storage conditions. As the product is water based it is important to keep the containers tightly shut to avoid evaporation and skinning of the product. Thermochromic Water Based Screen Inks should be stored away from solvents, sources of UV light and high temperature. Ink should be thoroughly mixed prior to application.


Please consult MSDS prior to use.


Shelf Life of Unmixed Ink                12 Months

Shelf Life of Mixed Ink                    24 Hours


Do not store in temperatures in Excess of 25°C/77°F


Do not freeze


All applications using any QCR Solutions Corp products should be thoroughly tested prior to approval for production.


Information in this Product Data Sheet is compiled from our general experience and data obtained from various technical publications. While we believe that the information provided herein is accurate at the date hereof, no responsibility for its completeness or accuracy can be assumed. Tests are carried out under controlled laboratory conditions. Information is given in good faith, but without commitment as conditions vary in every case. The information is provided solely for consideration, investigation and verification by the user. We do not except any liability for any loss, damage or injury resulting from its use (except as required by law). Please refer to the Material Safety Data Sheet before using products to ensure safe handling.


QCR Solutions Corp

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Phone: 772-237-5354   Fax: 772-672-3544   Email: Info@qcrsolutions.com

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