We will introduce VK Ink Series which realizes excellent weather resistance in combination with overcoat clear.


1. What is weather resistance?

1. Deterioration by natural environment and weather resistance

High-polymer materials such as pigment or resin which are used for inks deteriorate by light (ultraviolet rays), heat, water, or oxidation.


Main phenomena which may occur as deterioration of weather resistance (light fastness) in printed sample are as follows.

1. Color change, color fade, yellowing
2. Decrease in surface gloss and chalking phenomenon
3. Peel-off and crack
4. Contraction or curl in films or stickers


In general, "weather resistance" indicates characteristics of material (printed material) which are hard to change (deteriorate) by natural environment. "Light fastness" indicates characteristics which are hard to change with irradiation of light (sunlight) only.


2. Result of outdoor exposure test

Outdoor exposure test is the evaluation method of exposing the sample to the sunlight and weather (wind and rain) outdoor for a certain period. Places with good sunlight condition are selected for exposure.

Exposure places are; South Florida with strong sunlight and high humidity, Arizona in desert area of U.S.A., Okinawa prefecture, Choshi in Chiba prefecture in Japan, etc. (The following is the test data of Florida.)


Resistance item
Tested ink
Weather resistance
(Outdoor exposure,
24 months, Florida)
VK Ink Series
No defect
SP-3100AU Clear
No defect




2. Introduction of examples of VK Ink Series

1. Realization of excellent resistance in combination
          with SP-3100AU Clear

VK Ink series realizes more excellent weather resistance in combination with SP-3100AU Clear.

SP-3100AU Clear is isocyanate curable, urethane system, 2 pack type Clear.

This Clear provides really excellent gloss, excellent weather resistance and other resistances. It is overcoat clear suitable for vinyl chloride used for automobiles, motorcycles, and outdoor signboards.



2. Automobiles, motorcycles, and outdoor marking films

VK Ink Series has records of being used for exterior of automobiles and motorcycles which require high weather resistance and exterior marking films, etc.

The following photo is the exterior sticker for business equipment of outdoor application.








Teikoku Printing Inks Mfg, Co., Ltd./Laboratory
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