Blue Testing Pens and Ink

To better print on polymer plastics with adhesion of inks, it is inherent that the surface be pre-treated. Subsequently, the surface tension rises to a defined point, which is then measured for quality purposes.

Untreated PE and PP have a surface tension of about 30 dynes/cm. Well treated PE and PP should have a value of about 38 to 41 dynes/cm for quality printing to take place.

Polymer plastics with a surface tension of less than 37 dynes/cm have binding difficulties. Consequently, the ink may not adhere once applied, resulting in bad quality .

The value of treatment is tested by simply applying the ink by using a cotton swab or the felt-tipped pen onto the surface.

Values available are as follows:

• Test Pens BLUE, 17-05xx Series with FORMAMIDE SOLUTION are available from 28 to 72 dynes/cm, even levels
• Normally stocked: 36 / 38 / 40 / 42 / 44 / 46 / 48 / 50 / 52
• Liquid Ink Format (17-07xx)
  • 18 / 20 / 22 / 24 / 26, different chemical mixtures than the 28 to 72 levels
  • 28 to 58, both evens and odds
  • 60 to 72, even levels only
  • 76 / 84 / 90 / 105

• PP felt tip marker
• Approximately 5 mL contents
• Shelf life 6 months
• Color of test liquid is blue; Levels below 24 dyne/cm are clear