Job Cleanup in Packaging Printing

Activity:              Repair and Maintenance Industry:            MFG – Plastics Packaging Widget:               Screen Print Frames Soils:                     Ink – Screen and Adhesives Methods:           Agitation and Ultrasonic Materials:         Mild or Carbon Steel Products:          QX-490 Paint Stripper for Ferrous Metals Key Feature:   Performance

Cleaning Issue:

The customer provides packaging to protect pharmaceuticals, nutraceuticals and diagnostics from moisture and oxygen. As part of the manufacturing process, the customer prints information on the packaging using a silk screen process. The mesh is glued to the frame using Frame Fast 280, a cyanoacrylate based adhesive, and then sprayed with Frame Fast 304, an aerosol activator, to speed the curing process. These adhesive materials and the silk screen ink remain on the frame and require removal.

The current cleanup process after printing is as follows:

• the silk screen mesh is removed from the metal frame




• the frame is submerged in a 50 gallon immersion parts washer at 140 degrees for 3 hours with no agitation to remove the excess adhesive and ink




• the frame is rinsed with water

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Finding the Right Cleaning Process:

Two metal frames with silk screen mesh attached were received for testing as indicated below.

Frame 1 Before	Frame 2 Before

The frames were test cleaned using an immersion cleaning protocol and an ultrasonic cleaning protocol as outlined below.

Immersion Cleaning:

The silk screen mesh was removed from the frame prior to cleaning. Excess adhesive and ink remain on the frame after the screen is removed as indicated below.

The bottom quarter of Frame 1 was suspended in 20% Mirachem QX-490 Paint Stripper at 140°F. The frame was soaked without agitation, water rinsed and visually inspected periodically. As the testing progressed, gradual removal of the adhesive and ink was observed at each inspection. At approximately 2 hours, all of the adhesive and ink had been removed as indicated below.

Side A	Side B

The opposite end of the frame was then suspended in 50% Mirachem QX-490 Paint Stripper at 140°F. The dilution of the QX-490 was increased to determine if cleaning time would be reduced. The frame was soaked without agitation, water rinsed and visually inspected periodically. As in the previous test, gradual removal of the adhesive and ink was observed throughout the testing. Total removal of the adhesive and ink was achieved at approximately 1 hour as indicated below.

Side A	Side B

Ultrasonic Cleaning

Prior to test cleaning, the silk screen mesh was removed from Frame 2 leaving a thick coating of adhesive and ink residue, as indicated below.

One end of the frame was cleaned in 20% Mirachem QX-490 Paint Stripper in an ultrasonic at 160°F. After 20 minutes, the adhesive and ink had been removed as indicated below.

Side A	Side B

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Mirachem’s Recommendations:

Immersion Cleaning:

Based on our limited testing, it appears that the 50% dilution of Mirachem QX-490 Paint Stripper removed the adhesive and ink in approximately one hour while the 20% dilution removed the adhesive and ink in approximately two hours. Subject to the customer’s cleaning time constraints versus the incremental cost of the 50% dilution of QX-490 Paint Stripper, we recommend the customer perform a field test at the 20% dilution to establish a base line of cleaning performance. Note, prior to inserting the part, and then about once per hour, the agitation shelf will need to be activated to keep the QX-490 Paint Stripper mixture in solution.

Ultrasonic Cleaning:

Based on our testing in an ultrasonic with a 20% dilution of Mirachem QX-490 Paint Stripper at 160°F, it appears that the adhesive and ink can be cleaned within approximately 20 minutes. This is the most time efficient option, but the financial impact of purchasing an ultrasonic unit must be taken into consideration.

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Related Resources:

Mirachem QX-490 Product Webpage	Mirachem.com/QX490
ATR-1348 Photo Gallery
ATR-1348 Web Article