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A unique test method used to evaluate ink bonding force to plastic film

IP.com Disclosure Number: IPCOM000248759D
Publication Date: 2017-Jan-06
Document File: 3 page(s) / 159K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper describes a test method that can be used to evaluate the bonding force of ink on the surface of a plastic film. This test method is specifically designed for cases where the bonding force is relatively high and existing test methods are not effective. Two key features of the test method are: (1) A special sample configuration that reverses the detach direction compared to the traditional test method to produce shear peel forces and interface distortion to the ink layer; and (2) The use of a special testing tape with high bonding force to the ink. In the example described herein, the test tape's adhesive preferably contains acrylic acid with more than 7.0% mol ratio of acrylic acid in the polymeric structure of base acrylic adhesive.

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A unique test method used to evaluate ink bonding force to plastic film

This paper describes a test method that can be used to evaluate the bonding force of ink on the

surface of a plastic film. This test method is specifically designed for cases where the bonding

force is relatively high and existing test methods are not effective. Two key features of the test

method are: (1) A special sample configuration that reverses the detach direction compared to the

traditional test method to produce shear peel forces and interface distortion to the ink layer; and

(2) The use of a special testing tape with high bonding force to the ink. In the example described

herein, the test tape’s adhesive preferably contains acrylic acid with more than 7.0% mol ratio of

acrylic acid in the polymeric structure of base acrylic adhesive.

Background

An exemplary application where this type of test may be used is in LCD frame bonding and light

shielding in electronics. Typical tapes for this application include single coated insulated tape,

which consist of an acrylic pressure sensitive adhesive coated on the black ink side of a printed

PET film. The application involves aging (for example, for 1 hour at 65 °C) after the tape is

adhered to the LCD panel frame. The tape is then peeled off to check the internal components in

the LCD. The tapes are required to have no any adhesive and/or ink residue on the LCD panel

after aging and tape removal. However, ink transfer after aging, as shown in Fig. 1, is a serious

issue.

Fig. 1 ink residue

Attempts to improve the ink bonding force to the PET film in the tape are difficult to achieve

using existing test methods. The existing standard for evaluating ink bonding force is GB 9286-

1998 ISO 2409 1992. However, the ink bonding force of current films, even those that exhibit

ink transfer, is beyond the range of force covered by the existing test method. This new test

method is able to effectively evaluate the ink bonding force on PET film.

Description

The sample test configuration is illustrated in Fig. 2. In the existing test method shown in Fig.

2(a), such as GB 9286-1998 ISO 2409, the ink film is fixed on an even substrate, the test tape is

attached to the ink surface, then the test tape is peeled at an 180° angle. In the new test method,

testing tape is adhered to the substrate surface, the ink surface of the PET film is adhered to the

adhesive side of the testing tape, then the ink printed film is peeled from the adhesive surface.

substrate

bonding layer

PET film

Ink layer

Test tape

Peel direction

Adhesive

side Backing side

substrate bonding layer

backing of test tape

adhesive surface of test tape

Printed PET film

Peel direction

Ink side

PET side

(a) traditi...