Film | Specifications

How to Perform an Adhesive Loop Tack Strength Test - ASTM D6195

Posted by Andrew DeWolfe on Fri, Jun 04, 2010 @ 08:06 AM

Email Article |

Twitter |

digg it |

delicious |

StumbleUpon |

LinkedIn |

One method to measure the tack force / strength of an adhesive is to perform the "Loop Tack" test method described in specification ASTM D6195. The adhesives tested with this test are typically pressure sensitive adhesives (PSA) applied to films, labels, tapes, and stickers where the initial tack force is an important characteristic of the product. The specification describes two ways to perform the test. One method (Method B) uses a single purpose machine. Although the simplicity of one dedicated machine is nice, the loop tack method is uncommonly the sole test of any manufacturer. The other method (Method A) uses a universal testing machine otherwise known as a tensile testing machine. Using this method provides you with accurate test results, the same ease of use as the single purpose machine, and also allows you to use the universal testing machine for many other common adhesive and material tests such as 90 degree peel adhesion tests, 180 degree peel adhesion tests, and standard tensile strength testing. If you only need to perform the loop tack test you should consider a single purpose machine and follow Method B. If you have a tensile testing machine, or need to perform other adhesive and material tests, you should follow Method A.

This is a short video of the test followed by a simple summary to help determine if this test is right for your application. Please read the entire ASTM specification if you decide to perform the test.

Procedure:

1. Make a loop with your tape with the adhesive on the outside of the loop.

2. Place the loop in the top grip of the universal testing machine.

3. Bring the loop into contact with a 1" cube fastened to the bottom of the universal testing machine.

4. Remove the tape from the 1" cube fixture.

5. Report the peak and/or the average force during removal.

ASTM D6195 Loop Tack Adhesive Test

Test performed on an ADMET eXpert 7601 universal testing machine.

ASTM D6195 Adhesive Loop Tack Test Report

Test report generated from ADMET's MTESTQuattro testing software.

Click on these links for more information...

More Testing News

ASTM D882 Tensile Strength Properties of Thin Plastic Film

Posted by Andrew DeWolfe on Fri, Jan 08, 2010 @ 08:42 AM

Email Article |

Twitter |

digg it |

delicious |

StumbleUpon |

LinkedIn |

One of the most common specifications that our customers follow is ASTM D882 which is the Standard Test Method for Tensile Properties of Thin Plastic Sheeting. This test is very similar to the common ASTM D638 test whereby plastic material is pulled until in breaks in order to measure elongation, tensile modulus, tensile yield strength, and tensile strength at break. However, it is designed specifically for thin sheeting and film less than 1 mm (0.04") thick.

The nice part about ASTM D882 is that the specimens are rectangular strips of film and are not "dumbbell" or "dog bone" shaped. The flat geometry of the specimens and the typical characteristic of films having high elongation allow most users to avoid using an extensometer which allows them to reduce the cost of the testing system and simplifies their testing regimen.

The two main things to keep in mind in regards to equipment are the height of the testing machine and having grips designed to hold the thin film correctly. We always recommend our eXpert 7601single column test machine with 29" of crosshead travel for films with less than 300% elongation and our 53" model for really high elongation films that elongate up to 900%. The grips we recommend are pneumatic vise grips with rubber coated inserts. The rubber coated inserts help to keep the film from prematurely breaking at the grip edge, and in combination with the constant pneumatic pressure the film is prevented from slipping out of the grips during the test. We use foot pedals to allow the operator to open and close the grips with their feet because thin films usually require both hands to line everything up properly. If you have a 30" crosshead travel machine, the grips and load cell will take up about 12" of that travel. If you use a 4" gage length it will take up another 4" of the travel. This leaves 14" of testing travel which will be fine for materials with less than 350% elongation (14" crosshead travel / 4" original gage length = 3.5 * 100% = 350%) A 54" crosshead travel machine is better suited for materials that have elongation up to 950%.

We are always available to answer your questions. Should you have any questions, please feel free to call us @ 800-667-3220 or visit our website for more information.