Release Liner Ranges

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Release characteristics for release liners (release papers, release films, etc.) are most always given as a range, not a specific number. Sometimes the range is specified in general terms as premium, easy, medium, tight. This is true for most, if not all, release liner manufacturers.

The reason for this is complex; below, Rayven review some of the main culprits. The release force of a silicone coating is a relational value. It is not a specific attribute related only to the coating itself. Values like color and gloss are attributes that can be directly measured.

You just hit your sample with a calibrated gloss meter, and it spits out a gloss reading. Not so for a silicone release coating; which must be tested in relation to an adhesive of some type.

Because Rayven has to test an entire adhesive and release liner system, a lot of variability seeps into the test results. This variability and lack of repeatability forces the release liner manufacturer to quote release values in a general range and not a specific value. The following are some of the factors that affect the Release value and correlation of a Silicone and Pressure sensitive adhesive (PSA) release (or peel) value.

  • The type of test tape used will affect the release test results. Different types of tape include: acrylic adhesive, rubber based adhesives, blended adhesives, film backings, fabric backings, etc.

  • The variability of the test tape will affect the variability of the release test results. Most Pressure sensitive adhesive tapes have a large amount of lot to lot variation, many over 20%. The variability of the test tape will directly affect the variability of the release test results.

  • Often there is little correlation between the test tape and the adhesive used in the actual application. For example, the manufacturer of the release liner may use an Acrylic pressure sensitive adhesive test tape that is not similar at all to the Hot Melt Pressure Sensitive Adhesive used in the actual application.

  • The application temperature will affect the release value. Most liner testing is done in controlled laboratory conditions where the temperature and humidity are set. In the actual application the adhesive may be applied at a much higher temperature or humidity.

  • Many production Pressure Sensitive Adhesive products rely on the hot application of the adhesive directly to the liner. Other pressure sensitive adhesive (PSA) products involve a wet adhesive that is applied to the liner then dried or cured in an oven (transfer coating). The release numbers for these products will have a difficult time correlating to a room temperature test tape peel.

  • Mechanical qualities will affect the release values of a liner. The smoothness or roughness of the liner substrate will affect the release value. Lot to lot variation of the surface finish will usually give a corresponding variation it release.

  • The peel angle will affect the peel value of the test. Peel testing machines allow us to set the peel angle that we use in our tests. If the application calls for the peeling the product at some a different angle a difference in peel force can be expected.

  • Different peel speeds will give different release values. Rayven uses a standard peel speed and peel angle in our quality control testing, but we can tailor these parameters to be more representative of actual intended application.

These are only some of the parameters that affect release testing results, but they demonstrate that there is a lot more involved than what looks like on the surface as a simple testing parameter. In order to give better testing accuracy with complex applications, Rayven can often customize the testing process to yield more relevant results for the specific adhesive and application parameters.

Contact Rayven Inc. to create your custom solution for your corporation.