US 5,331,858 A · Hot tack tester

Abstract

A procedure and apparatus for testing the hot tack properties of heat sealable flexible packaging materials. A portion of a test strip of heat sealable material is lapped and a segment of this portion heat sealed together. Upon completion of the heat seal the unsealed ends of the test strip are pulled apart at a prescribed constant rate to gradually delaminate the heat seal while the heat seal is cooled at a prescribed rate. Force required to delaminate the seal is continuously recorded as a function of time as the heat seal cools, thus providing data on seal strength for a full range of temperatures of the heat seal as it cools over time. In the apparatus a threading bar intercepts the strip intermediate its ends and pulls a portion through the opening between opposed dies of a heat sealer and in doing so laps the portion of the strip pulled through the opening. The test strip is then liberated from the threading bar during or following heat sealing of the lapped portion, as by cutting the strip at the threader.

Claims13

Dependent claims

A method of testing the hot tack properties of a strip of heat sealable material which comprises overlaying a portion of said strip with another portion of said strip, creating a heat seal on a segment of said overlaid portion by subjecting said segment to heat and pressure, removing the heat sealed segment from said heat and pressure, pulling apart said heat seal at a constant rate to progressively delaminate said heat seal, cooling said heat seal during said delamination and measuring and capturing for retrieval the pulling force on the strip with time as delamination progresses and wherein the ends of said strip are each affixed to a respective gripper prior to overlaying of said strip in opposed directions with said grippers positioned sufficiently close to each other to provide adequate slack in said strip for portions thereof to be overlaid for heat sealing, said grippers following heat sealing of said portions are moved rapidly apart a distance to quickly move the heat sealed segment from said heat and pressure and take up the slack in said test strip and then said grippers are moved apart at a slower substantially constant rate to effect said progressive delamination of said seal.

Apparatus for testing heat seal bonds comprising

a. means for creating a heat seal in a segment of a lapped section of a test strip,
b. means for pulling the ends of said test strip in opposed directions to first move the heat sealed segment from the heat seal creating means and to fully extended said strip and then further to progressively delaminate said heat seal, said means for pulling the ends of the test strip in opposed directions including means for rapidly moving the heat sealed segment from the heat seal creating means and extending said strip to a fully extended position and means for then pulling the ends of the fully extended strip at lower constant rate of speed to progressively delaminate the seal, and
c. means for measuring the pulling force to delaminate said heat seal with time as the delamination progresses and capturing the measurements for retrieval.

Dependencies are inferred from the claim text.

Hot tack tester

Life of this patent

Hot tack tester

Life of this patent

Abstract

Claims13