In 1978 Theller designed and built the first laboratory heatsealer with millisecond
control of sealing time for simulation of high-speed vertical form-fill package sealing.
The first Mini Tensile Tester (MTT) was designed and built in 1979, as a companion
machine for laboratory heatsealers. The MTT is about the size of a typewriter -
a fraction of the size of most vertical tensile machines. Its grip travel is short,
designed specifically for testing seal strength, and it pulls horizontally. It can sit
on the lab bench next to the heatsealer for convenient and quick measurement of seal
strength.
This was followed in 1980 by development of an accurate test method for measuring
heatsealability of materials as a function of the interface temperature at the surfaces
being sealed.
In 1988 Theller published results of an investigation of the effect of heatsealing
variables on seal strength, and compared the results with expectations from the
heatsealing model based on diffusion of polymer chain ends.
Prior to 1990, Theller's model EB heatsealers had been digital machines, controlled by
hardware logic. In preparation for the introduction of a hot-tack machine, that
clearly should be computer-controlled and provided with graphic capability, the EB
heatsealer was redesigned with computer control and graphics and introduced as the
model PC Heatsealer.
A proposed 2-part test method was published in 1991 to measure: (1) the heatsealability of
thermoplastic surfaces of flexible web materials, plus (2) the effect of web thickness and
construction on heatseal strength when sealed at short dwell times simulating
commercial conditions.
F1921-98 was subsequently established employing substantially this
approach. The ASTM standard was adopted in 2004 employing the
Theller machine and procedure as method A.
The model HT Hot Tack Heatsealer was designed in 1992, with patent application, and
introduced at several trade shows in 1993. Patents were issued in 1994 and 1998. Since then over 100 machines have been sold worldwide.
In 2000, Dynisco Polymer Test, a wholly-owned subsidiary of Dynisco LLC, purchased patent rights to the Theller Hot Tack machine, plus world-wide sales and manufacturing rights. Both Theller heatsealers are now included in the Dynisco
product line, sold globally. For several years thereafter Theller Engineering
continued to handle service for Dynisco.
During this period Dynisco rewrote the software from DOS to Windows.
In 2004 Dynisco acquired Alpha Technologies, which was set up as a Dynisco
Division. Both sales and service were transferred to them. Theller
Engineering is no longer involved in any part of the business.
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