Labelexpo Europe - tesa® UV-Strips

New measurement technology for higher precision and greater efficiency in curing processes

Whether in the printing industry, in automotive construction, as corrosion protection in the manufacturing of metal packaging, to refine synthetic surfaces, or for sterilization – UV varnishes and coatings are being used today in more and more industries. The proportion of such coatings, which are cured using UV radiation, is rising in Asia by 9 % per year. In Europe and North America, as well, UV coatings are growing at an annual rate of 5 %, considerably higher than for conventional processes. And yet UV technology has its drawbacks: The dose of UV radiation must be precisely calibrated for the production process. Until now, there has been a lack of measurement technologies that are precise and yet easy to use at the same time. With tesa® UV-Strips, tesa, together with UV specialist Dr. Hönle AG, now offers a completely new system solution, the first of its kind on the market, to precisely determine the dose of UV radiation and thereby control processes dependably and quickly.

tesa® UV Strips: flexible handling combined with precise data

In all UV-reactive coatings, it is UV radiation that causes the mass that has been applied to harden. It is no longer necessary to cure these coatings in special systems in which solvent-based masses harden and the solvent evaporates. This also eliminates the necessity for labor-intensive, costly recovery of solvents, thereby reducing production times and cutting costs. Advantages from which numerous sectors, such as the automotive and printing industries and furniture production and medical technology segments, increasingly benefit. Automotive manufacturers, for example, are working on eliminating long post-painting furnace cycles at temperatures of up to 160° C by using UV varnishes instead. And in the particularly rapid process used to produce yogurt containers, the UV process is used to cure the colored print on the plastic in just fractions of a second.

How well the coating hardens depends on the dose of radiation. Previously, however, the dose could be determined only with measurement cells or simple self-adhesive measurement strips. The measurement cells have to be calibrated using a costly, labor-intensive process, are unsuitable for larger objects such as auto bodies due to their size, and often cannot be used in automated production. Measurement strips available on the market to date supply only very imprecise data. The tesa® UV-Strips, on the other hand, unite the flexibility of thin, self-adhesive measurement strips with the measuring precision of measurement cells. In addition, all data can be digitally saved and documented.

The new tesa technology comprises the tesa® UV-Strips and a special reader. The tesa® UV-Strip, for which patents are pending worldwide, is a photosensitive adhesive strip that turns red under UV light. This measurement strip is adhered to the surface that is to be coated, thus precisely measuring where the dose of radiation is needed – even in or on three-dimensional objects. After the object passes through the UV unit, the strip is removed and inserted into the reader. The precise UV dose is immediately readable and can be saved in the device or externally. Due to this precision and the reproducibility of data, the process and quality can be monitored continuously. Sources of error such as defective, soiled, or weakening UV lamps are identified quickly, reducing production waste and thus allowing the efficiency of UV technology to be fully utilized in optimum fashion.

With the tesa® UV-Strips technology, tesa is tapping into a new market segment with an extraordinarily broad application spectrum and high growth potential. Feedback from test clients attests to the considerable need for precise, user-friendly measurement techniques and the high degree of acceptance of the tesa solution. The first focus industry is the sheet-fed offset printing industry, which already relies to a large extent on UV varnishes.