One of the basic re­quire­ments for the clean­ing abil­i­ty of floor­ings is the op­ti­mi­sa­tion of sur­face en­er­gy with the aim of min­i­miz­ing soil ad­he­sion. This often is achieved by ap­ply­ing tem­po­rary floor-care prod­ucts.

These tem­po­rary coat­ings (based on poly­mers with and with­out wax) im­prove the clean­ing prop­er­ties and min­i­mize the abra­sion by daily use. This leads to sub­stan­tial­ly in­creased dura­bil­i­ty of the floor­ings.

After a cer­tain time, how­ev­er, the tem­po­rary films have to be re­moved by a water based strip­per and the film­ing with a new tem­po­rary floor care prod­uct has to be car­ried out. Be­fore new films can be ap­plied, the cleaned floor­ing has to dry in a suf­fi­cient way. This dry­ing time caus­es a lot of de­lays in the op­er­a­tional pro­ce­dure of the clean­ing ser­vice en­ter­pris­es.

As a re­sult the eco­nom­ic ef­fi­cien­cy of clean­ing en­ter­pris­es is af­fect­ed. A new method for the re­moval of tem­po­rary floor care prod­ucts is the ap­pli­ca­tion of the laser tech­nol­o­gy.

The re­spec­tive in­ves­ti­ga­tions were at first car­ried out with a CO2 laser (100 W power), as the ab­sorbance of com­mer­cial­ly avail­able floor care dis­per­sions is quite high (40-70 %) at the wave­length of the CO2 laser ra­di­a­tion (10,64 µm). This fa­cil­i­tates the de­coat­ing pro­cess­es.

An ef­fi­cient coat­ing re­moval by means of a CO2 laser is, how­ev­er, con­strained by a very nar­row ex­per­i­men­tal set up.

Even very small changes of laser pa­ram­e­ters, layer thick­ness, floor care dis­per­sion as well as soil­ing or age­ing of the floor­ings have a neg­a­tive im­pact on the de­coat­ing ef­fi­cien­cy. Treat­ing big­ger areas (10 x 40 cm2) de­mands there­fore an ex­ten­sive adap­ta­tion of the laser pro­cess con­di­tions.

Good coat­ing re­moval was ob­tained at up to 30 % high­er laser in­ten­si­ties (till 2100 W/cm2) and up to 30 % lower scan ve­loc­i­ties (1.7 bis 2.3 m/s).

Resid­u­al thin films com­pris­ing soil­ing traces may be re­moved ef­fi­cient­ly es­pe­cial­ly from PVC-floor­ings by means of a me­chan­i­cal dry af­ter-treat­ment by a scrub­ber dryer.

The non self-lim­it­ing char­ac­ter of the de­scribed laser pro­cess is a dis­ad­van­tage. Con­se­quent­ly local over­heat­ing of the floor­ings due to rel­a­tive­ly high laser ab­sorbance may lead to ir­re­versible dam­ages.

Due to the low scan ve­loc­i­ties men­tioned above, the use of a CO2 laser re­sult­ed in a rel­a­tive­ly low per­for­mance per time unit. High­er val­ues re­sult­ed by using a Nd:YAG laser. The re­sults show the fea­si­bil­i­ty of the laser-based re­moval of tem­po­rary coat­ings.

There still ex­ists re­search de­mand re­gard­ing the min­i­miza­tion of the dam­age of the floor­ings. An ap­proach for this pur­pose lies in the in­te­gra­tion of a laser-re­flec­tive layer into the coat­ings. There­fore a fol­low-up pro­pos­al on that topic has been sub­mit­ted to the fund­ing or­gan­i­sa­tion.

We thank the Ar­beits­ge­mein­schaft in­dus­trieller Forschungvere­ini­gun­gen e.V. (AiF) (As­so­ci­a­tion of In­dus­tri­al Re­search Or­gan­i­sa­tions) for fund­ing the pro­ject AiF 187 ZBG through a fi­nan­cial sup­port by the Fed­er­al Min­istry of Eco­nom­ic Af­fairs.

The re­search re­port is avail­able on re­quest from FRT.