in a preferred embodiment both half - shells ( 1 , 2 ) of the test cell ( 21 ) are made of glass . the circular test cell ( 21 ) is shown in fig1 in lateral cross - section , while fig2 is a plan view . the test cell ( 21 ) consists of an upper ( 1 ) and a lower half - shell ( 2 ). the upper half - shell ( 1 ) preferably encloses a larger volume than the lower one . both half - shells ( 1 , 2 ) are provided at their edges with a reinforcement ( 3 ). the edges of both half - shells ( 1 , 2 ) are congruent and are surface - ground in such a manner that it is possible to place the half - shells ( 1 , 2 ) on each other in a contour - sealed manner . the laterally protruding reinforcement edges ( 3 ) permit to mechanically press the half - shells ( 1 , 2 ) together by holding clamps or clips ( not shown ). between the half - shells ( 1 , 2 ) there is a carrier film ( 4 ) overlapping the cross - section of the shells including the projecting reinforcements ( 3 ). adhered to this carrier film ( 4 ) is the flat material ( 5 ), e . g . a tts , namely on that side of the carrier film ( 4 ) which faces towards the bottom part of the test cell ( 21 ). the tts ( 5 ) has the shape of a circular ring which is approximately at equal distances from the walls of the test cell ( 21 ), and is consequently arranged centrally in the test cell ( 21 ). in the simplest case the tts ( 5 ) consists of a pressure - sensitive adhesive layer ( 6 ) which adheres to the carrier film ( 4 ), as well as of a backing layer ( 7 ) covering the adhesive layer ( 6 ). in the bottom half - shell ( 2 ) of the test cell ( 21 ) there is , in centrical arrangement , a cylindrical supporting body ( 8 ). the free surface of the body ( 8 ) is preferably surface - ground and lies in the same plane as the surface - ground edges ( 3 ) of the lower half - shell . when the half - shells ( 1 , 2 ) have been assembled , with interposed carrier film ( 4 ), the supporting body ( 8 ) forms a support surface for the carrier film ( 4 ). the distance between the edge of the supporting body ( 8 ) and the edge of the circular hole in the tts preferably corresponds to the distance between the outer edge and the inner wall of the test cell ( 21 ). within the upper half of the test cell ( 21 ) there is a dumbbell - shaped stirring element ( 9 ) resting , by gravity , on the , planar , surface of the carrier film ( 4 ) facing away from the tts ( 5 ). the stirring element ( 9 ) may preferably be a standard product as used for laboratory requisites . it has a smooth and soft surface , e . g . of teflon . the distance between the two contact surfaces of the stirring element ( 9 ) on the carrier film ( 4 ) preferably corresponds to the mean value of outer and inner diameter of the flat material which is in the form of a tts ( 5 ). if the test cell ( 21 ) is placed on a magnetic stirring unit with support plate , the stirring element ( 9 ) in the test cell ( 21 ) can be rotated in a circular motion about the centre of the cell . preferably this takes place at a speed of 1 to 30 revolutions per minute . in such an assembly the contact pressure exerted by the stirring element ( 9 ) on the carrier film ( 4 ) is the sum of the weight of the stirring element ( 9 ) and the attractive force of the magnetic stirring unit acting on it . the magnetic properties of the stirring element ( 9 ), as well as the magnetic stirring unit thus have an influence on the test result and must be standardised . during the test , the two contact surfaces of the stirring element ( 9 ) follow a circular path on the carrier film ( 4 ). the centre of this circular path preferably corresponds to that of the tts ( 5 ). in the region of the contact surfaces a temporary elastic stretching of the carrier film ( 4 ) occurs , which conveys itself to the pressure - sensitive tts disposed at the counter face of the carrier film . in the course of the test this load leads to detachment of a greater or lesser degree , up to complete detachment , of the tts ( 5 ) from the carrier film ( 4 ). in an alternative assembly of the test set - up , magnetic power transfer is relinquished in favour of mechanical transfer ( fig3 ). the body putting a load on the tts , said body again being dumbbell - shaped , is now caused to rotate by a shaft ( 10 ) introduced from outside . the two end pieces ( 11 ) of the stirring element ( 9 ) are preferably supported in a freely rotatable manner at the transverse axle ( 12 ) thereof , so that they can roll on the carrier film ( 4 ) when the stirring element ( 9 ) is rotated . the penetration depth of the stirring element ( 9 ) into the carrier film ( 4 ) can be adjusted by means of the shaft ( 10 ). selecting a circular tts ( 5 ) in conjunction with the central support body ( 8 ) in the bottom half of the test cell results in a particularly favourable load geometry . in conjunction with the dumbbell - shaped stirring element ( 9 ) the tts ( 5 ) can be loaded until complete detachment from the carrier film ( 4 ) occurs . this detachment process is successively illustrated by fig6 a to 6 c . in the case of a circular , full - surface tts not having a central supported surface , loading by use of the dumbbell - shaped magnetic stirrer leads only to the detachment of the tts ( fig7 ). this embodiment , however , constitutes a comparatively ineffective assembly . furthermore , due to the tts having a circular ring shape as compared to a full - surface embodiment , the ratio of the edge region to the internal surface is increased . the ratio between the surface in the process of becoming detached and the surface still adhering is thereby increased too , so that the differentiation capacity of the model increases . finally , the circular ring shape reduces the probability of central detachments that lie entirely within the surface of the tts and which are not accessible to a preferred quantification technique . the material quality of the carrier film is of particular significance for the test result . preferred materials are polymers having marked elasticity and good water vapour permeability , while at the same time being practically insoluble in water . these properties are shown , in particular , by polyurethanes and ethyl vinyl acetate copolymers as well as silicone rubbers . polyethylene and polypropylene as well as the block polymers styrene - isobutylene - styrene ( sis ) and styrene - butadiene - styrene ( sbs ) are available with sufficient elasticities . their water vapour permeability is , however , low and hardly suitable for simulating the transpiration of the skin . suitable carrier materials for the tts are also human and animal skin . this can be used as full - thickness skin or in the form of isolated skin layers . however , such biogenic carriers , which are difficult to standardize , are not preferred by the invention since they are not suitable for standardized routine testing in a conventional laboratory . if a water - permeable carrier film ( 4 ) is used , the transpiration of the skin can be included in the test procedure by completely or partially filling the upper part of the test cell ( 21 ) with water or an aqueous solution . this is done by initially filling the lower half - shell ( 2 ) with liquid and assembling the test cell ( 21 ) with the cell being turned upside down . thereafter , the cell is turned over so that the liquid comes into contact with the carrier film ( 4 ) and covers the same completely or partially . such an assembly is shown in fig4 . the liquid ( 13 ), in the following designated as medium a , in this case covers the carrier film ( 4 ) completely . preferred liquids are water or isotonic sodium solution . by means of the assembly according to fig4 it is furthermore possible to simulate the release of low - molecular substances ( molecular weight up to 1000 da ) from the tts in or through the skin while the system is being worn , provided that a carrier film ( 4 ) is used that has sufficient diffusibility for these substances . here , the term substances is to be understood as meaning , in particular , active substances as well as permeation enhancers and plasticizers . the two latter groups are available in large number for the formulation of ttss and are known to those skilled in the art . should these substances be slightly soluble in the pure , aqueous medium a , other liquids are suitable too . in particular , these are mixtures of water with mono - or polyvalent alcohols , polyethylene glycols or polyvinyl pyrrolidone . as solvents , anionic , cationic , amphoteric or nonionic surface - active agents can be contained . also , proteins , preferably serum albumins of humans or animals , may be used for this purpose . in a further test set - up a water - insoluble film , which is , however , water - permeable through micropores ( pore diameter below 100 μm ), is used as the carrier . microporous polyethylene or polypropylene film is mentioned by way of example . preferably , the pores of this film are treated with a hydrophylizing agent in order to facilitate the passage of liquid water . if a set - up according to fig3 is used , the medium a , via the pores , comes into direct contact with the tts . this corresponds to sweating on human skin , where liquid water along with salts is released by glands of the skin via pores to the surface of the skin . it is in particular this form of water contact which in many pressure - sensitive adhesives leads to a deterioration of the adhesive properties , respectively to a detachment of the skin under formation of a moisture film forming between the adhesive layer and the skin . finally , with the test set - up according to fig5 it is possible to bring the tts into direct contact with liquid ( medium b ), from the outside and during the test . medium b ( 14 ) preferably is water or a solution of surface - active agents in water , so as to simulate the effects of washing , showering , bathing or swimming on the tts . the evaluation of the test is performed by quantification of the detached surface of the tts in ratio to the overall surface of the tts . the procedure described in the following is illustrated by fig8 a to 8 c . the carrier film ( 15 ) and the still adhering tts ( 16 ) are removed from the test cell at the end of the test . drops of a dye solution ( 17 ) are put on the edges of the tts ; the dye solution ( 17 ) is capable of entering into the cavities which have formed between the tts and the carrier film ( 18 ) due to detachment . the dye must be capable of colouring either the carrier film or the adhesive layer of the tts . by contrast , the backing layer of the tts ( that layer of the tts being located farthest from the carrier film ) must be practically uncolourable by the dye for a short time ( 5 to 10 minutes ). after a short duration of action ( 5 to 10 minutes ) the excess dye solution is wiped off with a cloth . if required , the backing layer of the tts is briefly aftercleaned with the solvent of the dye solution . the dyed surface of the carrier film which projects beyond the surface of the tts is removed . this is done by punching off excessive carrier film . the punching tool used therefor is the identical tool that was originally used for shaping the tts . at the end of the procedure , a circular ring - shaped tts ( 19 ) is obtained , which partially adheres to a carrier film of the same geometry . only the detached surface parts ( 20 ) have been coloured by the dye and are thus accessible to further evaluation . in the simplest case , this evaluation is performed by photocopying the dyed tts at full scale or at another , defined scale , onto a paper having uniform weight per unit area . the coloured surfaces are cut out from the photocopy and their portion of the overall surface of the tts is ascertained . compared to this inaccurate and laborious method , it is preferable to perform the evaluation by computer - aided image processing . to this end , the image of the dyed tts is produced by means of a conventional scanner or a digital camera ( ccd camera ), and is converted into a computer - readable form . in this image , it is then possible to perform a computer - aided calculation of the ratio of the dyed surface to the total surface , and thus of the detached portion of the tts . for this purpose , a large number of computer programs are available to those skilled in the art ( e . g . leco 2003 by leco corporation , image analysis group ). the results obtained with the test set - up and test procedure show the high informative value of the test method and reflect in a surprisingly reproducible manner the phenomena of detachment of a tts from the skin . ttss were tested which were made up only of a monolithic layer of adhesive and a backing layer . the backing layer preferably consisted of a transparent film ( hostaphan ® rn by hoechst ). as carrier film , a 51 - μm - thick eva film having a portion of vinyl acetate ( msp 98792 by 3m ) of 9 % was used . the test duration was 24 hours . as dye solution , the saturated solution of solvent red 19 in ethanol was used . the evaluation was effected by means of a sony ccd colour camera on a stand with connected image processing system leco 2003 , on a conventional pc . 1 . the uncrosslinked acrylate adhesive durotek 1051 shows a clearly larger detachment surface than the crosslinked adhesive of the same type ( durotak 1052 ). 2 . at n = 2 , uncrosslinked adhesive durotak 1051 and graded additions of crosslinking agent were tested . if no al is added , this identically results in 6 % of detached surface , with 0 . 01 % of al the detachment is at 4 . 5 %, and with 0 . 05 % of al it is finally at 3 %. this is in accord with the optimum additions of crosslinking agent known for this adhesive from 0 . 01 to 0 . 05 % of al . 3 . the addition of 1 % of eudragit e100 to durotak 1051 leads to a physical crosslinking which is already clearly distinguishable by a diminished detachment . 4 . when microporous pe film was used as carrier , hot - melt formulations based on ethyl cellulose already after 1 hour exhibited extreme water absorption and almost complete detachment ( in accordance with fig4 the upper half of the test cell was filled with water ). the moisture sensitivity of these systems had already been known from wearing tests . further , three of these formulations were tested on an eva film and again under action of water ( this time only water vapour ). the extent of the detachment coincided in order with the experience from wearing tests . one of the systems proved to be particularly inadequate and stood out in the test for a special effect : the matrix , which had initially been opaque , was clear as glass in the end , which proved that water absorption had taken place during the test procedure . 5 . moisture - sensitive ttss were tested on a microporous pe film with and without action of water ( according to fig4 ). it was only under action of water that a partial detachment took place , and the tts could subsequently be peeled off the carrier very easily . by contrast , the system tested under dry conditions showed practically no detachment and could be manually detached from the carrier only with great difficulty .