Device and Method for Testing Tack

Abstract

The disclosure relates to a testing device for testing tack, including: a test probe which has a test body; and a suspension which guides the test body, the suspension movably supporting the test body. The disclosure further relates to a testing machine for testing tack, including a measuring apparatus and a testing device of this type, which is connected to the measuring apparatus. Finally, the disclosure relates to a method for determining the tack. The method includes the steps of guiding a test probe of a test body onto a sample to be tested, placing the test probe onto the sample, lifting the test probe off of the sample, and sensing the force F as the test probe is lifted off.

Claims

1. A testing device for testing tack, comprising a test probe comprising a test body and a suspension guiding the test body, wherein the suspension supports the test body.

2. The testing device according to claim 1, wherein the suspension freely supports the test body in a Z-direction.

3. The testing device according to claim 1, wherein the suspension comprises a joint.

4. The testing device according to claim 3, wherein the joint supports the test body with a degree of freedom of at least 1.

5. The testing device according to claim 1, wherein the suspension comprises a bracket connectable to a lug of the test probe.

6. The testing device according to claim 1, wherein the test probe comprises a spherical body and is constituted by the same.

7. The testing device according to claim 1, wherein the test probe comprises a plate and is constituted by the same.

8. The testing device according to claim 1, wherein the test probe and/or the bracket comprise metal and is made from the same.

9. The testing device according to claim 1, wherein the test probe is coated and/or polished and/or cleaned with a solvent.

10. A testing machine for testing tack, comprising a measuring unit and a testing device connected to the measuring unit, according to claim 1.

11. The testing machine according to claim 10, further comprising a force meter, wherein the test probe is movably connected to the force meter via the suspension.

12. The testing machine according to claim 10, further comprising a sample receiving portion.

13. A method for determining tack comprising the steps of: (a) guiding a test probe of a test body onto a sample to be tested, (b) placing the test probe onto the sample, (c) lifting the test probe off the probe, and (d) sensing the force F when lifting off the test probe.

14. The method according to claim 13, wherein the method is carried out by a testing device according to claim 1.

15. The testing device according to claim 1, wherein the test probe comprises a disc or a ring, and is constituted by the same.

16. A testing machine for testing tack, comprising a force measuring unit, and a testing device connected to the measuring unit, according to claim 1.

17. The testing machine according to claim 10, further comprising a load cell wherein the test probe is movably connected to the force meter via the suspension.

18. The testing machine according to claim 10, further comprising a T-bar.

19. A method for determining tack of dermal adhesives, comprising the steps of: (a) guiding a test probe of a test body onto a sample to be tested, (b) completely placing the test probe onto the sample, (c) lifting the test probe off the probe, and (d) sensing the maximum force Fmax, when lifting off the test probe.

20. The method according to claim 13, wherein the method is carried out by a testing machine according to claim 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Hereunder the disclosure is described in detail on the basis of preferred embodiments with reference to the drawings in which:

[0041] FIGS. 1a and 1b schematically show prior art testing devices,

[0042] FIG. 2 shows a schematic view of a preferred embodiment of a testing device according to the disclosure,

[0043] FIG. 3 shows as schematic view of an embodiment of a testing machine according to the disclosure having a testing device according to the disclosure,

[0044] FIGS. 4a to 4e show schematic views of various preferred embodiments of test bodies according to the disclosure,

[0045] FIGS. 5a to 5d show schematic views of various preferred embodiments of test devices according to the disclosure, and

[0046] FIGS. 6a and 6b show schematic views of various preferred embodiments of sample receiving portions according to the disclosure for testing machines.

[0047] In the figures, identical components or elements are identified by the same reference numerals or variations thereof (for example 10 and 10). In particular, for the sake of clarity, elements already identified are preferably not provided with reference numerals in all figures.

DETAILED DESCRIPTION

[0048] FIG. 1a shows an idealized prior art testing device 10′. The testing device 10′ comprises a test body 12′ which, in turn, comprises a test probe 14′. The test body 12′ is guided by means of a suspension 18′, wherein the connection between the suspension 18′ and the test body 12′ is configured as a fixed or rigid suspension.

[0049] The test body 12′ is illustrated with the test probe 14′ in contact with the sample 50 to be tested which is a plaster or TTS, for example. The contact between the test probe 14′ and the sample 50 is realized in a touch area or touch point 15′.

[0050] Due to the rigid connection and thus rigid guide of the test body 12′, the force between the test body 12′ and the sample 50 to be tested depends, in particular in the touch area 15′, on the force at which the test body 12′ is guided via the suspension 18′. Hence, if in various experiments the test probe 14′ contacts the sample 50 at different forces, this results in particular in different pressing forces in the contact area and/or different immersion depths.

[0051] According to prior art, it is ideally preferred that the tip of the test probe 14′ merely touches a single point. However, here an immersion and/or contact always occur at several points.

[0052] FIG. 1b shows a prior art test device 10′ as used in practice. Here, the test probe 14′ contacts or is immersed into the sample 50 in a contact area 15′ comprising a plurality of contact points, which results in a non-reproducible test.

[0053] FIG. 2 shows an embodiment of a test device 10 according to the disclosure. The test device 10 comprises a test body 12. The test body 12 comprises a spherical test probe 14 as well as a lug 16 in particular integrally connected thereto.

[0054] The test body 12 is connected to the suspension 18 via the lug 16 which is a ring, in particular a metal ring, as illustrated. Since the suspension 18 is loosely or movably supported in the lug 16, the test body 12, when placed onto a sample 50, for example, completely freely rests on the sample 50 and is thus merely influenced by its own weight force.

[0055] The advantage of the geometric shape of the test probe 14 as compared to prior art is obvious since no matter how the test probe 14 is placed onto the adhesive surface of the sample 50, the contact area 15 is always the same. In the case of a spherical shape of the test probe 14, as illustrated, the contact area 15 is a point or a small circle. The same applies to test probes 14 configured as spherical segments (see FIG. 4b, for example). In the case of test probes 14 of other geometrical shapes, for example, cylindrical, hollow-cylindrical or cuboidal, there are corresponding contact areas or immersion depths.

[0056] According to the disclosure, in particular the size of the contact area is thus always the same and reproducible and preferably exclusively depends on the viscosity of the adhesive surface and/or the weight force of the test probe.

[0057] FIG. 3 shows a preferred embodiment of the disclosure of a testing machine 100.

[0058] The testing machine 100 comprises a measuring unit 102, in particular configured as a universal testing machine, such as a Z005 of Zwick/Roell, for example. The measuring unit 102 comprises a traverse 116 which is vertically displaceable along a guiding device 112. Two guiding bars 114′, 114″ of the guiding device 112 are shown. The traverse 116 can be displaced by an electric motor not shown, for example. The guiding bars 114′, 114″ end in a base body 118.

[0059] The displaceable traverse 116 has a force meter 104 connected thereto. The force meter 104 is in particular a load cell. To the force meter 104, in turn, a testing device 10 is connected via the suspension 18, wherein the testing device 10 is in particular configured like the testing device in FIG. 2.

[0060] The base body 118 has a sample receiving portion 106 connected thereto. The sample receiving portion 106 is illustrated as a T-bar having a horizontal plate 108 as well as a connecting column 110. The connecting column 110 is preferably connected to the base body 118 via a fixing means 120, such as clamping jaws of the measuring unit 102, for example.

[0061] A sample 50 is connected to the sample receiving portion 106, preferably via a double-sided pressure-sensitive adhesive tape.

[0062] Hence, the testing device 10 having the test probe 14 can contact the sample 50 by horizontally displacing the traverse 116. According to the disclosure, it is preferred here that the probe 14 is placed onto the sample 50 such that the suspension is free and thus not loaded. During a final vertical displacement in the opposite direction (upward) the lifting-off force, preferably the maximum lifting-off force, can be measured by the force meter 104 and thus the tack can be determined.

[0063] Another embodiment, not shown, according to the disclosure of the testing machine 100 comprises, similar to the embodiment of FIG. 3, a force meter 104 as well as a testing device 10 connected thereto. Such a testing machine 100 can be manually guided or operated, for example.

[0064] FIGS. 4a to 4e show various embodiments of the test body 12 according to the disclosure of the testing device 10.

[0065] FIG. 4 shows a spherical test probe 14 having a lug 16 connected thereto.

[0066] Instead of the spherical configuration an oval configuration is also possible, for example.

[0067] FIG. 4b shows a test probe 14 configured as a partial sphere. As illustrated, this is approximately a quarter sphere, wherein hemispheres or three quarters of a sphere etc. are also possible, for example.

[0068] FIG. 4c shows an embodiment of the test probe 14 configured as a round disc or a round cylinder.

[0069] FIG. 4d shows an embodiment of the test probe 14 configured as a plate or a cuboid.

[0070] FIG. 4e shows an embodiment of the test probe 14 configured as a hollow cylinder. Here, FIG. 4e does not show a lug 16 or the like. Here, it is possible to arrange, in the upper base area of the hollow cylinder, a plurality of lugs or other connecting devices for connecting to a suspension, for example.

[0071] In FIGS. 5a to 5d testing devices 10 having different preferred embodiments of suspensions 18 are illustrated.

[0072] FIG. 5ashows a suspension 18 comprising a hook, preferably a metal hook, particularly preferably a wire hook.

[0073] In FIG. 5b, the suspension 18 comprises a cord or a fiber and is in particular constituted by the same.

[0074] FIG. 5c shows a suspension 18 having a loop, preferably a wire loop.

[0075] In FIG. 5d, the suspension 18 comprises a telescopic suspension made up of two telescopic members, as illustrated.

[0076] In contrast to the embodiments of FIGS. 5a to 5c, the embodiment of FIG. 5d does not comprise a lug 16 of the test body 12 for connection to the suspension 18, but the telescopic suspension 18 is directly, preferably integrally, connected to the test probe 14.

[0077] In FIGS. 5a to 5d the test body 12 always comprises a spherical test probe 14. Of course, other embodiments, in particular the embodiments of FIGS. 4a to 4e, of the test probe 14 in combination with each embodiment of the suspension, preferably of FIGS. 5a to 5d, are feasible.

[0078] In FIGS. 6a and 6b two preferred embodiments of sample receiving portions 106 according to the disclosure for testing machines 100 are illustrated.

[0079] FIG. 6a shows an embodiment of the sample receiving portion 106 which essentially corresponds to the embodiment of the sample receiving portion 106 of FIG. 3. The sample receiving portion 106 comprises a T-bar having a horizontal plate 108 as well as a connecting column 110.

[0080] FIG. 6b shows an embodiment of the sample receiving portion 106 having a horizontal plate 108 as well as a cylindrical connecting column 110. The connecting column 110 is supported in a displaceable fixing device 120, preferably a ball joint fixing device 120, such that the sample receiving portion 106 can be fixed or arranged in various positions.

[0081] The method according to the disclosure for determining tack is preferably performed by means of devices illustrated in the Figures, or to which one or several features of the Figures are added.

[0082] Hereunder the present disclosure will be exemplified on the basis of a performed experiment.

EXPERIMENT EXAMPLE

[0083] The illustrated experiment example illustrates, on the one hand, a prior method for testing tack within the framework of the probe tack test (ASTM D 2979) as well as an embodiment of a method according to the disclosure for testing tack using an embodiment of a testing machine according to the disclosure having an embodiment of the testing device according to the disclosure.

Materials and Methods

[0084] Hereunder the materials and methods used are illustrated.

[0085] 1.1 Materials

[0086] Per n=6 commercially available TTS the prior art method for probe tack test (ASTM D 2979) was performed and the tack was checked.

[0087] TTS containing acrylate copolymers, polysiloxanes or polyisobutylenes were tested as samples. The trade names, batch codes and polymers are stated in Table 1:

TABLE-US-00001 TABLE 1 Three over-the-counter Nicotin TTS and one rivastigmine TTS only available on prescription for measuring the tack Trade name Batch code Polymer Nicotinell ® 81218417 Neutral acrylate vinyl acetate copolymer Niquitin ® 1609890 Polyisobutylene Nicorette ® 81216016 Acidic acrylate vinyl acetate copolymer Exelon ® 835220 Polysiloxane

[0088] 1.2 Methods

[0089] 1.2.1 Prior art method (probe tack test: ASTM D 2979)

[0090] First, the experiment was carried out by means of the prior art method for probe tack test ASTM D 2979 (test results see Table 2).

[0091] 1.2.2 Method of the illustrated experiment according to the disclosure

[0092] 1.2.2.1 Definition

[0093] The tack is the force required for removing a body from an adhesive surface after a short contact time.

[0094] 1.2.2.2 Pretreatment of the samples

[0095] Subsequently, the experiment was carried out using an embodiment of the testing machine according to the disclosure having a testing device according to the disclosure within the framework of an embodiment of the method according to the disclosure, as described below.

[0096] Prior to the test the samples were stored under the following conditions in a controlled thermal environment for at least 24 hours: Temperature: 23° C.±2° C. Relative humidity: 50% ±5% (abs.)

[0097] 1.2.2.3 Preparation of the experiment

[0098] The following preparations of the experiment described below were made.

[0099] 1.2.2.3.1 Devices and materials used [0100] Universal testing machine: Z005, Zwick/Roell [0101] Wire hook for suspending the test body from the load cell according to the embodiment of FIG. 5a [0102] Test body: Test probe configured as a polished solid steel sphere Diameter=2.54 cm with suspension lug (in particular according to the embodiment of FIG. 5a) [0103] Double-sided pressure-sensitive adhesive tape: Duplocoll 365, Lohmann Neuwied, for fastening the samples to the sample receiving portion [0104] Sample receiving portion: T-bar according to the embodiment of FIG. 6a [0105] Solvent for cleaning the test body (e.g. special benzine 80/110, ethyl acetate, . . . ) [0106] Lintfree cloth for cleaning the test body (e.g. from cotton wool or cellulose).

[0107] The experiment setup essentially corresponds to the setup of FIG. 3, however, in particular having a wire hook instead of the ring as a hanger.

[0108] 1.2.2.3.2. Preparation

[0109] The testing machine was set up as follows: The test body is cleaned with a suitable solvent and suspended in the load cell. A T-bar is fixed to the lower clamping jaw. The force indicator is set to zero. The test body is manually moved downward to such an extent that it slightly touches the plate of the T-bar. Now the actual distance is set to zero. The initial distance is approached again using the LE button. The distance between the T-bar and the test body is measured again (desired value: 100 mm).

[0110] For example, the following parameters are to be entered as test parameters (depending on machine type, test body and suspending device): [0111] LE=100 mm/min. (distance between T-bar and test body) [0112] Measurement path=10 mm [0113] Test velocity=300 mm/min. [0114] Clamping length after pre-travel=0 mm [0115] Velocity pre-travel=300 mm/min. [0116] Dwell time after pre-travel=1 sec

[0117] 1.2.2.4 Measurement

[0118] The sample is fixed to the T-bar by means of a double-sided pressure-sensitive adhesive tape with the adhesive side facing upward, and any protective film is peeled off.

[0119] After the sample has been fixed the measurement is started using the start button.

[0120] 1.2.2.5 Evaluation

[0121] The maximum value during the measurement (Fmax) is stated as the measured value. After completion of the measurement the mean of the individual values of the maxima is taken by the test program, and the mean value, the standard deviation and the relative standard deviation in % are taken.

[0122] This yielded the following results:

TABLE-US-00002 TABLE 2 Tack according to experiment as per ASTM D 2979 Nicotinell ®, Nicorette ®, TTS from Exelon ®, TTS from neutral TTS acidic acrylate acrylate Niquitin ®, Adhesive from poly- vinyl acetate vinyl acetate TTS from poly- Sample siloxane copolymer copolymer isobutylene 1 2.74N 3.09N 6.02N 0.42N 2 2.96N 2.96N 3.82N 0.47N 3 2.88N 2.66N 4.90N 0.35N 4 2.54N 3.72N 6.05N 0.42N 5 3.29N 2.84N 5.27N 0.24N 6 3.18N 2.68N 5.92N 0.25N MW 3.10N 2.99N 5.33N 0.36N S 0.29N 0.39N 0.88N 0.10N S rel 9.5% 13.1% 16.4% 26.7%

TABLE-US-00003 TABLE 3 Tack in accordance with the illustrated experiment setup according to the disclosure. Nicotinell ®, Nicorette ®, TTS from Exelon ®, TTS from neutral TTS acidic acrylate acrylate Niquitin ®, Adhesive from poly- vinyl acetate vinyl acetate TTS from poly- Sample siloxane copolymer copolymer isobutylene 1 2.53 N 3.62 N 3.73 N 0.32 N 2 3.03 N 3.21 N 3.92 N 0.22 N 3 2.63 N 3.63 N 4.13 N 0.23 N 4 2.81 N 3.42 N 4.58 N 0.24 N 5 2.39 N 3.46 N 4.72 N 0.39 N 6 2.75 N 3.58 N 4.82 N 0.21 N MW 2.69 N 3.49 N 4.32 N 0.27 N S 0.23 N 0.16 N 0.45 N 0.07 N S rel 8.4% 4.6% 10.5% 26.9%

[0123] The statistical results were calculated from the non-rounded raw data.

[0124] Although the illustrated experiment setup according to the disclosure was realized using a standard testing machine (Z005), the achieved results lie in the range of the results achieved by means of the special machine for the probe tack test (ASTM D 2979). It is however noticeable that the scattering, expressed by the relative standard deviations, at the values achieved by the less complex methods and devices is either considerably lower, but in no case worse than the scattering of the probe tack test (ASTM D 2979). This illustrates advantages offered by the disclosure.