Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N19/00—Investigating materials by mechanical methods
  • G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/0001—Type of application of the stress
  • G01N2203/0005—Repeated or cyclic
  • G01N2203/0007—Low frequencies up to 100 Hz
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/0014—Type of force applied
  • G01N2203/0016—Tensile or compressive
  • G01N2203/0017—Tensile
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/0014—Type of force applied
  • G01N2203/0016—Tensile or compressive
  • G01N2203/0019—Compressive

Definitions

• the invention relates to a method for testing the adhesion of a pressure-sensitive adhesive, flat body on a flat substrate, preferably for evaluating the adhesion of a multi-layer transdermal therapeutic system, and a testing device for carrying out the method.
• Transdermal therapeutic systems are flat, layered pharmaceutical products that are intended to enable continuous delivery of active ingredients through the human skin over a specific application period. Nicotine patches, motion sickness patches and hormone replacement therapy using TTS, especially in women going through the menopause, are certainly the most well-known examples.
• an active substance carrier film is generally provided, namely a carrier film which is coated with a polymer mass which contains the active substance and is adhesive to the skin.
• One or more active substances with or without auxiliary substances can be embedded in the polymer matrix.
• Document CN 2 08 476 753 U discloses a paper-plastic bag recognition device comprising a workbench, a gripping block, a fixed plate and a turntable. It is characterized, among other things, by the fact that the surface of the workbench is provided with a notch (2) which is firmly connected to the top surface of the workbench.
• DE 200 05615 U1 discloses a device for measuring the adhesive strength of plasters, which makes it possible to measure the adhesion of plasters on human skin under standardized conditions.
• DE 200 05615 U1 discloses a device for measuring the adhesive strength of plasters on human skin, in which a lifting device is connected to a plaster via a thread and the tensile force when it is pulled off is measured with a force sensor.
• the disadvantage here is that on the one hand a test person is required and on the other hand an absolute measurement of the tensile force required for detachment can be made, but no statement can be made about the long-term adhesion with movement and changes in moisture content of the skin.
• WO 9846980 A1 discloses a method and a device for determining the adhesive behavior of pressure-sensitive adhesive sheetlike structures, including transdermal therapeutic systems, which are applied to an elastic carrier film for testing.
• the carrier film is then clamped in a test cell and subjected to repeated loading and unloading with alternating elastic strains by defined loading forces from the side facing away from the fabric, including with a magnetic stirring bar.
• the disadvantage here is that the burden is applied by an object/magnetic stirring rod acting on the upper side of the freely clamped and only centrally supported carrier foil. As a result, weight and acceleration forces also act on the fabric and can falsify the result.
• the object of the present invention was therefore to provide an improved test method and an improved device for qualitatively assessing the adhesion of a pressure-sensitive adhesive formed, flat body on a flat substrate, which simulate the actual load situations and environmental conditions that occur on a flat substrate, for example a flat body applied to the human skin in the form of a pressure-sensitive adhesive is also subjected to it and for which a simple qualitative assessment is made possible and is sufficiently informative.
• the force repeatedly deforming the flat substrate is applied by a dumbbell-shaped magnetic stirring bar that is driven by a magnetic stirrer and is movable in a vessel that is open at the top is that the dumbbell-shaped magnetic stirring bar rotates below the substrate with the same deformation.
• the vector of the force for deformation thus points in a direction out of the vessel opening
• a further advantageous embodiment is that the flat substrate is moistened to saturation or to saturation, preferably to saturation with deionized water.
• adhesives are popular because they do not release any environmentally harmful substances; however, they are sensitive to water or moisture.
• Demineralized water also known as deionized water, fully desalinated water (VE water) or deionate, is water (H20) without the salts that occur in normal spring and tap water, which are dissolved as anions and cations.
• a further advantageous embodiment is that the force deforming the planar substrate in an oscillating manner is in the form of a compressive force which produces a migrating or rotating deflection of the substrate in the adhesive area orthogonally to its surface.
• a compressive force which produces a migrating or rotating deflection of the substrate in the adhesive area orthogonally to its surface.
• Such migratory orthogonal deflection closely approximates the movement of skin on extremities, such as in joint areas, where repetitive stretching and folding occurs.
• This is supported by a further configuration that is advantageous in this direction, which consists in the fact that the flat substrate is placed under tension during the action of the force.
• another advantageous embodiment is that the force that deforms the flat substrate in an oscillating manner is applied by a dumbbell-shaped magnetic stirring rod that is driven by a magnetic stirrer and can be moved in a vessel in such a way that the magnetic stirring rod, also known as the “stirring fish” in test laboratory jargon , rotates underneath the flat substrate with deformation of the same, preferably at a speed of 100 to 120 rpm and over a period of 24 hours.
• a testing device is particularly suitable for carrying out the method according to the invention, which has a vessel open at the top, preferably a cylindrical glass beaker, and an element arranged movably in the vessel in the form of a dumbbell-shaped magnetic stirring bar, which protrudes above the vessel rim in height.
• the test device also includes a drive which causes a rotary and/or stirring movement of the element in the vessel, the drive being designed as a magnetic stirrer (7) arranged underneath the vessel.
• the flat substrate which can protrude beyond the surface of the vessel opening and covers the element causing the rotating and stirring movement, the flat substrate being provided on its upper side with the flat body designed to be pressure-sensitive in such a way that the latter is at least partially above the Vessel opening and located in the area of the rotating and/or stirring movement, formed vessel opening, completes the testing device.
• the device also has a clamping device for fixing the planar substrate, which can act on the substrate surfaces protruding beyond the vessel opening and fix the planar substrate in such a way that the underside of the clamping device clamps and possibly spans the vessel opening and the movable element.
• the movable element which projects beyond the edge of the vessel, is designed in the shape of a dumbbell, namely in the form of a rod connected at the end with balls or disks.
• the diameter of the balls or disks is greater than the height of the inner edge of the vessel, as a result of which the dumbbell-shaped element with its end balls or disks protrudes beyond the edge of the vessel.
• the required mechanical loading is effected by a force acting on two spaced-apart contact points between the balls or disks of the dumbbell-shaped element and the flat substrate.
• a rotation or a stirring movement of such Elements are then sufficiently twist-free and balanced with regard to reaction forces, so that no constant load peaks can occur at just a few points on the flat substrate.
• a further advantageous embodiment of the testing device is that the movable element is designed as a magnetic, preferably plastic-coated, magnetic stirring bar.
• the well-known magnetic stirring bars, stirring bars or stirring magnets are usually coated with plastic (e.g. PTFE) or glass to reduce friction and are chemically inert.
• the clamping device has a base plate provided with a receptacle or a continuous recess for the vessel. Tensioning or clamping devices are provided in the edge area of the base plate, which are arranged around the receptacle or recess, preferably symmetrically and at equal intervals.
• simple threaded rods provided with wing nuts can be used here, with which the flat substrate provided with corresponding punched-out portions for the threaded rods can be clamped.
• the vessel is held in a form-fitting manner on the base plate and cannot be moved by the stirring movement, while on the other hand, an adjustable tension for the flat substrate is provided in the simplest way, which can be varied as finely as desired, for example by using washers between the substrate and base plate.
• the mechanical load is terminated and the remaining adhesive strength of the flat body designed to be pressure-sensitive is assessed visually, in particular the remaining adhesive strength at its edges.
• the decrease in the adhesive strength at the edges is reflected in detachment and in the edges standing up.
• the detachment can then easily be determined by a visual inspection and can be described, for example, in rough percentages of the circumference of the flat body designed to be pressure-sensitive.
• this is done by means of a grid placed on the pressure-sensitive adhesive flat body, preferably a transparent grid film.
• the lifted surface parts that are no longer adhesive are visible through the grid or the grid film, for example in the form of bulges or ripples in the pressure-sensitive adhesive surface body.
• the ratio of the “still sticking” surface portion of the flat body designed to be pressure-sensitive adhesive can be determined in relation to its total surface.
• the total area can also be calculated more easily:
• Another advantageous method for assessing the remaining adhesive strength of a flat body with a transparent pressure-sensitive adhesive design consists in determining the ratio of opaque surface portions to transparent surface portions of the flat body with a pressure-sensitive adhesive design in a similar manner.
• the remaining adhesive strength of a flat body designed to be pressure sensitive can also be assessed quantitatively by measuring and comparing the peeling force from the flat substrate before and after mechanical loading. This is preferably done using a peel test known in the prior art, which can be carried out as a 90° peel test or 180° peel test. The latter is more suitable for relatively soft substrates, since the substrate is then only loaded by pull-off forces acting parallel and on its surface.
• a peel test known in the prior art, which can be carried out as a 90° peel test or 180° peel test. The latter is more suitable for relatively soft substrates, since the substrate is then only loaded by pull-off forces acting parallel and on its surface.
• FIG. 1 shows a testing device according to the invention without a stretched flat substrate
• Fig. 2 a base plate of the test device according to the invention in FIG. 1,
• FIG. 5 shows a test device according to the invention according to FIG.
• FIG. 1 shows an overview of a testing device 1 according to the invention, but for the sake of a better overview initially without the stretched flat substrate 17.
• a vessel that is open at the top is clearly visible, here designed as a cylindrical beaker 2, in which there is a movable element, namely the movably arranged, plastic-coated, dumbbell-shaped magnetic stirring rod 3, also known as the “stirring fish”.
• the dumbbell-shaped magnetic stirring bar 3 consists of a rod 6 connected to disks 4, 5 at the end.
• the discs 4 and 5 protrude 4 mm beyond the upper edge of the beaker 2.
• a magnetic stirrer 7 is used here to drive the dumbbell-shaped magnetic stirring rod 3 with a magnetic core.
• the magnetic stirrer 7 has at least one electrically driven, rotating magnet within its table 8, the speed of which can be adjusted.
• the rotating magnet inside the table 8 acts on the magnetic core in the dumbbell-shaped magnetic stirring rod 3 and also causes the latter to rotate.
• the dumbbell-shaped magnetic stirring rod 3 i.e. the element that acts on the side of the flat substrate 17 facing away from the bonded test specimen and acts on the latter and mechanically loads the substrate 17, can be designed in a different shape than the dumbbell shape used here, for example as a cylindrical element or as a ball that is forcibly guided on a circular path.
• the drive of the element can also be designed differently, for example with an electric motor, which is connected to the stirring element via an axis reaching directly into the vessel via a rotary feedthrough.
• FIGS. 2 and 3 also shows a base plate 9 and a spacer plate 10, as can also be seen more clearly in FIGS. 2 and 3 are shown.
• the base plate 9 and the spacer plate 10 are provided with a continuous recess 11 for the beaker 2 .
• a recess 11 in the base plate 9 can also be designed as a receptacle for the beaker 2, namely as a recess provided in the base plate 9 with approximately the outer diameter of the beaker 2.
• both the base plate 9 and the spacer plates 10 can have a different geometric design than in this exemplary embodiment, for example in a different form than the rectangular shape provided here. The same applies to the recess 11 or receptacle for the vessel and for the vessel as such.
• FIG. 5 The closed or clamped clamping device or clamping can be seen in FIG. 5, in which the entire test device 1 is shown in its composition, ie ready for use in the operating state. It can be seen here that the flat substrate 17 is placed on the cylindrical beaker 2 and is clamped on the spacer plate 10 arranged above the base plate 9 with the aid of the threaded rods 12 , the washers 14 and the wing nuts 15 . The beaker 2 and the dumbbell-shaped magnetic stirring rod 3 are therefore located below the flat substrate 17 in this view or arrangement and are therefore not visible in FIG.
• the flat body 18 to be tested is applied to the flat substrate 17, here designed as a transdermal therapeutic system (TTS) applied as a pressure-sensitive adhesive.
• TTS transdermal therapeutic system
• the pressure-sensitive adhesive flat body 18, i.e. the test body is partly above the vessel opening and in the area of the stirring movement, namely here with about 1/3 of its total area, so that the edge area 19 of the TTS 18 is particularly strong in this test arrangement is loaded by the applied over the dumbbell-shaped magnetic stirring rod 3 deformation and force.
• loads are avoided by the weight of the dumbbell-shaped magnetic stirring rod 3 or by the force of gravity acting on the flat substrate.
• TTS pressure-sensitive adhesive formed flat body

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=80683949

Family Applications (1)

Country Status (8)

Family Cites Families (7)

• 2021
  • 2021-03-01 DE DE102021104874.5A patent/DE102021104874B4/de active Active
• 2022
  • 2022-02-25 CA CA3211278A patent/CA3211278A1/en active Pending
  • 2022-02-25 CN CN202280018549.6A patent/CN117015697A/zh active Pending
  • 2022-02-25 BR BR112023016393A patent/BR112023016393A2/pt unknown
  • 2022-02-25 EP EP22708907.5A patent/EP4302069A1/de active Pending
  • 2022-02-25 JP JP2023553051A patent/JP2024508022A/ja active Pending
  • 2022-02-25 US US18/279,954 patent/US20240151635A1/en active Pending
  • 2022-02-25 WO PCT/EP2022/054780 patent/WO2022184572A1/de active Application Filing

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