MODIFIED PHYLLOSILICATES FOR CONTROLLING THE UNWINDING FORCE OF PRESSURE-SENSITIVE ADHESIVE MATERIALS AND IMPROVING THE BARRIER PROPERTIES OF ADHESIVE TAPES

Abstract

Pressure-sensitive adhesive material comprising an acrylate dispersion wherein the acrylate dispersion comprises (i) an aqueous acrylate polymer dispersion containing polymers composed of a) acrylate monomers and, optionally, b) ethylenically unsaturated comonomers that are not acrylates, and (ii) modified phylosilicates

Claims

1. A pressure-sensitive adhesive comprising an acrylate dispersion, wherein the acrylate dispersion comprises (i) an aqueous polymeric acrylate dispersion, comprising polymers constructed of a) monomeric acrylates and optionally b) ethylenically unsaturated comonomers which are not acrylates, and (ii) modified phyllosilicates.

2. The pressure-sensitive adhesive as claimed in claim 1, wherein the pressure-sensitive adhesive comprises (I) 24 to 89.9 wt % of the aqueous acrylate dispersion, (II) 10 to 75.9 wt % of a tackifier, and (III) 0.1 to 5 wt % of modified phyllosilicates, in the form of a solution or dispersion comprising modified phyllosilicates and having a defined modified phyllosilicate solids content, in each case based on the overall composition of the pressure-sensitive adhesive.

3. The pressure-sensitive adhesive as claimed in claim 1, wherein the pressure-sensitive adhesive comprises an aqueous acrylate dispersion having a solids content of 50 to 60 wt % based on the aqueous acrylate dispersion.

4. The pressure-sensitive adhesive as claimed in claim 1, wherein the acrylate dispersion has a gel value of greater than or equal to 40%, determined by means of Soxhlet extraction.

5. The pressure-sensitive adhesive as claimed in claim 1, wherein the pressure-sensitive adhesive comprises a dried acrylate dispersion and is electrically conductive and/or antistatic, the pressure-sensitive adhesive being more particularly an electrically conductive and/or antistatic coating.

6. The pressure-sensitive adhesive as claimed in claim 1, wherein the pressure-sensitive adhesive is a dried acrylate dispersion and comprises between 15 and 100 parts by weight of a tackifier, based on the mass of the dried polymeric dispersion.

7. The pressure-sensitive adhesive as claimed in claim 1, wherein the acrylate dispersion comprises polymers constructed of a) greater than or equal to 40 wt % of monomeric acrylates and b) 0 to 60 wt % of ethylenically unsaturated comonomers, where the monomeric acrylates comprise mono-, di- and/or polyfunctional acrylates and where the ethylenically unsaturated comonomers are selected from the group consisting of ethylene-containing monomers, vinyl-functional monomers, and unsaturated hydrocarbons having 3 to 8 C atoms.

8. The pressure-sensitive adhesive as claimed in claim 1, wherein the acrylate dispersion comprises polymers constructed of (I)a) monomeric acrylates selected from the group consisting of 40 to 90 wt % of n-butyl acrylate, 2-ethylhexyl acrylate and/or ethyl acrylate and 0 to 2 wt % of a di- or polyfunctional monomer, b) ethylenically unsaturated comonomers at 10 to 60 wt %, selected from the group consisting of at least one ethylenically unsaturated monofunctional monomer or a mixture thereof and 0 to 10 wt % of an ethylenically unsaturated monomer having an acid or acid-anhydride function, or (II)a) monomeric acrylates selected from the group consisting of 90 to 99 wt % of n-butyl acrylate and/or 2-ethylhexyl acrylate and 0 to 2 wt % of a di- or polyfunctional monomer, b) ethylenically unsaturated comonomers at 10 to 1 wt %, selected from the group consisting of at least one ethylenically unsaturated monofunctional monomer or a mixture thereof and 0 to 10 wt % of an ethylenically unsaturated monomer having an acid or acid-anhydride function, or (III)a) monomeric acrylates selected from the group consisting of 30 to 75 wt % of alkyl acrylic esters having C.sub.4 to C.sub.12 alkyl radicals, b) ethylenically unsaturated comonomers at 5 to 25 wt % of ethylene, 20 to 55 wt % of vinyl acetate, and 0 to 10 wt % of other ethylenically unsaturated compounds; where the acrylate dispersion is prepared by reacting the monomers as per I, II and/or III in an emulsion polymerization.

9. The pressure-sensitive adhesive as claimed in claim 1, wherein the modified phyllosilicates are natural or synthetically produced three-layer phyllosilicates.

10. The pressure-sensitive adhesive as claimed in claim 1, wherein the modified phyllosilicates are swellable.

11. The pressure-sensitive adhesive as claimed in claim 1, wherein the modified phyllosilicates are surface-modified with polar organic compounds, the surface modification taking place substantially via polar and/or ionic interactions.

12. The pressure-sensitive adhesive as claimed in claim 1, wherein the modified phyllosilicates have a surface area of 50 m.sup.2/g to 1000 m.sup.2/g.

13. The pressure-sensitive adhesive as claimed in wherein the diameter of the phyllosilicates is from 10 to 1000 nm at a height of about 1 nm.

14. An adhesive tape for wrapping cables, comprising a textile carrier and a pressure-sensitive adhesive as claimed in claim 1, applied on at least one side of the carrier and comprising (i) a dried polymeric acrylate dispersion comprising polymers constructed of a) monomeric acrylates and optionally b) ethylenically unsaturated comonomers which are not acrylates, and (ii) modified phyllosilicates, where the pressure-sensitive adhesive comprises between 15 and 100 parts by weight of a tackifier (based on the mass of the dried polymeric dispersion).

15. The adhesive tape as claimed in claim 14, wherein the pressure-sensitive adhesive applied on at least one side of the carrier comprises an electron beam (EBC)-crosslinked polymeric acrylate dispersion.

16. The adhesive tape as claimed in claim 14, wherein the pressure-sensitive adhesive has an ASTM D3330 peel adhesion to steel of at least 4.5 N/cm (for a pressure-sensitive adhesive coatweight of 90 g/m.sup.2 on woven polyester fabric carrier) and/or the pressure-sensitive adhesive has an LV 312 unwind force of less than or equal to 4.0 N/cm at 30 m/min and/or the pressure-sensitive adhesive has an ASTM D3330 peel adhesion to the reverse of the adhesive-tape carrier of at least 3.0 N/cm (for a pressure-sensitive adhesive coatweight of less than or equal to 90 g/m.sup.2 on woven polyester fabric carrier).

17. The adhesive tape as claimed in claim 14, wherein the TFT (Threshold Flagging Time) is greater than or equal to 700 minutes.

18. A method for wrapping cables which are subject to elevated temperature and/or humidity, wherein said cables are wrapped with the adhesive tape of claim 14.

19. A method for reducing the migration of plasticizers from cable sheathing or for delaying the embrittlement of cable sheathing, which comprises forming said sheathing with the adhesive tape of claim 14.

20. The method of claim 19, wherein the amount of plasticizers in wt % in the cable sheathing after at least 2000 h is still at least 60% of the original amount in the cable sheathing, measured under the conditions of LV 312.

21. A method for jacketing elongate material, which comprises jacketing said elongate material with the adhesive tape of claim 14, where the adhesive tape is passed in a helical line around the elongate material or alternatively where the elongate material is wrapped in axial direction by the tape.

22. A cable loom, jacketed with an adhesive tape of claim 14.

23. A method for producing the adhesive tape of claim 14 from a textile carrier and a pressure-sensitive adhesive applied on at least one side of the carrier, which comprises applying the pressure-sensitive adhesive to at least one side of the textile carrier, and optionally drying the pressure-sensitive adhesive.

24. The method as claimed in claim 23, characterized in that wherein the pressure-sensitive adhesive comprises an aqueous acrylate dispersion which is prepared by the process of emulsion polymerization.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0281] FIG. 1 shows the adhesive tape in a lateral section,

[0282] FIG. 2 shows a detail section of a cable harness which is composed of a bundle of individual cables and is jacketed with the adhesive tape of the invention, and

[0283] FIG. 3 shows an advantageous application of the adhesive tape,

[0284] FIGS. 4 to 7 show measurement of flagging resistance according to LV 312 or to TFT method,

[0285] FIG. 8 shows interaction of cohesion and adhesion during detachment of the tape end,

[0286] FIG. 9 shows mode of functioning of the barrier layer,

[0287] FIG. 10 shows a diagrammatic construction of a phyllosilicate crystal,

[0288] FIG. 11 shows shear stress sweep 25° C. viscosity,

[0289] FIG. 12 shows discoloration in the case of the PVC reference lead from Gebauer & Griller,

[0290] FIG. 13 shows undiscolored specimens (gleaming metallically).

[0291] Shown in FIG. 1, in a section in the transverse direction (transverse section), is the adhesive tape, consisting of a woven fabric carrier 1, on one side of which a layer of a self-adhesive coating 2 is applied. FIG. 2 shows a cut-out section of a cable harness which is composed of a bundle of individual cables 7 and is jacketed with the adhesive tape 11 of the invention. The adhesive tape is passed in a helicoidal movement around the cable harness. The cable harness detail shown has two turns I and II of the adhesive tape. Further turns would extend toward the left, but are not shown here. In a further embodiment for jacketing, two tapes 60, 70 of the invention, furnished with an adhesive, are laminated with their adhesives at an offset (preferably by 50% in each case) to one another, producing a product as shown in FIG. 3. Shown diagrammatically in FIG. 9 is a barrier layer 4, which is composed of individual three-layer silicates 3 and which prevents migration of the plasticizer molecules 2a from the substrate 1, such as a cable insulation 1, to the outer surface of the adhesive tape, with the consequence that only small amounts of migrated plasticizer molecules 2b are present. FIG. 10 shows diagrammatically an individual Laptonite crystal having a diameter of around 25 nm and thickness of 0.92 nm. There are partial charges of the outer edges.

EXAMPLES

[0292] Outline of the examples: The adhesive tape of the invention is described below in preferred embodiment by means of a number of examples, without wishing thereby to subject the invention to any restriction whatsoever. In addition, comparative examples are given, which show noninventive adhesive tapes.

[0293] To illustrate the invention, example adhesive tapes were produced according to the following scheme: The PSA dispersions were mixed from polymer dispersion and resin dispersion in line with the example formulas, and were intimately homogenized using a stirrer. The PSA dispersions were subsequently adjusted, by stirred incorporation of a modified phyllosilicate, to a viscosity of approximately 500 Pa*s at a shear rate of 0.1 s.sup.−1

[0294] Using a film-drawing apparatus, a woven polyester fabric specified in the examples was coated with the thickened example PSA dispersion in such a way as to result, after drying in a forced-air oven at 85° C. for 5 minutes, in an adhesive coatweight of approximately 20 g/m.sup.2. In a second work-step, the fabric impregnated in this way was coated analogously with the same dispersion, so as to result, after drying in a forced-air oven at 85° C. for 10 minutes, in a total adhesive coatweight of 90 g/m.sup.2, respectively, as specified in the examples.

[0295] Assessment criteria: The criteria for an application-compatible adhesive tape for the wrapping of cables is presently the peel adhesion to steel, the peel adhesion to the reverse face in combination with the unwind force at 30 m/min. Unwind force of rolls after storage at room temperature, around 23° C., over 4 weeks, at 50% atmospheric humidity.

[0296] Test procedure: Unless expressly stated otherwise, the measurements are carried out under test conditions of 23±1° C. and 50±5% relative humidity.

Measurement of Flagging Resistance to LV 312 or TFT Method (Threshold Flagging Time)

[0297] For determining the flagging behavior by the TFT method, a test is employed in which an additional flexural stress is generated by the application of the test specimens, prepared in a flat format, to a 1½″ core. The combination of tensile load by a test weight and flexural stress causes flagging-like detachment of the adhesive tape starting from the bonded upper end, and ultimate failure by dropping of the test specimens (see FIG. 4, which also shows the schematic construction). The time in minutes before dropping is the result. The critical parameters for the holding time of the test specimens are weight and temperature, the weight being selected such as to result in values of at least 100 minutes.

[0298] The cylindrically shaped test mandrel is a 1½″ card core with an external diameter of 42±2 mm, provided with a marking line 5 mm adjacent to the vertex line.

[0299] The adhesion base is the adhesive tape's own reverse face.

[0300] The manual roller has a weight of 2 kg.

[0301] The test weight is 1 kg.

[0302] The test conditions are 23±1° C. and 50±5% relative humidity, or 40° C. in the heating cabinet.

[0303] The test is carried out on strips of adhesive tape 19 mm wide. A strip with a length of 400 mm is adhered to release paper and cut to form three strips with a length of 100 mm each. This should be done using a fresh cutter blade. The reverse face must not be touched. A small piece of card is adhered beneath one of the ends of each strip, and the assembly is perforated (see FIG. 5). The test strips are then individually bonded centrally to strips of the broader adhesion base (adhesive tape with a width 1% times that of the adhesive tape under test), so that the small piece of card still overlaps just (2 to 3 mm) at the end (see FIG. 6). The test specimens are rolled down using the 2 kg manual roller at a rate of 10 m/min in 3 cycles. The finished test samples, in other words the test strips together with adhesion base, are then adhered to the card core in such a way that the upper end of the test specimen overlaps the vertex point by 5 mm (see FIG. 7). In this operation, only the adhesion base, and not the test specimen, must be pressed on. The test specimens fully prepared are left for 20±4 hours without weight loading in a controlled-climate chamber at 40° C.

[0304] Weights with a mass of one kilogram are then hung onto the specimens, and the stopwatches are started. The measurement ends after failure of all three test specimens of one sample. The median of the three individual measurements is reported in minutes. The holding time is reported in minutes. In this context, a TFT value of greater than or equal to 700 minutes, preferably greater than or equal to 1000 minutes, more preferably greater than or equal to 1200 minutes, very preferably greater than or equal to 2000 minutes is considered to be a lower limit with regard to resistance to flagging.

Unwind Force

[0305] Measurement of the unwind force to LV 312 with a haul-off speed of 30 m/min.

Softening Point

[0306] Measurement according to ASTM E28-99 (2009)

Plasticizer Extraction

[0307] 0.5 to 1 g of a comminuted sample is extracted with 20 to 100 ml of toluene (n-toluene) in an ultrasound bath at 60° C. for 60 minutes. The amount of plasticizer is determined by GC-MS. Using this method it is possible to detect plasticizer contents of 5 mg/kg.

Thermal Aging

[0308] LV 312-1 (in particular from page 10 onward).

Rheology

[0309] Experimental details: instrument: Rheometer DSR 200 N from Rheometric Scientific, [0310] measuring head: 200 g air-mounted with normal force, [0311] measuring geometry: plate/cone, [0312] heating: Peltier elements with regulation and primary cooling, [0313] diameter: 25 mm (cone), cone angle: 0.1 rad., gap: 0.053 mm, shear stress sweep (cone), [0314] temperature: 25° C., [0315] initial shear stress: 0.1 Pa, final shear stress: 4790 Pa, [0316] points per decade: 10 [0317] shear rate of 100 s.sup.−1

Gel Value

[0318] The gel value is determined by Soxhlet extraction, which extracts soluble constituents from polymers in a continuous extraction. In the case of determination of the gel value of (aqueous) polyacrylate PSAs, a suitable solvent such as tetrahydrofuran, for example, extracts the soluble fractions of a polymer—the so-called sol—from the insoluble fractions—the so-called gel. Preparation: the material for extraction is applied in a thin film—film thickness generally 120 μm—to siliconized release paper and dried at 80° C. for around 12 hours (forced-air drying cabinet). The films are stored in a desiccator over drying agent. The Whatman 603 extraction sleeves are dried at 80° C. for 12 h, the empty weight of the sleeves is determined, and they are stored in a desiccator before being used.

Gel Value Determination

[0319] Around 1 g of PSA is weighed out into an extraction sleeve. A 100 ml round-bottomed flask of the Soxhlet apparatus is filled with 60 ml of tetrahydrofuran and heated to boiling. THF vapors ascend through the vapor tube of the Soxhlet apparatus and condense in the condenser, and THF drips into the extraction sleeve and extracts sol fraction. In the course of the extraction, the THF I runs back into the flask with the extracted sol. Dissolved sol accumulates in the flask increasingly. After 72 hours of continuous extraction, the sol is completely dissolved in the THF. Then, after the apparatus has been cooled to room temperature, the extraction sleeve is withdrawn and is dried at 80° C. for 12 hours. The sleeves are stored in a desiccator to constant mass and then weighed. The gel value of the polymer is calculated using the following formula:

[00001]$\mathrm{Gel}.Math..Math.\mathrm{value}=\frac{m_3-m_1}{m_2-m_1}.Math.100.Math.\%$

where [0320] m.sub.1: mass of extraction sleeve, empty [0321] m.sub.2: mass of extraction sleeve+polymer [0322] m.sub.3: mass of extraction sleeve+gel

Measurement of Peel Adhesion

[0323] For measuring the peel adhesion of the pure dispersions, coated-out samples of the adhesives were prepared first of all. For this purpose, the dispersions were applied to a PET film (polyethylene terephthalate) with a thickness of 23 μm, and were drawn down using a film-drawing apparatus in such a way as to result, after drying for 5 minutes at 105° C. in a forced-air drying cabinet, in an adhesive coatweight of 30 g/m.sup.2.

[0324] Using a cutter knife, strips 20 mm wide and 25 cm long were cut from this sheet. For measuring the peel adhesion of the formulations with resin, coated-out samples were drawn down as described above onto woven polyester fabrics, and likewise cut using a cutter knife into strips 20 mm wide and 25 cm long. The peel adhesion to steel of the specimens was measured to ASTM D3330. The peel adhesion to the reverse face was measured according to ASTM D3330.

Flexural Stiffness

[0325] The flexural stiffness is determined using a KWS basic 2000 mN Softometer (from Wolf Messtechnik GmbH). (MD) stands for machine direction, meaning that the flexural stiffness is determined in machine direction.

Composition of an Inventive Polymer Dispersion:

[0326]

TABLE-US-00003 Monomer Polymer A 2-Ethylhexyl acrylate 93  Butyl acrylate Acrylic acid 4 Acrylonitrile 3 Methyl methacrylate — Vinyl acetate —

[0327] The glass transition temperature of polymer A: −47° C.

[0328] The PSAs listed in table 1 were formulated from the polymer A by blending with tackifier resin dispersions. The number here indicates the parts by weight of tackifier per 100 parts by weight of polymer A (based in each case on solids).

TABLE-US-00004 TABLE 1 PSA comprising polymer Polymer A Softening point 100 parts polymer A Tackifier type ° C. to 45 parts resin Snowtack 100 G rosin 99 30 wt % ester resin, Lawter

[0329] The glass transition temperature of the pressure-sensitive adhesive formulation was determined as the dynamic Tg by means of rheological analysis (temperature sweep) at 7 to 8° C.

Example 1

[0330] Carrier: woven PET, 130 g/m.sup.2 [0331] Warp: 48 threads/cm×167 dtex [0332] Weft: 24 threads/cm×167 dtex

[0333] PSA: resin-modified acrylate dispersion, 90 g/m.sup.2 [0334] (polymer A with 30% rosin ester resin) [0335] +addition of: [0336] 1.1 2.5 wt % (liquid on liquid) of a solution of a synthetic phyllosilicate with 25 wt % solids content (Laponite SL 25, from Rockwood). This corresponds to 1.1 wt % (solid on solid) for a solids concentration of the acrylate dispersion of 57.4 wt %. [0337] 1.2 5.0 wt % (liquid on liquid) of a solution of a synthetic phyllosilicate with 25 wt % solids content (Laponite SL 25, from Rockwood). This corresponds to 2.2 wt % (solid on solid) for a solids concentration of the acrylate dispersion of 56.54 wt %. [0338] 1.3 7.0 wt % (liquid on liquid) of a solution of a synthetic phyllosilicate with 25 wt % solids content (Laponite SL 25, from Rockwood). This corresponds to 3.2 wt % (solid on solid) for a solids concentration of the acrylate dispersion of 55.9 wt %.

Comparative Example 1

[0339] Carrier: woven PET, 130 g/m.sup.2 [0340] Warp: 48 threads/cm×167 dtex [0341] Weft: 24 threads/cm×167 dtex

[0342] PSA: resin-modified acrylate dispersion, 90 g/m.sup.2 [0343] (polymer A with 30 wt % rosin ester resin)

Comparative Example 2

[0344] Carrier: woven PET, 130 g/m.sup.2 [0345] Warp: 48 threads/cm×167 dtex [0346] Weft: 24 threads/cm×167 dtex

[0347] PSA: resin-modified acrylate dispersion, 90 g/m.sup.2 [0348] (polymer A with 30 wt % rosin ester resin) [0349] +addition of:

[0350] CP 1.1 5 wt % (solid on solid) of a fine kaolin grade [0351] (Amazon Premium SD, from Cadam)

[0352] CP 1.2 15 wt % (solid on solid) of a fine kaolin grade [0353] (Amazon Premium SD, from Cadam)

[0354] CP 1.3 25 wt % (solid on solid) of a fine kaolin grade [0355] (Amazon Premium SD, from Cadam)

Comparative Example 3

[0356] Carrier: woven PET, 130 g/m.sup.2 [0357] Warp: 48 threads/cm×167 dtex [0358] Weft: 24 threads/cm×167 dtex

[0359] PSA: Acrylate hotmelt, 90 g/m.sup.2 [0360] UV dose: 25 mJ/cm.sup.2

TABLE-US-00005 TABLE 1 Peel adhesion, unwind force and TFT Peel Peel adhesion adhesion Unwind to steel to reverse force at TFT** Method face Method 30 m/min* Method Addition ASTM ASTM Method (see of D3330 D3330 LV 312 above) filler N/cm N/cm N/cm min Values for 2.5 wt % 5.9 4.1 3.8 1096 example 1 Laponite SL 25 (liquid on liquid) 5.0 wt % 5.3 3.4 2.5 755 Laponite SL 25 (liquid on liquid) 7.0 wt % 4.1 1.7 1.7 507 Laponite SL 25 (liquid on liquid) Values for — 5.8 4.5 6.9 1234 comparative example 1 Values for 5.0 wt % 4.5 6.9 6.2 comparative Amazon example 2 Premium SD (solid on solid) 15.0 wt % 4.5 6.9 5.6 522 Amazon Premium SD (solid on solid) 25.0 wt % 4.5 6.9 4.5 Amazon Premium SD (solid on solid) Values for — 5.5 6.5 5.8 207 comparative example 3 *all rolls were slit at identical tension **TFT = TFT value (Threshold Flagging Time)

[0361] The series of experiments for example 1 shows forcefully how the addition of an organically modified phyllosilicate may affect the unwind forces of a pressure-sensitive adhesive tape. The addition of just 2.5 wt % (liquid on liquid) to the adhesive, with experimental parameters otherwise the same, results in a design of adhesive which, in contrast to the original, unfilled adhesive (comparative example 1), experiences a reduction in unwind force of around 3 N/cm, corresponding to a percentage decrease of approximately 45%.

[0362] The peel adhesion to steel and to the tape's own fabric reverse face, in contrast, do not experience any significant change.

[0363] Applied to a cable loom, a modified adhesive design of this kind does not exhibit any weaknesses in terms of the standing-up of tape ends (flagging).

[0364] By adding larger amounts of the phyllosilicate, the unwind force can be reduced further. At an amount of 5 wt % (liquid on liquid), the unwind force is already around 36% of the original figure. Up to this point, the peel adhesion to smooth surfaces (see PA steel) shows no significant drop. With the rough surface of the fabric reverse face, the slightly reduced flowability of the adhesive is manifested noticeably. The result is a decrease in the peel adhesion to reverse face of around 1 N/cm in comparison to the unfilled adhesive.

[0365] From this point in time on, under high tensile and flexural stresses in the application, slight flagging may occur. Through the use of soft carrier materials, which exhibit only a slight tendency toward resilience, however, it is still possible to realize flagging-free products with this kind of design of adhesive.

[0366] At quantities above 5 wt %, a “physical overcrosslinking” can be observed. The effects on the peel adhesions are now significant here, with the peel adhesion to the reverse face decreasing by more than 60%. The already low level of unwind force can hardly be reduced further, and so such quantities ought not to be used.

[0367] Comparative example 2 serves for comparison with a common filler based on kaolin. This is a decidedly fine kaolin grade having an average particle size of <2 μm for the maximum diameter (at least 97%<2 μm).

[0368] In contrast to the highly soluble organic modified phyllosilicate based on smectite, the kaolin is not dispersed as thoroughly within the adhesive, and so is present more as an alien body in the form of unincorporated phases in the adhesive. As a result, it is not possible for a three-dimensional network to form on the basis of physical bonds between polymer chains and filler particles. Consequently, even when added at high levels of 25 wt % (solid on solid) to the adhesive, a comparatively small decrease in the unwind force is observed. Conversely, there is a massive detriment to the (instantaneous) peel adhesion to rough substrates, since the coarse particles very largely prevent rapid flow-on when the adhesive tape is pressed on. The peel adhesion to reverse face reduces accordingly, when 25 wt % of kaolin is added, to a value of around 40% of the original value. In such a case, the effects on the flagging behavior are dramatic, since the adhesive tape stands up at the ends just a short time after application, in order to be able to compensate the tensile and flexural strains which occur in the course of bonding.

[0369] Comparative example 3 serves for comparison with the technical adhesive data for a standard commercial fabric-backed adhesive tape with an acrylate hotmelt coating.

[0370] The effect on plasticizer migration was carried out with the adhesive design and the carrier of example 1: [0371] Carrier: PET woven 130 g/m.sup.2 [0372] PSA: resin-modified acrylate dispersion, 90 g/m.sup.2 [0373] (polymer A with 30% rosin ester resin) [0374] Addition of [0375] 5.0 wt % (liquid on liquid) of a solution of a synthetic phyllosilicate with [0376] 25 wt % solids content [0377] (Laponite SL 25, from Rockwood) [0378] corresponding to about 2.2 wt % solid on solid (the solids content of the completed dispersion adhesive/PSA is 56.5 wt %)

[0379] Serving as a comparative example is comparative example 1, which is identical in construction to example 1 but without Laponite SL 25. [0380] Carrier: PET woven 130 g/m.sup.2 [0381] PSA: resin-modified acrylate dispersion, 90 g/m.sup.2 [0382] (polymer A with 30 wt % rosin ester resin)

TABLE-US-00006 TABLE 2 plasticizer content in weight percent based on lead (cable + insulation); PVC Gebauer & Griller, type 67218 Comparative Example 1 example 1 adhesive adhesive tape with unbonded tape without Laponite Laponite SL25 unaged 21.4 2000 h 19.8 12.9 18.1 2500 h 18.8 11.6 16.7 3000 h 17.4 10.0 14.2

[0383] To illustrate the invention, example adhesive tapes were produced according to the following scheme: the PSA dispersions were mixed from polymer dispersion and resin dispersion in accordance with the example formulas, and were intimately homogenized using a stirrer. The PSA dispersions were then adjusted to a viscosity of around 500 Pa*s at a shear rate of 0.01 s.sup.−1 by stirred incorporation of an associative polyurethane thickener (Borchigel 0625, OMG Borchers). Using a film-drawing apparatus, a woven polyester fabric (as specified in the examples) was coated with the thickened example PSA dispersion so that drying in a forced-air oven at 85° C. for 5 minutes resulted in an adhesive coatweight of around 20 g/m.sup.2. The woven fabric impregnated in this way was coated analogously with the same dispersion, in a second workstep, so that drying in a forced-air oven at 85° C. for 10 minutes resulted in an overall adhesive coatweight of 60, 70 or 90 g/m.sup.2, respectively, in accordance with the information in the examples.

TABLE-US-00007 TABLE 3 samples SL 25 (Laptonite) - determination of viscosity (flow curve) at 25° C. - for rheology see FIG. 11: Sample designation TV 416 adhesive 1 PS 34-468 + 30 wt % TR 602 + 1 wt % Borchigel 0625 TV 416 adhesive 2 PS 34-468 + 30 wt % TR 602 + 4.7 wt % SL 25 TV 416 adhesive 3 PS 34-468 + 30 wt % TR 602 + 1.51 wt % Evo Dot VD 2

[0384] Procedure: shear stress sweep (flow curve) at 25° C. with a plate/cone measuring system, 1.sup.st shear stress sweep 25° C., during shear stress sweep (FIG. 11) the viscosity of the samples was imaged. The values for the viscosity at 2 shear rates are evident from table 4.

TABLE-US-00008 TABLE 4 Sample designation Viscosity 0.1 s.sup.−1 Viscosity 1000 s.sup.−1 TV 416 adhesive 1 PS 34-468 + 525 Pa s 0.61 Pa s 30 wt % TR 602 + 1 wt % Borchigel 0625 (designation “1” in FIG. 11) TV 416 adhesive 2 PS 34-468 + 485 Pa s 0.33 Pa s 30 wt % TR 602 + 4.7 wt % SL 25 (designation “2” in FIG. 11) TV 416 adhesive 3 PS 34-468 + 1030 Pa s 0.34 Pa s 30 wt % TR 602 + 1.51 wt % Evo Dot VD 2 (designation “3” in FIG. 11)

Summary and Outlook:

[0385] The samples show the typical behavior of a thickened dispersion adhesive with properties of structural viscosity.

LV 312 test: testing for cable compatibility

[0386] For all temperature classes B, C, D

[0387] Test result matrix: assess test specimens

[0388] Take lead harness from the oven, assess (A), wrap around 20 mm mandrel, assess (W, K, R, V)J carrying out kV testing, assess (HS), untape (ET, FL, FT, E, TS), wrap around 2 mm, assess (WKR) wrap around 10 mm mandrel, assess (WKRV)

[0389] Evaluation tables 5a, 5b, 5c:

[0390] Test passed without failure: 1

[0391] Test passed: tape no longer tacks TS

[0392] Test failed: 0

[0393] A: after storage, HS: kV test negative, R: tears in adhesive tape, W: lead unsatisfactory after winding around the mandrel; K: cable loom flattened; TS: adhesive tape no longer tacks; FL: insulation color no longer apparent; FT: discoloration of adhesive tape (brown), ET: lead unsatisfactory on removal of the adhesive tape; V: shift in position of cable tape; E: lead unsatisfactory on untwisting.

Comparative Example 1, Without Laponite:

[0394] Adhesive tape designation: tested temperature class: T2

TABLE-US-00009 TABLE 5a Test group 1 Long-term thermal aging Storage period 500 h 1000 h 1500 h 2000 h 2500 h 3336 h Mandrel 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 diameter in mm Lead test group 1e (PVC, G&G) T = 105° C. With 1 1 1 1 1 1 1 1 1 1 1 0/w 1 0/w 0/w 1 0/w 0/w adhesive tape Lead test group 1e (PVC, Coroplast) T = 105° C. With 1 1 1 1 1 1 1 1 0/w 1 0/w 0/w 1 0/w 0/w 1 0/w 0/w adhesive tape
Example 1, with 5 wt % Laponite:

[0395] Adhesive tape designation: tested temperature class: T2

TABLE-US-00010 TABLE 5b Test group 1 Long-term thermal aging Storage period 500 h 1000 h 1500 h 2000 h 2500 h 3336 h Mandrel 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 diameter in mm Lead test group 1e (PVC, G&G) T = 105° C. With adhesive 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0/w tape Lead test group 1e (PVC, Coroplast) T = 105° C. With adhesive 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0/w tape
Reference specimen without tape:

[0396] Adhesive tape designation: tested temperature class: T2

TABLE-US-00011 TABLE 5c Test group 1 Long-term thermal aging Storage period 500 h 1000 h 1500 h 2000 h 2500 h 3336 h Mandrel 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 20 10 2 diameter in mm Lead test group 1e (PVC, G&G) T = 105° C. With adhesive 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tape Lead test group 1e (PVC, Coroplast) T = 105° C. With adhesive 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tape

Determination of Plasticizer Content:

[0397] Extraction of the plasticizers with n-toluene in an ultrasound bath for quantitative determination [0398] Determination of the plasticizers by GC-MS [0399] Determination limit 5 mg/kg