Self-adhesive, heat-sensitive recording material

Abstract

The invention relates to a self-adhesive, heat-sensitive recording material, comprising a carrier substrate, a heat-sensitive, color-forming layer that is applied on one side of the carrier substrate and contains at least a non-phenolic color developer in and at least one color former, a siliconized layer on the upper side of the heat-sensitive, color-forming layer that is applied on the carrier substrate, as well as an adhesive layer on the side of the carrier substrate facing away from the heat-sensitive, color-forming layer.

Claims

1. A self-adhesive, heat-sensitive recording material, comprising a carrier substrate, a heat-sensitive colour-forming layer applied to one side of the carrier substrate, said layer comprising at least one non-phenolic colour developer and at least one colour former, a siliconised layer on an upper side of the heat-sensitive colour-forming layer applied on the carrier substrate, and an adhesive layer on a side of the carrier substrate facing away from the heat-sensitive colour-forming layer, characterised in that the siliconised layer rests directly on the heat-sensitive colour-forming layer, that the siliconized layer is majoritively at least one siloxane and that the heat-sensitive colour-forming layer comprises at least one flaky pigment, and wherein the self-adhesive, heat-sensitive recording material is carrier-free and can be rolled up on itself so that the heat-sensitive colour-forming layer onto which the siliconized layer is applied is in direct contact with the adhesive layer.

2. A self-adhesive heat-sensitive recording material according to claim 1, characterised in that the carrier substrate is paper, synthetic paper and/or a plastic film.

3. A self-adhesive heat-sensitive recording material according to claim 1, characterised in that the self-adhesive heat-sensitive recording material is a carrier-free self-adhesive heat-sensitive recording material.

4. A self-adhesive heat-sensitive recording material according to claim 1, characterised in that the at least one colour developer is sulfonylurea and/or a compound of formula (I), ##STR00003## wherein Ar.sub.1 and Ar.sub.2 are a phenyl group and/or a C.sub.1-C.sub.4-alkyl-substituted phenyl group.

5. A self-adhesive, heat-sensitive recording material according to claim 4, characterised in that the sulfonylurea is N′-(p-toluenesulfonyl)-N′-phenylurea, N-(p-toluenesulfonyl)-N′-3-(p-toluenesulfonyl-oxy-phenyl)-urea and/or 4,4′-bis-(p-tolylsulfonylureido)-diphenylmethane.

6. A self-adhesive, heat-sensitive recording material according to claim 4, characterised in that the siliconised layer additionally contains an initiator.

7. A self-adhesive, heat-sensitive recording material according to claim 4, characterised in that the siliconised layer additionally contains a photoinitiator.

8. A self-adhesive, heat-sensitive recording material according to claim 1, characterised in that the at least one colour former is a triphenylmethane-type, fluoran-type, azaphthalide-type and/or fluorene-type dye.

9. A self-adhesive, heat-sensitive recording material according to claim 1, characterised in that the adhesive layer comprises at least one hot-melt adhesive.

10. A self-adhesive, heat-sensitive recording material according to claim 2, characterised in that the at least one flaky pigment is present in an amount of about 5 to about 60 wt. %, in relation to the total solids content of the heat-sensitive layer.

11. A self-adhesive, heat-sensitive recording material according to claim 1 wherein said at least one flaky pigment comprises kaolin.

12. A self-adhesive, heat-sensitive recording material according to claim 1, characterised in that the at least one colour former is fluoran dye.

13. A self-adhesive, heat-sensitive recording material according to claim 1, characterised in that the siliconised layer comprises acrylic polyorganosiloxane.

14. The self-adhesive heat-sensitive recording material according to claim 13, wherein the acrylic polyorganosiloxane comprises a mixture of at least two acrylic polyorganosiloxanes.

15. A self-adhesive, heat-sensitive recording material according to claim 1, characterised in that the adhesive layer includes a hot-melt adhesive comprised of rubber and/or acrylate.

16. The self-adhesive heat-sensitive recording material according to claim 1, characterized in that the flaky pigment has a ratio of diameter to thickness of about 15 to 30:1.

17. The self-adhesive heat-sensitive recording material according to claim 1, characterized in that at least about 85% of the flaky pigment is comprised of particles having a particle size of about <41m.

18. The self-adhesive heat-sensitive recording material according to claim 1, wherein the siliconized layer consists essentially of siloxane.

19. A self-adhesive, heat-sensitive recording material, comprising a paper carrier substrate, a heat-sensitive colour-forming layer applied to one side of the paper carrier substrate, said heat-sensitive colour-forming layer comprising at least one non-phenolic colour developer, which is N-(ptoluenesulfonyl)-N′-(3-(p-toluenesulfonyloxy)phenyl)-urea and/or [N-[2-(3-phenylureido)phenyl]benzenesulfonamide, at least one colour former, which is 3-N-n-dibutylamino-6-methyl-7-anilinofluoran, at least one flaky pigment, which is talcum in an amount from about 5 to 60 wt.% in relation to the total solids content of the heat-sensitive colour-forming layer, a binder, and a sensitizer, which is 2-benzyloxynaphthalene, a siliconized layer on an upper side of the heat-sensitive colour-forming layer applied on the carrier substrate, wherein the siliconized layer is based on at least one siloxane and contains a photoinitiator, and an adhesive layer on a side of the carrier substrate facing away from the heat-sensitive colour-forming layer, characterised in that the siliconized layer rests directly on the heat-sensitive colour-forming layer.

20. A self-adhesive, heat-sensitive recording material, comprising a carrier substrate, a heat-sensitive colour-forming layer applied to one side of the carrier substrate, said layer comprising at least one non-phenolic colour developer and at least one colour former, a siliconised layer on an upper side of the heat-sensitive colour-forming layer applied on the carrier substrate, and an adhesive layer on a side of the carrier substrate facing away from the heat-sensitive colour-forming layer, characterised in that the siliconised layer rests directly on the heat-sensitive colour-forming layer, and wherein the heat-sensitive colour-forming layer comprises at least one flaky pigment and at least one sensitizer selected from the group of fatty acid amide, ethylene-bis-fatty acid amide, wax, carboxylic acid ester, aromatic ether, aromatic sulfone, aromatic sulfonamide.

21. A self-adhesive, heat-sensitive recording material, comprising a carrier substrate, a heat-sensitive colour-forming layer applied to one side of the carrier substrate, said layer comprising at least one non-phenolic colour developer and at least one colour former, a siliconised layer on an upper side of the heat-sensitive colour-forming layer applied on the carrier substrate, and an adhesive layer on a side of the carrier substrate facing away from the heat-sensitive colour-forming layer, characterised in that the siliconised layer rests directly on the heat-sensitive colour-forming layer, and wherein the heat-sensitive colour-forming layer comprises at least one flaky pigment and at least one sensitizer which have a melting point between about 90 and about 150 ° C.

Description

EXAMPLES

(1) An aqueous application suspension for forming the heat-sensitive colour-forming layer of a heat-sensitive recording paper was applied under laboratory conditions by means of a bar coater on one side of a thermal base paper of 69 g/m.sup.2. After drying, a thermal recording sheet was obtained. The amount of heat-sensitive colour-forming layer applied was between 4.0 and 4.5 g/m.sup.2

(2) On a production scale, the aqueous application suspension was applied to a paper sheet of a weight per unit area of 64 g/m.sup.2 by means of the curtain coating method. The viscosity of the aqueous application suspension was 170-570 mPas (according to Brookfield, 100 rpm, 20° C.) (in the deaerated state). The coating unit was arranged in-line. The curtain coating method was operated at a speed of 450 m/min.

(3) After application of the aqueous application suspension, the drying process of the coated paper carrier took place in a conventional manner. The application weight per unit area of the dry heat-sensitive layer was 4.0-4.5 g/m.sup.2.

(4) The formulas specified below were produced in that initially the dispersions A1, A2, B and C were mixed separately by grinding the components in a bead mill and said dispersions together with the other components were then mixed well with one another.

(5) The heat-sensitive coating suspensions thus obtained (Formulas 1a, 1b, 2a, 2b, and 3), stemming from the Tables 1 to 6 below, were used to produce semi-finished products from a paper carrier and a heat-sensitive colour-forming layer.

(6) TABLE-US-00001 TABLE 1 Parts by Formula 1a Component weight Note/trade name Chemical nomenclature Dispersion A1 Colour former 1 11.06 S-205 3-(N-ethyl-N- isopentylamino)-6- methyl-7-anilinofluoran PVA low viscosity, 20.04 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion A2 Colour former 2 16.58 ODB-2 3-N-n-dibutylamino-6- methyl-7-anilinofluoran PVA low viscosity, 30.05 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion B Colour developer 76.79 Bisphenol A 4,4′- isopropylenediphenol PVA low viscosity, 54.41 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion C Sensitiser 25.62 BON 2-benzyloxynaphthalene PVA low viscosity, 18.15 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Stearic acid amide 108.17 dispersion (25%) Zinc stearate 54.9 dispersion (30%) PCC slurry (56%) 121.77 Precipitated calcium carbonate Optical brightener 5.75 Blankophor PT Anionic stilbene (31.3%) derivative PVA high viscosity, 330 Poval 28-99 Polyvinyl alcohol solution high-saponified (10%) Crosslinking agent, 11.29 Cartabond type, glyoxal-based (42%) from Archroma Rheological agent 0.83 Sterocoll type, BASF Polyacrylamide, anionically modified

(7) TABLE-US-00002 TABLE 2 Parts by Formula 1b Component weight Note/trade name Chemical nomenclature Dispersion A1 Colour former 1 11.06 S-205 3-(N-ethyl-N- isopentylamino)-6- methyl-7-anilinofluoran PVA low viscosity, low- 20.04 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion A2 Colour former 2 16.58 ODB-2 3-N-n-dibutylamino-6- methyl-7-anilinofluoran PVA low viscosity, low- 30.05 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion B Colour developer 76.79 Bisphenol A 4,4′- isopropylenediphenol PVA low viscosity, low- 54.41 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion C Sensitiser 25.62 BON 2-benzyloxynaphthalene PVA low viscosity, low- 18.15 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Stearic acid amide 108.17 dispersion (25%) Zinc stearate 54.9 dispersion (30%) Kaolin slurry (72%) 94.71 ASP 109 Optical brightener 5.75 Blankophor PT Anionic stilbene (31.3%) derivative PVA high viscosity, 330 Poval 28-99 Polyvinyl alcohol solution high-saponified (10%) Crosslinking agent, 11.29 Cartabond type, glyoxal-based (42%) from Archroma Rheological agent 0.83 Sterocoll type, BASF Polyacrylamide, anionically modified

(8) TABLE-US-00003 TABLE 3 Parts by Formula 2a Component weight Note/trade name Chemical nomenclature Dispersion A1 Colour former 1 9.0 S-205 3-(N-ethyl-N- isopentylamino)-6- methyl-7-anilinofluoran PVA low viscosity, low- 16.31 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion A2 Colour former 2 21.0 ODB-2 3-N-n-dibutylamino-6- methyl-7-anilinofluoran PVA low viscosity, low- 38.05 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion B Colour developer 60 NKK 1304 N-[2-(3- Phenylureido)phenyl]benzenesulfonamide PVA low viscosity, low- 70.59 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion C Sensitiser 36 BON 2-benzyloxynaphthalene PVA low viscosity, low- 25.51 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Stearic acid amide 176.77 dispersion (25%) Zinc stearate 0 dispersion (30%) Kaolin slurry (72%) 94.88 ASP 109, BASF Optical brightener 2.88 Blankophor PT Anionic stilbene (31.3%) derivative PVA high viscosity, 330 Poval 28-99, from Polyvinyl alcohol solution high-saponified (10%) Kuraray Crosslinking agent, 11.29 Cartabond type, glyoxal-based (42%) from Archroma Rheological agent 0.83 Sterocoll type, BASF Polyacrylamide, anionically modified

(9) TABLE-US-00004 TABLE 4 Parts by Formula 2b Component weight Note/trade name Chemical nomenclature Dispersion A1 Colour former 1 0 S-205 3-(N-ethyl-N- isopentylamino)-6- methyl-7-anilinofluoran PVA low viscosity, low- 0 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion A2 Colour former 2 30.0 ODB-2 3-N-n-dibutylamino-6- methyl-7-anilinofluoran PVA low viscosity, low- 54.36 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion B Colour developer 60 PF201 N-(p-toluenesulfonyl)-N′- (3-(p- toluenesulfonyloxy)phenyl)- urea PVA low viscosity, low- 70.59 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Dispersion C Sensitiser 36 BON 2-benzyloxynaphthalene PVA low viscosity, low- 25.51 Poval 4-85, from Polyvinyl alcohol solution saponified (15%) Kuraray Stearic acid amide 176.77 dispersion (25%) Zinc stearate 0 dispersion (30%) Kaolin slurry (72%) 94.88 ASP 109, BASF Optical brightener 2.88 Blankophor PT Anionic stilbene (31.3%) derivative PVA high viscosity, 330 Poval 28-99, from Polyvinyl alcohol solution high-saponified (10%) Kuraray Crosslinking agent, 11.29 Cartabond type, glyoxal-based (42%) from Archroma Rheological agent 0.83 Sterocoll type, BASF Polyacrylamide, anionically modified

(10) TABLE-US-00005 TABLE 5 Parts by Formula 3 Component weight Note/trade name Chemical nomenclature Dispersion A1 Colour former 1 0 S-205 3-(N-ethyl-N- isopentylamino)-6- methyl-7-anilinofluoran PVA low viscosity, 0 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion A2 Colour former 2 29 ODB-2 3-N-n-dibutylamino-6- methyl-7-anilinofluoran PVA low viscosity, 52.54 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion B Colour developer 46.4 PF201 N-(p-toluenesulfonyl)-N′- (3-(p- toluenesulfonyloxy)phenyl)- urea PVA low viscosity, 30.94 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Dispersion C Sensitiser 15.47 BON 2-benzyloxynaphthalene PVA low viscosity, 10.96 Poval 4-85, from Polyvinyl alcohol solution low-saponified (15%) Kuraray Stearic acid amide 213.6 dispersion (25%) Zinc stearate 41.26 dispersion (30%) Kaolin slurry (72%) 117.85 ASP 109, BASF Optical brightener 1.85 Blankophor PT Anionic stilbene (31.3%) derivative PVA high viscosity, 290 Poval 28-99 Polyvinyl alcohol solution high-saponified (10%) Crosslinking agent, 9.94 Cartabond type, glyoxal-based (42%) from Archroma Rheological agent 1.61 Sterocoll type, BASF Polyacrylamide, anionically modified

(11) A mixture of 50 parts of TEGO RC 902, 25 parts of TEGO RC 711 and 25 parts of TEGO RC 1772 (as matting agent), plus 3 to 5 parts of SR 9051 as an adhesion additive and 1.5 parts of photoinitiator A18 (manufacturer: Evonik, Germany; exception: SR9051 from Sartomer, Archema Group) was produced for the siliconisation. The siliconisation of the heat-sensitive colour-forming layer was carried out by means of a five-fold roller application with prior corona treatment.

(12) The self-adhesive heat-sensitive recording materials based on the application suspensions listed in tables 1 to 5 were carrier-free and evaluated as described below. The results can be found in tables 6 and 7.

(13) Storage Stability of the Carrier-Free, Self-Adhesive, Heat-Sensitive Recording Material:

(14) In order to evaluate the storage stability of a carrier-free, self-adhesive, heat-sensitive recording material, the heat-sensitive recording material siliconised on the upper side (i.e. directly on the thermal reaction layer) was provided on both sides with hot-melt adhesives in order to simulate roll winding (i.e. the adhesive effect of the upper side and lower side).

(15) The adhesives used were Technomelt PS 8746 (Henkel) and Collano L1 945 (Collano). These were already coated onto a carrier film.

(16) For carrying out the procedure, an adhesive film was first laminated on the rear side of the thermal paper at room temperature and then a checkerboard pattern was thermally printed with 10 energy gradations on an Atlantek 200 thermal printer. The image density (optical density, OD) was measured from the printed image by means of a SpectroEye densitometer (from X-Rite).

(17) A further strip of the same thermal paper, which is laminated on the rear side in the same manner but was not thermally printed in this case, was likewise laminated on the upper side with the adhesive film and subsequently stored in a climate-controlled cabinet at 60° C./50% relative humidity between Plexiglas plates and with a weight load of 10.5 kg. After defined time intervals of 1, 2 and 4 weeks, a sample was taken in each case and equilibrated at room temperature for 1 hour. The adhesive film was then removed from the upper side and the thermal side was dynamically printed on the Atlantek 200 thermal printer in order to determine the remaining writing performance. The following applies:

(18) $\%\mathrm{change}\mathrm{in}\mathrm{writing}\mathrm{performance}=\left(\frac{\mathrm{Image}\mathrm{density}\mathrm{after}\mathrm{storage}}{\mathrm{Image}\mathrm{density}\mathrm{before}\mathrm{storage}}-1\right)*100$

(19) (Image density determined at an energy density of 0.45 mJ/dot)

(20) Determination of the Release Values

(21) The applied method makes it possible to determine the force required to remove the release paper from the adhesive-coated upper material. This allows a pre-evaluation of the processing behaviour: very low values result in premature detachment of labels during the production or dispensing process; high values lead to tearing during the punch grid removal or to dispensing problems in the case of automatic dispensing.

(22) The release force during a slow peel is the force required to peel a self-adhesively coated material from its release paper (or vice versa, the release paper from the self-adhesive material) at an angle of 180° and a clamping speed of 300 mm/min.

(23) Apparatus Required:

(24) The test apparatus used was a device that can separate a composite at a peel angle of 180° and a clamp speed of 300 mm/min with ±2% accuracy. The test apparatus had a back plate on which test strips were applied in such a way that an angle of 180° was maintained during the test. Metal bearing weights produced a pressure of 6.86 kPa (70 g/cm.sup.2) on the material samples. The test strips were cut from a representative sample of the material. The strips were 50 mm wide and at least 175 mm long in the running direction. The cut was clean and straight. At least three strips were provided for each material sample.

(25) Conditions:

(26) The test strips were held at 23±2° C. for 20 hours between two flat metal plates under a pressure of 6.86 kPa (70 g/cm.sup.2). This results in good contact between the release material and the adhesive. After this pressure storage, the strips between the plates were removed and equilibrated for at least four hours under standard conditions (23±2° C. and 50±5% rh) before the measurement.

(27) Testing Process:

(28) Each test strip was fastened over its full surface to the test plate using double-sided adhesive tape, followed by a peel test at 180°. In the process, the label was detached from the release material. The clamp speed was set to 300 mm/min. During the test, the force was read five times at intervals of 10 mm in the middle region of the strip. The average value for each strip is obtained from these five measurements.

(29) Results:

(30) The release force during a slow peel is given as the mean value in centinewtons per 50 mm (cN/50 mm).

(31) The release values were determined using two different adhesives (tesa 7475 and 7476).

(32) Determining Silicone Application

(33) This test method enables rapid and precise determination of the amount of silicone of a release coating with minimal sample preparation. The release coating is located on a carrier material, as is used for producing release material for self-adhesive labels or other release applications.

(34) Definition:

(35) The silicone application weight is defined as the amount of cured silicone release coating per standard area of a carrier material. It is given in grams per square metre (9/).

(36) Devices:

(37) The method is based on x-ray fluorescence (XRF) analysis.

(38) Material Samples:

(39) A suitable number of test pieces were taken from a representative sample of the cover material of a laminate or siliconised release material to be examined. Contamination of the samples, especially with silicone-containing material, was avoided. The samples were cut out or stamped out onto a dry clean sheet of tissue paper and then grasped at the edge only by means of tweezers. The samples did not have to be pre-conditioned.

(40) Testing Process:

(41) The samples were then introduced into the device and moved into a special measuring chamber, where the irradiation with the primary x-ray radiation causes the emission of the secondary x-ray fluorescence which is characteristic of the examined element, in this case silicon. After a time of 30 to 60 seconds, the measurement was complete and the program gave the silicone application weight directly in g/m.sup.2 of silicone (see also test results below). The XRF technique is a relative method, and not an absolute method. Therefore, a calibration curve had to be produced before routine analyses could be carried out. The calibration requires the device to be configured to register silicon x-ray radiation and then known standards to be measured. However, it should be emphasised that each carrier material provides a different background radiation. It is therefore not only necessary to produce the calibration curve for measuring a series of different silicone application weights, but also to carry this out separately for each carrier material.

(42) Results:

(43) The results are specified directly in grams of silicone per square metre. It should be noted here that elemental silicon has already been computationally converted to silicone.

(44) A plurality of samples were taken from a representative coated substrate in order to detect possible fluctuations over the sheet width. In general, the longer the measurement time, the higher the measurement accuracy. Accuracies are on the order of ±0.05 to ±0.01 (g/m.sup.2).

(45) Methylene Blue Test

(46) Application Area:

(47) This test method describes a method for evaluating the coverage quality of silicone coatings. This test can only be carried out with paper substrates which can be stained with the colour test solution used.

(48) Definition:

(49) The coating quality is evaluated by testing with methylene blue stain. A certain amount of the coloured liquid is applied to the silicone-coated liner for a limited time; then the dye is rinsed off or wiped off, and the liner is dried. The coating quality is evaluated visually.

(50) Procedure:

(51) a. A 1-litre polyethylene bottle was placed on an electronic balance.

(52) b. 5 grams of methylene blue were weighed into the vessel.

(53) c. 1 litre of distilled water was added using a graduated cylinder. The vessel was closed and shaken intensively in order to dissolve the dye.

(54) Test Equipment:

(55) 1. Cobb tester with ring having a diameter of approximately 11.5 cm.

(56) 2. Stopwatch with countdown and alarm function.

(57) 3. Small container with 200-ml marking.

(58) 4. Methylene blue solution.

(59) 5. Absorbent cleaning paper.

(60) Material Samples:

(61) Several samples of the release material were evaluated. If these samples originated from a specific point of the paper sheet, this was recorded accordingly for reference purposes.

(62) Staining Test:

(63) 1. Cutting out a 14 cm×14 cm sample of the release paper. No holes or perforations are allowed in the protective paper.

(64) 2. The silicone surface was not touched before the test, since otherwise the staining can be distorted. The release paper sample is placed with the silicone side up under the test ring of the Cobb tester.

(65) 3. The ring is clamped on so that the dye does not escape during the test.

(66) 4. 200 ml of the colour solution is filled into the Cobb tester, and the stopwatch is started. The exposure time was 120 seconds.

(67) 5. The stain solution is drained after the exposure time chosen for the test, the test ring is released, and the test ring is lifted from the sample.

(68) 6. The test pattern is dabbed with absorbent paper, and the sample is dried for a further five minutes. When the sample is dry, it can be examined or measured.

(69) Results:

(70) The subjective assessment of the sample takes into account the general staining of the liner and the penetration of the colour solution into the base paper. No penetration should be visible in the case of good coating quality. The more visible and intensive the staining is, the greater the risk is that the adhesive will migrate through the silicone coating to the base paper and can thus cause release value problems (possibly dispensing problems in the case of labels or release value problems in the case of adhesive tapes, etc.).

(71) The staining was evaluated using a scale of + to ++++, wherein ++++ represents complete staining of the base paper, such as with raw paper, and + represents a perfect colour test without visible penetration.

(72) The methods described above can also be found in the ‘FINAT Technical Handbook: Test Methods’ 9th edition, August 2014, (FINAT, Worldwide Association for Self-Adhesive Labels and Related Products, The Hague, Netherlands).

(73) Test Results:

(74) TABLE-US-00006 TABLE 6 Results for determining release value and storage stability Release values Release values Writing performance % Silicone (tesa 7475) (tesa 7476) 60° C./50% rh application Acrylate tape rubber tape Technomelt PS 8746 Collano L1 945 No. Formula (g/m.sup.2) cN/in cN/in 1 wk. 2 wk. 4 wk. 1 wk. 2 wk. 4 wk. 1. Form. 1a 0.84 blocked — — — blocked — — — (BPA and PCC) 2. Form. 1a 1.34 509 355 — — — — — — (BPA and PCC) 3. Form. 1a 1.05 966 464 — — — — — — (BPA and PCC) 4. Form. 1b 0.75 35 — — — 37.4 — — — (BPA and kaolin) 5. Form. 1b 1.45 5  46 — — — — — — (BPA and kaolin) 6. Form. 1b 1.10 6  51 — — — — — — (BPA and kaolin) 7. Ricoh top 0.78 9 — — — 98.7 — — — coat 150 UTB 8. Ricoh top 0.54 11 — 100.0  101.7  99.4 97.3 99.5 36.6 coat 150 UTB 9. Form. 2a 0.69 16 169 86.3 80.1 75.3 73.2 75.4 10.6 (NKK 1304 and kaolin) 10. Form. 2a 0.82 9 — — — 76.3 — — — (NKK 1304 and kaolin) 11. Form. 2b 0.68 12 156 69.2 54.8 26.0 54.9 26.1  9.2 (PF201 and kaolin) 12. Form. 3 0.76 203 — — — 19.1 — — — (PF201 and kaolin) BPA: Bisphenol A PCC: precipitated CaCO.sub.3 NKK 1304: N-[2-(3-phenylureido)phenyl]benzenesulfonamide PF201: N-(p-toluenesulfonyl)-N′-(3-(p-toluenesulfonyl-oxy-phenyl)-urea

(75) The formulations 7 and 8 correspond to a self-adhesive heat-sensitive recording material on a carrier material (top coat) according to the prior art (manufacturer: Ricoh; paper type 150 UTB). The formulas 9 to 12 are embodiments according to the invention.

(76) TABLE-US-00007 TABLE 7 Results of methylene blue test No. Formula Methylene blue colouration 1 Form. 1a (BPA and PCC) ++++ 2 Form. 1a (BPA and PCC) +++ 3 Form. 1a (BPA and PCC) ++++ 4 Form. 1b (BPA and kaolin) ++ 5 Form. 1b (BPA and kaolin) + 6 Form. 1b (BPA and kaolin) + 7 Ricoh top coat 150 UTB + 8 Ricoh top coat 150 UTB + 9 Form. 2a (NKK 1304 and kaolin) + 10 Form. 2a (NKK 1304 and kaolin) + 11 Form. 2b (PF201 and kaolin) + 12 Form. 3 (PF201 and kaolin) + (++++) = clear blue colouration, (+++) = blue colouration, (++) = slight blue colouration, (+) = barely visible blue colouration BPA: Bisphenol A PCC: Precipitated CaCO.sub.3 NKK 1304: N-[2-(3-phenylureido)phenyl]benzenesulfonamide PF201: N-(p-toluenesulfonyl)-N′-(3-(p-toluenesulfonyl-oxy-phenyl)-urea

(77) Tables 6 and 7 show that the heat-sensitive recording material according to the invention has very good release values for an average silicone application, has very good writing performance even after a storage time of 4 weeks at 60° C. and 50% relative humidity and can be very well siliconised, which is evident from the very little blue colouration after the methylene blue test.