EP3219507A1 - Self-adhesive thermosensitive recording material - Google Patents

Abstract

A self-adhesive thermosensitive recording material comprising a support substrate, a heat-sensitive color-forming layer provided on one side of the support substrate, comprising at least one non-phenolic color developer and at least one color former, a siliconized layer on top of the heat-sensitive color forming layer coated on the support substrate, and an adhesive layer on the heat-sensitive color-forming layer facing away from the carrier substrate.

Description

The present invention relates to a pressure-sensitive heat-sensitive recording material comprising a support substrate, a heat-sensitive color-forming layer provided on one side of the support substrate comprising at least one non-phenolic color developer and at least one color former, a siliconized layer on top of the heat-sensitive color-forming layer applied to the support substrate. and an adhesive layer on the side of the carrier substrate remote from the heat-sensitive color-forming layer, a process for its production and its use. The invention also relates to a semi-finished product, its preparation and its use for the production of the self-adhesive heat-sensitive recording material.

Self-adhesive thermosensitive recording materials for direct thermal printing applications, which have a heat-sensitive color-forming layer (thermal reaction layer) applied to a support substrate and an adhesive layer on the other side of the support substrate, are known. In the heat-sensitive color-forming layer, a color former and a color developer are usually present, which react with one another under the action of heat and thus lead to a color development. These self-adhesive thermosensitive recording materials are usually applied to a release liner ("liner" or "liner") so that the individual units of the pressure-sensitive thermosensitive recording material do not stick to each other.

Also known are so-called linerless self-adhesive thermosensitive recording materials. In this case, a siliconized layer is usually applied to the heat-sensitive color-forming layer. These materials are characterized in that they are not applied to a carrier material, but can be rolled onto themselves, so that the heat-sensitive color-forming layer, to which a siliconized layer is applied, is in direct contact with the adhesive layer. In addition, since components of the adhesive layer, especially the plasticizers, can attack the heat-sensitive color-forming layer, resulting in reduced writing performance, these carrierless self-adhesive thermosensitive recording materials have a topcoat located between the heat-sensitive color-forming layer and the siliconized layer is.

However, the use of a protective layer is associated with significantly increased production costs, so that the cost advantages are consumed by the use of a strapless material again. In addition, the open-pore surface of conventional thermal papers without protective layer does not allow good coatability with silicone. Consequently, high silicone application rates are required that not only drive up manufacturing costs but are also responsible for deposits on the thermal print heads.

So revealed the US 4,851,383 A a self-adhesive thermosensitive recording material comprising a substrate having a heat-sensitive layer on one side and an adhesive layer on the other side. A protective layer on top of the heat-sensitive layer is provided with a siliconized layer.

The DE 19757589 B4 discloses a carrierless heat-sensitive recording adhesive sheet comprising a support, a heat-sensitive recording layer provided on one side of the support, a barrier layer provided on the heat-sensitive recording layer, a release layer provided on the barrier layer, and one on top of the other Side layer of the support, wherein the barrier layer is formed of a coating composition comprising colloidal silica, which is in the form of a colloid containing water as a dispersing medium, and at least one resin selected from water-soluble resins and water-dispersible resins.

The US 5,840,657 discloses a multi-layered, carrierless recording material having a heat-sensitive layer containing a phenolic color developer on one side and an adhesive layer on the other side. In addition, two further layers, a base layer and a cover layer, of a polymer are applied to the heat-sensitive layer. The carrier material is only partially coated in order to make selected parts of the surface printable.
The object of the present invention is to overcome the above-described disadvantages of the prior art. In particular, it is an object to provide a self-adhesive heat-sensitive recording material with the lowest possible production costs, which also has a high resistance to the plasticizers contained in the adhesive layer and in addition to a desirable high dynamic pressure sensitivity and a good storage stability, especially under conditions of high storage temperature and ambient humidity shows without losing the functional properties necessary for the application, such as surface whiteness and thermal sensitivity. In addition, the self-adhesive thermosensitive recording material should enable good siliconizability of the surface of the heat-sensitive color-forming layer. Further, it is desirable to provide a pressure-sensitive heat-sensitive recording material which can be used without a support. Finally, it is desirable to provide an environmentally friendly recording material.

According to the invention, this object is achieved with a self-adhesive thermosensitive recording material according to claim 1, comprising a carrier substrate, a heat-sensitive color-forming layer applied on one side of the carrier substrate comprising at least one non-phenolic color developer and at least one color former, a siliconized layer on top of the Carrier substrate applied heat-sensitive color-forming layer, and an adhesive layer on the heat-sensitive color-forming layer facing away from the Carrier substrate, which is characterized in that the siliconized layer rests directly on the heat-sensitive color-forming layer.

Due to the direct contact of the siliconized layer on the heat-sensitive color-forming layer and the concomitant absence of a protective layer between the siliconized layer and the heat-sensitive color-forming layer, the production of the self-adhesive heat-sensitive recording material according to the invention is associated with significantly lower costs and significantly lower costs.

The heat-sensitive color-forming layer preferably additionally contains at least one platelet-shaped pigment.

The at least one platelet-shaped pigment is preferably selected from the group consisting of kaolin, Al (OH) ₃ and / or talc. Particularly preferred is the use of kaolin. Very particularly preferred is the use of a Streichkaolin. Such a material is available, for example, under the trade name Kaolin ASP 109 (BASF, Germany).

The use of these platelet-shaped pigments, in particular kaolin, has the particular advantage that the heat-sensitive color-forming layer can be siliconized very well.

By platelet-shaped pigment is meant a pigment in which the diameter-to-thickness ratio is about 7 to 40 to 1, preferably about 15 to 30 to 1.

The particle size of the platelet-shaped pigment is preferably adjusted so that at least about 70%, preferably at least about 85%, of the particles have a particle size of about <2 μm (Sedigraph). The pH of the platelet-shaped pigment in aqueous solution is preferably 6 to 8.

The at least one platelet-shaped pigment is preferably contained in the heat-sensitive color-forming layer of the self-adhesive thermosensitive recording material of the present invention in an amount of about 5 to about 60% by weight, more preferably in the amount of about 15 to about 55 wt .-%, based on the total solids content of the heat-sensitive layer before. If less than 5% by weight of the platelet-shaped pigment is present, this has the disadvantage that the good siliconizability is no longer present. The use of more than 60% by weight has the disadvantage that the propensity to deposit on the printhead increases and the writing power decreases because the relationships between pigments, binders, colorants and developers are adversely affected.

The selection of the carrier substrate is not critical. However, it is preferred to use paper, synthetic paper and / or a plastic film as the carrier substrate.

Preferably, the self-adhesive thermosensitive recording material of the present invention is a linerless self-adhesive thermosensitive recording material.

In this case, carrierless means that the self-adhesive heat-sensitive recording material according to the invention is not applied to a carrier material, but wound up on itself. This has the advantage that the manufacturing costs can be further reduced, more meters per roll are feasible, no disposal costs for disposal of the liner is necessary and more labels can be transported per specific cargo space volume.

wobei Ar₁ und Ar₂ ein Phenyl-Rest und/oder ein C₁-C₄-Alkyl-substituierter Phenyl-Rest sind.The at least one non-phenolic color developer is preferably a sulfonylurea and / or a compound of the formula (I)

wherein Ar ₁ and Ar _{2 are} a phenyl radical and / or a C ₁ -C ₄ alkyl-substituted phenyl radical.

A compound of the formula (I) is very particularly preferred.

The C ₁ -C ₄ -alkyl-substituted phenyl radical is preferably a methyl radical, more preferably a para-methyl radical.

In a particularly preferred embodiment, Ar ₁ and Ar _{2 are} a para-methyl-substituted phenyl radical.

In a further particularly preferred embodiment, Ar _{1 is} a phenyl radical and Ar _{2 is} a para-methyl-substituted phenyl radical.

In a most preferred embodiment, each of Ar ₁ and Ar ₂ is a phenyl radical, that is, the at least one color developer is N- (2- (3-phenylureido) phenyl) benzenesulfonamide (hereinafter also referred to as NKK 1304; Manufacturer: Nippon Soda Co. Ltd.).

The sulfonyl urea contained in the color-forming heat-sensitive layer of the self-adhesive thermosensitive recording material of the present invention in addition to or in lieu of a color developer of formula (I) is preferably selected from the group consisting of N '- (p-toluenesulfonyl) -N'-phenyl-urea, N - (p-toluenesulfonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea, (trade name Pergafast 201 ^{®, manufactured} by BASF PF201) and / or 4,4'-bis (p-tolylsulfonylureido) - diphenylmethane.

Very particular preference is given to an embodiment of the self-adhesive heat-sensitive recording material, which is characterized in that the heat-sensitive color-forming layer comprises N- (2- (3-phenylureido) -phenyl) benzenesulfonamide (NKK 1304) and / or N- (p-toluenesulfonyl) - N'-3- (p-toluenesulphonyl-oxy-phenyl) urea (Pergafast 201 (PF201), from BASF) as a color developer.

Use of N- (2- (3-phenylureido) phenyl) benzenesulfonamide (NKK 1304) and / or N- (p-toluenesulfonyl) -N'-3- (p-toluenesulphonyl-oxy-phenyl) -urea (PF201) has the particular advantage that the writing performance is good even with prolonged storage.

Most preferred is the use of N- (2- (3-phenylureido) phenyl) benzenesulfonamide (NKK 1304), since its use leads to an even better writing performance even on prolonged storage.

The use of a non-phenolic color developer is environmentally friendly.

The sulfonyl urea and / or the compound of formula (I) are preferably present in an amount of from about 5 to about 40 weight percent, more preferably in an amount of from about 10 to about 25 weight percent, based on the total Solids content of the heat-sensitive layer, before. If the quantity of color developer drops below 5% by weight, this has the disadvantage that the writing power is no longer given. If the amount of 40% by weight of color developer is exceeded, this has the disadvantage that the economy suffers without the writing performance still appreciably increasing.

With regard to the choice of the color former, the present invention is not subject to any significant restrictions. However, the color former is preferably a triphenylmethane-type, fluoran-type, azaphthalide-type and / or fluorene-type dye. A most preferred color former is a fluoran-type dye, because of its availability and balanced application properties, it enables the provision of a recording material with an attractive price / performance ratio.

• 3-Diethylamino-6-methyl-7-anilinofluoran,
• 3-(N-Ethyl-N-p-toludinamino)-6-methyl-7-anilinofluoran,
• 3-(N-Ethyl-N-isoamylamino)-6-methyl-7-anilinofluoran,
• 3-Diethylamino-6-methyl-7-(o,p-dimethylanilino)fluoran,
• 3-Pyrrolidino-6-methyl-7-anilinofluoran,
• 3-(Cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran,
• 3-Diethylamin-7-(m-trifluoromethylanilino)fluoran,
• 3-N-n-Dibutylamin-6-methyl-7-anilinofluoran,
• 3-Diethylamino-6-methyl-7-(m-methylanilino)fluoran,
• 3-N-n-Dibutylamin-7-(o-chloroanilino) fluoran,
• 3-(N-Ethyl-N-tetrahydrofurfurylamin)-6-methyl-7-anilino-fluoran,
• 3-(N-Methyl-N-propylamin)-6-methyl-7-anilinofluoran,
• 3-(N-Ethyl-N-ethoxypropylamin)-6-methyl-7-anilinofluoran,
• 3-(N-Ethyl-N-isobutylamin)-6-methyl-7-anilinofluoran und/oder
• 3-Dipentylamin-6-methyl-7-anilinfluoran.

Particularly preferred fluoran-type dyes are:

• 3-diethylamino-6-methyl-7-anilinofluoran,
• 3- (N-ethyl-Np-toludinamino) -6-methyl-7-anilinofluoran,
• 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran,
• 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran,
• 3-pyrrolidino-6-methyl-7-anilinofluoran,
• 3- (cyclohexyl-N-methylamino) -6-methyl-7-anilinofluoran,
• 3-diethylamino-7- (m-trifluoromethylanilino) fluoran,
• 3-Nn-dibutyl-6-methyl-7-anilinofluoran,
• 3-diethylamino-6-methyl-7- (m-methylanilino) fluoran,
• 3-Nn-dibutylamine-7- (o-chloroanilino) fluoran,
• 3- (N-ethyl-N-tetrahydrofurfurylamine) -6-methyl-7-anilino-fluoran,
• 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran,
• 3- (N-ethyl-N-ethoxypropylamine) -6-methyl-7-anilinofluoran,
• 3- (N-ethyl-N-isobutylamine) -6-methyl-7-anilinofluoran and / or
• 3-dipentylamino-6-methyl-7-anilinofluoran.

The at least one color former is preferably present in an amount of from about 2 to about 20 weight percent, preferably from about 5 to about 15 weight percent, based on the total solids content of the heat-sensitive layer.

If, in addition to the at least one color former, a further color former is present, this is preferably present in an amount of from 0.5 to 5% by weight, based on the total solids content of the heat-sensitive layer.

If the amount of color former is below 2% by weight, this has the disadvantage that the functionality no longer exists. If the amount of 20 wt .-% of color former is exceeded, then this has the disadvantage that the economy suffers significantly without the writing performance still increases significantly.

The self-adhesive thermosensitive recording material of the present invention may contain conventional additives such as sensitizers, stabilizers, binders, release agents and / or brighteners in the heat-sensitive color-forming layer.

In general, suitable sensitizing agents are substances whose melting point is between about 90 and about 150 ° C. and which in the molten state dissolve the color-forming components (color former and color developer) without disturbing the formation of the color complex.

Preferably, the sensitizer is a fatty acid amide such as stearamide, behenamide or palmitamide, an ethylene-bis-fatty acid amide such as N, N'-ethylene-bis-stearic acid amide or N, N'-ethylene-bis-oleic acid amide, a wax such as polyethylene wax or Montan wax, a carboxylic acid ester such as dimethyl terephthalate, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di (p-methylbenzyl) oxalate, di (p-chlorobenzyl) oxalate or di (p-benzyl) oxalate, an aromatic ether such as 1, 2-diphenoxy-ethane, 1,2-di (3-methylphenoxy) ethane, 2-benzyloxynaphthalene or 1,4-diethoxynaphthalene, an aromatic sulfone, such as diphenylsulfone, and / or an aromatic sulfonamide, such as benzenesulfonanilide or N-benzyl- p-toluenesulfonamide.

Particularly preferred is the use of fatty acid amides, since they are inexpensive to purchase.

The stabilizer is preferably sterically hindered phenols, more preferably 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexyl-phenyl) -butane, 1,1,3-tris ( 2-methyl-4-hydroxy-5-tert-butylphenyl) -butane, 1,1-bis (2-methyl-4-hydroxy-5-tert-butyl-phenyl) -butane.

Also urea-urethane compounds of the general formula (II), commercial product UU (urea-urethanes), or derived from 4,4'-dihydroxydiphenylsulfone ethers, such as 4-benzyloxy-4 '- (2-methylglycidyloxy) -diphenylsulfon (trade name NTZ ^® -95, Nippon soda Co. Ltd.), or oligomeric ethers of the general formula (III) (trade name ^® D90, Nippon soda Co. Ltd.) are used as stabilizers in the inventive recording material can be used.

Particularly preferred are the urea-urethane compounds of the general formula (II).

In a further preferred embodiment, at least one binder is present in the heat-sensitive color-forming layer. These are preferably water-soluble starches, starch derivatives, methylcellulose, hydroxyethylcellulose, carboxymethylcelluloses, partially or fully saponified polyvinyl alcohols, chemically modified polyvinyl alcohols or styrene maleic anhydride copolymers, styrene-butadiene copolymers, acrylamide (meth) acrylate copolymers, acrylamide acrylate Methacrylate terpolymers, polyacrylates, poly (meth) acrylic esters, acrylate-butadiene copolymers, polyvinyl acetates and / or acrylonitrile-butadiene copolymers.

In another preferred embodiment, at least one release agent (anti-sticking agent) or lubricant is present in the heat-sensitive color-forming layer. These agents are preferably fatty acid metal salts, such as zinc stearate or calcium stearate, or else behenate salts, synthetic waxes, for example in the form of fatty acid amides such as stearic acid amide and behenic acid amide, fatty acid alkanolamides such as stearic acid methylolamide, paraffin waxes of various melting points, ester waxes different molecular weights, ethylene waxes, propylene waxes of different hardnesses and / or natural waxes, such as carnauba wax or montan wax.

For controlling the surface whiteness of the heat-sensitive recording material of the present invention, optical brighteners may be incorporated in the heat-sensitive color-forming layer. These are preferably stilbenes.

In order to improve certain coating properties, it is preferred in individual cases to the compelling constituents of the heat-sensitive recording material according to the invention further ingredients, in particular rheology aids, such as thickeners and / or surfactants to add.

The area coat weight of the (dry) heat-sensitive color-forming layer of the self-adhesive heat-sensitive recording material of the present invention is preferably about 1 to about 10 g / m ² , more preferably about 2 to about 6 g / m ² . If a surface application weight of 1 g / m ^{2 is} exceeded, this has the disadvantage that no functionality is given. If a surface application weight of 10 g / m ^{2 is} exceeded, this has the disadvantage that this is uneconomical and negative properties, such as dropping the print head, increase.

As mentioned above, directly on the heat-sensitive color-forming layer is a siliconized layer. This siliconized layer is preferably based on at least one siloxane. In this preferred embodiment, this is at least one poly (organo) siloxane, especially an acrylic-poly (organo) siloxane.
In a further embodiment, the siliconized layer of the self-adhesive heat-sensitive recording material according to the invention comprises a mixture of at least two siloxanes. Preference is given to a mixture of at least two acrylic-poly (organo) siloxanes.
Examples of very particularly preferred siloxanes are siloxanes which are known under the trade names TEGO®RC902 and TEGO®RC711 (both from Evonik, Germany).

The surface coverage of the siliconized layer is about 0.3 to about 2.5 g / m ² , preferably about 0.5 to about 1.5 g / m ² , and most preferably about 0.6 to about 1.0 g / m ² . If a surface application weight of 0.3 g / m ^{2 is} exceeded, this has the disadvantage that the release effect is no longer present. If a surface application weight of 2.5 g / m ^{2 is} exceeded, then This has the disadvantage that the economy decreases and the risk of deposits on the thermal head of the printer increases.

The siliconized layer is preferably anhydrous. It is also preferable that the siliconized layer does not contain Pt catalysts.

The siliconized layer preferably contains an initiator, more preferably a photoinitiator. This serves for free radical curing of the silicone. This is very particularly preferably the TEGO® photoinitiator A18 (from Evonik, Germany). The siliconized layer may preferably contain further additives, such as matting agents and / or adhesion additives.

The adhesive layer applied on the side of the carrier material facing away from the heat-sensitive color-forming layer comprises at least one adhesive, preferably a hotmelt adhesive.

Particularly preferably, the hotmelt adhesive is a hot melt adhesive based on rubber and / or acrylate.

Examples of very particularly preferred hot-melt adhesives are known under the trade names TLH4280E (Bostik), PS8746 (Henkel / Technomelt), PS1212 (Novamelt) and / or L1945 (Collano).

The surface application weight of the adhesive layer is preferably about 10 to about 40 g / m ² , more preferably about 12 to about 25 g / m ² . If a surface application weight of 10 g / m ^{2 is} exceeded, this has the disadvantage that the adhesive effect no longer exists. If a surface application weight of 40 g / m ^{2 is} exceeded, this has the disadvantage that the cost-effectiveness decreases and the risk of adhesion of deflection rollers and cutting blades in label dispensers increases.

In a most preferred embodiment, the self-adhesive heat-sensitive recording material according to the invention is unsupported, the at least one color developer is a sulfonylurea and the platelet-shaped pigment is a prankkaolin. In this most preferred embodiment, the sulfonyl urea is present in an amount of from about 5 to about 40 percent by weight, based on the total solids content of the heat-sensitive Shift, in front. The flaky pigment in this most preferred embodiment is present in an amount of from about 5 to about 60 percent by weight, based on the total solids content of the heat-sensitive layer.

In a likewise very particularly preferred embodiment, the self-adhesive heat-sensitive recording material according to the invention is unsupported, the at least one color developer N- (2- (3-phenylureido) phenyl) benzenesulfonamide and the platelet-shaped pigment is a prankkaolin. The amounts of N- (2- (3-phenylureido) phenyl) benzenesulfonamide and platelet kaolin used in this embodiment are also about 5 to about 40 wt% and about 5 to about 60 wt%, respectively.

The self-adhesive thermosensitive recording material of the present invention can be obtained by known production methods.

However, the production method of the present invention is characterized in that an aqueous suspension containing the starting materials of the heat-sensitive color-forming layer is applied to a support substrate and dried, then the heat-sensitive color-forming layer is siliconized, and an adhesive layer is applied to the side of the support substrate remote from the heat-sensitive color-forming layer ,

Most preferably, the self-adhesive heat-sensitive recording material of the present invention is obtained by a method of applying and drying an aqueous suspension containing the starting materials of the heat-sensitive color-forming layer to a support substrate, the aqueous application suspension having a solid content of about 20 to about 75% by weight. , preferably from about 25 to about 50% by weight, coated and dried by the curtain coating process at an operating speed of the coater of at least about 400 m / min, the heat-sensitive color-forming layer is subsequently siliconized, and that on the the heat-sensitive color-forming layer facing away from the carrier substrate, an adhesive layer is applied.

This method is particularly advantageous from an economic point of view.

If the value of the solids content of about 20 wt .-% is exceeded, then the efficiency deteriorates because a large amount of water must be removed from the line by gentle drying in a short time, which adversely affects the coating speed. If, on the other hand, the value of 75% by weight is exceeded, then this only leads to an increased technical outlay in order to ensure the stability of the coating curtain during the coating process.

• Beim Curtain-Coating-Beschichtungsverfahren (Vorhangbeschichtungsverfahren) wird ein frei fallender Vorhang einer Beschichtungsdispersion gebildet. Durch freien Fall wird die in Form eines dünnen Filmes (Vorhangs) vorliegende Beschichtungsdispersion auf ein Substrat "gegossen", um die Beschichtungsdispersion auf das Substrat aufzubringen. Die DE 10196052 T1 offenbart den Einsatz des Curtain-Coating-Beschichtungsverfahrens bei der Herstellung von Informationsaufzeichnungsmaterialien u.a. auch von wärmeempfindlichen Aufzeichnungsmaterialien, wobei mehrschichtige Aufzeichnungsschichten durch Aufbringen des aus mehrere Beschichtungsdispersionsfilmen bestehenden Vorhangs auf Substrate erfolgen.

As mentioned above, it is advantageous to prepare the self-adhesive thermosensitive recording material of the present invention by a method in which the aqueous coating suspension is applied by the curtain coating method at an operation speed of the coating unit of at least about 400 m / min. The so-called curtain-coating method is known to the person skilled in the art and is characterized by the following criteria:

• In the curtain coating (curtain coating) process, a free falling curtain of coating dispersion is formed. By free fall, the coating dispersion in the form of a thin film (curtain) is "poured" onto a substrate to apply the coating dispersion to the substrate. The DE 10196052 T1 discloses the use of the curtain coating process in the production of information recording materials, including thermosensitive recording materials, wherein multi-layered recording layers are formed by applying the curtain consisting of a plurality of coating dispersion films to substrates.

The setting of the operating speed of the coater to at least about 400 m / min has both economic and technical advantages. The operating speed is particularly preferably at least about 750 m / min, very particularly preferably at least about 1000 m / min and very particularly preferably at least about 1500 m / min. It was particularly surprising that even at the latter speed, the resulting heat-sensitive recording material is impaired in any way, and that the operation is carried out optimally even at this high speed.

In a preferred embodiment of the process according to the invention, the aqueous deaerated application suspension has a viscosity of about 100 to about 1000 mPas (Brookfield, 100 rpm, 20 ° C.). If the value of about 100 mPas is exceeded or exceeded the value of about 1000 mPas, then this leads to a poor runnability of the coating on the coating unit. More preferably, the viscosity of the aqueous deaerated application suspension is about 150 to about 700 mPas.

In a preferred embodiment, to optimize the process, the surface tension of the aqueous application suspension can be adjusted to about 30 to about 60 mN / m, preferably about 35 to about 50 mN / m (measured according to the static ring method according to Du Noüy, DIN 53914) ,

The formation of the heat-sensitive color-forming layer can be done on-line or in a separate coating process off-line. This also applies to any subsequently applied layers or intermediate layers.

It is advantageous if the dried heat-sensitive color-forming layer is subjected to a smoothing action. It is advantageous here to adjust the Bekk smoothness, measured to DIN 53101, to about 150 to about 1500 seconds, preferably to about 250 to about 800 seconds.

The preferred embodiments mentioned in connection with the self-adhesive heat-sensitive recording material according to the invention also apply to the process according to the invention.

The present invention also relates to a self-adhesive thermosensitive recording material obtainable according to the above-described method of the present invention.

The present invention further includes a process for producing a semifinished product characterized by applying and drying, on a supporting substrate, an aqueous suspension containing the starting materials of the heat-sensitive color-forming layer. The semi-finished product according to the invention is therefore analogous to the invention self-adhesive thermosensitive recording material produced, but still without subsequent siliconization and application of the adhesive layer.

The preferred embodiments mentioned in connection with the self-adhesive heat-sensitive recording material according to the invention and the method for producing the same apply correspondingly to the method for producing the semi-finished product and the semi-finished product itself, which is also included in the present invention.

The present invention also encompasses the use of a semi-finished product comprising a carrier substrate, a heat-sensitive color-forming layer applied on one side of the carrier substrate, comprising at least one color developer and at least one color former for the preparation of a self-adhesive thermosensitive recording material as described above.

• Die vorliegende Erfindung stellt ein selbstklebendes wärmeempfindliches Aufzeichnungsmaterial bereit, welches bevorzugt trägerlos ist und neben einer wünschenswert hohen dynamischen Druckempfindlichkeit auch eine außerordentlich gute Lagerstabilität, insbesondere auch unter Bedingungen hoher Lagertemperatur und Umgebungsfeuchte, zeigt, ohne dass die für die Anwendung notwendigen funktionellen Eigenschaften, wie beispielsweise Oberflächenweisse und thermische Ansprechempfindlichkeit, verloren gehen. Zudem ermöglicht die Zusammensetzung der wärmeempfindlichen farbbildenden Schicht eine gute Silikonisierbarkeit derselben. Das erfindungsgemäße selbstklebende wärmeempfindliche Aufzeichnungsmaterial ist bevorzugt trägerlos und kann somit auf sich selbst aufgewickelt werden. Die farbbildende Schicht weist eine hohe Beständigkeit gegenüber den Bestandteilen der Klebeschicht auf, besonders gegenüber hydrophoben Stoffen, wie Weichmachern, fettigen oder öligen Stoffen, etc. Dies ermöglicht die Bereitstellung eines trägerlosen selbstklebenden wärmeempfindlichen Aufzeichnungsmaterials. Ferner ist das erfindungsgemäße selbstklebende wärmeempfindliche Aufzeichnungsmaterial umweltverträglich.

The advantages associated with the present invention can be summarized essentially as follows:

• The present invention provides a self-adhesive thermosensitive recording material, which is preferably strapless and in addition to a desirable high dynamic pressure sensitivity also an extremely good storage stability, especially under conditions of high storage temperature and ambient humidity shows, without the necessary functional properties for the application, such as Surface whiteness and thermal sensitivity are lost. In addition, the composition of the heat-sensitive color-forming layer enables good siliconizability thereof. The self-adhesive heat-sensitive recording material according to the invention is preferably carrierless and can thus be wound up on itself. The color-forming layer has a high resistance to the components of the adhesive layer, especially to hydrophobic substances such as plasticizers, fatty or oily substances, etc. This enables to provide a carrier-less self-adhesive thermosensitive recording material. Further, the self-adhesive heat-sensitive recording material of the present invention is environmentally friendly.

The self-adhesive thermosensitive recording material of the present invention is well suited for POS (point-of-sale) and / or label applications. It Also suitable for the production of stickers, labels and luggage tag trailers.

The invention will now be explained in detail by way of non-limiting examples.

The application of an aqueous application suspension for forming the heat-sensitive color-forming layer of a heat-sensitive recording paper was carried out on a laboratory scale by means of a bar blade on one side of a thermal base paper of 69 g / m ² . After drying, a thermal recording sheet was obtained. The application amount of the heat-sensitive color-forming layer was from 4.0 to 4.5 g / m ² .

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

After application of the aqueous application suspension, the drying process of the coated paper support was carried out in a customary manner. The basis weight of the dry heat-sensitive layer was 4.0-4.5 g / m ² .

The following formulations were prepared by first mixing the dispersions A1, A2, B and C separately by milling the ingredients in a bead mill and then mixing these dispersions well together with the other components.

The thus obtained heat-sensitive coating suspensions (formulations 1a, 1b, 2a, 2b, and 3), which are shown in Tables 1 to 6 below, were used to prepare semi-finished products of paper support and heat-sensitive color-forming layer. Table 1: Recipe 1a component Parts by weight Comment / trade name chem. nomenclature Dispersion A1 Color former 1 11.06 S-205 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 20,04 Poval 4-85, Kuraray polyvinyl alcohol Dispersion A2 Color former 2 16.58 ODB-2 3-Nn-dibutylamino-6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 30.05 Poval 4-85, Kuraray polyvinyl alcohol Dispersion B color developer 76.79 Bisphenol A 4,4'-isopropyl! Endipheno! PVA low viscosity, low saponified (15%) 54.41 Poval 4-85, Kuraray polyvinyl alcohol Dispersion C Sensitization tel 25.62 BON 2-benzyloxynaphthalene PVA low viscosity, low saponified (15%) 18.15 Poval 4-85, Kuraray polyvinyl alcohol Stearic acid amide dispersion (25%) 108.17 Zinc stearate dispersion (30%) 54.9 PCC slurry (56%) 121.77 precipitated calcium carbonate optical brightener (31.3%) 5.75 Blankophor PT anionic stilbene derivative PVA highly viscous, highly saponified (10%) 330 Poval28-99 polyvinyl alcohol Crosslinker, glyoxal based (42%) 11.29 Cartabond type, company Archroma rheology aids 0.83 Sterocoll type, BASF Polyacrylamide anionic modified Recipe 1b component Parts by weight Comment / trade name chem. nomenclature Dispersion A1 Color former 1 11.06 S-205 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 20,04 Poval 4-85, Kuraray polyvinyl alcohol Dispersion A2 Color former 2 16.58 ODB-2 3-Nn-dibutylamino-6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 30.05 Poval 4-85, Kuraray polyvinyl alcohol Dispersion B color developer 76.79 Bisphenol A 4,4'-isopropyl! Endipheno! PVA low viscosity, low saponified (15%) 54.41 Poval 4-85, Kuraray polyvinyl alcohol Dispersion C Sensitization tel 25.62 BON 2-benzyloxynaphthalene PVA low viscosity, low saponified (15%) 18.15 Poval 4-85, Kuraray polyvinyl alcohol Stearic acid amide dispersion (25%) 108.17 Zinc stearate dispersion (30%) 54.9 Kaolin slurry (72%) 94.71 ASP-109 optical brightener (31.3%) 5.75 Blankophor PT anionic stilbene derivative PVA highly viscous, highly saponified (10%) 330 Poval28-99 polyvinyl alcohol Crosslinker, glyoxal based (42%) 11.29 Cartabond type, company Archroma rheology aids 0.83 Sterocoll type, BASF Polyacrylamide anionic modified Recipe 2a component Parts by weight Comment / trade name chem. nomenclature Dispersion A1 Color former 1 9.0 S-205 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 16.31 Poval 4-85, Kuraray polyvinyl alcohol Dispersion A2 Color former 2 21.0 ODB-2 3-Nn-dibutylamino-6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 38.05 Poval 4-85, Kuraray polyvinyl alcohol Dispersion B color developer 60 NKK 1304 N- [2- (3-phenylureido) phenyl] benzenesulfonamide PVA low viscosity, low saponified (15%) 70.59 Poval 4-85, Kuraray polyvinyl alcohol Dispersion C Sensitization tel 36 BON 2-benzyloxynaphthalene PVA low viscosity, low saponified (15%) 25.51 Poval 4-85, Kuraray polyvinyl alcohol Stearic acid amide dispersion (25%) 176.77 Zinc stearate dispersion (30%) 0 Kaolin slurry (72%) 94.88 ASP 109, Fa. BASF optical brightener (31.3%) 2.88 Blankophor PT anionic stilbene derivative PVA highly viscous, highly saponified (10%) 330 Poval 28-99, Kuraray polyvinyl alcohol Crosslinker, glyoxal based (42%) 11.29 Cartabond type, company Archroma rheology aids 0.83 Sterocoll type, BASF Polyacrylamide anionic modified Recipe 2b component Parts by weight Comment / trade name chem. nomenclature Dispersion A1 Color former 1 0 S-205 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 0 Poval 4-85, Kuraray polyvinyl alcohol Dispersion A2 Color former 2 30.0 ODB-2 3-Nn-dibutylamino-6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 54.36 Poval 4-85, Kuraray polyvinyl alcohol Dispersion B color developer 60 PF201 N- (p-toluenesulfonyl) -N '- (3- (p-toluenesulfonyloxy) phenyl) urea) PVA low viscosity, low saponified (15%) 70.59 Poval 4-85, Kuraray polyvinyl alcohol Dispersion C sensitizer 36 BON 2-benzyloxynaphthalene PVA low viscosity, low saponified (15%) 25.51 Poval 4-85, Kuraray polyvinyl alcohol Stearic acid amide dispersion (25%) 176.77 Zinc stearate dispersion (30%) 0 Kaolin slurry (72%) 94.88 ASP 109, Fa. BASF optical brightener (31.3%) 2.88 Blankophor PT anionic stilbene derivative PVA highly viscous, highly saponified (10%) 330 Poval 28-99, Kuraray polyvinyl alcohol Crosslinker, glyoxal based (42%) 11.29 Cartabond type, company Archroma rheology aids 0.83 Sterocoll type, BASF Polyacrylamide anionic modified Recipe 3 component Parts by weight Comment / trade name chem. nomenclature Dispersion A1 Color former 1 0 S-205 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 0 Poval 4-85, Kuraray polyvinyl alcohol Dispersion A2 Color former 2 29 ODB-2 3-Nn-dibutylamino-6-methyl-7-anilinofluoran PVA low viscosity, low saponified (15%) 52.54 Poval 4-85, Kuraray polyvinyl alcohol Dispersion B color developer 46.4 PF201 N- (p-toluenesulfonyl) -N '- (3- (p-toluenesulfonyloxy) phenyl) urea PVA low viscosity, low saponified (15%) 30.94 Poval 4-85, Kuraray polyvinyl alcohol Dispersion C sensitizer 15.47 BON 2-benzyloxynaphthalene PVA low viscosity, low saponified (15%) 10.96 Poval 4-85, Kuraray polyvinyl alcohol Stearic acid amide dispersion (25%) 213.6 Zinc stearate dispersion (30%) 41.26 Kaolin slurry (72%) 117.85 ASP 109, Fa. BASF optical brightener (31.3%) 1.85 Blankophor PT anionic stilbene derivative PVA highly viscous, highly saponified (10%) 290 Poval28-99 polyvinyl alcohol Crosslinker, glyoxal based (42%) 9.94 Cartabond type, company Archroma rheology aids 1.61 Sterocoll type, BASF Polyacrylamide anionic modified

For siliconization, a mixture of 50 parts TEGO RC902, 25 parts TEGO RC711 and 25 parts TEGO RC1772 (as matting agent) was prepared, plus 3 to 5 parts SR9051 as adhesion additive and 1.5 parts photoinitiator A18 (manufacturer: Evonik, Germany; SR9051 from Sartomer, Archema Group). The siliconization of the heat-sensitive color-forming layer was carried out by means of a five-fold roller application with prior corona treatment.

The self-adhesive thermosensitive recording materials based on the order suspensions listed in Tables 1 to 5 were unsupported and evaluated as described below. The results are shown in Tables 6 and 7.

Storage stability of the carrier-free self-adhesive heat-sensitive recording material:

In order to evaluate the storage stability of a strapless self-adhesive thermosensitive recording material, the heat-sensitive recording material siliconized on the upper side (i.e., directly on the thermal reaction layer) was coated on both sides with hot melt adhesives to simulate a roll winding (i.e., adhesive influence from the top and bottom).

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

To carry out the respective adhesive film was first laminated to the back of the thermal paper at room temperature and then thermally printed on a Atlantek 200 thermal printer, a checkerboard pattern with 10 energy gradings. From the printed image, the image density (optical density, OD) was measured by means of a SpectroEye Densitometer (X-Rite).

Another strip of the same thermal paper, which in the same way back-laminated, but no longer thermally printed, was also laminated on top with the adhesive film and then in a climatic chamber at 60 ° C / 50% rel. Humidity between Plexiglas plates and one Weight load of 10.5 kg stored. After defined time intervals of 1, 2 and 4 weeks, a pattern was taken in each case and conditioned at room temperature for 1 hour. Then, the adhesive sheet was removed from the top and the thermal side printed on the Atlantek 200 thermal printer dynamically to determine the remaining writing power. Where: $$\%\mathit{Ver}\ddot{a}\mathit{Change\; in\; the\; writing\; performance}=\left(\frac{\mathit{Image\; density\; after\; storage}}{\mathit{Image\; density\; before\; storage}}\right)*100\%$$

(Image density determined at an energy density of 0.45 mJ / dot) Determination of the separation values

The method used allows the determination of the force required to peel the release paper from the adhesive-coated facing. This allows for pre-evaluation of processing performance - very low values result in premature peel-off of labels during the manufacturing or dispensing process - high values lead to tearing in the punched grid deduction or dispensing problems with automatic dispensing.

The slow release force is the force required to peel off a self-adhesive coated material from its release paper (or, conversely, the release liner from the self-adhesive material) at an angle of 180 ° and a nip speed of 300 mm / min.

• Als Prüfgerat wurde ein Gerät eingesetzt, das einen Verbund mit einem Abzugswinkel von 180° und einer Klemmengeschwindigkeit von 300 mm/min bei ±2% Genauigkeit trennen kann. Das Prüfgerät hatte eine Rückenplatte, auf der Teststreifen so angebracht wurden, dass ein Winkel von 180° während der Prüfung beibehalten wurde. Lagergewichte aus Metall, erzeugten einen Druck von 6,86 kPa (70 g/cm²) auf die Materialproben. Die Teststreifen wurden aus einem repräsentativen Muster des Materials geschnitten. Die Streifen waren 50 mm breit und in Laufrichtung mindestens 175 mm lang. Der Schnitt war sauber und gerade. Von jedem Materialmuster wurden mindestens drei Streifen bereitgestellt.

Required devices:

• The tester used was a device capable of separating a bond with a deduction angle of 180 ° and a terminal speed of 300 mm / min at ± 2% accuracy. The tester had a backplate on which test strips were mounted to maintain a 180 ° angle during the test. Metal bearing weights created a pressure of 6.86 kPa (70 g / cm 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. Of each material sample, at least three strips were provided.

Conditions: The test strips were stored for 20 hours at 23 ± 2 ° C between two flat metal plates under a pressure of 6.86 kPa (70 g / cm ² ). This creates a good contact between release material and adhesive. After pressure bearing, the strips were removed between plates and conditioned for a minimum of four hours under standard conditions (23 ± 2 ° C and 50 ± 5% RH) prior to measurement.

• Jeder Teststreifen wurde mit seiner vollen Fläche mit doppelseitigem Klebeband auf der Testplatte befestigt, so dass ein Abzugtest bei 180° erfolgte. Dabei wurde das Etiketten- vom Trennmaterial abgelöst. Die Klemmengeschwindigkeit wurde auf 300 mm/min eingestellt. Während der Prüfung wurde die Kraft fünfmal in Abstanden von 10 mm im mittleren Bereich des Streifens abgelesen. Aus diesen fünf Messungen ergibt sich der Durchschnittswert für jeden Streifen.

test procedure:

• Each test strip was attached to its full face with double-sided tape on the test plate so that a 180 ° peel test was performed. The label was removed from the release material. The clamp speed was set to 300 mm / min. During the test, the force was read five times at 10 mm intervals in the middle area of the strip. From these five measurements, the average value for each strip is obtained.

• Die Trennkraft bei langsamem Abzug wird als Mittelwert in Centinewton pro 50 mm (cN/50 mm) angegeben.
• Die Bestimmung der Trennwerte wurde mit zwei verschiedenen Klebstoffen (tesa 7475 und 7476) durchgeführt.

Results:

• The release force on slow draw is given as the mean in centinewtons per 50 mm (cN / 50 mm).
• The determination of the release values was carried out with two different adhesives (tesa 7475 and 7476).

Silicone application determination _

This test method allows a fast and accurate determination of the amount of silicone in a release coating with minimal sample preparation. The release coating is on a backing material such as is used to make release liners for self-adhesive labels or other release applications.

• Das Silikonauftragsgewicht wird als die Menge ausgehärteter Silikontrennbeschichtung pro Standardflache eines Trägermaterials definiert. Es wird in Gramm pro Quadratmeter (g/m²) angegeben.

Definition:

• The silicone application weight is defined as the amount of cured silicone release coating per standard area of support material. It is expressed in grams per square meter (g / m ² ).

• Die Methode beruht auf der Analyse der Röntgenfluoreszenz (RFA).

Equipment:

• The method is based on the analysis of X-ray fluorescence (RFA).

• Eine geeignete Anzahl von Prüfkörpern wurde einem repräsentativen Muster des zu untersuchenden Abdeckmaterials eines Laminats oder silikonisierten Trennmaterials entnommen. Eine Verunreinigung der Proben, vor allem mit silikonhaltigem Material wurde vermieden. Die Muster wurden auf ein trockenes, sauberes Blatt Seidenpapierpapier ausgeschnitten oder -gestanzt und dann nur mit einer Pinzette am Rand angefasst. Die Proben mussten nicht vorkonditioniert werden.

Material samples:

• An appropriate number of test specimens were taken from a representative sample of the cover material of a laminate or siliconized release material to be tested. Contamination of the samples, especially with silicone-containing material was avoided. The samples were cut or punched on a dry, clean sheet of tissue paper and then touched with tweezers on the edge. The samples did not have to be preconditioned.

• Die Proben wurden dann in das Gerät eingeführt und in eine spezielle Messkammer bewegt, wo die Bestrahlung mit der primären Röntgenstrahlung die Emission der sekundären Röntgenfluoreszenz, die für das untersuchte Element, in diesem Fall Silizium, charakteristisch ist, hervorruft. Nach einer Zeit von 30 bis 60 Sekunden war die Messung abgeschlossen und das Programm gab das Silikonauftragsgewicht direkt in g/m² Silikon an (siehe auch "Ergebnisse" unten). Die RFA-Technik ist eine relative und keine absolute Methode. Deshalb musste eine Kalibrierungskurve erstellt werden, bevor Routineanalysen durchgeführt werden konnten. Die Kalibrierung erfordert das Einrichten des Geräts zur Registrierung von Silizium-Röntgenstrahlung und anschließend die Messung bekannter Standards. Es muss aber nachdrücklich betont werden, dass jedes Trägermaterial eine unterschiedliche Untergrundstrahlung liefert. Es ist deshalb zur Erstellung der Kalibrierungskurve nicht nur notwendig, eine Reihe von unterschiedlichen Silikonauftragsgewichten zu messen, sondern dies auch für jedes Trägermaterial getrennt durchzuführen.

test procedure:

• The samples were then introduced into the apparatus and moved to a special measuring chamber where the exposure to the primary x-ray radiation causes the emission of secondary x-ray fluorescence characteristic of the element under investigation, in this case silicon. After a period of 30 to 60 seconds, the measurement was completed and the program reported the silicone application weight directly in g / m ² silicone (see also "Results" below). The RFA technique is a relative and not an absolute method. Therefore, a calibration curve had to be created before routine analysis could be performed. Calibration requires setting up the device to register silicon X-rays and then measuring known standards. It must be emphasized, however, that each substrate provides a different background radiation. Therefore, to make the calibration curve, it is not only necessary to measure a number of different silicone coating weights, but to do so separately for each substrate.

• Die Ergebnisse werden direkt in Gramm Silikon pro Quadratmeter angegeben. Es ist zu beachten, dass hier bereits von elementarem Silizium auf Silikon umgerechnet wurde.

Results:

• The results are given directly in grams of silicone per square meter. It should be noted that this has already been converted from elemental silicon to silicone.

Several samples were taken from a representative coated substrate to detect potential variations across the web width. In general, the longer the measuring time, the higher the measuring accuracy. Accuracies are on the order of ± 0.05 to ± 0.01 (g / m ² ).

Methylene blue test

• Dieses Prüfverfahren beschreibt eine Methode zur Bewertung der Deckungsqualität von Silikonbeschichtungen. Diese Prüfung kann nur mit Papiersubstraten durchgeführt werden, die mit der verwendeten Farbprüflösung angefärbt werden können.

Scope of application:

• This test method describes a method for evaluating the coverage quality of silicone coatings. This test can only be performed on paper substrates that can be stained with the color proofing solution used.

• Die Beschichtungsqualität wird durch Prüfung mit Methylenblau als Farbstoff bewertet. Es wird eine bestimmte Menge der Farbflüssigkeit für eine begrenzte Zeit auf den silikonbeschichteten Liner aufgebracht; danach wird das Färbemittel abgespült oder abgewischt, und der Liner wird getrocknet. Die Beschichtungsqualität wird optisch ausgewertet.

Definition:

• The coating quality is evaluated by testing with methylene blue as a dye. A certain amount of the colored liquid is applied to the silicone-coated liner for a limited time; after that, the colorant is rinsed or wiped off, and the liner is dried. The coating quality is evaluated optically.

1. a. Eine 1 Liter Polyethylenflasche wurde auf eine elektronische Waage gestellt.
2. b. Es wurden 5 Gramm Methylenblau in das Gefäß eingewogen.
3. c. 1 Liter destilliertes Wasser wurde mithilfe eines Messzylinders zugeben. Das Gefäß wurde verschlossen und intensiv geschüttelt, um den Farbstoff zu lösen.

Method:

1. a. A 1 liter polyethylene bottle was placed on an electronic balance.
2. b. 5 grams of methylene blue were weighed into the vessel.
3. c. 1 liter of distilled water was added using a graduated cylinder. The vessel was sealed and shaken vigorously to dissolve the dye.

1. 1. Cobb-Tester mit Ring mit einem Durchmesser von etwa 11,5 cm.
2. 2. Stoppuhr mit Rückwärtslauf und Alarmfunktion.
3. 3. Kleiner Behälter mit 200 ml-Markierung.
4. 4. Methylenblaulösung.
5. 5. Saugfähiges Reinigungspapier.

test equipment:

1. 1. Cobb tester with ring with a diameter of about 11.5 cm.
2. 2nd stopwatch with reverse and alarm function.
3. 3. Small container with 200 ml mark.
4. 4. Methylene blue solution.
5. 5. Absorbent cleaning paper.

• Es wurden mehrere Proben des Trennmaterials bewertet. Wenn diese Proben von einer bestimmten Stelle der Papierbahn stammten, wurde dies zu Referenzzwecken entsprechend notiert.

Material samples:

• Several samples of the release material were evaluated. If these samples came from a specific location on the paper web, this was noted accordingly for reference purposes.

1. 1. Ausschneiden einer 14 cm x 14 cm großen Probe des Trennpapiers. Es dürfen sich im Schutzpapier keine Löcher oder Perforationen befinden.
2. 2. Die Silikonoberfläche wurde vor der Prüfung nicht berührt, da sonst die Anfärbung verfälscht werden kann. Einlegen der Trennpapierprobe mit der Silikonseite nach oben unter den Prüfring des Cobb-Testers.
3. 3. Festklemmen des Rings, damit das Färbemittel während der Prüfung nicht austritt.
4. 4. Füllen von 200 ml der Farblösung in den Cobb-Tester, und Starten der Stoppuhr. Die Einwirkzeit betrug 120 Sekunden.
5. 5. Ablassen der Farbemittellösung nach der für die Prüfung gewählten Einwirkzeit, Ablösen des Prüfrings, und Abheben desselben von der Probe.
6. 6. Abtupfen des Prüfmusters mit Saugpapier, und Trocknen der Probe für weitere fünf Minuten. Ist das Muster getrocknet, kann es untersucht bzw. vermessen werden.

staining test:

1. 1. Cut out a 14 cm x 14 cm sample of the release paper. There must be no holes or perforations in the backing paper.
2. 2. The silicone surface was not touched before the test, otherwise the staining can be falsified. Place the release paper sample with the silicone side up under the test ring of the Cobb tester.
3. 3. Clamp the ring to prevent the dye from leaking out during the test.
4. 4. Fill 200 ml of the dye solution into the Cobb tester, and start the stopwatch. The exposure time was 120 seconds.
5. 5. Discharge of the colorant solution after the test time selected for the test, detachment of the test ring, and lifting it from the sample.
6. 6. Dab the test sample with absorbent paper and dry the sample for another five minutes. Once the pattern has dried, it can be examined or measured.

• Die subjektive Beurteilung des Musters berücksichtigt die generelle Anfärbung des Liners und die Penetration der Farblösung in das Basispapier. Bei einer guten Beschichtungsqualität sollte keine Penetration sichtbar sein. Je sichtbarer und intensiver die Anfärbung ist, desto größer ist das Risiko, dass der Klebstoff durch die Silikonbeschichtung zum Basispapier wandert und somit Trennwertprobleme verursachen kann (eventuell Spendeprobleme bei Etiketten oder Trennwertprobleme bei Klebebändern, etc.).

Results:

• The subjective evaluation of the pattern takes into account the general staining of the liner and the penetration of the dye solution into the base paper. With a good coating quality, no penetration should be visible. The more visible and intense the staining, the greater is the risk that the adhesive will migrate through the silicone coating to the base paper and thus cause release problems (possibly label dispensing problems or adhesive tape release problems, etc.).

The staining was rated on a scale from + to ++++, where ++++ represents a complete staining of the base paper, as in the base paper, and + a perfect color test with no apparent penetration.

The methods described above can also be found in the "FINAT TECHNISCHES HANDBUCH, Testmethoden" 9th edition, August 2014 (FINAT, World-wide Association for self-adhesive labels and related products, The Hague, Netherlands).

test results:

Table 6: Results of separation value determination and storage stability silicone order cutpoints cutpoints Write power% 60 ° C / 50% RH No. recipe (tesa 7475) (tesa 7476) Acrylatband Kautschukband Technomelt PS8746 Collano L1 945 (g / m ² ) CN / in CN / in 1 week. 2 weeks. 4 weeks. 1 week. 2 weeks. 4 weeks. 1. Rec.1a (BPA and PCC) 0.84 splinted - - - n.b., blocked - - - Second Rec.1a (BPA and PCC) 1.34 509 355 - - - - - - Third Rec.1a (BPA and PCC) 1.05 966 464 - - - - - - 4th Rez.1b (BPA and kaolin) 0.75 35 - - - 37.4 - - - 5th Rez.1b (BPA and kaolin) 1.45 5 46 - - - - - - 6th Rez.1b (BPA and kaolin) 1.10 6 51 - - - - - - 7th Ricoh Topcoat 150 UTB 0.78 9 - - - 98.7 - - - 8th. Ricoh Topcoat 150 UTB 0.54 11 - 100.0 101.7 99.4 97.3 99.5 36.6 9th Rez.2a (NKK 1304 and kaolin) 0.69 16 169 86.3 80.1 75.3 73.2 75.4 10.6 10th Rez.2a (NKK 1304 and kaolin) 0.82 9 - - - 76.3 - - - 11th Rez.2b (PF201 and kaolin) 0.68 12 156 69.2 54.8 26.0 54.9 26.1 9.2 12th Rez.3 (PF201 and kaolin) 0.76 203 - - - 19.1 - - - BPA: Bisphenol A
PCC: precipitated CaCO ₃
NKK 1304: N- [2- (3-phenylureido) phenyl] benzenesulfonamide
PF201: N- (p-toluenesulfonyl) -N '- (3- (p-toluenesulfonyl-oxy-phenyl) -urea

The formulations 7 and 8 correspond to a self-adhesive thermosensitive recording material on a carrier material (TopCoat) according to the prior art (manufacturer Fa. Ricoh, paper type 150 UTB). The formulations 9 to 12 are embodiments of the invention. Table 7: Results Methylene blue test No. recipe Methylene blue staining 1 Rec.1a (BPA and PCC) ++++ 2 Rec.1a (BPA and PCC) +++ 3 Rec.1a (BPA and PCC) ++++ 4 Rez.1b (BPA and kaolin) ++ 5 Rez.1b (BPA and kaolin) + 6 Rez.1b (BPA and kaolin) + 7 Ricoh Topcoat 150 UTB + 8th Ricoh Topcoat 150 UTB + 9 Rez.2a (NKK 1304 and kaolin) + 10 Rez.2a (NKK 1304 and kaolin) + 11 Rez.2b (PF201 and kaolin) + 12 Rez.3 (PF201 and kaolin) + (++++) = distinct blue coloration, (+++) = blue coloration, (++) = slight blue coloration, (+) = barely visible blue coloration
BPA: Bisphenol A
PCC: Precipitated CaCO ₃
NKK 1304: N- [2- (3-phenylureido) phenyl] benzenesulfonamide
PF201: N- (p-toluenesulfonyl) -N '- (3- (p-toluenesulfonyl-oxy-phenyl) -urea

It can be seen from Tables 6 and 7 that the heat-sensitive recording material according to the invention has very good release values with medium silicone coating, very good writing performance even after storage for 4 weeks at 60 ° C. and 50% relative humidity. Moisture shows and is very easy siliconisable, which is reflected in the very low blue color after the methylene blue test.

Claims (17)

Self-adhesive thermosensitive recording material comprising a support substrate,
a heat-sensitive color-forming layer applied on one side of the support substrate, comprising at least one non-phenolic color developer and
at least one color former,
a siliconized layer on top of the heat-sensitive color-forming layer applied on the support substrate, as well as
an adhesive layer on the side of the carrier substrate facing away from the heat-sensitive color-forming layer,
characterized in that the siliconized layer rests directly on the heat-sensitive color-forming layer. Self-adhesive heat-sensitive recording material according to claim 1, characterized in that the heat-sensitive color-forming layer additionally contains at least one platelet-shaped pigment, preferably a kaolin, and more preferably a prankkaolin. Self-adhesive heat-sensitive recording material according to at least one of the preceding claims, characterized in that the carrier substrate is paper, synthetic paper and / or a plastic film. Self-adhesive thermosensitive recording material according to at least one of the preceding claims, characterized in that the self-adhesive thermosensitive recording material is a strapless self-adhesive thermosensitive recording material. Self-adhesive thermosensitive recording material according to at least one of the preceding claims, characterized in that the at least one color developer sulfonyl urea and / or a compound of the formula (I)

wherein Ar ₁ and Ar _{2 are} a phenyl radical and / or a C ₁ -C ₄ alkyl-substituted phenyl radical. Self-adhesive thermosensitive recording material according to claim 5, characterized in that the sulfonyl urea N '- (p-toluenesulfonyl) -N'-phenyl-urea, N- (p-toluenesulfonyl) -N'-3- (p-toluenesulphonyl-oxy phenyl) urea, and / or 4,4'-bis (p-tolylsulfonylureido) -diphenylmethane. Self-adhesive thermosensitive recording material according to at least one of the preceding claims, characterized in that the at least one color former is a triphenylmethane-type, fluoran-type, azaphthalide-type and / or fluorene-type, preferably fluoran-type, dye. Self-adhesive heat-sensitive recording material according to at least one of the preceding claims, characterized in that the siliconized layer is based on at least one poly (organo) siloxane, preferably an acrylic-poly (organo) siloxane. Self-adhesive thermosensitive recording material according to claim 8, characterized in that the siliconized layer additionally contains an initiator, preferably a photoinitiator. Self-adhesive thermosensitive recording material according to at least one of the preceding claims, characterized in that the adhesive layer comprises at least one hot melt adhesive, preferably based on rubber and / or acrylate. Self-adhesive thermosensitive recording material according to at least one of claims 2 to 10, characterized in that the at least one platelet-shaped pigment in an amount of about 5 to about 60 wt .-%, preferably from about 15 to about 55 wt .-%, based on the total solids content of the heat-sensitive layer. A process for producing a pressure-sensitive thermosensitive recording material according to at least one of the preceding claims, characterized by applying and drying an aqueous suspension containing the starting materials of the thermosensitive coloring layer to a support substrate, then siliconizing the thermosensitive coloring layer and then thermosetting on the thermosensitive color forming layer Layer facing away from the carrier substrate, an adhesive layer is applied. A self-adhesive thermosensitive recording material obtainable according to the method of claim 12. A process for the production of a semifinished product, characterized in that on a carrier substrate, an aqueous suspension containing the starting materials of the heat-sensitive color-forming layer, comprising at least one color developer and at least one color former, is applied and dried. Semi-finished product obtainable according to the method of claim 14. Use of the semifinished product according to claim 15 for the production of a self-adhesive heat-sensitive recording material according to at least one of the preceding claims 1 to 13. Use of a self-adhesive heat-sensitive recording material according to at least one of the preceding claims 1 to 13 as a label.