DE10259457B4 - Method for applying pressure-sensitive adhesive tapes to rough and / or uneven surfaces - Google Patents

Abstract

A method for applying pressure-sensitive adhesive tapes to rough and / or uneven surfaces, characterized in that a bi- or multi-functional aziridine is applied to the rough and / or uneven surfaces as a reactive primer, and above a pressure-sensitive adhesive tape with a soft, flowable, crosslinkable pressure-sensitive adhesive wherein the PSA is based on a comonomer composition containing copolymerizable monomers having one or more functional groups suitable for a crosslinking reaction by bi- or multi-functional aziridines.

Description

The The invention relates to a method for applying pressure-sensitive adhesive tapes rough and / or uneven surfaces.

In industry are hot melt processes (Hotmelt process) with solvent-free Coating technology for the production of pressure-sensitive adhesives from growing Importance, as the environmental requirements are getting bigger and the prices for solvents continue to rise. In addition, the quality of the pressure-sensitive adhesive tapes becomes clear increased. Even pressure-sensitive tapes with a high level of application can be produced without bladder inclusions. This has always been one of the core problems of the conventional one Solvent coating. Farther high coating speeds can be achieved with the hotmelt technology achieve.

The DE 41 19 034 A describes a method in which a self-adhesive can be applied to a surface by means of a primer. The JP 07 133 467 A discloses an adhesive material, wherein first an attachment of an adhesive acrylate layer is carried out by means of a primer layer on a substrate. Both documents refer to the improvement of the adhesion of self-adhesive to substrates, by the use of crosslinkers, the adhesion-promoting property of the primer can be improved. Crosslinking of the adhesives by means of the primer is not described.

For industrial Applications are particularly suitable for acrylic PSAs. polyacrylates are very weather-resistant and can be used in a wide temperature range. To a sufficient high cohesion Acrylic hotmelts are made with UV radiation or electron beams networked. Both methods have advantages and disadvantages in terms of networking of resin-blended polyacrylates, high mass orders, web speed etc. on. Nevertheless, there are some applications that deal with both Can not realize networking mechanisms.

A industrial application is z. As the bonding of uneven surfaces with a paint film. Here takes over the PSA is responsible for the paint film on the substrate bind, but at the same time has to compensate for the unevenness of the substrate, with it to the outside the paint leaves a flat impression. To compensate for the surface roughness Very soft adhesives are used, which can easily flow. These known soft, flowable adhesives However, they have the disadvantage that they continue even after the bonding flow, so that the film flows away in the direction of gravity, ie on the substrate later shifts.

task The invention is therefore to make it possible on rough and / or uneven surfaces non-stickable pressure-sensitive adhesive tapes applied.

The The object of the invention is achieved by a method in which applied to the rough and / or uneven surfaces a reactive primer who is one for the crosslinking of the pressure-sensitive adhesive of the pressure-sensitive adhesive tape is suitable Contains agent, and above a pressure-sensitive adhesive tape with a soft, flowable, crosslinkable PSA.

The uneven surface is provided with a reactive primer, which after bonding diffused with the pressure-sensitive adhesive tape into the PSA and the PSA slowly cross-linked. The pressure-sensitive adhesive tape consists of a carrier and a soft, flowable PSA, preferably with a high level of application that reduces the unevenness slow flow compensated. The Auffließvorgang can still be supported by a soft foam carrier.

According to the invention as Reactive primer used a bi- or multi-functional aziridine, being in the basic mixture for the PSA copolymerizable monomers with one or more functional groups are included, resulting in a crosslinking reaction by bi- or multi-functional aziridines are suitable.

By Diffusion of the reactive primer into the PSA becomes the soft Adhesive crosslinked and thus increases the cohesion. The pressure-sensitive adhesive tape bonding let yourself thus also for Applications with higher cohesion deploy. To the carrier material Be the unevenness of the substrate by the pressure-sensitive adhesive balanced.

The Invention is thus for the bonding of uneven surfaces with a paint film very well suited.

• a) Acrylsäure und Methacrylsäure-Derivate mit einem Anteil von 70 bis 99,5 Gewichtsprozent, CH₂ = C(R₁)(COOR₂) (I)wobei R₁ = H oder CH₃ ist und R₂ = eine Alkylkette mit 2 bis 20 C-Atomen;
• b) copolymerisierbare olefinisch ungesättigte Monomere mit funktionellen Gruppen mit einem Gewichtsanteil von 0 bis 30 Gewichtsprozent;
• c) copolymerisierbare Monomere mit einer oder mehreren funktionellen Gruppen, die zu einer Vernetzungsreaktion via bi- oder multifunktionellen Aziridinen geeignet sind.

Crosslinked polyacrylates which comprise a polymer based on the following comonomer composition are used as the pressure-sensitive adhesive:

• a) acrylic acid and methacrylic acid derivatives in a proportion of 70 to 99.5 percent by weight, CH ₂ = C (R ₁ ) (COOR ₂ ) (I) wherein R ₁ = H or CH ₃ and R ₂ = an alkyl chain having 2 to 20 C atoms;
• b) copolymerizable olefinically unsaturated monomers having functional groups in a weight proportion of 0 to 30 weight percent;
• c) copolymerizable monomers having one or more functional groups which are suitable for a crosslinking reaction via bi- or multi-functional aziridines.

The Composition of the corresponding comonomers is chosen so that the resulting PSAs according to D. Satas [Handbook of Pressure Sensitive Adhesive Technology, 1989, published by VAN NOSTRAND REINHOLD, New York] have pressure-sensitive adhesive properties and moreover easy on uneven surfaces auffließen.

In a preferred embodiment are PSAs having a dynamic flow viscosity of <100,000 Pa · s at 0.1 rad / s and room temperature, in a more preferred Dimensioning of <50,000 Pa · s at 0.1 rad / s and room temperature, in a very preferred design of <10,000 Pa · s 0.1 rad / s and room temperature. For determining the flow viscosity of PSAs The rheology (DMA, test D) is particularly suitable.

Of the Reactive primer is preferably used at a weight fraction of 0.5 used up to 10%. The weight proportions refer to the crosslinking PSA. The proportion of reactive component in Reactive primer should not be below 25% by weight to one enough high reactivity across from to obtain the PSA. In a preferred embodiment, the reactive fraction is 50% by weight or greater.

The reactive primer is applied to the rough surface with a mass application of 1 to 50 g / m ² , preferably 2 to 25 g / m ² .

When Monomers for the PSA are preferably Acrylmomonere with alkyl groups consisting of 4 to 14 carbon atoms, in particular 4 to 9 used. Examples of this are n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, n-nonyl acrylate and their branched isomers, such as z. B. 2-ethylhexyl acrylate. Other vinyl monomers in combination can be used with acrylate monomers include vinyl esters, Vinyl ethers, vinyl halides, vinylidene halides, and nitriles of ethylenically unsaturated Hydrocarbons. Examples of these are vinyl acetate, N-vinylformamide, vinylpyridine, Acrylamides, ethyl vinyl ether, vinyl chloride, vinylidene chloride, acrylonitrile, maleic anhydride and styrene.

in the In view of this invention, comonomers should definitely be included which definitely react with multifunctional aziridines. These monomers contain hydroxy, amine, carboxylic acid and Amide groups. Examples of this are monomers, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate and their methacrylates, Acrylic acid, methacrylic acid, t-butylaminoethyl methacrylate, acrylamides and methacrylamides as well Allyl alcohol. Their weight content is between 0.5 and 10%, in particular between 1 and 6%.

The Reaction can be achieved by addition of a catalyst, such as. B. dibutyltin dilaurate, be accelerated.

To prepare the polyacrylate PSAs, a free-radical polymerization is carried out. The polymerization for the preparation of the PSA can be carried out in polymerization reactors, which are generally provided with a stirrer, several feed vessels, reflux condenser, heating and cooling and are equipped for working under N ₂ atmosphere and overpressure.

The radical polymerization can occur in the presence of an organic Solvent, be carried out in water or in substance. It is preferred so little solvent as possible used. The polymerization time is - depending on the conversion and temperature - between 6 and 48 h.

In the solvent polymerization, the solvents used are esters of saturated carboxylic acids (such as ethyl acetate), aliphatic hydrocarbons (such as n-hexane or n-heptane), ketones (such as acetone or methylethyl ketone), petroleum spirit or mixtures of these solvents used. The polymerization initiators used are customary radical-forming compounds, such as, for example, peroxides and azo compounds. Initiator mixtures can also be used. In the polymerization, thiols can also be used as further regulators for lowering the molecular weight and reducing the polydispersity. As so-called polymerization regulators z. As alcohols and ethers are used.

To the polymerization of the PSA from solution to a carrier material coated. The polymerization medium is under reduced pressure removed, this process at elevated temperatures, for example in the range of 80 to 150 ° C carried out becomes. The polymers can then in solvent-free Condition, in particular as a hotmelt PSA, used and coated become. In some cases It is also advantageous to produce the polymers in substance and to process.

The blends described in this invention may be further modified to achieve the optimum adhesive properties. To increase the cohesion, crosslinkers may be added prior to crosslinking. Furthermore, the polymers for the preparation of PSAs are optionally mixed with resins. Examples of suitable resins are terpene, terpene phenolic resins, C ₅ and C ₉ hydrocarbon resins, pinene, indene and rosin resins alone and also in combination with one another. In principle, however, it is possible to use all resins soluble in the corresponding polyacrylate, in particular reference is made to all aliphatic, aromatic, alkylaromatic hydrocarbon resins, hydrocarbon resins based on pure monomers, hydrogenated hydrocarbon resins, functional hydrocarbon resins and natural resins.

Furthermore, various fillers (for example, carbon black, TiO ₂ , solid or hollow spheres of glass or other materials, nucleating agents), blowing agents, compounding agents and / or anti-aging agents can be added.

Plasticizers are added to improve the Auffließverhaltens the PSA. For acrylate hotmelts commercial phosphates / polyphosphates are used. Some examples are z. Santicizer 141 ^™ from Monsanto, Hostaflam OP 910 ^™ and Hostaflam TP OP 550 ^™ from Clariant, Fyroflex RDP ^™ from Akzo Chemical and Reofos 65 ^™ or 90 ^™ from Great Lake Chemicals. The list should not be conclusive.

A refinement which makes the process according to the invention particularly favorable for the production of, for example, pressure-sensitive adhesive tapes is characterized in that the pressure-sensitive adhesive is processed further out of the melt and that it is preferably applied to a support with a mass application of greater than 50 g / m ² ,

When Support material for example tapes, In this case, it is possible to use the materials familiar to the person skilled in the art, such as films (Polyester, PET, PE, PP, BOPP, PVC), nonwovens, foams, fabrics and fabric films and release paper (glassine, HDPE, LDPE). In another embodiment The invention uses a lacquered film.

For bonding, the surface is provided with a primer containing the reactive primer, which diffuses slowly into the PSA after bonding. The precursor contains as cross-linking substance a bi- or multi-functional aziridine. An example of a multifunctional aziridine is Crosslinker CX-100 ^™ from ICI. The reactive primer is applied conventionally from solution or as a pure substance via a doctor blade or a bar to the substrate.

The reactive primer is applied undiluted, in solvent or in dispersion or in the transfer process with the aid of a coated support, for. As a transfer tape, applied to the surface. For diluting the difunctional or polyfunctional aziridines, it is preferable to use an aqueous polyacrylate dispersion, such as e.g. Neocryl A-45 ^™ from Zeneca. The dispersion binds the reactive primer and thus facilitates the handling of the Beschikqhtung the substrate via smear or using the transfer technique. In addition, with the mixing ratio of dispersion to reactive primer, the amount to be diffused into the PSA can be controlled.

The Crosslinking of the PSA after Adhesive Tape Adhesion extends at room temperature. For acceleration, the Substratverklebung be heated, being 120 ° C not exceeded should be.

The Method involves the use of one common as such Polymer crosslinker as a reactive primer for the attachment of a pressure-sensitive adhesive tape with a soft, flowable, crosslinkable Pressure-sensitive adhesive on a rough and / or uneven surface.

It can be a sales unit made of a pressure-sensitive adhesive tape and a reactive primer Tobe offered. This sales unit consists of two separate Ingredients, a pressure sensitive adhesive tape and a reactive primer, the a crosslinking agent for the soft flowable PSA of the pressure-sensitive adhesive tape.

Of the Reactive primer is preferably in the form of a solution or as a dispersion in a suitable packaging. In presence of the reactive primer in liquid This form is first set up by the user of the sales unit the rough and / or uneven surface, on which the pressure-sensitive adhesive tape is to be applied, coated, d. H. brushed or rolled. In a further step will be then the pressure-sensitive adhesive tape applied. Due to the soft, flowable PSA of pressure-sensitive adhesive tape optimally adapts to contours of a surface at. the reactive primer diffuses into the PSA and it comes to crosslinking or gelling of the PSA, the on this way is solidified so that they no longer "wander" or shift on the substrate can be.

In a further preferred embodiment invention, the reactive primer is applied to a transfer belt. By this embodiment the application of the reactive primer to the surface is facilitated.

The Crosslinking of the pressure-sensitive adhesive after application of the pressure-sensitive adhesive tape usually runs at room temperature. For acceleration, the Substratverklebung be heated, being 120 ° C not exceeded should be.

in the Following, the invention will be explained in more detail by examples.

EXAMPLES

In dependence from the desired ones Adhesive properties of the PSA will be a selection met with acrylic and vinyl monomers.

test methods

The following Test methods were applied to the adhesive properties of the PSAs produced.

Determination of Gel Content (Test A):

The careful dried solvent-free Adhesive samples are made into a polyethylene nonwoven bag (Tyvek fleece) shrink wrapped. From the difference in sample weights before extraction and after The extraction by toluene is the gel value, that is not in Toluene soluble Weight fraction of the polymer determined.

Shear strength (Test B):

One 13 mm wide strip of tape was applied to a smooth steel surface, the was cleaned three times with acetone and once with isopropanol applied. The order surface was 20 mm × 13 mm (length × width). Subsequently With a weight of 2 kg, the pressure sensitive adhesive tape was applied four times to the steel beams pressed. At room temperature, a weight of 1 kg was applied to the pressure-sensitive adhesive tape attached and the time to drop the weight measured. The measured shear times are given in minutes and correspond to the mean of three measurements.

180 ° bond strength test (Test C):

A 20 mm wide strip of PSA encapsulated PSA was applied to steel plates. The pressure-sensitive adhesive strip was pressed onto the substrate twice with a 2 kg weight. The pressure-sensitive adhesive tape was then immediately removed from the substrate at 300 mm / min and at a 180 ° angle. The steel plates were washed twice with acetone and once with isopropanol. For measurements on the PE substrate, only new plates were used. The measurement results are given in N / cm and are averaged out of three measurements. All measurements were taken at room temperature under air-conditioned Conditions performed.

Dynamic-Mechanical Analysis, DMA (Test D)

The Measurements were taken with the device Dynamic Stress Rheometer performed by Rheometrics. At 25 ° C was the mechanical loss factor tan δ in dependence the frequency is tracked at an interval of 0.1 to 100 rad / s. It was measured with parallel plate arrangement.

Examined samples

The samples used for the experiments were prepared as follows:
The polymers were prepared conventionally via a free radical polymerization; the average molecular weight M _w was about 800,000 g / mol after GPC measurement.

Gel permeation chromatography GPC

The determination of the average molecular weight M _w and the polydispersity PD was carried out by the company Polymer Standards Service in Mainz. The eluent used was THF containing 0.1% by volume of trifluoroacetic acid. The measurement was carried out at 25 ° C. The precolumn used was PSS-SDV, 5 μ, 10 ³ Å, ID 8.0 mm × 50 mm. For separation, the columns PSS-SDV, 5 μ, 10 ³ and 10 ⁵ and 10 ⁶ , each with ID 8.0 mm × 300 mm were used. The sample concentration was 4 g / l, the flow rate 1.0 ml per minute. It was measured against PMMA standards.

Preparation of the reactive primer:

50 parts by weight of Crosslinker CX-100 ^™ (from ICI) were intensively mixed with 50 parts by weight of Neocryl A-45 ^™ (Zeneca) with vigorous stirring and then coated at 4 g / m ² onto a steel plate and a siliconized release paper. The smeared primer was dried at room temperature.

Example 1:

A reactor conventional for radical polymerizations was charged with 0.6 kg of acrylic acid, 0.400 kg of maleic anhydride, 2.4 kg of N-tert-butylacrylamide, 36.6 kg of 2-ethylhexyl acrylate and 26.6 kg of acetone / isopropanol (97: 3) , After nitrogen gas was passed through the reaction solution with stirring for 45 minutes, the reactor was heated to 58 ° C and 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)] was added thereto. Subsequently, the outer heating bath was heated to 75 ° C and the reaction was carried out constantly at this external temperature. After 2 h, the next addition of 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)]. After 4 and 8 h each with 20 kg of acetone / isopropanol mixture (97: 3) was diluted. After a reaction time of 36 hours, the polymerization was stopped and the reaction vessel was cooled to room temperature. To prepare the pressure-sensitive adhesive, the polymer was mixed in solution with 9 parts by weight of Foral 85 ^™ rosin resin (Hercules), 18 parts by weight of Norsolene M1080 ^™ hydrocarbon resin (Cray Valley) and 8 parts of Great Lake Chemicals phosphate Reofos 65 ^™ . The mixture was freed from the solvent under reduced pressure and then coated from the melt through a slot die from Pröls at 115 ° C. with 150 g / m ² onto a corona-treated 25 μm thick PET film.

to Bonding the pressure-sensitive adhesive tape to that with the reactive primer steel plate with a 2 kg weight and pressed then after one day and after seven days according to the test method B and C checked. For comparison, a sample was also stored at 50 ° C for one day and also tested according to test methods B and C.

to Determination of the gel value, the pressure-sensitive adhesive tape was on with the Applied reactive primer-providing siliconized release paper and after one day storage at room temperature and 50 ° C and after tested for seven days at room temperature according to the test method A.

Example 2 (reference example):

It The procedure was analogous to Example 1. For testing with the test methods A, B and C was the corresponding pressure-sensitive adhesive tape of Example 1 on siliconized release paper and on steel - each without reactive primer - laminated.

The results are shown in the following Table 1: Table 1 example storage KK steel [N / cm] SSZ 10 N [min] Gel [%] 1 1d, RT 10.0 85 33 1 1d, 50 ° C 9.7 220 52 1 7d, RT 9.4 245 51 2 1d, RT 10.5 1 0 2 1d, 50 ° C 10.2 1 0 2 7d, RT 12.6 1 0

Of the Comparison of Examples 1 and 2 shows that by the diffusing Reactive primer, the PSA is crosslinked. After a day lies the gel value at 33% after seven days at over 50%. The reaction can be accelerated by the action of temperature. With the growing Gelwert also increases the cohesion and thus also the shear strength of the pressure-sensitive adhesive tape. The adhesive forces on Steel hardly differ, because in the adhesion measurement (see Example 2) breaks through the low cohesion very quickly cohesively.

Around demonstrating universal applicability became further examples according to the inventive method bonded.

Example 3:

A reactor conventional for radical polymerizations was charged with 1.2 kg of acrylic acid, 0.400 kg of maleic anhydride, 1.2 kg of N-tert-butylacrylamide, 37.2 kg of 2-ethylhexyl acrylate and 26.6 kg of acetone / isopropanol (97: 3) , After nitrogen gas was passed through the reaction solution with stirring for 45 minutes, the reactor was heated to 58 ° C and 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)] was added thereto. Subsequently, the outer heating bath was heated to 75 ° C and the reaction was carried out constantly at this external temperature. After 2 h, the next addition of 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)]. After 4 and 8 h each with 20 kg of acetone / isopropanol mixture (97: 3) was diluted. After a reaction time of 36 hours, the polymerization was stopped and the reaction vessel was cooled to room temperature. To prepare the pressure-sensitive adhesive, the polymer was mixed in solution with 9 parts by weight of Foral 85 ^™ rosin resin (Hercules), 18 parts by weight of Norsolene M1080 ^™ hydrocarbon resin (Cray Valley) and 6 parts by weight of Great Lake Chemicals phosphate Reofos 65 ^™ . The mixture was freed from the solvent under reduced pressure and then coated from the melt through a slot die from Pröls at 115 ° C. with 150 g / m ² onto a corona-treated 25 μm thick PET film.

to Bonding the pressure-sensitive adhesive tape to that with the reactive primer steel plate with a 2 kg weight and pressed then after one day and after seven days according to the test method B and C checked. For comparison, a sample was also stored at 50 ° C for one day and also tested according to test methods B and C.

to Determination of the gel value, the pressure-sensitive adhesive tape was on with the Applied reactive primer-providing siliconized release paper and after one day storage at room temperature and 50 ° C and after tested for seven days at room temperature according to the test method A.

Example 4 (reference example):

It The procedure was analogous to Example 1. For testing with the test methods A, B and C was the corresponding pressure-sensitive adhesive tape of Example 1 on siliconized release paper and on steel - each without reactive primer - laminated.

Example 5:

A reactor conventional for radical polymerizations was treated with 0.6 kg of acrylic acid, 0.400 kg of maleic anhydride, 3.2 kg of N-tert-butylacrylamide, 17.9 kg of 2-ethylhexyl acrylate, 17.9 kg of n-butyl acrylate and 26.6 kg of acetone / Isopropanol (97: 3). After nitrogen gas was passed through the reaction solution with stirring for 45 minutes, the reactor was heated to 58 ° C and 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)] was added thereto. Subsequently, the outer heating bath was heated to 75 ° C and the reaction was constant performed at this outdoor temperature. After 2 h, the next addition of 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)]. After 4 and 8 h each with 20 kg of acetone / isopropanol mixture (97: 3) was diluted. After a reaction time of 36 hours, the polymerization was stopped and the reaction vessel was cooled to room temperature. To prepare the pressure-sensitive adhesive, the polymer was mixed in solution with 9 parts by weight of Foral 85 ^™ rosin resin (Hercules), 18 parts by weight of Norsolene M1080 ^™ hydrocarbon resin (Cray Valley) and 6 parts by weight of Great Lake Chemicals phosphate Reofos 65 ^™ . The mixture was freed from the solvent under reduced pressure and then coated from the melt through a slot die from Pröls at 115 ° C. with 150 g / m ² onto a corona-treated 25 μm thick PET film.

to Bonding the pressure-sensitive adhesive tape to that with the reactive primer steel plate with a 2 kg weight and pressed then after one day and seven days after the test method B and C checked. For comparison, a sample was also stored at 50 ° C for one day and also after Test methods B and C were tested.

to Determination of the gel value, the pressure-sensitive adhesive tape was on with the Applied reactive primer-providing siliconized release paper and after one day storage at room temperature and 50 ° C and after tested for seven days at room temperature according to the test method A.

Example 6 (reference example):

It The procedure was analogous to Example 1. For testing with the test methods A, B and C was the corresponding pressure-sensitive adhesive tape of Example 1 on siliconized release paper and on steel - each without reactive primer - laminated.

Example 7:

A reactor conventional for radical polymerizations was reacted with 0.6 kg of acrylic acid, 0.400 kg of maleic anhydride, 3.2 kg of methyl acrylate, 17.9 kg of 2-ethylhexyl acrylate, 17.9 kg of n-butyl acrylate and 26.6 kg of acetone / isopropanol (97: 3) filled. After nitrogen gas was passed through the reaction solution with stirring for 45 minutes, the reactor was heated to 58 ° C and 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)] was added thereto. Subsequently, the outer heating bath was heated to 75 ° C and the reaction was carried out constantly at this external temperature. After 2 h, the next addition of 40 g of AIBN [2,2'-azobis (2-methylbutyronitrile)]. After 4 and 8 h each with 20 kg of acetone / isopropanol mixture (97: 3) was diluted. After a reaction time of 36 hours, the polymerization was stopped and the reaction vessel was cooled to room temperature. To prepare the pressure-sensitive adhesive, the polymer was mixed in solution with 9 parts by weight of Foral 85 ^™ rosin resin (Hercules), 18 parts by weight of Norsolene M1080 ^™ hydrocarbon resin (Cray Valley) and 6 parts by weight of Great Lake Chemicals phosphate Reofos 65 ^™ . The mixture was freed from the solvent under reduced pressure and then coated from the melt through a slot die from Pröls at 115 ° C. with 150 g / m ² onto a corona-treated 25 μm thick PET film.

to Bonding the pressure-sensitive adhesive tape to that with the reactive primer steel plate with a 2 kg weight and pressed then after one day and seven days after the test method B and C checked. For comparison, a sample was also stored at 50 ° C for one day and also after Test methods B and C were tested.

to Determination of the gel value, the pressure-sensitive adhesive tape was on with the Applied reactive primer-providing siliconized release paper and after one day storage at room temperature and 50 ° C and after tested for seven days at room temperature according to the test method A.

Example 8 (reference example):

It The procedure was analogous to Example 1. For testing with the test methods A, B and C was the corresponding pressure-sensitive adhesive tape of Example 1 on siliconized release paper and on steel - each without reactive primer - laminated.

The technical adhesive evaluations are shown in the following table (Table 2): Table 2 example storage KK steel [N / cm] SSZ 10 N [min] Gel [%] 3 1d, RT 9.7 90 35 3 1d, 50 ° C 9.1 215 52 3 7d, RT 9.5 275 51 4 1d, RT 11.6 1 0 4 1d, 50 ° C 12.0 1 0 4 7d, RT 11.5 1 0 5 1d, RT 10.9 105 32 5 1d, 50 ° C 10.3 250 55 5 7d, RT 10.3 240 53 6 1d, RT 12.2 1 0 6 1d, 50 ° C 11.9 1 0 6 7d, RT 12.4 1 0 7 1d, RT 11.0 75 35 7 1d, 50 ° C 10.4 185 56 7 7d, RT 11.1 205 52 8th 1d, RT 12.0 1 0 8th 1d, 50 ° C 11.8 1 0 8th 7d, RT 12.2 1 0

Of the Comparison of the examples shows that the diffusing reactive primer can be used universally in acrylate PSAs. So can z. As well as methyl acrylate and butyl acrylate as comonomers for polyacrylates be used. After one day, the gel values are around 35% after seven days at over 50%. The reaction can in turn be accelerated by the action of temperature become. With the increasing gel values, the cohesion and hence the shear strength of the pressure-sensitive adhesive tapes.

Claims (7)

A method for applying pressure-sensitive adhesive tapes to rough and / or uneven surfaces, characterized in that a bi- or multi-functional aziridine is applied to the rough and / or uneven surfaces as a reactive primer, and above a pressure-sensitive adhesive tape with a soft, flowable, crosslinkable pressure-sensitive adhesive wherein the PSA is based on a comonomer composition containing copolymerizable monomers having one or more functional groups suitable for a crosslinking reaction by bi- or multi-functional aziridines. Method according to claim 1, characterized in that that the reactive primer is present in a proportion by weight of 0.5 to 10% by weight is used. A method according to claim 1 or 2, characterized in that are used as pressure-sensitive adhesive crosslinkable polyacrylates which contain a polymer based on the following comonomer composition a) acrylic acid and methacrylic acid derivatives in a proportion of 70 to 99.5 weight percent, CH ₂ = C (R ₁ ) (COOR ₂ ) (I), wherein R ₁ = H or CH ₃ and R ₂ = an alkyl chain having 2 to 20 C atoms; b) copolymerizable olefinically unsaturated monomers having functional groups in a weight proportion of 0 to 30 weight percent; c) copolymerizable monomers having one or more functional groups which are suitable for a crosslinking reaction via bi- or multi-functional aziridines or isocyanates. Method according to one of claims 1 to 3, characterized in that a pressure-sensitive adhesive tape with more than 50 g / m ^{2 of} mass application is used. Method according to one of claims 1 to 4, characterized the PSA has a flow viscosity at room temperature of <100,000 Pa · s 0.1 rad / s, more preferably <50,000 Pa.s at 0.1 rad / s, and more preferably <10,000 Pa · s at 0.1 rad / s. Method according to one of claims 1 to 4, characterized that the reactive primer undiluted, in solvent or in dispersion, preferably in aqueous polyacrylate dispersion applied or in the transfer process by means of a coated carrier on the surface is applied. Method according to one of claims 1 to 5, characterized after application of the pressure-sensitive adhesive tape to the reactive primer on the surface a storage at least at room temperature over at least 12, preferably 24 hours becomes.