EP3189109A1

EP3189109A1 - Method for increasing the adhesion between the first surface of a first web-type material and a first surface of a second web-type material

Info

Publication number: EP3189109A1
Application number: EP15766070.5A
Authority: EP
Inventors: Arne Koops; Marco Kupsky; Klaus KEITE-TELGENBÜSCHER; Stephan ZÖLLNER; Thomas Schubert
Original assignee: Tesa SE
Current assignee: Tesa SE
Priority date: 2014-09-05
Filing date: 2015-09-01
Publication date: 2017-07-12
Also published as: DE102014217821A1; MX2017002641A; MX2017002353A; WO2016034571A1; TW201623499A; CN106660276A; CN107073922A; US20170282445A1; US20170283656A1; WO2016034738A1; EP3189110A1

Abstract

The invention relates to a method for increasing the adhesion between the first surface of a first web-type material and a first surface of a second web-type material, the first web-type material and the second web-type material being supplied to a lamination nip continuously and with the same direction of the web. In said nip, the first surface of the first web-type material and of the second web-type material are laminated together and both first surfaces of the first web-type material and of the second web-type material are treated with a plasma over the whole surface, in particular such that the plasma acts continuously on the two first surfaces starting from a region in front of the lamination nip to right into the lamination nip. The lamination nip is formed by a pressure roller and a counter-pressure roller and at least one of the surfaces of the rollers or both are equipped with a dielectric. The plasma or the corona a produced by a nozzle. The first web-type material comprises an adhesive compound layer which is arranged in the first web-type material such as to form the first surface of the first web-type material.

Description

tesa Societas Europaea

Hamburg

description

A method for increasing the adhesion between the first surface of a first sheet material and a first surface of a second sheet

material

The invention relates to a method for increasing the adhesion between the first surface of a first sheet material and a first surface of a second sheet material.

In the field of industrial manufacturing, there is a need for simple pre-treatment techniques to improve the bonding properties of a part to be joined.

• Typically, complex processes such as wet chemical cleaning and primer surface priming are used to achieve high strength bonds with a self-adhesive tape.

· In particular, the simple physical pretreatment techniques under atmospheric pressure (corona, plasma, flame) are now used advantageously for the surface treatment of the joining part in order to achieve a higher anchoring force with a self-adhesive tape. To improve the adhesion properties of adherend surfaces and pressure-sensitive adhesive tape, pretreatments of the surfaces may be performed. These pretreatments enable or strengthen the intermolecular forces of the joining partners. There are various options for pretreatment, including chemical pretreatment by primer application or physical pretreatment by means of plasma or corona treatment. G. Habenicht, 2009, Springer Verlag, Berlin / Heidelberg, gives an introduction to surface treatment: The strength of adhesive bonds or the bond between surface and pressure-sensitive adhesive tape can be strengthened by chemical bridges. The basis of these chemical bridges are organosilicon compounds (silanes) which, in addition to increased strength, also enable improved aging behavior with respect to moist atmospheres.The chemical primer is applied to the surface prior to application of the pressure-sensitive adhesive tape Since the intermolecular forces between the silane molecules are weak, the bifunctional adhesion promoter reacts below with the adherend surface (polycondensation reaction) and the adhesive molecules of the pressure-sensitive adhesive tape (polyaddition or polymerization reaction tion).

The reaction mechanism is shown schematically in the attached figure (see Figure 13).

Plasma is called the 4th state of matter. It is a partial or fully ionized gas. By supplying energy, positive and negative ions, electrons, other excited states, radicals, electromagnetic radiation and chemical reaction products are generated. Many of these species can cause changes in the surface to be treated. In sum, this treatment leads to an activation of the adherend surface, specifically a higher reactivity.

This treatment can be carried out both on the surface of the adherend, as well as on the adhesive. Also, a combination of both treatments is possible. Likewise, this treatment is used to increase the adhesion between the first surface of a first sheet material (eg an adhesive) and a first surface of a second sheet material (eg a backing material). The corona treatment, also called corona discharge, takes place as a high-voltage discharge with direct contact to the adherend surface. The discharge converts nitrogen from the ambient air into a reactive form. Due to the impact of the incident electrons, molecular cleavages occur at the adherend surface. The resulting free valences allow attachment of the reaction products of the corona discharge. These deposits allow improved adhesion properties of the adherend surface.

This treatment, equivalent to the plasma, can take place on the adherend surface, adhesive mass of the pressure-sensitive adhesive tape and combined on both surfaces.

If two or more than two layers are to be laminated together, typically one or both interfaces are physically pretreated prior to lamination.

It is known that the treatment by means of corona and plasma has a limited durability with respect to the activation of the boundary layer, so that it is treated promptly or predominantly directly before the process of lamination.

Plasma and corona pretreatments are described or mentioned, for example, in DE 2005 027 391 A1 and DE 103 47 025 A1.

DE 10 2007 063 021 A1 describes an activation of adhesives by means of a filamentary corona treatment. It is disclosed that the previous plasma / corona pretreatment has a positive effect on the shearing life and the Auffließverhalten the bond. It has not been recognized that the method can cause an increase in the bond strength.

Like DE 10 2007 063 021 A1, DE 10 201 1075 470 A1 describes the physical pretreatment of adhesive and carrier / substrate. The pretreatments are carried out separately before the joining step and can be of the same or different design. The two-sided pretreatment achieves higher adhesion and anchoring forces than only substrate pretreatment.

In DE 24 60 432 A two webs are to be joined by introducing a plastic plastic film which serves as a primer to form a laminate. The plasma is formed between the two laminating rollers, which are grounded and a high-voltage electrode, which at the same time has an opening for the bonding agent formed. The air flowing around the roller should be influenced by the plasma in the mold, so that the adhesion promoter does not cool down too early and there are no air pockets in the laminate.

In DE 27 54 425 A reference is made to DE 24 60 432 A. New arrangements are described for the same task. According to FIG. 1, the plasma is formed between the two lamination rollers, one of which is dielectrically coated. As in DE 24 60 432 A, only the lamination of flat film webs by means of a thermoplastic polymer melt is described.

In DE 19846 814 A1 various arrangements are described, which provide the task for an improved corona treatment of the webs before laminating together. It is only generally spoken by railways and the term films only in connection with DE 198 02 662 A1 called. There is no mention of adhesives.

Here, too, the plasma is formed according to claim 2 between two laminating rollers. The dielectric is formed by at least one moving belt.

DE 41 27 723 A1 describes the production of multilayer laminates of plastic film webs and plastic plates, in which at least one joining side is treated with an aerosol corona directly before the joining step. As shown in Figure 1, this flow-driven corona can also be aimed directly at the lamination gap. As aerosol, monomers, dispersions, colloidal systems, emulsions or solutions are considered.

The prior art is characterized in that the pretreatments predominantly relate to the carrier material or the joining part in order to build up a higher anchoring force to the adhesive or to the self-adhesive tape.

Although, by appropriate plasma / corona treatments, the anchoring forces can be clearly increased compared to untreated mating partners, however, one encounters in many systems that do not go into the cohesive failure on one Kind of border that can not be overcome with the previous corona and plasma systems.

As stated in the context of this invention, this is due to the nature of the adhesives and their interaction with the substrates. An interaction usually takes place via charges or functional groups. These functional groups are generated by plasma or corona pretreatment on the surfaces and are diverse and distinct in nature. They arise essentially immediately after termination of the contact of plasma or corona and surface by reactions with atmospheric oxygen. Control of these groups can be done in part and within narrow limits by the process gases and process modes used. A significant increase is accordingly only possible if covalent bonds between the joining partners can be generated. This raises the question of whether one can generate these covalent bonds by a suitable process, without first reacting the radicals on the treated surfaces with gaseous components.

The object of the invention is to find the stated positive effects in the case of physical surface modification of pressure-sensitive adhesives and support materials in order to achieve high-strength compounds. The core of the task is to achieve a high anchorage between the pressure sensitive adhesive layer and the carrier material. This object is achieved by a method as shown in the main claim. The subject of the dependent claims are advantageous developments of the subject invention. Furthermore, the invention relates to a second, alternative method.

Accordingly, the invention relates to a method for increasing the adhesion between the first surface of a first sheet material and a first surface of a second sheet material, wherein The first sheet-like material and the second sheet-like material are fed continuously and in the same direction to a lamination nip in which the first sheet-like material and the second sheet-like material are laminated together with their respective first surface,

Both first surfaces of the first web-shaped material and the second web-like material are treated over the entire area with a plasma, preferably in such a way that the plasma acts continuously on the first two surfaces, starting before the laminating gap into the laminating gap,

The laminating gap is formed by a pressure roller and a counterpressure roller which builds up a counterpressure,

• At least one of the lateral surfaces of the rolls or both are equipped with a dielectric and

• the plasma or the corona are generated by a nozzle. The first sheet-like material has an adhesive compound view arranged in the first sheet-like material to form the first surface of the first sheet-like material.

It is particularly advantageous if the plasma or the corona extends as far as the line where the two sheet-like materials are laminated together.

When a plasma treatment is mentioned below, a corona treatment is meant and vice versa. The principle of the plasma and corona pre-treatment units is based on the fact that a gas flow (air, gas, gas mixtures) is passed through the discharge site and the discharge itself or only the activated gas flow is brought to the treatment site. The activation of the two interfaces is thus carried out simultaneously with the lamination. Thus, the generated chemical groups can produce the anchoring directly after the formation in the composite, without degradation or alteration of the surface by short-term storage in air influence.

In addition, two treatment units are not needed for the pretreatment. Manufacturers of pre-treatment equipment offer suitable corona and nozzle geometries, which can treat a laminating gap, but in principle only for a specific interface (gap, area, three-dimensional) are used. Examples of suitable nozzle geometries from Plasmatreat include hole, slot and rotary nozzles.

In the figure 7 the following nozzles can be seen.

Punch nozzle: Dot-shaped plasma jet with a small treatment width, but intensive treatment

Ring outlet nozzle: stationary, circular plasma jet

Rotary Nozzle: Rotating-point plasma jet with broader

Treatment width;

(see also WO 01/43512 A1)

Rotary Nozzle: Rotating-point plasma jet with lower

Treatment width, depending on the outlet angle of the concentrically arranged outlet opening in the rotating nozzle

5 Slot nozzle: outlet opening is slot-shaped and can

own different web widths

The outlet angle at a rotary nozzle influences the treatment width.

FIG. 8 shows two rotary nozzles which have different outlet angles for the concentrically arranged hole nozzles. This can be used to adjust a nozzle for specific laminating angles (pointed, flat).

Furthermore, pendulum nozzles are known and suitable.

In this type of nozzle, the nozzle head is deflected by a high-frequency pendulum motion. As a result, higher treatment widths can be realized. By the pendulum movement can in the Zusammenführpunkt the tape with the substrate both interfaces are treated. An example of a pendulum nozzle can be found in DE 20 2008 013 560 U1 and shown in FIG. 6:

Other nozzle types are known and suitable, for example the plasma curette (see FIG. 9).

This is a linear nozzle or a multiple arrangement of hole nozzles, which is brought by flow geometries as plasma curtain on the treatment surface. This can be applied with turbulent but also laminar flow, so that the laminating gap is intensively pretreated.

The SpotTEC from Tantec looks like this (see FIG. 10): The principle of the unit is to bring the filamentary discharge between two ironing electrodes over the blowing out by means of compressed air or other gases / gas mixtures in the direction of the substrate. Suitable flow of the gas ensures that the pre-treatment penetrates deep into the pretreatment gap. Ultimately, the vast pre-treatment systems are suitable for a laminating gap. A treatment of a wide laminating gap is possible if the pretreatment unit is arranged with several units.

Solutions for this purpose are provided by Tigres, in which two perforated nozzles are used for larger treatment widths (see FIG. 11),

or the company Tantec (see FIG. 12),

be used in the corona ironing electrodes.

The first and the second web-shaped material preferably run in the same direction in the lamination.

Since the plasma is preferably formed up to the laminating gap, the first sheet-like material and the second sheet-like material are laminated together with their respective first surface in the plasma. According to a first preferred embodiment of the invention, any point on the plasma-treated surface of the first sheet material and / or the second sheet material provides the path from the beginning of the plasma treatment to the laminating gap in a time less than 2.0 seconds, preferably less as 1.0 s, more preferably less than 0.5 s. Even times of less than 0.5 s, preferably less than 0.3 s, more preferably less than 0.1 s are possible according to the invention.

According to a variant of the invention, a third web-shaped material is fed to the laminating gap so that the second web-shaped material lies between the first and third web-shaped material.

The web direction of the third sheet material is the same as that showing the first and second sheet materials. In a further variant of the invention, a multiplicity of further sheet-like materials are fed to the laminating gap in addition to the first and the second sheet-like material, wherein feeding takes place such that the individual sheet-like materials enter the laminating gap between the first and the second sheet-like material. The individual further sheet-like materials are selected so that a non-adhesive carrier layer and a second non-adhesive carrier are never laminated directly to one another in the laminating gap.

The laminating gap is formed by a pressure roller and by a counterpressure roller, which builds up the counterpressure desired for lamination. Preferably, the rollers run in opposite directions, more preferably with the same peripheral speed.

In the laminating nip, the peripheral speed and the direction of rotation of the rollers are identical to the web speed and web direction of the first and second web-shaped material. Optionally existing further webs further preferably also have identical web speed and web direction.

The rolls preferably have the same diameter, more preferably the diameter is between 50 to 500 mm. Advantageously, the lateral surface of the rollers is smooth, in particular ground. The surface roughness of the rolls is preferably R _a is less than 50 μηι, preferably less than 10 μηι. "R _a " is an industry standard unit for surface finish quality and represents the average height of the roughness, in particular the average absolute distance from the centerline of the roughness profile within the evaluation range.

The roll surface of the non-dielectric coated roll may be steel, stainless steel or chrome plated steel. The surface can also be nickel plated or gold plated. It should only be electrically conductive and remain under the influence of plasma. The surface should show no corrosion under plasma action.

Furthermore, it is possible to cool or to heat one or both rolls with oil, water, steam, electrical or other tempering media in a preferred range of -40 ° C to 200 ° C. Preferably, both rolls are unheated.

For the layer of the dielectric which covers the entire lateral surface (also referred to simply as a surface) of one or both rolls, ie over the entire circumference of the roll (s), preference is given to ceramic, glass, plastics, rubbers such as styrene-butadiene rubbers, chloroprene Rubbers, butadiene rubbers (BR), acrylonitrile-butadiene rubbers (NBR), butyl rubbers (HR), ethylene-propylene-diene rubbers (EPDM) and polyisoprene rubbers (IR) or silicone.

The dielectric encloses the roller (s) firmly, but may be removable, for example in the form of two half-shells. The thickness of the layer of dielectric on the roller (s) is preferably between 1 to 5 mm.

According to the invention, it is provided that the dielectric is not a traveling web, which covers the lateral surface of one of the rolls only in sections (or two adjacent webs covering the lateral surfaces of both rolls only in sections).

According to a preferred variant, only one roller of the roller pair which forms the laminating gap is covered with a dielectric.

According to a preferred variant, both rolls of the roll pair, which forms the laminating gap, are covered with a dielectric. Preferably, the plasma is generated between one or more nozzles and the rollers, preferably when operating with compressed air or N ₂ . The plasma treatment takes place at a pressure which is close to (+/- 0.05 bar) or at atmospheric pressure.

The plasma treatment can take place in different atmospheres, wherein the atmosphere can also include air. The treatment atmosphere may be a mixture of various gases selected from, inter alia, N ₂ , O ₂ , H ₂ , CO ₂ , Ar, He, ammonia, forming gases, gas mixtures with O ₂ and H ₂ , in which case water vapor or other constituents may also be added , No limitation is made by this sample listing.

According to an advantageous embodiment of the invention, the following pure or mixtures of process gases form a treatment atmosphere: N ₂ , compressed air, O ₂ , H ₂ , C0 ₂ , Ar, He, ammonia, ethylene, siloxanes, acrylic acids and / or solvents, wherein in addition water vapor or other volatiles may be added. Preference is given to N ₂ and compressed air. The atmospheric pressure plasma can be formed with a mixture of process gases, the mixture preferably containing at least 90% by volume of nitrogen and at least one noble gas, preferably argon.

According to a preferred embodiment of the invention, the mixture consists of nitrogen and at least one noble gas, more preferably the mixture consists of nitrogen and argon.

In principle, it is also possible to add coating or polymerizing constituents to the atmosphere, as gas (for example ethylene) or liquids (aerosolized as aerosol). There is almost no limitation on the aerosols in question. In particular, the indirect plasma techniques are suitable for the use of aerosols, since there is no risk of contamination of the electrodes.

Their proportion should not exceed 5 vol .-%. Frequently used gas flows are 10 to 500 l / min to carry the filament or the after-discharge separated activated plasma ("after glow") into the laminating gap.

For the generation of the plasma and the action on the sheet-like materials, all the types of nozzles mentioned are basically suitable, provided that the plasma acts continuously into the laminating gap.

A possible variant of the plasma treatment is the use of a fixed plasma jet.

An equally possible plasma treatment uses an arrangement of several nozzles, offset if necessary, for gapless, partially overlapping treatment in a sufficient width. Rotary or non-rotating round nozzles can be used here.

Linear electrodes with a gas outlet opening are particularly suitable, which advantageously extend over the entire length of the laminating gap.

Further preferably, they have a constant distance to the laminating gap over the entire length of the laminating gap. According to a further advantageous embodiment of the invention, the treatment distance of the plasma generator to the laminating gap is 1 to 100 mm, preferably 3 to 50 mm, particularly preferably 4 to 20 mm.

Further preferably, the plasma generator perpendicular to the plane, which in turn is perpendicular to the plane defined by the roll axes plane, are shifted in height, preferably simultaneously in height and at a distance from the lamination.

Further preferably, the speed at which the webs are guided into the laminating gap, between 0.5 to 200 m / min, preferably 1 to 50 m / min, more preferably 2 to 20 m / min (each including the specified margins of the areas ).

According to an advantageous embodiment of the invention, the web speeds of the first, second, third or other web are all the same. The first sheet-like material has an adhesive compound view arranged in the first sheet-like material to form the first surface of the first sheet-like material.

The first sheet-like material may be a double-sided adhesive tape consisting of a first adhesive layer, a substrate and a second layer of adhesive, which is optionally covered with a so-called liner for protection.

A liner (release paper, release film) is not part of an adhesive tape or label, but only an aid for their production, storage or for further processing by punching. In addition, unlike a tape carrier, a liner is not firmly bonded to an adhesive layer. Single-layer double-sided self-adhesive tapes, so-called transfer tapes, are constructed in such a way that the pressure-sensitive adhesive layer forming the single layer contains no carrier and only siliconized with appropriate release materials, for example Release papers or release films is covered.

Particularly preferably, the first web-shaped material comprises a pressure-sensitive adhesive or consists of this, that is, an adhesive which allows a permanent connection with almost all adhesive reasons even under relatively weak pressure and can be removed from the primer again after use substantially residue-free. A PSA is permanently tacky at room temperature, so it has a sufficiently low viscosity and high tack, so that it wets the surface of the respective Klebegrunds already at low pressure. The adhesiveness of the adhesive is based on its adhesive properties and the removability on their cohesive properties.

The PSA layer is preferably based on natural rubber, synthetic rubber or polyurethanes, wherein the PSA layer preferably consists of pure acrylate or, in the majority, of acrylate. The PSA may be blended with tackifiers to improve adhesive properties.

In principle, all known substance classes are suitable as tackifiers, also referred to as tackifier resins. Tackifiers are, for example, hydrocarbon resins (for example polymers based on unsaturated C ₅ or C ₉ monomers), terpene-phenolic resins, polyterpene resins based on raw materials such as, for example, Oc- or β-pinene, aromatic resins such as coumarone-indene resins or resins based on Styrene or oc-methylstyrene such as rosin and its derivatives, for example, disproportionated, dimerized or esterified rosin, for example reaction products with glycol, glycerol or pentaerythritol, to name but a few. Preference is given to resins without readily oxidizable double bonds, such as terpene-phenolic resins, aromatic resins and particularly preferably resins which are prepared by hydrogenation, for example hydrogenated aromatic resins, hydrogenated polycyclopentadiene resins, hydrogenated rosin derivatives or hydrogenated polyterpene resins.

Preference is given to resins based on terpene phenols and rosin esters. Also preferred are tackifier resins having a softening point above 80 ° C according to ASTM E28-99 (2009). Particular preference is given to resins based on terpene phenols and rosin esters having a softening point above 90 ° C. according to ASTM E28-99 (2009). Typical amounts used are 10 to 100 parts by weight based on polymers of the adhesive.

To further improve the cable compatibility, the adhesive formulation may optionally be blended with sunscreen or primary and / or secondary anti-aging agents.

To improve the processing properties, the adhesive composition may also be blended with conventional processing aids such as defoamers, deaerators, wetting agents or leveling agents. Suitable concentrations are in the range of 0.1 to 5 parts by weight based on the solids.

More preferably, the second sheet-like material is a carrier material.

The carrier material used in the present case are preferably polymer films or film composites. Such films / film composites can from all common to Plastics used in film production, by way of example but not by way of limitation:

Polyethylene, polypropylene - especially the oriented polypropylene (OPP) produced by mono- or biaxial stretching, cyclic olefin copolymers (COC), polyvinyl chloride (PVC), polyesters - in particular polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polycarbonate (PC), polyamide (PA), polyethersulfone (PES) or polyimide (PI).

These materials are also preferably used as a carrier layer in the first sheet-like material, if in this a carrier is present.

Support material according to the invention comprises in particular all flat structures, for example, in two dimensions expanded films or film sections, tapes with extended length and limited width.

According to a further preferred variant of the invention, the second sheet-like material is viscoelastic.

A viscoelastic polymer layer can be considered to be a very high viscosity liquid which under pressure loading exhibits the flow behavior (also called "creep") .Such viscoelastic polymers or such a polymer layer have in particular the ability to with slow force acting on the forces acting on them They are able to dissipate the forces into vibrations and / or deformations (which in particular may also be reversible, at least in part), thus "buffering" the forces acting on them and favoring a mechanical destruction by the acting forces to avoid, but advantageously at least reduce or at least delay the time of the occurrence of destruction. In the case of a very rapidly acting force, viscoelastic polymers usually exhibit an elastic behavior, that is to say the behavior of a completely reversible deformation, whereby forces which go beyond the elasticity capacity of the polymers can lead to a break. In contrast, there are elastic materials that show the described elastic behavior even with slow force. By admixtures, fillers, foaming or the like, such viscoelastic compositions can still be widely varied in their properties. Due to the elastic components of the viscoelastic polymer layer, which in turn contribute substantially to the adhesive properties of adhesive tapes having such a viscoelastic support layer, the stress can not relax completely, for example due to tensile or shear stress. This is expressed by the relaxivity, which is defined as ((tension (t = 0) - tension (t) / tension (t = 0)) ^* 100% Typically, viscoelastic backings have a relaxivity of more than 50%.

Particularly preferably, expandable microballoons are used for foaming.

Microballoons are elastic hollow spheres which have a thermoplastic polymer shell. These balls are filled with low-boiling liquids or liquefied gas. As shell material find in particular polyacrylonitrile, PVDC, PVC or polyacrylates use. Hydrocarbons of the lower alkanes, for example isobutane or isopentane, which are enclosed in the polymer shell as a liquefied gas under pressure, are particularly suitable as the low-boiling liquid

The second sheet material may also be or contain an adhesive.

Further preferably, the third sheet-like material has or consists of an adhesive composition, more preferably the adhesive is a pressure-sensitive adhesive.

As (adhesive) adhesives, all adhesives can be used, as they are mentioned above.

According to a particularly advantageous embodiment of the invention, a three-layered product is laminated together. On an adhesive or non-adhesive foam carrier based on acrylate (second sheet material) are laminated on both sides of PSAs (first and third sheet-like material).

According to the invention, it is not excluded that some or all of the surfaces involved in the process have already been subjected to a first physical pretreatment (possibly also a plasma treatment). Finally, it is not excluded according to the invention if between the second surface of the first web-shaped material and / or the second surface of the second web-shaped material and / or the second surface of the third second web-shaped material and the cylindrical surface of one or the cylindrical surfaces of both rolls another or two more tracks are performed, which are optionally recyclable. These serve to reduce damage to the first and / or the second and / or the third sheet material.

The plasma treatment and the lamination take place simultaneously according to the preferred variant. For this purpose, the plasma is formed in the lamination gap. The radicals generated by the plasma on the surface of the carrier and the surface of the adhesive can not react with atmospheric oxygen and thus can not interact with the counterpart, since the time between generation and lamination goes to zero. This results in significant not previously expected adhesion increases, which can not be achieved by separate pretreatments.

The process can achieve an increase in the bond between the layers over a wide range of PSAs and substrates. The process is robust and not dependent on optimized treatment for each mass and / or optimized treatment for each substrate.

The effect of the method taught is synergistic, ie more than the sum of the individual effects of the treatment of carrier material or adhesive.

The following desirable properties can be combined in an adhesive tape by the invention:

o High Peel Strength

o High Initial Adhesion

o High Shear Resistance

o High Temperature Resistance

o Suitability for substrates with Low Surface Energy (LSE) Several figures show advantageous variants of the method according to the invention, without wishing to induce any restriction whatsoever.

FIG. 1 shows a method not according to the invention - the nozzle is not present. Otherwise, FIG. 1 reflects the method according to the invention. It is shown a lamination, which is formed by a pressure roller 1 1 and by a counter-pressure roller 12, which builds up the lamination for desired back pressure. The same size rollers 1 1, 12 run in opposite directions, with the identical peripheral speed.

On the pressure roller 1 1, a layer of a dielectric 1 1 1 is present.

Due to the tension 32 between the rollers 11, 12, a plasma 31 is formed in the laminating gap. An inventively prescribed nozzle is not present.

The laminating gap is fed with a first sheet-like material 21 and a second sheet-like material 22 continuously and with the same web direction. In this, the first web-shaped material 21 and the second web-shaped material 22 are laminated together with their respective first surface, so that a laminate 23 is formed. The first sheet-like material 21 is a layer of adhesive, the second sheet-like material 22 a carrier.

Both first surfaces of the first web-shaped material 21 and of the second web-shaped material 22 are treated over the entire surface with a plasma 31, in such a way that the plasma 31 acts continuously on the first two surfaces, starting before the laminating gap into the laminating gap.

Figure 2 shows a simplified section of Figure 1, in which of the rollers 1 1, 12 only a quarter is shown. Both roll surfaces are each equipped with a dielectric 1 1 1, 121.

The plasma 31 is generated by the inventively provided linear nozzle 33 due to the tension 32 between the rollers 1 1, 12 and the nozzle 33rd

According to a variant of the method according to the invention, the invention relates to a method for increasing the adhesion between the self-adhesive surface of a web-shaped Material and a surface of a substrate to which the sheet-like material is to be applied with the self-adhesive surface, wherein

The web-like material is fed continuously to a laminating gap, in which the web-shaped material of the self-adhesive surface is laminated to the surface of the substrate,

• the self-adhesive surface of the web-like material and the surface of the substrate are treated over the entire surface with a plasma, in particular in such a way that the plasma continuously acts on the two surfaces starting from the laminating gap into the laminating gap,

The laminating gap is formed by a pressure element and the substrate,

• the surface of the pressure element is equipped with a dielectric and

• the plasma or the corona are generated by a nozzle.

The sheet-like material has an adhesive gauge which is disposed in the sheet material so as to be directly laminated to the substrate in direct contact with the ground.

It is particularly advantageous if the plasma or the corona extends as far as the line where the sheet-like material is laminated to the substrate.

Since the plasma or corona is formed in the lamination nip, the web-shaped material is preferably laminated to the substrate in plasma or corona.

According to a preferred embodiment of the invention, any point on the plasma-treated surface of the sheet material and / or the substrate will provide the path from the beginning of the plasma treatment to the laminating gap in a time less than 2.0 seconds, preferably less than 1.0 s, more preferably less than 0.5 s. Even times of less than 0.5 s, preferably less than 0.3 s, more preferably less than 0.1 s are possible according to the invention.

According to a variant of the invention, a second sheet-like material is fed to the laminating gap so that the second sheet-like material lies between the (first) sheet-like material and the substrate. The web direction of the second web-shaped material is the same as that showing the (first) web-shaped material.

In a further variant of the invention, a multiplicity of further sheet-like materials are fed to the laminating gap in addition to the (first) sheet-like material and the substrate, wherein feeding takes place such that the individual sheet-like materials between the (first) sheet-like material and the substrate into the laminating gap enter. The individual further sheet-like materials are selected so that a non-adhesive carrier layer and a second non-adhesive carrier are never laminated directly to one another in the laminating gap.

The laminating gap is formed by a pressure element and the substrate. The pressure element builds up the desired back pressure for lamination.

The pressure element is preferably a roller, more preferably with a diameter between 50 to 500 mm, a doctor blade or a pressure plate.

The doctor blade or the pressure plate may, for example, have a semi-cylindrical shaped laminating surface. Preferably, the diameter of the roller or of the semi-cylindrical shaped laminating surface is between 50 and 500 mm. Advantageously, the lateral surface of the rollers or generally the surface of the pressure element is smooth, in particular ground.

The surface roughness is preferably R _a is less than 50 μηι, preferably less than 10 μηι. "R _a " is an industry standard unit for surface finishing quality and represents the average height of the roughness, in particular the average absolute distance from the centreline of the roughness profile within the evaluation range. electrically or other temperature control media in a preferred range of -40 ° C to 200 ° C to cool or to heat.The pressure element is preferably unheated. The thickness of the layer of the dielectric on the pressure element is preferably between 1 to 5 mm.

According to the invention, it is provided that the dielectric is not a traveling web, which only partially covers the lateral surface of the pressure element, in particular of the roller.

The sheet-like material may be a double-sided adhesive tape consisting of a first adhesive layer, a substrate and a second layer of adhesive, which is optionally covered with a so-called liner for protection.

The adhesive coating of the sheet-like material can be applied to a carrier material.

In the present case, the abovementioned polymer films or film composites are preferably used as the carrier material.

According to a further preferred variant of the invention, the sheet-like material is viscoelastic.

An adhesive may be applied to the substrate, more preferably a pressure-sensitive adhesive. As (adhesive) adhesives, all adhesives can be used, as they are mentioned above.

According to a particularly advantageous embodiment of the invention, a three-layered product is laminated to a substrate, preferably a three-layered product of an adhesive or non-adhesive foam carrier based on acrylate, are applied to both sides of pressure-sensitive adhesives.

Finally, it is not excluded according to the invention, if between the surface facing away from the surface of the sheet material and the lateral surface the pressure element another track is performed, which is optionally recyclable. This serves to reduce damage to the web-shaped material.

FIG. 3 shows a laminating gap which is formed by a pressure roller 1 1, which builds up the counterpressure desired for lamination, and by the substrate 12. On the pressure roller 1 1, a layer of a dielectric 1 1 1 is present.

Due to the tension 32 between the roller 11 and the linear electrode 33, a plasma 31 is formed in the laminating gap.

In the laminating nip, a sheet-like material 21 consisting of a layer of adhesive is laminated to the substrate 12.

Both surfaces of the web-like material 21 and the substrate 12 are treated over the entire surface with a plasma 31, in such a way that the plasma 31 continuously acts on the surfaces starting from the laminating gap into the laminating gap.

The platen roller 1 1 moves together with the linear electrode 33 at a continuous speed in the direction indicated by the arrow.

FIG. 4 differs from FIG. 1 in that, instead of a counterpressure roller 1 1, a pressure element in the form of a pressure plate 11 with a semi-cylindrical shaped laminating surface is used.

FIG. 5 differs from FIG. 3 in that, instead of the linear electrode 33, a nozzle 33 through which process gas can flow is used.

Claims

claims

A method for increasing the adhesion between the first surface of a first sheet material and a first surface of a second sheet material, wherein

the first web-shaped material and the second web-shaped material are fed continuously and with the same web direction to a laminating gap, in which the first web-shaped material and the second web-shaped material are laminated together with their respective first surface,

both first surfaces of the first web-shaped material and the second web-like material are treated over the entire surface with a plasma, in particular such that the plasma continuously acts on the first two surfaces, starting from the lamination nip into the laminating nip, the laminating nip of a pressure roller and a counter-pressure roller is formed and at least one of the surfaces of the rollers or both are equipped with a dielectric,

the plasma or the corona are generated by a nozzle,

wherein the first sheet-like material has an adhesive gauge disposed in the first sheet-like material to form the first surface of the first sheet-like material.

Method according to claim 1,

characterized in that

any point on the plasma treated surface of the first sheet material and / or the second sheet material further the path from the beginning of the plasma treatment to the laminating gap in a period of less than 2.0 s, preferably less than 1.0 s preferably less than 0.5 s travels.

Method according to claim 1 or 2,

characterized in that

a third sheet material is fed to the laminating nip so that the second sheet material is between the first and third sheet materials.

4. The method according to at least one of claims 1 to 3,

characterized in that

a plurality of further sheet-like materials are fed to the laminating nip in addition to the first and the second sheet-like material, feeding being such that the individual sheet-like materials enter between the first and second sheet-like material in the laminating nip, and the individual further sheet-like materials are selected be that in the laminating nip never a non-adhesive support layer and a second non-adhesive support layer are laminated directly to each other.

5. The method according to at least one of the preceding claims,

characterized in that

the rollers have a diameter between 50 to 500 mm.

6. The method according to at least one of the preceding claims,

characterized in that

a layer of ceramic, glass, plastic, rubber or silicone is selected for the dielectric.

7. The method according to at least one of the preceding claims,

characterized in that

the thickness of the layer of dielectric on the roller (s) is between 1 and 5 mm.

8. The method according to at least one of the preceding claims,

characterized in that

the plasma is generated between one or more nozzles and the rollers, preferably when operating with compressed air or N ₂ .

9. The method according to at least one of the preceding claims,

characterized in that

the plasma is generated by means of a linear electrode with a gas outlet opening, preferably one which extends over the entire length of the laminating gap extends and further preferably over the entire length of the lamination has a constant distance to the lamination.

10. The method according to at least one of the preceding claims,

characterized in that

the treatment distance of the plasma generator to the laminating gap is 1 to 100 mm, preferably 3 to 50 mm, particularly preferably 4 to 20 mm.

Method according to at least one of the preceding claims,

characterized in that

the plasma generator perpendicular to the plane, which in turn is perpendicular to the plane spanned by the roll axes, can be displaced in height, preferably simultaneously in height and at a distance from the laminating gap.

12. The method according to at least one of the preceding claims,

characterized in that

the speed at which the webs are guided into the laminating gap is between 0.5 and 200 m / min, preferably between 1 and 50 m / min, more preferably between 2 and 20 m / min.

13. The method according to at least one of the preceding claims,

characterized in that

the second sheet material is a carrier material.

14. The method according to at least one of the preceding claims,

characterized in that

the third sheet material has an adhesive gauge disposed in the third sheet material to form the outer surface of the third sheet material and laminated together with the second sheet material.

15. The method according to at least one of the preceding claims,

characterized in that

the first sheet-like material is a PSA layer based on natural rubber, synthetic rubber or polyurethanes, preferably the PSA layer of pure acrylate or mostly of acrylate (with a thermal crosslinker system and / or hotmelt and / or UV-crosslinked and / or UV-polymerized).

16. The method according to at least one of the preceding claims,

characterized in that

the PSA layer forms a carrierless, single-layered, double-sided adhesive tape.

17. The method according to at least one of the preceding claims,

characterized in that

the PSA layer is applied to a support, preferably on a film, a foam, a nonwoven and / or a fabric, most preferably on a viscoelastic support.

18. The method according to at least one of the preceding claims,

characterized in that

the thickness of the PSA layer or the adhesive tape thus formed is> 20 μm, preferably> 100 μm, very particularly preferably> 300 μm, and / or at most <2500 μm, more preferably <1500 μm, more preferably <1000 μm.

19. A method for increasing the adhesion between the self-adhesive surface of a sheet material and a surface of a substrate to which the sheet-like material is to be applied with the self-adhesive surface, wherein

the web-shaped material is continuously fed to a laminating nip in which the web-shaped material of the self-adhesive surface is laminated to the surface of the substrate,

the self-adhesive surface of the sheet-like material and the surface of the substrate are treated over the entire surface with a plasma, in particular in such a way that the plasma continuously acts on the two surfaces beginning in front of the laminating gap into the laminating gap,

the laminating gap is formed by a pressure element and the substrate and the surface of the pressure element is equipped with a dielectric and the plasma or the corona are generated by a nozzle.

20. The method according to claim 19,

characterized in that

the pressure element is a roller, preferably with a diameter between 50 to 500 mm, a doctor blade or a pressure plate.