Layered construction with adhesive tape and two layers of backing

Abstract

The invention relates to a construction with the aid of which a tape can be wound in a simple manner and with less complex equipment to form a bobbin. This is achieved by a layered construction comprising: - a tape comprising at least one outer pressure sensitive adhesive layer (PSA-A); - a release liner (RL) on the outer pressure sensitive adhesive layer (PSA-A); and - an interliner (IL) on the side of the tape opposite the outer pressure sensitive adhesive layer (PSA-A), wherein at least the side of the interliner facing away from the tape is formed to be adhesive; and the construction is characterized in that all the layers of the layered construction are substantially flush with one another. The invention also relates to a bobbin comprising a bobbin core and a layered construction according to the invention, which is wound in a plurality of layers crosswise onto the bobbin core, and a method for producing such a bobbin.

Description

[0001] This invention pertains to the technical field of adhesive tapes, which are of various types used for temporary or permanent bonding of a wide variety of substrates. More specifically, this invention relates to layered structures comprising an adhesive tape and two pads, and which allow the tape to be easily wound (wound, Aufwickeln) to form a spool (spool spool, Spule).

[0002] In the context of industrial and / or automated use and processing of tapes, such as in the automotive industry, it is often preferable to provide available tapes in quasi-continuous run lengths. Therefore, tapes are conveniently delivered from tape manufacturers to users in packages capable of accommodating extremely long lengths. For the most common type of packaging (called a spool, which is manufactured by winding the tape onto a core without axial advance (feed), resulting in a roll with the same width as the tape), it is generally not possible to achieve considerable run lengths and narrow tape widths. An alternative type of packaging available for decades is the "spool," sometimes also called a "level wound spool" (or simply "spool"). When wound around the spool, the winding is carried out with axial advance, which is typically uniform across the spool width and, in its respective case, oriented at predetermined spool edges and thus reversed when transitioning to the next layer of turns. Incidentally, for the terminology of spooling technology, please refer to the electronic textbook "Technical Information on the Principles of Spooling" by Neal Rothwell, published on the Internet on July 1, 2001, from Double R Controls Ltd., England.

[0003] The starting material typically used for manufacturing tapes is a roll with a very high width, such as 200 to 600 mm (master roll), from which multiple individual strips are produced by means of a cutter to the width required for the intended use of the tape. Therefore, the winding operation generally includes or consists of the following steps:

[0004] a) Unwind (unwind) the mother roll;

[0005] b) Produce multiple individual strips (“strips”) of the desired width that are substantially parallel;

[0006] c) The individual strips are wound onto a corresponding number of winding frames to form cross-wound spools.

[0007] Tape for winding typically has a release liner on one side and, where appropriate, an intermediate liner on the remaining side, which provides additional protection during winding and subsequent storage as a spool. In the case of single-sided lined tapes with little or no side edge adhesiveness, the intermediate liner is practically laminated to the unwound tape of the same width before the cutting unit, if desired. Thus, cutting is performed on tapes with double-sided liners, which then exist as a layered structure with mutually flush layers and can be wound into a spool in this form. Typical tapes with little or no side edge adhesiveness are, for example, those consisting of a PE foam core and corresponding pressure-sensitive adhesive layers on the two main sides of the PE foam's cross-section. The two secondary sides of the tape's cross-section are the side edges. Foamed PE does not possess pressure-sensitive adhesiveness or tackiness, making it impossible or almost impossible for the side edges of the tape to adhere to each other.

[0008] Typical tapes with strong side edge adhesiveness are, for example, foamed pressure-sensitive adhesives (single-layer foam tapes) or multi-layer foam tapes with a foamed acrylate-based core and additional pressure-sensitive adhesive layers.

[0009] For tapes with pronounced side-edge adhesiveness, the intermediate liner must typically be wider than the tape itself, and therefore protrude at least on one side, and usually on both sides. This protrusion prevents the side edges of the tape wound onto a spool from sticking together (a phenomenon also known as "verblocken"). However, this protrusion means the intermediate liner cannot be laminated before cutting, but must instead be trimmed to the target width only after cutting and placed individually onto each tape. This is significant logistical and technical work, requiring additional workstations on the winding machine and reducing the winding speed. Due to the more complex and slower operation, winding tapes with side-edge adhesiveness is significantly more expensive than winding tapes without side-edge adhesiveness.

[0010] There has been no shortage of attempts in the existing technology to find optimized solutions specifically for tapes with significant side edge adhesive characteristics.

[0011] EP 3 216 838 A1 describes composite material systems, including:

[0012] - Tape (A), which includes a pressure-sensitive adhesive layer and a heat-activated adhesive layer;

[0013] - A release liner located on the pressure-sensitive adhesive layer of the tape (A); and

[0014] - Tape (B), comprising a carrier layer, a release layer on one side of the carrier layer, and a pressure-sensitive adhesive layer on the side of the carrier layer opposite to the release layer;

[0015] The pressure-sensitive adhesive layer of the tape (B) is in direct contact with the heat-activated adhesive layer of the tape (A), and the tape (B) has an adhesive force (peel adhesion) of no more than 5 N / cm to the heat-activated adhesive layer of the tape (A) (as determined according to EN 1939:2003). The tacky side of the interlayer pad (tape (B)) is oriented toward the heat-sealing layer of the tape (A) to create adhesion between the interlayer pad and the tape. The interlayer pad is described as having a wider adhesive band.

[0016] EP 2 746 356 A1 discloses a roll of acrylic foam tape, the roll comprising acrylic foam tape, the acrylic foam tape further comprising acrylic foam having opposing first and second main surfaces. The first main surface comprises a pressure-sensitive adhesive protected by a first pad; the second main surface comprises a heat-activated adhesive. The acrylic foam tape is wound (wound) around a core in a helical manner into a cross-wound spool; a second pad is disposed on the heat-activated adhesive and extends on at least one edge of the second main surface. The acrylic foam is thermally cross-linked.

[0017] DE 10 201 7 223 768A1 describes a separable pad suitable for lining an adhesive tape; a double-sided adhesive tape lined with the pad; and a spool on which such tape is wound. The pad should protrude over at least one of the two edges of the tape itself. This construction is intended to reduce the tendency for folds to form during the winding and unwinding (unwinding) of a thick, preferably foamed, adhesive tape, and to stabilize the spool.

[0018] EP 1 035 185 A2 describes a multi-layered, cross-wound spool of carrier-free, double-sided pressure-sensitive adhesive transfer tape, the spool consisting of a pressure-sensitive layer of adhesive film wound together with a separable overlay and additionally with an intermediate layer to form a spool body. The intermediate overlay has weak pressure-sensitive adhesiveness at least on the back side and is wider than the adhesive tape.

[0019] EP 2 039 506 A1 describes a release liner consisting of a single layer or laminate, and comprising a release layer having a release adhesion (23°C) of 0.02 to 0.5 N / 20 mm to an acrylic substrate. A tape is also described, wherein such a release liner adheres to one of its pressure-sensitive adhesive surfaces, the width of the release liner being greater than the width of the pressure-sensitive adhesive surface.

[0020] The object of this invention is to provide a structure by which adhesive tape can be easily and with relatively simple equipment wound into a spool. The first and general subject matter of this invention accompanying this object is a layered structure comprising:

[0021] - A tape comprising at least one pressure-sensitive adhesive (PSA A) outer layer;

[0022] - Release liner (RL) located on the outer layer (PSA-A) of the pressure-sensitive adhesive; and

[0023] - Intermediate pad (IL), which is located on the side of the tape opposite to the outer layer (PSA-A) of the pressure-sensitive adhesive, wherein at least the side of the intermediate pad facing away from the tape is adhesively provided;

[0024] Furthermore, it is characterized in that all layers of the layered structure are substantially flush with each other. This structure, on the one hand, allows for stable positioning of the various portions (segments) or layers of the padded tape on the spool, even under external or internal loads, and on the other hand, allows for production in such a way that the intermediate pad (IL) can be laminated onto the tape unwound from the master roll during the production of the master roll or in the winding machine, and therefore before cutting. Thus, it is not necessary to separately laminate the intermediate pad, trimmed to the target width, onto the corresponding individual tape trimmed to the target width; instead, the layered structure can be obtained from the master roll itself, trimmed to the target width, and then immediately wound to form a spool. Additionally, due to the firmness of the pressure-sensitive adhesive of the portions or layers, dimensionally stable spools can be produced even under low winding tension, thereby allowing for very gentle winding of the tape without compression, and avoiding adhesion between portions despite the lack of intermediate pad width.

[0025] As commonly understood, tape is a strip-shaped structure provided in a pressure-sensitive adhesive manner, which may or may not have a carrier material. The layered structure tape of the present invention comprises at least one pressure-sensitive adhesive outer layer. Beyond this, the structure of the tape is substantially arbitrary. The tape may include one, two, or more carrier materials or carrier layers, which may consist of all common materials, and more specifically, then, of films or foams. The tape may also include any desired functional layers, such as barrier layers.

[0026] The statement "includes at least one pressure-sensitive adhesive outer layer" also covers tapes consisting of only a single layer of pressure-sensitive adhesive (adhesive transfer tape).

[0027] Therefore, the object of the present invention is the layered structure according to the invention and thus the tape can preferably be wound into a spool - that is, the tape preferably has corresponding deformability and sufficient dimensional stability such that when the layers are wound one on top of the other (overlapping each other), they will not be squeezed out (pressed) and slipped (slipped off), thereby losing the properties of the tape.

[0028] According to the present invention, a pressure-sensitive adhesive, or PSA, refers to a substance that is persistently tacky at least at room temperature and also possesses adhesive properties, as is typically the case in ordinary use. A PSA is characterized by its ability to be applied to a substrate and remain adhered there, without a more detailed definition of the pressure to be applied or the duration of exposure to that pressure. Generally, although in principle dependent on the precise properties of the PSA and the substrate, temperature, and atmospheric humidity, brief exposure to minimal pressure (not exceeding a brief, mild contact) is sufficient to achieve an adhesive effect; in other cases, longer exposure to higher pressure may be required.

[0029] PSAs exhibit specific viscoelastic properties, resulting in persistent tack and adhesion. These adhesives are characterized by a viscous flow process when they are mechanically deformed, along with the development of restoring elastic forces. These two processes are related to each other in their respective proportions, depending not only on the precise composition, structure, and degree of cross-linking of the PSA, but also on the rate and duration of deformation and on the temperature.

[0030] A certain proportionate viscous flow is necessary for adhesion. Only viscous components (typically generated by macromolecules with relatively high mobility) allow for effective wetting and flow onto the substrate to be bonded. High-viscosity flow components result in high-pressure adhesive tack (also known as stickiness or surface tack), and therefore usually also result in high adhesion. Highly cross-linked systems, crystalline polymers, or polymers with glassy curing lack flowable components and therefore typically have no tack or at least very little tack.

[0031] Proportional elastic restoring forces are necessary for achieving cohesion. They are generated, for example, by macromolecules with very long, highly coiled chains, and also by macromolecules that are physically or chemically cross-linked, and they allow the transmission of forces acting on the adhesive bond. As a result, adhesive bonds can withstand sufficiently long-term loads, for example, acting on them in the form of sustained shear loads, over relatively long periods of time.

[0032] To more accurately describe and quantify the degree of elastic and viscous components and their proportions relative to each other, variables of storage modulus (G') and loss modulus (G”) are introduced, which can be determined by dynamic mechanical analysis (DMA). G' is a measure of the elastic component of the material, and G” is a measure of the viscous component. Both variables depend on the deformation frequency and temperature.

[0033] The variable can be determined using a rheometer. In this case, for example, the material under study is exposed to sinusoidal oscillating shear stress in a plate / plate arrangement. In a shear stress-controlled instrument, the deformation is measured as a function of time, and the temporal shift of this deformation relative to the introduced shear stress is measured. This temporal shift is called the phase angle δ.

[0034] The energy storage modulus G' is defined as follows: G' = (τ / γ)·cos(δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between the shear stress vector and the deformation vector). The loss modulus G” is defined as follows: G” = (τ / γ)·sin(δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between the shear stress vector and the deformation vector).

[0035] At 23°C, at 10 0 Up to 10 1 When the deformation frequency is in radians per second, both G' and G” are at least partially located at 10 3 Up to 10 7 When the Pa range is within the specified range, the substance is specifically considered a pressure-sensitive adhesive, and is so defined specifically for the purposes of this invention. "Partially" means that at least a portion of the G' or G' curve is located within the range of 10 Pa. 0 (including endpoints) to 10 1 Deformation frequency range in radians per second (including endpoints) (x-axis) and from 10 3 Pa (including endpoints) to 10 7 The range of G' or G” values ​​(vertical axis) of Pa (including endpoints) is defined within the window.

[0036] The tape with the layered structure of the present invention may include one or two pressure-sensitive adhesive outer layers—that is, it may consist of only a single PSA layer, thus existing in the form of a so-called adhesive transfer tape, or it may have a PSA layer only on one or both sides of the carrier material, thus being available as a single-sided or double-sided tape. The carrier material itself may also be pressure-sensitive adhesive, so that even a tape with an additional PSA layer provided only on one side can be configured as a double-sided tape. Furthermore, the tape may also have one or more pressure-sensitive adhesive inner layers for bonding other layers present within the tape's structure to each other.

[0037] The design of the PSA outer layer (PSA-A) and any optional additional PSA outer layers is also largely arbitrary, as long as it does not contradict the purpose of this invention.

[0038] In one embodiment, the tape includes a foam layer. A “foam layer” or “foamed layer” refers to a layer comprising a matrix material and multiple cavities, such that the density of the foam is reduced to a technically usable level compared to the density of the pure matrix material. In the case of tape, the foam is more particularly a continuous polymer matrix filled with air / bubbles—either having or without their own shell—e.g., filled with expanded polymer microspheres and / or hollow glass spheres—resulting in a foam with a density, for example, from 100 to 900 g / L. The foamed layer typically imparts particularly advantageous properties to the tape, examples of higher peel adhesion on uneven substrates, and the ability to dampen impacts and compensate for varying thermally induced expansion and clearance tolerances. However, specifically, tapes with foamed layers are particularly susceptible to side-edge adhesiveness, thus the advantages of the layered structure of the present invention in manufacturing spool tapes are particularly prominent here.

[0039] The matrix material of the foam layer preferably includes at least one poly(meth)acrylate, at least one synthetic rubber, natural rubber and / or a mixture of two or more of these polymers, and more preferably the matrix material includes at least one poly(meth)acrylate and / or at least one synthetic rubber.

[0040] "Poly(meth)acrylate" is understood to be a polymer obtainable by free radical polymerization of acrylic and / or methacrylic monomers and optionally further copolymerizable monomers. More particularly, "poly(meth)acrylate" is a polymer whose monomer base consists of acrylic acid, methacrylic acid, acrylates and / or methacrylates in an amount of at least 50% by weight, wherein acrylates and / or methacrylates are included at least partially, preferably up to at least 30% by weight, based on the total monomer base of the polymer.

[0041] In one embodiment, the foam layer comprises a total of 40 to 70% by weight, preferably 45 to 60% by weight, of poly(meth)acrylate, based on the total weight of the foam layer in each case. In another embodiment, the foam layer comprises a total of at least 90% by weight, preferably at least 95% by weight, of poly(meth)acrylate, based on the total weight of the foam layer in each case. One (single) poly(meth)acrylate or two or more poly(meth)acrylates may be present. The foam layer is particularly based on poly(meth)acrylate.

[0042] The glass transition temperature of the poly(meth)acrylate in the foam layer is preferably <0°C, more preferably between -20°C and -50°C. The glass transition temperature of the polymer blocks in the polymer or block copolymer is determined in this invention by means of dynamic scanning calorimetry (DSC), wherein the glass transition is considered as a step in the thermogram.

[0043] In one embodiment, the poly(meth)acrylate of the foam layer comprises at least one proportionally copolymerized (preferably reacting with an epoxy group to form a covalent bond) functional monomer. More preferably, the proportionally copolymerized (more preferably reactive with an epoxy group to form a covalent bond) functional monomer comprises at least one functional group selected from: carboxylic acid group, sulfonic acid group, phosphonic acid group, hydroxyl group, acid anhydride group, epoxy group, and amino group; more particularly, it comprises at least one carboxylic acid group. Very preferably, the poly(meth)acrylate comprises proportionally copolymerized acrylic acid and / or methacrylic acid. All of the mentioned groups are reactive with epoxy groups, thus making the poly(meth)acrylate advantageously suitable for thermal crosslinking with the introduced epoxide.

[0044] In another embodiment, the poly(meth)acrylate of the foam layer comprises at least one proportionally copolymerized monomer having at least one functional group capable of supporting or initiating subsequent radiation crosslinking, particularly by UV radiation. The poly(meth)acrylate of the foam layer preferably comprises a proportionally copolymerized benzoin acrylate or at least one proportionally copolymerized acrylate-functionalized benzophenone derivative.

[0045] Crosslinking poly(meth)acrylate with electron beams is also possible in principle.

[0046] The poly(meth)acrylate of the foam layer can preferably be derived from the following monomers:

[0047] a) At least one acrylate and / or methacrylate of formula (1):

[0048] CH2=C(R I (COOR) II (1),

[0049] Where R I =H or CH3, and R II Alkyl groups having 4 to 18 carbon atoms;

[0050] b) At least one olefinic unsaturated monomer having at least one functional group selected from the following: carboxylic acid group, sulfonic acid group, phosphate group, hydroxyl group, acid anhydride group, epoxy group and amino group;

[0051] c) Optionally additional acrylates and / or methacrylates and / or olefinic unsaturated monomers, which may be copolymerized with component (a).

[0052] It is particularly advantageous to select monomers of component a) in the amount of 45 to 99% by weight, monomers of component b) in the amount of 1 to 15% by weight, and monomers of component c) in the amount of 0 to 40% by weight, these figures being based on a mixture of monomers of a base polymer without the addition of any possible additives such as resins.

[0053] The monomer in component a) is generally a plasticized, more nonpolar monomer. Particularly preferred is R in monomer a). II It is an alkyl group having 4 to 10 carbon atoms or 2-propylheptyl acrylate or 2-propylheptyl methacrylate. The monomer of formula (1) is more particularly selected from n-butyl acrylate, n-butyl methacrylate, n-pentyl acrylate, n-pentyl methacrylate, n-pentyl acrylate, n-hexyl acrylate, n-hexyl methacrylate, n-heptyl acrylate, n-octyl methacrylate, n-nonyl acrylate, isobutyl acrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-propylheptyl acrylate and 2-propylheptyl methacrylate.

[0054] The monomers of component b) are particularly preferably selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, aconitic acid, dimethacrylic acid, β-acryloyloxypropionic acid, trichloroacrylic acid, vinylacetic acid, vinylphosphonic acid, maleic anhydride, hydroxyethyl acrylate, particularly 2-hydroxyethyl acrylate, hydroxypropyl acrylate, particularly 3-hydroxypropyl acrylate, hydroxybutyl acrylate, particularly 4-hydroxybutyl acrylate, hydroxyhexyl acrylate, particularly 6-hydroxyhexyl acrylate, hydroxyethyl methacrylate, particularly 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, particularly 3-hydroxypropyl methacrylate, hydroxybutyl methacrylate, particularly 4-hydroxybutyl methacrylate, hydroxyhexyl methacrylate, particularly 6-hydroxyhexyl methacrylate, allyl alcohol, glycidyl acrylate, and glycidyl methacrylate.

[0055] An example monomer of component c) is as follows:

[0056] Methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, benzyl acrylate, benzyl methacrylate, sec-butyl acrylate, tert-butyl acrylate, phenyl acrylate, phenyl methacrylate, isobornyl acrylate, isobornyl methacrylate, tert-butylphenyl acrylate, tert-butylphenyl methacrylate, dodecyl methacrylate, isodecyl acrylate, lauryl acrylate, n-undecyl acrylate, stearyl acrylate, tridecyl acrylate, dodecyl acrylate, cyclohexyl methacrylate, cyclopentyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-butoxyethyl acrylate 3,3,5-Trimethylcyclohexyl acrylate, 3,5-Dimethyladamantyl acrylate, 4-cumylphenyl methacrylate, Ethyl cyanoacrylate, Ethyl cyanomethacrylate, 4-Biphenyl acrylate, 4-Biphenyl methacrylate, 2-Naphthyl acrylate, 2-Naphthyl methacrylate, Tetrahydrofurfuryl acrylate, Diethylaminoethyl acrylate, Diethylaminoethyl methacrylate, Dimethylaminoethyl acrylate, Dimethylaminoethyl methacrylate, Methyl 3-methoxyacrylate, 3-Methoxybutyl acrylate, 2-Phenoxyethyl methacrylate, Butyl diethylene glycol methacrylate, Ethylene glycol acrylate, Ethylene glycol monomethacrylate, Methoxy polyethylene glycol methacrylate 350, Methoxy polyethylene glycol methacrylate Diol methacrylate 500, Propylene glycol monomethacrylate, Butoxydiethylene glycol methacrylate, Ethoxytriethylene glycol methacrylate, Octafluoroamyl acrylate, Octafluoroamyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2,2,3,3,4,4,4-methacrylate 8-Pentadecylfluorooctyl ester, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, N-(1-methylundecyl)acrylamide, N-(n-butoxymethyl)acrylamide, N-(butoxymethyl)methacrylamide, N-(ethoxymethyl)acrylamide, N-(n-octadecyl)acrylamide; N,N-dialkyl-substituted amides such as N,N-dimethylacrylamide and N,N-dimethylmethacrylamide; N-benzylacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, N-tert-octylacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, acrylonitrile, methacrylonitrile; vinyl ethers such as vinyl methyl ether, ethyl vinyl ether, vinyl isobutyl ether;Vinyl esters such as vinyl acetate; vinyl halides, vinylidene halides, vinylpyridine, 4-vinylpyridine, N-vinylphthalimide, N-vinyllactam, N-vinylpyrrolidone, styrene, α-methylstyrene and p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, 3,4-dimethoxystyrene; macromonomers such as 2-polystyrene methacrylate (4000 to 13000 g / mol weight average molecular weight Mw as determined by GPC), poly(methyl methacrylate) ethyl methacrylate (2000 to 8000 g / mol Mw).

[0057] The monomers of component (c) can also be advantageously selected such that they contain functional groups that assist subsequent radiation crosslinking (e.g., by electron beam, UV). Suitable copolymerizable photoinitiators are, for example, benzoin acrylate and acrylate-functionalized benzophenone derivatives. Monomers for crosslinking assisted by electron bombardment are, for example, tetrahydrofurfuryl acrylate, N-tert-butylacrylamide, and allyl acrylate.

[0058] Poly(meth)acrylates are preferably prepared by conventional free radical polymerization or controlled free radical polymerization. Poly(meth)acrylates can be prepared by copolymerizing monomers using conventional polymerization initiators and optionally chain transfer agents, by polymerization at conventional temperatures in bulk, in emulsions such as in water or liquid hydrocarbons, or in solution.

[0059] Poly(meth)acrylate is preferably prepared by copolymerizing monomers in a solvent, more preferably in a solvent having a boiling range of 50 to 150°C, more particularly 60 to 120°C, using 0.01 to 5% by weight, more particularly 0.1 to 2% by weight of a polymerization initiator, based on the total weight of the monomers in each case.

[0060] In principle, all conventional initiators are suitable. Examples of radical sources are peroxides, hydroperoxides, and azo compounds, such as benzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, di-tert-butyl peroxide, cyclohexylsulfonylacetyl peroxide, diisopropyl percarbonate, tert-butyl peroctanoate, and benzylpinacol. A preferred radical initiator is 2,2'-azobis(2-methylbutyronitrile) (from DuPont). 67 TM ) or 2,2'-azobis(2-methylpropionitrile) (2,2'-azobisisobutyronitrile; AIBN; from DuPont) 64 TM ).

[0061] Preferred solvents for preparing poly(meth)acrylates include alcohols such as methanol, ethanol, n-propanol and isopropanol, n-butanol and isobutanol, particularly isopropanol and / or isobutanol; hydrocarbons such as toluene and gasoline particularly having a boiling range of 60 to 120°C; ketones, particularly acetone, methyl ethyl ketone, methyl isobutyl ketone; esters such as ethyl acetate; and mixtures of the foregoing solvents. Particularly preferred solvents are mixtures containing isopropanol in amounts of 2 to 15% by weight, more particularly 3 to 10% by weight, based on the solvent mixture used in their respective cases.

[0062] Poly(meth)acrylates can also be prepared in a solvent-free manner. For example, monomers can be prepolymerized under the influence of heat or UV radiation until they have a slurry consistency; the resulting slurry, which contains not only monomers but also polymers, can then be mixed with further components and subsequently shaped into webs. Final polymerization and crosslinking (where appropriate) are carried out shortly after shaping by further heat treatment or UV irradiation of the resulting webs. Other components mixed with the slurry may include foaming agents, examples of hollow polymeric microspheres or hollow glass spheres; in this case, the foam is obtained directly through final polymerization.

[0063] In another variation of the process for producing the foam layer, the preparation (polymerization) of poly(meth)acrylate is followed by concentration, and further processing of the poly(meth)acrylate is essentially solvent-free. The polymer can be concentrated in the absence of crosslinking agents and accelerators. Another possibility is to add one of these classes of compounds to the polymer prior to concentration, allowing concentration to proceed in the presence of this or these substances.

[0064] Following the concentration step, the polymer can be transferred to a compounding machine, where it is blended with further components, including, in particular, a blowing agent. Concentration and compounding can also optionally be carried out in the same reactor.

[0065] Weight-average molecular weight M of polyacrylate w Preferably, the molecular weight is in the range of 20,000 to 2,000,000 g / mol; very preferably, it is in the range of 100,000 to 1,500,000 g / mol, and most preferably, it is in the range of 150,000 to 1,000,000 g / mol. For this purpose, polymerization may be advantageous in the presence of suitable chain transfer agents such as thiols, halogen compounds, and / or alcohols to produce the desired average molecular weight. The number-average molar mass M in this specification... n and weight-average molar mass M w The figures are based on routine determinations by gel permeation chromatography (GPC).

[0066] The poly(meth)acrylate in the foam layer preferably has a polydispersity (PD) < 4 and therefore a relatively narrow molecular weight distribution. Despite the relatively low molecular weight, the foam based on it exhibits particularly good shear strength after crosslinking. Furthermore, the lower polydispersity makes it easier to process from the melt, as the flow viscosity is lower for substantially the same application properties than that of poly(meth)acrylate with a wider distribution. Narrowly distributed poly(meth)acrylates can be advantageously prepared by anionic polymerization or by controlled radical polymerization, the latter being particularly suitable. Such poly(meth)acrylates can also be prepared via N-oxygenation. Additionally, atom transfer radical polymerization (ATRP) can be advantageously used to synthesize narrowly distributed poly(meth)acrylates, wherein the initiator used preferably comprises a monofunctional or bifunctional secondary or tertiary halide, and the halide is extracted using Cu, Ni, Fe, Pd, Pt, Ru, Os, Rh, Co, Ir, Ag, or Au complexes. RAFT polymerization is also suitable.

[0067] In one embodiment, the poly(meth)acrylate is crosslinked via a linkage reaction between its contained functional groups and a thermal crosslinking agent—particularly in the sense of addition or substitution reactions. All of the following thermal crosslinking agents can be used:

[0068] -Not only does it ensure a sufficiently long run time so that there is no gelling during processing operations, especially during extrusion processes,

[0069] Furthermore, it leads to rapid post-crosslinking of the polymer to the desired degree of crosslinking at temperatures below the processing temperature, and more specifically at room temperature.

[0070] The thermal crosslinking agent is preferably used at 0.1 to 5% by weight, more particularly at 0.2 to 1% by weight, based on the total amount of the polymer to be crosslinked.

[0071] Cross-linking via a complexing agent (also known as a chelate) is also possible. An example of a preferred complexing agent is aluminum acetylacetonate.

[0072] The poly(meth)acrylate in the foam layer is preferably crosslinked by means of epoxides and / or by means of one or more epoxy-containing substances. Epoxy-containing substances are more particularly polyfunctional epoxides, i.e., those having at least two epoxy groups; correspondingly, the overall result is an indirect connection of the poly(meth)acrylate structural units carrying functional groups. Epoxy-containing substances can be aromatic compounds and aliphatic compounds.

[0073] Particularly preferably, the poly(meth)acrylate is crosslinked by means of a crosslinking agent-accelerator system (“crosslinking system”) to obtain more effective control over run time, crosslinking kinetics, and degree of crosslinking. The crosslinking agent-accelerator system preferably comprises at least one epoxy group-containing substance as a crosslinking agent and at least one substance as an accelerator that promotes the crosslinking reaction at a temperature below the melting temperature of the polymer to be crosslinked.

[0074] In one embodiment, the foam layer or the matrix material of the foam layer includes at least one synthetic rubber.

[0075] The foam layer may comprise a total of 15 to 50 wt%, more preferably 20 to 40 wt%, of synthetic rubber, based on the total weight of the foam layer in each case, and particularly, the foam layer then further comprises at least one poly(meth)acrylate. In this case, preferably, the synthetic rubber is present as a dispersion in the poly(meth)acrylate in the foam layer. Therefore, the poly(meth)acrylate and the synthetic rubber are preferably each homogeneous. In this embodiment, preferably, the foam layer comprises 40-70 wt% of at least one poly(meth)acrylate and 15-50 wt% of at least one synthetic rubber, based on the total weight of the foam layer in each case.

[0076] The foam layer may also be based on synthetic rubber, and in this case contain at least 90% by weight, preferably at least 95% by weight, of synthetic rubber in total, based on the total weight of the foam layer in each case. One or two or more types of synthetic rubber may be present in the foam layer.

[0077] The synthetic rubber used in the foam layer is preferably composed of AB, ABA, or (AB) compounds. n (AB) n X or (ABA) n X-structured block copolymers

[0078] in

[0079] - Block A is a polymer formed independently of each other by polymerization of at least one vinyl aromatic compound;

[0080] - Block B is a polymer formed independently of each other by polymerization of conjugated dienes and / or isobutylene having 4 to 18 carbons, or a partially or fully hydrogenated derivative of such polymers.

[0081] -X is a group (residue) of the coupling reagent or initiator; and

[0082] -n is an integer ≥2.

[0083] In particular, in the presence of multiple synthetic rubbers, all of these rubbers in the foam layer are block copolymers having the structure described above. Therefore, the foam layer may also include a mixture of different block copolymers having the above-described structure.

[0084] Therefore, the preferred synthetic rubber (also known as a vinyl aromatic block copolymer) comprises one or more rubber blocks B (soft blocks) and one or more glass blocks A (hard blocks). More preferably, the synthetic rubber is a block copolymer having an AB, ABA, (AB)3X, or (AB)4X structure, wherein A, B, and X conform to the above definitions. Very particularly preferably, all the synthetic rubber in the foam layer is a block copolymer having an AB, ABA, (AB)3X, or (AB)4X structure, wherein A, B, and X conform to the above definitions. More particularly, the synthetic rubber in the foam layer is a mixture of block copolymers having an AB, ABA, (AB)3X, or (AB)4X structure, said mixture preferably comprising at least a diblock copolymer AB and / or a triblock copolymer ABA.

[0085] Block A is particularly a glass block having a preferred glass transition temperature (Tg, DSC) above room temperature. More preferably, the Tg of the glass block is at least 40°C, more particularly at least 60°C, very preferably at least 80°C, and particularly preferably at least 100°C. The fraction of vinyl aromatic block A in the entire block copolymer is preferably 10 to 40% by weight, more preferably 20 to 33% by weight. The vinyl aromatic compound used to construct block A preferably comprises styrene and α-methylstyrene. Therefore, block A can be in the form of a homopolymer or a copolymer. More preferably, block A is polystyrene.

[0086] Block B is a rubber block or soft block, particularly having a preferred Tg below room temperature. The Tg of the soft block is more preferably less than 0°C, more particularly less than -10°C, for example less than -40°C, and very preferably less than -60°C.

[0087] Preferred conjugated dienes used as monomers for soft block B are particularly selected from butadiene, isoprene, ethylbutadiene, phenylbutadiene, pentadiene, hexadiene, ethylhexadiene, dimethylbutadiene, and farnesene isomers, as well as any desired mixtures of these monomers. Block B may also be in the form of homopolymers or copolymers.

[0088] The conjugated diene used as the monomer for soft block B is more preferably selected from butadiene and isoprene. For example, soft block B is polyisoprene, polybutadiene, or a partially or fully hydrogenated derivative of one of these polymers, such as, in particular, polybutenebutadiene; or a polymer of a mixture of butadiene and isoprene. Very preferably, block B is polybutadiene.

[0089] The matrix material of the foam layer can, in principle, be foamed in any known manner, for example, using expandable or pre-expanded microspheres; using other hollow microspheres such as hollow polymer spheres, hollow glass spheres, or hollow ceramic spheres; using solid spheres such as solid polymer spheres, solid glass spheres, solid ceramic spheres, or solid carbon spheres; chemically, by reacting to release gas, or physically, by introducing a foaming agent or foaming gas. The foam layer preferably comprises at least partially expanded microspheres or hollow glass spheres.

[0090] "Microspheres" are understood as hollow microspheres that are elastic and therefore expandable in their basic state, and that have a thermoplastic polymer shell. These spheres are filled with a low-boiling-point liquid or liquefied gas. Shell materials used specifically include polyacrylonitrile, PVDC, PVC, or polyacrylate. Commonly used low-boiling-point liquids are hydrocarbons, particularly lower alkanes such as isobutane or isopentane, which are encapsulated as liquefied gas within the polymer shell under pressure.

[0091] The outer polymer shell is softened by exposing the microspheres, specifically by exposing them to heat. Simultaneously, the liquid foaming gas present within the shell undergoes a transformation to its gaseous state. The microspheres then undergo irreversible expansion, expanding in three dimensions. Expansion ends when the internal pressure matches the external pressure. Since the polymer shell is retained, the result is a closed-cell foam.

[0092] Several types of microspheres are commercially available, differing primarily in their size (6 to 45 μm diameter in their unexpanded state) and the onset temperature required for expansion (75 to 220 °C). Unexpanded microspheres are also available as aqueous (aqueous) dispersions with a solids or microsphere fraction of approximately 40 to 45 wt%, and additionally as polymer-bonded microspheres (masterbatches) (e.g., with a microsphere concentration of approximately 65 wt% in ethylene-vinyl acetate). Like unexpanded microspheres, both microsphere dispersions and masterbatches are suitable for use as is in the foaming of foam matrix materials.

[0093] Foamed layers can also be produced using so-called pre-expanded microspheres. In this group, expansion occurs before being incorporated (introduced) into the polymer matrix. Regardless of the preparation method and initial form of the microspheres used, the foamed layer preferably comprises at least partially expanded microspheres.

[0094] The term "at least partially expanded microspheres" is understood to mean that the microspheres have expanded to at least the extent that they produce a technically meaningful reduction in matrix material density compared to the same layer comprising unexpanded microspheres. This means that the microspheres do not necessarily need to undergo full expansion. Preferably, the "at least partially expanded microspheres" in their respective cases expand to at least twice their maximum extent in their unexpanded state.

[0095] The phrase "at least partially expanded" refers to the expansion state of an individual microsphere and is not intended to imply that only a portion of the microspheres must undergo (initial) expansion. Therefore, if "at least partially expanded microspheres" are present in the carrier layer, it means that all of these "at least partially expanded microspheres" have undergone at least partial expansion in the aforementioned sense, and that unexpanded microspheres are not among the "at least partially expanded microspheres".

[0096] The foam layer preferably comprises silica, more preferably precipitated silica that has been surface-modified with dimethyldichlorosilane. This is advantageous because it can be used to adjust the thermal shear strength of the foam layer and, more specifically, to increase the thermal shear strength of the foam layer. Furthermore, silica can be significantly used in the transparent layer. Silica is preferably present in the foam layer at a maximum of 15% by weight, based on the total amount of all polymers present in the foam layer.

[0097] Other components of the foam layer may be conventional additives, such as plasticizers, aging inhibitors, fillers, and / or flame retardants.

[0098] The compressive strength of the foam layer at 25% indentation depth (DIN EN ISO 3386-2 (2010), 25×25 mm, initial load 4 kPa, indentation speed 30 mm / min, first cycle) is preferably greater than 10 N / cm. 2 More preferably, greater than 15 N / cm 2 More specifically, greater than 30 N / cm 2 .

[0099] The foam preferably has the high compressive strength described above, so that it substantially maintains its shape and size even under sustained load. Advantageously, even with unplanned high loads on the spool, there is no lateral (transverse) extrusion (squeezing). For this behavior, it is also advantageous when the layup distance between adjacent portions of the layered structure of the invention wound onto the spool is sufficiently large. However, this distance should not be too large, causing the strip to tilt on the spool and / or penetrate into grooves and thus deform when the winding direction changes.

[0100] The foam layer can be an inner layer in the tape structure, and therefore PSAs can be provided on one or both sides. In one embodiment, the foam layer itself has pressure-sensitive adhesive properties, and preferably, the foam layer is the outer PSA layer (PSA-A) of the tape in the layered structure of the present invention.

[0101] The layered structure of the present invention includes a release liner (RL) located on the outer layer of the PSA (PSA-A).

[0102] Adhesive tapes coated with adhesive on one or both sides are typically wound into rolls or spools at the end of the production process, as already described. In the case of double-sided tape, to prevent the PSAs from contacting each other, or in the case of single-sided tape, to ensure easier unwinding, a cover material (also called a release liner) is applied to the adhesive before the tape is wound. To a technician, these types of cover materials are called release liner, or simply liner. In addition to covering single-sided or double-sided tape, liners are also used to encapsulate labels.

[0103] The release liner further ensures that the adhesive is not contaminated before use. Furthermore, the release liner can be adjusted by the properties and composition of the release material to allow the tape to be unwound with the required force (easily or with difficulty). When adhesive is applied to both sides of the tape, the release liner also serves to ensure that the correct side of the adhesive is exposed first during unwinding.

[0104] The liner or release liner is not an integral part of the tape or label, but merely a tool used in its production, storage, or further processing. Furthermore, unlike the tape carrier, the liner is not firmly bonded to the adhesive layer.

[0105] Industrially used release liner is a paper or film carrier equipped with an anti-adhesion (barrier) coating composition (also known as a release or anti-adhesion composition) to reduce the tendency of adhered products to these surfaces (release effect function). Generally and accordingly, for release liner (RL), the anti-adhesion coating compositions (also known as release coatings) that can be used cover a wide range of different substances: waxes, fluorinated or partially fluorinated compounds, and especially silicones, as well as various copolymers with silicone portions. In recent years, silicones have become a widely established release material in the tape industry due to their ease of processing, low cost, and wide range of properties. In addition, liners with polyolefin release layers have also attracted attention.

[0106] The release layer of the release liner (RL) is preferably derived from a crosslinkable silicone system. These crosslinkable silicone systems include mixtures of crosslinking catalysts / initiators and so-called thermosetting condensation-crosslinked or addition-crosslinked polysiloxanes, or radiation-induced crosslinked polysiloxanes. The silicone release layer (SR1) is preferably derived from radiation (UV or electron beam), condensation-crosslinked, or addition-crosslinked systems, more preferably from addition-crosslinked systems.

[0107] The silicone release layer of the release liner (RL) may be derived from solvent-containing and / or solvent-free systems, and preferably from solvent-free systems.

[0108] Silicone-based release agents based on addition crosslinking are typically cured by hydrogen silanization. Formulations used to produce these release agents usually contain the following components:

[0109] - Linear or branched polydiorganosiloxanes containing alkenyl groups

[0110] - Polyorganohydrosiloxane crosslinking agent, and

[0111] - Hydrogenation silanization catalyst.

[0112] Established catalysts (hydrosilylation catalysts) for addition crosslinking silicone systems particularly include platinum or platinum compounds, such as Karstedt catalysts (Pt(0) complexes). More specifically, such addition crosslinking exfoliation coatings may include the following components:

[0113] a) Linear or branched dimethylpolysiloxanes, consisting of about 80 to 200 dimethylpolysiloxane units, terminated at the chain end with a vinyldimethylsiloxy unit. A typical example is a solvent-free addition crosslinked silicone oil with terminal vinyl groups;

[0114] b) Linear or branched crosslinking agents that contain only methylhydrosiloxy units in the chain (homopolymer crosslinking agents) or are composed of methylhydrosiloxy and dimethylhydrosiloxy units (copolymer crosslinking agents), wherein the chain ends are saturated with trimethylhydrosiloxy or dimethylhydrosiloxy units. A typical example of this type of product is a hydrogen-polysiloxane with a high content of reactive Si-H.

[0115] c) Silicone MQ resin, which has vinyl dimethylsiloxy units and commonly used trimethylsiloxy units as M units;

[0116] d) Silicone-soluble platinum catalysts, such as platinum-divinyltetramethyldisiloxane complexes, commonly known as Karstedt complexes.

[0117] Silicone-containing systems used to produce release coatings are commercially available from companies such as Dow Corning, Wacker, or Momentive.

[0118] Silicone stripping systems are typically applied in an uncrosslinked state and then crosslinked.

[0119] Among specified silicones, addition-crosslinked silicones offer the greatest economic advantage. However, an undesirable property of these systems is their sensitivity to catalyst poisons such as heavy metal compounds, sulfur compounds, and nitrogen compounds (see R. Dittmeyer et al., "Chemische Technik, Prozesse und Produkte", Vol. 5, 5th ed., Wiley-VCH, Weinheim, Germany, 2005, Sections 6-5.3.2, p. 1142). Electron donors are generally considered to be platinum poisons (A. Colas, Silicone Chemistry Overview, Technical Paper, Dow Corning). Therefore, phosphorus compounds, such as phosphine and phosphites (salts), can also be considered platinum poisons. Due to the presence of catalyst poisons, the crosslinking reactions between the various components of the silicone stripper cease or occur only to a very small extent. Therefore, the presence of catalyst poisons, especially platinum poisons, is generally strictly avoided in the production of anti-adhesive silicone coatings.

[0120] Specific embodiments of silicone systems include, for example, polysiloxane block copolymers with urea blocks, or fluorosilicone release systems, particularly used in tapes containing silicone adhesives. Alternatively, photoactivated catalysts, known as photoinitiators, can be used in combination with UV-curable cationic crosslinked epoxide- and / or vinyl ether-based siloxanes and / or UV-curable free radical crosslinked siloxanes (e.g., acrylate-modified siloxanes). A further possibility is the use of electron beam-curable silicone acrylates. Photopolymerizable organopolysiloxane materials can also be used. Examples will include materials that are crosslinked in the presence of a photosensitizer through a reaction between organopolysiloxanes having hydrocarbon groups directly bonded to silicon atoms and substituted with (meth)acrylate groups. Also usable are materials in which the crosslinking reaction occurs in the presence of a photosensitizer between organopolysiloxanes having hydrocarbon groups directly bonded to silicon atoms and substituted with thiol groups and organopolysiloxanes having vinyl groups directly bonded to silicon atoms. In the case of organopolysiloxane materials having hydrocarbon groups directly bonded to silicon atoms and substituted with epoxy groups, a crosslinking reaction is induced by releasing a catalytic amount of acid, which is obtained by photolysis via an added onium salt catalyst. Other organopolysiloxane materials that can be cured via a cationic mechanism include, for example, materials having propyleneoxysiloxane end groups.

[0121] Depending on the intended use, silicone systems may also include additional additives, such as stabilizers or flow control agents.

[0122] The layered structure of the present invention further includes an intermediate liner (IL) located on the side of the tape opposite to the outer PSA layer (PSA-A), the side of the intermediate liner facing away from the tape being adhesively provided.

[0123] The intermediate liner (IL) preferably comprises a carrier layer comprising uniaxially oriented (stretched) polypropylene (MOPP), polyester, polyamide, or paper, or more preferably composed of MOPP, polyester, polyamide, or paper. These materials have advantageous stiffness and are therefore particularly suitable for maintaining the dimensional stability of the foam strip and its orientation parallel to the winding core. Particularly preferred is the polyester, which is polyethylene terephthalate (PET).

[0124] The adhesively fitted, tape-opposite side of the intermediate liner (IL) is preferably formed of a PSA, which is, in principle, arbitrarily provided, provided it is suitable for use with the intermediate liner. A “suitable PSA for use with the intermediate liner” preferably exhibits good anchoring to the carrier material of the intermediate liner; where appropriate, this anchoring can also be aided by pre-treating the carrier or the PSA. Furthermore, the adhesive preferably has good cohesive strength, so as to avoid residue when the intermediate liner is removed and to prevent “exudation” under the temperature and pressure present within the spool.

[0125] PSA is preferably based on poly(meth)acrylate or natural rubber. PSA preferably has a concentration of 1 to 30 g / m³. 2 The coating weight. Its peel adhesion (Afera 5001, Method A, 300 mm / min, 180°, steel) is preferably 0.3 to 5 N / cm, more preferably 1 to 4 N / cm. More specifically, the peel adhesion of the PSA relative to the associated release liner (RL) in the spool structure (Afera 5001, Method F, 300 mm / min, 90°, outside of the release liner (RL)) is preferably 0.1 to 3 N / cm. Due to this peel adhesion, the intermediate liner or layered structure of the present invention generally does not slip (fall off) during and after winding onto the spool, but on the other hand, the intermediate liner can be separated from the release liner by conventionally applied force. Of interest here is the side of the release liner, in other words, the side that is not located on the outer layer of the PSA (PSA-A), which is preferably siliconized or a polyethylene (PE) or polypropylene (PP) layer.

[0126] "The side of the intermediate pad (IL) that is adhesively fitted" refers to the outer side; therefore, the adhesive fit is not related to the inner layer in the pad structure, but rather points outwards; thus, the intermediate pad (IL) can produce an outward-pointing adhesive effect on the relevant side. The adhesive fit of the side of the intermediate pad (IL) opposite to the tape is preferably formed by a poly(meth)acrylate-based PSA, more particularly based on an aqueous poly(meth)acrylate dispersion.

[0127] The total thickness of the intermediate liner (IL) (DIN EN 1942 (2003), 10 mm disc, 51 kPa) is preferably 50 to 300 μm, more preferably 70 to 150 μm. These ranges have proven particularly advantageous because the tendency of the wound layers of the layered structure to adhere to each other is greatly minimized, while the flexibility of the layered structure (e.g., in terms of its bending capacity) is also greatly reduced. (In other words) there are no adverse effects.

[0128] The tensile strength of the intermediate liner (IL) (ISO 527-3 (1995-08); specimen type 2, test speed 150 mm / min) is preferably 10 to 150 N / cm, more preferably 50 to 110 N / cm.

[0129] The side of the intermediate pad (IL) facing the tape is formed by the following:

[0130] - Release layer, everything said about the release layer of the release liner (RL) applies here, or

[0131] - The additional pressure-sensitive adhesive layer, all the statements above regarding the pressure-sensitive adhesive forming the intermediate liner (IL) on the side opposite to the tape, applies here.

[0132] In one embodiment, the tape of the layered structure of the present invention includes an outer heat-activated adhesive layer, which is directly adjacent to an intermediate pad (IL), and the side of the intermediate pad (IL) facing the tape is formed by another pressure-sensitive adhesive layer, and all the above statements regarding the pressure-sensitive adhesive forming the side of the intermediate pad (IL) away from the tape apply here.

[0133] "Heat-activated adhesive layer" (hereinafter also referred to as "heat-activated adhesive") means an adhesive layer that is not adhesive at room temperature and only requires heating to produce sufficient adhesion to a substrate to create an adhesive bond with the substrate. "Heating" generally refers to exposure to temperatures in the range of about 60 to about 200°C, and more particularly, in the range of 120°C to 200°C according to the invention.

[0134] The heat-activated adhesive layer is preferably a polyolefin layer. The polyolefin may be derived from one or more olefin monomers. The material of the heat-activated adhesive layer is preferably selected from polyethylene, polypropylene, ethylene-propylene copolymers, and mixtures of these polymers. More preferably, the material of the heat-activated adhesive layer is polypropylene.

[0135] Another subject of the invention is a spool, comprising a spool core and a layered structure of the invention, the layered structure being wound in multiple layers crosswise around the spool core, wherein...

[0136] - In the innermost layer, the adhesively fitted side of the intermediate liner (IL) rests directly on the spool core, and

[0137] - In each layer, the adhesively fitted side of the intermediate liner (IL) forms the inner side of the layered structure facing the spool core.

[0138] The spool of the present invention is advantageously implemented because the intermediate pad (IL) adheres to the corresponding underlying layer of the tape provided with the release pad (RL). Due to this principle, adjacent tape layers maintain their distance from each other even under internal and external loads on the spool, loads that may occur during storage, transport, and use. Furthermore, reduced winding tension can be utilized during winding, thus the tape can be gently wound without extrusion.

[0139] The spool of the present invention preferably has a diameter of up to 500 mm, more preferably 200 mm to 400 mm. The weight of the spool preferably does not exceed 20 kg, more preferably 5 to 15 kg. The tape of the layered structure of the present invention preferably has a running length of up to 2000 m, more preferably 200 to 1600 m on the spool. The width of the tape, and therefore—because the layers are substantially flush with each other—of the layered structure on the spool of the present invention is preferably 2 to 40 mm, more preferably 3 to 20 mm. The thickness of the layered structure on the spool of the present invention is preferably 200 to 3000 μm, more preferably 400 to 1600 μm, wherein as the thickness increases, the running length (Laufmeter) can be correspondingly reduced, and narrower dimensions become increasingly difficult to wind. The lay-up distance between adjacent portions of the layered structure of the present invention on the spool is preferably greater than 0.7 mm, more preferably 0.8 to 2 mm. In principle, the lay-up distance in the inner layers of the spool can be greater than the lay-up distance in the outer layers.

[0140] pass Figure 1 This makes the layered structure of the present invention clearer. Figure 1 The layered structure of the present invention located on the spool core is schematically shown, wherein the order of the various layers shown is exemplary. Figure 1 The markings in the text are as follows:

[0141] 1- Tape

[0142] 2-Release Liner (RL)

[0143] 3-Pressure-sensitive adhesive outer layer (PSA-A) of the tape

[0144] 4-Intermediate Pad (IL)

[0145] 5-Carrier of Intermediate Liner (IL)

[0146] 6-Intermediate pad (IL) is adhesively fitted to the side facing away from the tape.

[0147] 7-Spool core

[0148] Another subject of the present invention is a method for manufacturing the spool of the present invention, comprising:

[0149] -Provides a layered structure of the present invention that can be wound into a master roll;

[0150] - Separate layered structures, so that multiple webs with a lower web width than the master roll can be obtained from the webs forming the master roll;

[0151] - Provides spool cores; and

[0152] - Wind the webs onto the spool core separately, so that

[0153] o generates multiple overlapping layers;

[0154] In the innermost layer, the adhesively fitted side of the intermediate liner (IL) rests directly on the spool core; and

[0155] In each layer, the adhesively fitted side of the intermediate liner (IL) forms the inner side of the layered structure facing the spool core.

[0156] The method of the present invention can be carried out advantageously without the need for a separate lamination of an intermediate pad that is wider than the tape, and therefore can be carried out significantly more efficiently than conventional methods.

[0157] In an alternative method, the web is wound onto the spool core in such a manner that, in the innermost layer, the release liner (RL) on the pressure-sensitive adhesive outer layer (PSA-A) lies directly on the spool core, and correspondingly, in each further layer, it also forms a layered structure facing inward toward the spool core. Since, in this case, the adhesively fitted side of the intermediate liner (IL) faces outward in the final layer, the spool will be wrapped with an additional release liner. Example

[0158] Test methods

[0159] Test Method T1: Visual Evaluation

[0160] Trim the tapes listed in Table 1 (each tape has a release liner on one side and an intermediate liner on the opposite side) from the master roll to the corresponding specified width, and cross-wind them into spools according to the parameters specified in the table. Store the resulting spools under the following conditions:

[0161] - One month at 23℃

[0162] - One month at 40℃

[0163] - 2 months at 40℃.

[0164] A visual assessment was then conducted accordingly based on the following (negative) criteria:

[0165] 1. Does the spool deviate from its original cylindrical shape?

[0166] 2. Does the spool core protrude asymmetrically to the left and right?

[0167] 3. Is the distribution of the wound tape across the width of the spool uneven (the distance between adjacent tape sections is different)?

[0168] 4. Have the outermost strips slipped off the edge of the spool / Are they no longer in their original position?

[0169] If all questions receive a "no" answer, the visual assessment is rated "good"; otherwise, it is rated "bad".

[0170] Test method T2: Unwinding behavior

[0171] After storage as described in method T1, the spool is unwound on an Ehnert AWS18G unwinder without pressure rollers and without using an intermediate liner winding machine; the unwinding speed is 15 m / min.

[0172] In this case, the evaluation criteria are as follows:

[0173] 5. Can the belt be unwound uniformly around the axis without force peaks, especially at points where the direction changes?

[0174] 6. Are the composite materials held together (no accidental separation of the liner)?

[0175] 7. Is it always possible to cleanly separate adjacent strip portions (without adhesion between adjacent strip portions), especially in areas where the winding direction changes (a maximum of 5 slight, reversible adhesions are acceptable, but as indicated in the table)?

[0176] 8. Are the intermediate pads and release pads on the tape equal?

[0177] 9. Is there any perceptible deviation in the distance between adjacent sections of tape?

[0178] 10. Are the peeling liner and intermediate liner not folded?

[0179] 11. Do the tape portions at the opposite points in the winding direction maintain their curved shape (compare two strips, each 1m long from the center of the spool and from the turning point; assess their parallelism when placed side by side)?

[0180] 12. Is it possible to remove the intermediate pad evenly and without clicking after unwinding?

[0181] If all questions receive a "yes" answer, the unwinding behavior is rated "good"; otherwise, it is rated "bad". Table 1 also lists the observed but still acceptable defects.

[0182] Use the following adhesive materials as intermediate backing (corresponding to intermediate backing (IL)):

[0183] Intermediate pad 1 (IL1): Adhesive tape 64250 (Single-sided acrylic tape with MOPP backing; commercially available, total thickness 80μm; tensile strength 100N / cm)

[0184] Intermediate pad 2 (IL2): Adhesive tape 4360 (Single-sided acrylic tape with PE backing; commercially available; total thickness 51 μm; tensile strength 13 N / cm)

[0185] Intermediate pad 3 (IL3): Adhesive tape 50600 (Single-sided silicone tape with PET backing; commercially available; total thickness 80μm; tensile strength 50N / cm)

[0186] Use the following tapes:

[0187] Tape 1: ACX plus 7805PV29 (Double-sided acrylic foam tape with a release liner on one side; commercially available), 6mm width; compressive strength 46N / cm 2

[0188] Tape 2: ACX plus 77115PV28 (Double-sided acrylic foam tape with a release liner on one side; commercially available), 10mm wide; compressive strength 37N / cm 2

[0189] Tape 3: ACX plus 7812PV29 (Double-sided acrylic foam tape with a release liner on one side; commercially available), 4mm wide; compressive strength 46N / cm 2

[0190] Tape 4: ACX plus 77811PV 15 (Double-sided acrylic foam tape with a release liner on one side; commercially available), 6mm wide; compressive strength 16N / cm 2 .

[0191] The corresponding structure is provided in the form of a master roll with adhesive tape, an applied release liner, and an intermediate liner. The master roll is unwound and cut using a winding machine. The resulting layered structure, cut to the target width, is then wound using a winding machine to form a cross-wound spool; the corresponding parameters are reported in Table 1.

[0192] Table 1:

[0193]

Claims

1. A layered structure, comprising: - A tape comprising at least one pressure-sensitive adhesive outer layer (PSA-A); - A release liner (RL) located on the outer layer (PSA-A) of the pressure-sensitive adhesive; and - Intermediate pad (IL), which is located on the side of the tape opposite to the outer layer of pressure-sensitive adhesive (PSA-A), the side of the intermediate pad opposite to the tape is adhesively provided; Its characteristic is that all layers of the layered structure are substantially flush with each other. The gasket is not firmly bonded to the adhesive layer. The release liner (RL) and the intermediate liner (IL) are positioned on opposite sides of the tape.

2. The layered structure as described in claim 1, characterized in that, The intermediate liner (IL) includes a carrier layer, which includes MOPP, polyester, polyamide, or paper.

3. The layered structure as described in any one of claims 1 and 2, characterized in that, The tape includes a poly(meth)acrylate-based foam layer.

4. The layered structure as described in any of the preceding claims, characterized in that, The side of the intermediate pad (IL) facing away from the tape is formed of a pressure-sensitive adhesive based on poly(meth)acrylate or natural rubber.

5. The layered structure as described in claim 1 or 2, characterized in that, The tape consists of only a single pressure-sensitive adhesive layer.

6. The layered structure as described in claim 1 or 2, characterized in that, The tape has a pressure-sensitive adhesive layer on only one or both sides of the carrier material.

7. The layered structure as described in claim 6, characterized in that, The carrier material itself is a pressure-sensitive adhesive.

8. The layered structure as described in claim 3, characterized in that, The foam layer comprises a total of 40 to 70% by weight of poly(meth)acrylate, based on the total weight of the foam layer.

9. The layered structure as described in claim 8, characterized in that, The foam layer comprises a total of 45 to 60% by weight of poly(meth)acrylate, based on the total weight of the foam layer.

10. The layered structure as described in claim 3, characterized in that, The foam layer comprises a total of at least 90% by weight of poly(meth)acrylate, based on the total weight of the foam layer.

11. The layered structure as described in claim 10, characterized in that, The foam layer comprises a total of at least 95% by weight of poly(meth)acrylate, based on the total weight of the foam layer.

12. The layered structure as described in claim 3, characterized in that, The glass transition temperature of the poly(meth)acrylate in the foam layer is <0℃.

13. The layered structure as described in claim 12, characterized in that, The glass transition temperature of the poly(meth)acrylate in the foam layer is between -20°C and -50°C.

14. The layered structure as described in claim 3, characterized in that, The poly(meth)acrylate of the foam layer contains at least one functional monomer that is copolymerized in proportion and reacts with epoxy groups to form covalent bonds.

15. The layered structure as described in claim 14, characterized in that, The functional monomer contains at least one functional group selected from the following: carboxylic acid group, sulfonic acid group, phosphonic acid group, hydroxyl group, acid anhydride group, epoxy group and amino group.

16. The layered structure as described in claim 14, characterized in that, Poly(meth)acrylates contain acrylic acid and / or methacrylic acid copolymerized in proportion.

17. The layered structure as described in claim 3, characterized in that, The poly(meth)acrylate of the foam layer comprises at least one proportionally copolymerized monomer having at least one functional group capable of supporting or initiating subsequent radiation crosslinking.

18. The layered structure as claimed in claim 17, characterized in that, The functional groups can support or trigger subsequent crosslinking via UV radiation.

19. The layered structure as described in claim 3, characterized in that, The poly(meth)acrylate of the foam layer is derived from the following monomers: a) At least one acrylate and / or methacrylate of formula (1): CH2=C(R I )(COOR II )(1), Where R I = H or CH3, and R II Alkyl groups having 4 to 18 carbon atoms; b) At least one olefinic unsaturated monomer having at least one functional group selected from the following: carboxylic acid group, sulfonic acid group, phosphate group, hydroxyl group, acid anhydride group, epoxy group and amino group; c) Optionally additional acrylates and / or methacrylates and / or olefinic unsaturated monomers that can copolymerize with component (a).

20. The layered structure as described in claim 3, characterized in that, Poly(meth)acrylates are cross-linked through the bonding reaction between the functional groups they contain and a thermal cross-linking agent.

21. The layered structure as described in claim 20, characterized in that, The thermal crosslinking agent is used at 0.1 to 5% by weight, based on the total amount of the polymer to be crosslinked.

22. The layered structure as described in claim 3, characterized in that, The foam layer comprises at least one type of synthetic rubber.

23. The layered structure as described in claim 22, characterized in that, The foam layer comprises a total of 15 to 50% by weight of synthetic rubber, based on the total weight of the foam layer.

24. The layered structure as described in claim 23, characterized in that, The foam layer comprises a total of 20 to 40% by weight of synthetic rubber, based on the total weight of the foam layer.

25. The layered structure as described in claim 22, characterized in that, The synthetic rubber exists as a dispersion in the poly(meth)acrylate within the foam layer.

26. The layered structure as described in claim 25, characterized in that, Both poly(meth)acrylate and synthetic rubber are homogeneous phases.

27. The layered structure as described in claim 25, characterized in that, The foam layer comprises 40-70% by weight of at least one poly(meth)acrylate and 15-50% by weight of at least one synthetic rubber, respectively, based on the total weight of the foam layer.

28. The layered structure as described in claim 1 or 2, characterized in that, The tape includes a foam layer based on synthetic rubber.

29. The layered structure as described in claim 28, characterized in that, The foam layer contains at least 90% by weight of synthetic rubber, based on the total weight of the foam layer.

30. The layered structure as described in claim 29, characterized in that, The foam layer contains at least 95% by weight of synthetic rubber, based on the total weight of the foam layer.

31. The layered structure as described in claim 3, characterized in that, The matrix material of the foam layer has been foamed using expandable or pre-expanded microspheres.

32. The layered structure as described in claim 31, characterized in that, The foam layer comprises silica.

33. The layered structure as described in claim 32, characterized in that, The foam layer comprises precipitated silica that has been surface-modified with dimethyldichlorosilane.

34. The layered structure as described in claim 1 or 2, characterized in that, The release layer of the release liner (RL) is derived from a crosslinkable silicone system.

35. The layered structure as described in claim 34, characterized in that, The crosslinkable silicone system comprises a mixture of a crosslinking catalyst / initiator and a thermocurable condensation-crosslinked or addition-crosslinked polysiloxane, or a radiation-induced crosslinked polysiloxane.

36. The layered structure as described in claim 2, characterized in that, The polyester is polyethylene terephthalate (PET).

37. The layered structure as described in claim 4, characterized in that, The pressure-sensitive adhesive has a concentration of 1 to 30 g / m 2 The weight of the coating.

38. The layered structure as described in claim 4, characterized in that, The side of the intermediate pad (IL) facing away from the tape is formed of a pressure-sensitive adhesive based on poly(meth)acrylate.

39. The layered structure as described in claim 38, characterized in that, The side of the intermediate pad (IL) facing away from the tape is formed by a pressure-sensitive adhesive based on a water-based poly(meth)acrylate dispersion.

40. The layered structure as described in claim 1 or 2, characterized in that, The total thickness of the intermediate liner (IL) is 50 to 300 μm.

41. The layered structure as described in claim 40, characterized in that, The total thickness of the intermediate liner (IL) is 70 to 150 μm.

42. The layered structure as described in claim 1 or 2, characterized in that, The side of the intermediate pad (IL) facing the tape is formed by the following: - Peel-off layer, or - An additional pressure-sensitive adhesive layer.

43. The layered structure as described in claim 1 or 2, characterized in that, The tape includes an outer heat-activated adhesive layer that is directly adjacent to an intermediate pad (IL), and the side of the intermediate pad (IL) facing the tape is formed by another pressure-sensitive adhesive layer.

44. The layered structure as described in claim 43, characterized in that, The heat-activated adhesive layer is a polyolefin layer.

45. A spool comprising a spool core and a layered structure as described in any of the preceding claims, the structure being wound in a plurality of intersecting layers around the spool core, wherein... - In the innermost layer, the adhesively fitted side of the intermediate liner (IL) rests directly on the spool core, and - In each layer, the adhesively fitted side of the intermediate liner (IL) forms the inner side of the layered structure facing the spool core.

46. ​​The spool as described in claim 45, characterized in that, The spool has a diameter of up to 500 mm.

47. The spool as described in claim 46, characterized in that, The spool has a diameter of 200 mm to 400 mm.

48. The spool as described in claim 45 or 46, characterized in that, The weight of the spool is no more than 20 kg.

49. The spool as described in claim 48, characterized in that, The weight of the spool is 5 to 15 kg.

50. The spool as described in claim 45 or 46, characterized in that, The tape of the layered structure has a running length of up to 2000 m on the spool.

51. The spool as described in claim 50, characterized in that, The tape of the layered structure has a running length of 200 to 1600 m on the spool.

52. The spool as described in claim 45 or 46, characterized in that, The width of the layered structure on the spool is 2 to 40 mm.

53. The spool as described in claim 52, characterized in that, The width of the layered structure on the spool is 3 to 20 mm.

54. The spool as described in claim 45 or 46, characterized in that, The thickness of the layered structure on the spool is 200 to 3000 μm.

55. The spool as described in claim 54, characterized in that, The thickness of the layered structure on the spool is 400 to 1600 μm.

56. The spool as described in claim 45 or 46, characterized in that, The adjacent portions of the layered structure are laid at a distance greater than 0.7 mm on the axis.

57. The spool as described in claim 56, characterized in that, The adjacent portions of the layered structure are laid at a distance of 0.8 to 2 mm on the axis.

58. A method for manufacturing a spool as described in any one of claims 45 to 57, comprising: - Provides a layered structure as described in any one of claims 1 to 44, wound into a master roll; - Separate layered structures, so that multiple webs with a lower web width than the master roll can be obtained from the webs forming the master roll; -Provide spool cores; and - Wind the webs onto the spool core separately, so that ○ This generates multiple overlapping layers; ○ In the innermost layer, the side of the intermediate pad (IL) that is adhesively fitted is located directly on the spool core; and In each layer, the adhesively fitted side of the intermediate liner (IL) forms the inner side of the layered structure facing the spool core.

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