Weatherproof adhesive with good flow properties and adhesive tapes based on it

Description

[0001] The present invention relates to an adhesive compound for permanent bonding with high weather resistance, adhesive tapes based thereon and their use.

[0002] Styrene block copolymer-containing pressure-sensitive adhesives are well-known and used in a wide variety of self-adhesive tapes for diverse purposes. The combination of polystyrene and polydiene blocks results in mechanical and adhesive properties that are advantageous for many applications. However, improved aging resistance is desired for certain applications. For this purpose, styrene block copolymers are frequently used in which the polydiene block is hydrogenated and thus saturated. Due to their relatively low adhesive strength, such formulations are particularly suitable for reversible pressure-sensitive applications, but also as hot melts.

[0003] Problems arise when one wants to "tackify" such age-stable adhesives, i.e., increase their tackiness to ensure that the adhesive bond is formed under the lowest possible pressure and with the shortest possible contact time, because tackification is difficult when using block copolymers whose elastomer blocks are essentially completely saturated; it requires a special resin / soft resin combination.

[0004] This is especially true when an adhesive is intended for adhesion to porous and / or fibrous substrates. The requirements in this case, namely a certain degree of flow of the adhesive into the porous substrate, cannot be adequately met by conventional weather-resistant adhesives. This is particularly true if, in addition to good adhesion to porous substrates, the squeezing out of the adhesive, also known as "oozing," is to be avoided. Oozing occurs when the adhesive is too soft and therefore not dimensionally stable, and in the case of a wound adhesive tape, it oozes out of the roll at the sides. It is known to add plasticizers to an adhesive to adjust its flowability.

[0005] Age-resistant adhesives are known, for example, from DE 102 52 089 A1. This document discloses adhesives comprising at least one block copolymer with one or two terminal blocks consisting of vinyl aromatics and one block consisting of a conjugated diene in which the proportion of 1,2-linked diene is selectively hydrogenated. Hydrogenated hydrocarbon resins are very preferably used as adhesive resins. Plasticizers are mentioned; they are used up to a maximum of 5 wt.%, preferably without being used at all. While the adhesives obtained in this way exhibit increased age resistance, their adhesive properties, particularly their initial tackiness, on porous and / or fibrous surfaces can still be improved. Adhesive compounds with increased aging stability and improved adhesive strength and tackiness, in order to be used also on rough and non-polar substrates, are described in DE 10 2008 034 369 A1 and EP 2 147 959 A1.These are also adhesives containing at least one block copolymer that is selectively hydrogenated or saturated in the elastomer block, with, for example, the terminal double bonds being primarily saturated. The adhesives described in the aforementioned publications are those with a first block copolymer comprising one or more terminal blocks consisting of vinyl aromatics and at least one block consisting of conjugated dienes, in which the terminal double bonds formed by 1,2-linkage are hydrogenated to more than 80%, while the double bonds in the main chain, formed by 1,4-linkage, are hydrogenated to less than 30%, and at least one second block copolymer comprising one or more terminal blocks consisting of vinyl aromatics and at least one block consisting of conjugated dienes, in which at least 95% of the double bonds are hydrogenated.Plasticizers used include plasticizer oils such as mineral oils or low molecular weight liquid polymers such as low molecular weight polybutenes.

[0006] Further adhesives based on an SBBS block copolymer are described in JP 2002 / 097,432 A, US 7,268,178 B2, WO 2010 / 009854 A1, US 2017 / 292048 A1, JP 2017 / 186487 A and US 2011 / 0086563 A1. Plasticizers are either not included or are used in the form of liquid compounds, particularly vegetable and mineral oils.

[0007] Those skilled in the art are therefore aware that plasticizers for pressure-sensitive adhesive formulations based on hydrogenated styrene block copolymers primarily include oils (paraffinic or naphthenic) and liquid polyolefins or rubbers or liquid hydrocarbon resins. The known adhesives still offer potential for optimization, particularly with regard to their adhesive properties, especially tack, on porous and / or fibrous surfaces.

[0008] The present invention was therefore based on the objective of providing an adhesive compound that has high long-term stability and is particularly suitable for bonding to porous and / or fibrous materials, which may also be flexible and / or non-polar, and which in particular has good tack.

[0009] Surprisingly, it was found that an adhesive compound consisting of an elastomer, at least one adhesive resin, optionally a soft resin and optionally at least one further additive, wherein the adhesive compound has one of the following two compositions A or B: Composition A:

[0010] Aa) 35 wt.% to 60 wt.% of an elastomer component containing at least 80 wt.% of at least one type of vinyl aromatic block copolymer, which contains at least one block consisting of conjugated dienes in which the terminal double bonds formed by 1,2-linkage are hydrogenated to more than 80%, while the double bonds in the main chain, formed by 1,4-linkage, are hydrogenated to less than 30%; Ab) 0 wt.% to 40 wt.% of at least one type of a first adhesive resin, which is a partially or fully hydrogenated hydrocarbon resin with a degree of hydrogenation of at least 65%; Ac) 10 wt.% to 50 wt.% of at least one type of a second adhesive resin, which is a rosin ester; Ad) 0 wt.% to 25 wt.% of a soft resin with a melt viscosity at 25°C and 1 Hz of at least 5 Pa s; Ae) 0 wt.% up to 5 wt% of at least one other additive, wherein the total proportion of adhesive resin is 20 wt.% to 50 wt.%; or Composition B: Ba) 35 wt.% to 60 wt.% of an elastomer component containing at least 80 wt.% of at least one type of vinyl aromatic block copolymer, which contains at least one block consisting of conjugated dienes in which the terminal double bonds formed by 1,2-linkage are hydrogenated to more than 80%, while the double bonds in the main chain, formed by 1,4-linkage, are hydrogenated to less than 30%, Bb) 10 wt.% to 50 wt.% of at least one type of first adhesive resin, which is a partially or fully hydrogenated hydrocarbon resin with a degree of hydrogenation of at least 65%, Bc) 0 wt.% to 10 wt.% of at least one type of second adhesive resin, which is a rosin ester, Bd) 15 wt.% to 25 wt.% of a soft resin with a melt viscosity at 25°C and 1 Hz of at least 5 Pa s, Be)0 wt.% to 5 wt.-% of at least one other additive, wherein the total proportion of adhesive resin is 10 wt.% to 50 wt.%, and the proportion of low-viscosity plasticizers in the adhesive mass is at most 1 wt.%. It meets these requirements and allows it to flow into a porous and / or fibrous substrate to create a good bond, while simultaneously exhibiting sufficient cohesion to prevent oozing, good long-term stability, and good initial tack. "Good long-term stability" refers in particular to stability against temperature, light, and oxidation.

[0011] "Consisting of" or "comprising" within the meaning of the present invention means that an (adhesive) composition, adhesive, or (adhesive) formulation contains only the compounds listed and no other ingredients are present. In the present invention, the terms (adhesive) composition, adhesive, and (adhesive) formulation are used synonymously.

[0012] Preferred embodiments of the adhesive compound are set out in the dependent claims. (a) elastomer component

[0013] The elastomer component (block copolymer component) contains at least 80 wt% of at least one type of vinyl aromatic block copolymer (such as, in particular, a styrene block copolymer) which contains at least one block consisting of conjugated dienes in which the terminal double bonds, formed by 1,2-linkage, are hydrogenated to more than 80%, while the double bonds in the main chain, formed by 1,4-linkage, are hydrogenated to less than 30%. The vinyl aromatic block copolymer is preferably a styrene block copolymer, more preferably a polystyrene-poly(butadiene- co -butylene) block copolymer (SBBS). A polystyrene-poly(butadiene-co-butylene) block copolymer (SBBS) is generally understood to be a block copolymer that is selectively saturated (hydrogenated) in the elastomeric block, i.e., soft block, with the terminal double bonds being primarily hydrogenated. The polystyrene-poly(butadiene- co-butylene) block copolymer typically has one or more terminal polystyrene blocks and at least one poly(butadiene-co-butylene) block. The polystyrene-poly(butadiene- co -butylene) block copolymer can have various structures or a mixture of different structures. Thus, SBBS can be, in particular, a triblock copolymer, a diblock copolymer, a linear or radial higher multiblock copolymer, or a mixture thereof. The polystyrene-poly(butadiene- co- butylene) block copolymer, at least partially, polystyrene-poly(butadiene- co -butylene)-polystyrene (i.e., triblock copolymer). The polystyrene-poly(butadiene- co -butylene) block copolymer can also be used according to the invention as a mixture with other vinyl aromatic block copolymer (in particular styrene block copolymer) as defined above.

[0014] Preferably, the elastomer component consists entirely of the previously described polystyrene-poly(butadiene- co -butylene) block copolymer (SBBS).

[0015] If additional vinyl aromatic block copolymers are used, these can be, in particular, saturated styrene block copolymers. The saturation refers not to the styrene block itself, but to the elastomer block, i.e., the soft block. The saturated styrene block copolymers are typically selected from the group consisting of polystyrene-poly(ethylene- co -butylene)-polystyrene (SEBS), polystyrene-poly(ethylene-co-propylene)-polystyrene (SEPS), elastomer block saturated polystyrene-poly(isoprene-co-butadiene)-polystyrene (SEEPS), polystyrene-poly-iso-butylene-polystyrene (SiBS) and any mixture thereof.

[0016] The proportion of the elastomer component in the adhesive is 35% to 60% by weight. These weight proportions ensure the desired cohesion of the adhesive.

[0017] The elastomer component advantageously contains at least a proportion of a diblock copolymer consisting of an A-block (polymer block, predominantly formed from a vinyl aromatic compound such as styrene) and a B-block (polymer block, predominantly formed by polymerization of butadiene (and subsequent hydrogenation as defined above)). Diblock copolymers contribute to the tack and flowability of the adhesive. At least one vinyl aromatic block copolymer, such as a styrene block copolymer, is typically a triblock copolymer or a higher multiblock copolymer with at least two A-blocks and at least one B-block. This triblock copolymer can have a linear ABA structure. Radial block copolymers, as well as star-shaped and linear multiblock copolymers, can also be used. Triblock and multiblock copolymers contribute to cohesion. Several different diblock copolymers can be used.Several triblock and / or multiblock copolymers can be used. The total block copolymer content in the adhesive is at least 35 wt.% and at most 60 wt.%. Significantly lower elastomer content leads to insufficient cohesion, resulting in reduced holding power and / or excessive oozing. Significantly higher elastomer content leads to a decrease in bond strength, particularly on non-polar substrates. Flow behavior on porous and / or fibrous substrates is also impaired.

[0018] The proportion of diblock copolymers relative to the elastomer component in the adhesive formulation is preferably at least 25 wt.%, very preferably at least 50 wt.%. Preferably, the elastomer component contains at most 90 wt.% diblock copolymer. Higher diblock proportions lead to insufficient cohesion, which manifests itself in reduced holding power. Accordingly, the proportion of triblock or higher multiblock copolymer in the elastomer component is preferably from 10 wt.% to 75 wt.%, more preferably from 10 wt.% to 50 wt.% relative to the elastomer component. Among the triblock or higher multiblock copolymers, the triblock copolymers are particularly preferred.

[0019] The weight-average molar mass of the block copolymers is between 50,000 g / mol and 500,000 g / mol, preferably between 75,000 g / mol and 200,000 g / mol (each determined according to Test IVb). The proportion of vinyl aromatic block in the vinyl aromatic block copolymers can vary from block copolymer type to block copolymer type in the formulation, but is typically at least 12 wt.%, preferably at least 25 wt.%, and at most 40 wt.%, preferably at most 35 wt.%. Too low a vinyl aromatic content leads to insufficient physical crosslinking, which is created in the vinyl aromatic block copolymers by microphase separation. Physical crosslinking is important for holding power and tear strength and counteracts oozing. Conversely, if the vinyl aromatic content is too high, the adhesive loses its tackiness.

[0020] Polystyrene-poly(butadiene- co-butylene) block copolymers can be obtained, for example, from the company Asahi Kasei under the brand names "Tuftec P" and "Tufprene".

[0021] Polystyrene-polyisobutylene block copolymers are available under the brand name "Sibstar" from Kaneka. SEBS and SEPS can be obtained from Kraton under the name "Kraton G". SEPS and SEEPS are offered, for example, as "Septon" by Kuraray. SEBS is distributed by Asahi under the name "Tuftec H" and by Dynasol under the name Calprene CH. (b) First adhesive resin

[0022] Adhesive resins are special compounds with a lower molecular weight compared to elastomers, typically with a molecular weight (Test IVa) MW < 5,000 g / mol. Typically, the molecular weight MW is from 500 to 5,000 g / mol, preferably from 500 to 2,000 g / mol. The at least one first adhesive resin is a partially or fully hydrogenated hydrocarbon resin with a degree of hydrogenation of at least 65%. Preferably, the degree of hydrogenation is at least 70%, particularly at least 80%, and most preferably the hydrocarbon resin is fully hydrogenated.

[0023] Particularly suitable are, among others: Hydrogenated polymers of dicyclopentadiene (e.g., Escorez 5300 series; Exxon Chemicals / / Sukorez series from Kolon) Hydrogenated polymers of preferably C8 and C9 aromatics (e.g., Regalite and Regalrez series; Eastman Chemical / / Arkon P series; Arakawa), these can be formed by hydrogenation of polymers from pure aromatic streams or by hydrogenation of polymers based on mixtures of different aromatics Partially hydrogenated polymers of C8 and C9 aromatics (e.g., Regalite and Regalrez series; Eastman Chemical / / Arkon M; Arakawa) Hydrogenated polyterpene resins (e.g., Clearon P; Yasuhara) Hydrogenated C5 / C9 polymers (e.g., ECR-373; Exxon Chemicals) Aromatic-modified selectively hydrogenated dicyclopentadiene derivatives (e.g., Escorez 5600 series; Exxon Chemicals) Hydrogenated C5 polymers (for example, Eastotac series; Eastman Chemical)

[0024] Examples of particularly suitable first adhesive resins are the hydrogenated hydrocarbon resins sold under the names Regalite R 1100 and R 1125 by Eastman Chemical.

[0025] The total proportion of first adhesive resin is 0 wt.% to 40 wt.%, preferably 10 wt.% to 30 wt.% in variant A and 10 wt.% to 50 wt.%, preferably 20 wt.% to 40 wt.% in variant B. (c) Second adhesive resin

[0026] The second adhesive resin, at least one of which is a rosin ester, has a resin softening temperature (according to Test V) of at least approximately 70 °C, preferably at least approximately 90 °C, and at most +140 °C, preferably at most +120 °C. The rosin ester used can be a resin based on non-hydrogenated, partially, and / or fully hydrogenated rosin ester. In particular, it is a stabilized and / or hydrogenated type.

[0027] The main component of the aforementioned rosin resins are resin acids, comprising primarily pimaric acid and abietic acid. Other resin acids present and / or synthetically modified include neoabietic acid, palustric acid, dihydroabietic acid or dehydroabietic acid, iso-pimaric acid, levopimaric acid, and boswellic acid. Tall oil is an oily mixture obtained from solid rosin resin, comprising, in addition to the aforementioned resin acids, fatty acids, particularly unsaturated fatty acids with 18 carbon atoms, and sterols. The resin acids and / or fatty acids are esterified, particularly with triethylene glycol, glycerol, or pentaerythritol, and optionally oligomerized, stabilized, (partially, extensively, or fully) hydrogenated, dehydrogenated, and / or disproportionated.

[0028] Resins from Eastman Chemical such as glycerol esters of rosin resin or tall oil-based resins such as Permalyn™< 2085, Permalyn™< 5095, Permalyn™< 5095-C, hydrogenated or partially hydrogenated rosin resin such as Foral™< 105-E CG, Foral™< 85-E, Foral™< 85-E CG, Foral™< 105-E, Dymerex™< AX-E, Foralyn™< E, Poly-Pale™< , Staybelite™< Resin-E, pentaerythritol esters of rosin or tall oil-based resins such as Permalyn™< 51 1 -M, Permalyn™< 3100, Permalyn™< 51 10, Permalyn™< 51 10-C, Permalyn™< 61 10, Permalyn™< 61 10-M and Permalyn™< 8120 are examples of resins that can be used.

[0029] Resins from the company Pinova, such as Pinova™ Ester Gum 8DA, Melhi® NLM, Pexalyn® 9085, Staybelite® Ester 5, Staybelite® Ester 5A, Staybelite® Ester 10, Staybelite® Ester 10A, Foral® 85, Foral® 85LB, Foral® 2085, Pentalyn® A, Pexalyn® 9100, Pexalyn® T100, Pexalyn® 295, Pentalyn® H, Pentalyn® HA, Pentalyn® 830, Pentalyn® FC, Pentalyn® G, Pentalyn® X, and Foral® 105, are further examples of resins that can be used.

[0030] Resins from the company DRT such as Granolite SG, Granolite P, Dertoline SG2, Dernatac G95, Dernatac P105, Hydrogral P are further examples of resins that can be used.

[0031] Preferred examples of the second type of adhesive resin are rosin ester resins or crude tall oil ester resins, with hydrogenated or disproportionated rosin esters being particularly preferred. Specifically mentioned here are Foral 105-E, Foral 85-E, and especially Foral AX-E (all products of Eastman Chemical).

[0032] The total proportion of the second adhesive resin in variant A is 10 wt.% to 50 wt.%, preferably 20 wt.% to 40 wt.%, very preferably 25 wt.% to 35 wt.%.

[0033] In variant B, the proportion of the second adhesive resin is 0 wt.% to 10 wt.%.

[0034] The total proportion of adhesive resin is 20 wt.% to 50 wt.% in variant A, and 10 wt.% to 50 wt.% in variant B. (d) Plasticizers

[0035] In accordance with this invention, soft resins with a melt viscosity of at least 5 Pa·s at 25°C and 1 Hz are used as plasticizers. Preferably, the melt viscosity at 25°C and 1 Hz is at least 25 Pa·s.

[0036] The soft resin may preferably be a rosin-based or hydrocarbon-based soft resin. In particular, resins from the C5 resin classes, polyterpene resins (made from α-pinene, β-pinene, δ-limonene, or mixtures of these starting materials), C9 resins, aromatically modified α-pinene resins, aromatically modified β-pinene resins, aromatically modified δ-limonene resins, and aromatically modified dipentene resins may be selected. The rosin-based plasticizer is, in particular, a hydrogenated or stabilized rosin ester.

[0037] In variant A of the present invention, the weight fraction of the soft resins is 0 wt.% to 25 wt.%, preferably 5 wt.% to 20 wt.%.

[0038] In a second embodiment of the present invention, the weight fraction of the soft resins is 15 wt.% to 25 wt.%.

[0039] Conventional low-viscosity plasticizers such as mineral oils are disadvantageous in the context of this invention. Their proportion in the overall formulation is at most 1% by weight; preferably, such plasticizers are completely omitted, i.e., the inventive adhesive compositions are preferably free of low-viscosity plasticizers. This absence of low-viscosity plasticizers prevents the coated surfaces from becoming greasy. (e) Optional additional additives

[0040] The adhesive compound can be further modified with additives, primarily protective agents. These include primary and secondary aging inhibitors, light and UV protectants, flame retardants, as well as fillers, dyes, and pigments. The adhesive compound can thus be colored as desired or be white, gray, or black.

[0041] Typical amounts of additive used are up to 2 wt%, based on the total adhesive composition.

[0042] Fillers or pigments can be added in higher doses, typically up to a proportion of 5% by weight based on the total adhesive composition.

[0043] The following additives can typically be used: Primary antioxidants such as sterically hindered phenols; secondary antioxidants such as phosphites or thioethers; process stabilizers such as C-radical scavengers; flame retardants; light stabilizers such as UV absorbers or sterically hindered amines; dyes and / or pigments (such as...)Carbon black) Processing aids (nano)fillers such as silicon dioxide, aluminum oxide, titanium dioxide or layered silicates, as well as color pigments and dyes (for transparent but specifically colored formulations) and optical brighteners, end block reinforcing resins and optionally other polymers of a preferably elastomeric nature; suitable elastomers include, among others, those based on pure hydrocarbons, for example, chemically saturated elastomers such as saturated ethylene-propylene copolymers, α-olefin copolymers, polyisobutylene, butyl rubber, ethylene-propylene rubber, as well as chemically functionalized hydrocarbons such as halogen-containing, acrylate-containing, allyl- or vinyl ether-containing polyolefins.

[0044] Antioxidants are used in particular in amounts of 0.2% to 1.5% by weight. Antiaging agents selected from the group of mono- and / or polynuclear phenols, which have a benzyl thioether group in the ortho- and / or para-position to the phenolic OH group, are particularly preferred.

[0045] The addition of at least one UV protectant is also preferred, particularly in an amount of 0.5 wt.% to 2 wt.%.

[0046] The present invention also relates to adhesive tapes containing at least one layer of an adhesive mass according to the invention.

[0047] Typical product structures include adhesive tapes (single-sided or double-sided), films, and die-cut pieces. Single-sided or double-sided adhesive tapes, films, or die-cut pieces contain at least one layer of a carrier permanently embedded in the product. If no permanently embedded carrier layer is used (in the case of a so-called transfer adhesive tape), then the thickness of the adhesive layers is at least 20 µm and up to 1 mm. Layer thicknesses between approximately 40 µm and approximately 800 µm are highly preferred. Numerous applications are also conceivable for adhesive tapes between approximately 75 µm and approximately 400 µm, provided that no further layers, such as permanently embedded carrier material, are used.When adhesive layers based on adhesive masses according to the invention are used on a carrier material permanently present in the adhesive tape (double-sided adhesive tapes), the layer thicknesses of these adhesive layers are at least 15 µm and preferably at most 250 µm, preferably at least 50 µm and very preferably at most 150 µm.

[0048] In the case of double-sided adhesive tapes that have at least one carrier permanently embedded in the product, different adhesives can be applied to the two sides of the carrier. This makes it possible to bond surfaces with very different properties. For example, double-sided adhesive tapes are conceivable that contain a carrier layer permanently embedded in the tape, the first main surface of which is assigned a layer A of an adhesive according to the invention, and the second main surface of which is assigned a layer B of an adhesive layer selected from another source. A polyacrylate-based adhesive can advantageously be selected for layer B. A polyisobutylene-based adhesive can also be advantageously selected for layer B. A polyethylene vinyl acetate (EVA)-based adhesive can also be advantageously selected for layer B.For layer B, it is also advantageous to select an adhesive mass based on saturated styrene block copolymers that do not correspond to the descriptions for adhesive mass formulations according to the invention, i.e., for example, other types of adhesive and / or soft resins or adhesive and / or soft resins in other proportions.

[0049] However, for layer B, a further layer of an adhesive mass according to the invention can also be selected, in the same or different manner compared to the one selected for layer A.

[0050] In principle, all film-forming and / or extrusion-capable polymers can be used to produce the optionally at least one carrier film that remains permanently in the product. See, for example, the compilation by Nentwig [J. Nentwig, Kunststofffolien, Chapter 5, 2nd ed., 2000, C. Hanser, Munich]. In a preferred design, polyolefins are used. Preferred polyolefins are produced from ethylene, propylene, butylene, and / or hexylene, whereby the pure monomers can be polymerized or mixtures of the aforementioned monomers can be copolymerized. The physical and mechanical properties of the polymer film, such as the softening temperature and / or the tensile strength, can be controlled by the polymerization process and by the selection of the monomers.

[0051] In a further preferred embodiment of this invention relating to carrier films that remain permanently in the product, polyvinyl acetates are used. In addition to vinyl acetate, polyvinyl acetates can also contain vinyl alcohol as a comonomer, whereby the free alcohol content can be varied within wide limits. In a further preferred embodiment of this invention, polyesters are used as the carrier film. In a particularly preferred embodiment of this invention, polyesters based on, for example, polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) are used. It is also possible to use halogenated hydrocarbons as the film base material, such as polyvinylidene chloride or fluorinated systems. In a further preferred embodiment of this invention, polyamides are used to produce films. The polyamides can consist of a dicarboxylic acid and a diamine or of several dicarboxylic acids and diamines.In addition to dicarboxylic acids and diamines, higher-functionality carboxylic acids and amines can also be used, even in combination with the aforementioned dicarboxylic acids and diamines. Cyclic, aromatic, or heteroaromatic starting monomers are preferably used to stiffen the film. In a further preferred embodiment of this invention, polymethacrylates are used to produce films. Here, the glass transition temperature of the film can be controlled by selecting the monomers (methacrylates and, in some cases, acrylates). Furthermore, the polymethacrylates can also contain additives to, for example, increase the flexibility of the film, raise or lower the glass transition temperature, or minimize the formation of crystalline segments. In another preferred embodiment of this invention, polycarbonates are used to produce films.Furthermore, in another embodiment of this invention, polymers and copolymers based on vinyl aromatics and vinyl heteroaromatics can be used to produce the at least one optional carrier film.

[0052] The optional carrier film can be monoaxially oriented, biaxially oriented, or non-oriented.

[0053] To produce a film-like material, it may be advisable to add additives and other components that improve film-forming properties, reduce the tendency to form crystalline segments, and / or selectively improve or, if necessary, worsen mechanical properties. Other optional additives may include oxidation inhibitors, light stabilizers (especially UV stabilizers), antioxidants, additional stabilizers, flame retardants, pigments, dyes, and / or blowing agents.

[0054] The optional carrier film can be used as a single-layer structure or as a multi-layer composite, for example, produced by co-extrusion. Furthermore, the carrier film can be pre-treated on one or both sides and / or coated with a functional layer. If both sides are pre-treated and / or coated, the type and / or extent of the pre-treatment and / or coating can be the same or different. Such pre-treatment and / or coating can, for example, improve the anchoring of an additional layer, such as the adhesive layer A or other optionally used layers.For this purpose, it is particularly advantageous if one or both sides of the carrier film are pretreated with one or different types of primers and / or if one or both sides of the carrier film are pretreated by corona treatment and / or flame treatment and / or plasma treatment and / or other methods for surface activation.

[0055] The optional carrier film can be transparent and colorless or transparent and colored, according to this invention. Furthermore, it is also according to the invention if the film is not transparent and is white, gray, black, or colored.

[0056] The optionally at least one layer of a support material has a layer thickness between 5 µm and 500 µm, preferably between 10 µm and 100 µm.

[0057] The adhesive composition of the present invention is particularly suitable for porous and / or rough and / or fibrous surfaces. The substrate can also be flexible. The substrate can also be non-polar. It can be, in particular, woven fabrics, non-woven fabrics, and knitted fabrics, especially nonwovens.

[0058] Examples of fiber-containing substrates are nonwovens, which are sheet-like structures made of individual fibers. All nonwovens defined according to the standard DIN EN 29092 (1992 / 08) can be used. The nonwoven consists of loosely laid fibers that are not yet bonded together. Strength results from the inherent adhesion of the fibers. A distinction is also made between bonded and unbonded nonwovens. The fibers are statistically distributed. Nonwovens can be differentiated according to the fiber material. Fiber materials can include mineral fibers, such as glass, mineral wool, or basalt; animal fibers, such as silk or wool; plant fibers, such as cotton or cellulose; chemical fibers, such as polyamide, polypropylene, polyphenylene sulfide, polyacrylonitrile, polyimide, polytetrafluoroethylene, aramid, or polyester; or mixtures of the aforementioned substances.The fibers can be mechanically strengthened by needling or water jets, chemically by adding binders, or thermally by softening in a suitable gas stream, between heated rollers, or in a steam stream.

[0059] In a highly preferred embodiment of the invention, cellulose-based nonwovens are used. Polyolefin-based nonwovens are also preferred as a substrate. The basis weight of the nonwovens is preferably between 4 and 100 g / m², and particularly preferably between 10 and 70 g / m². Such nonwovens are commercially available, for example, from Glatfelter. The thickness of these nonwovens is preferably between 20 and 100 µm, and most preferably between 30 and 60 µm.

[0060] If an object with a porous surface is to be attached to an object with a smooth surface, double-sided adhesive tapes are very suitable. One side of the tape is coated with an adhesive according to the present invention, while the other side has an adhesive that adheres well to smooth surfaces. An example of such an application is the application of protective covers to an object requiring protection. The protective cover consists of a fiber-containing, i.e., porous, nonwoven fabric, which can be polyolefin-based. An example of such a protective cover material is spunbonded olefin Tyvek® from DuPont (http: / / www.dupont.de / produkte-und-dienstleistungen / verpackungsmaterialien-undloesungen / industrielle-verpackungen / use-and-applications / protective-covers.html dated December 18, 2017).

[0061] The adhesives according to the invention allow a certain degree of flow of the adhesive into the porous and / or fibrous substrate while simultaneously ensuring the requirements for weather resistance. In addition to good adhesion to porous substrates, the squeezing out of the adhesive, the so-called "oozing," is avoided despite the addition of plasticizers.

[0062] Adhesive films can be any size in both dimensions. Adhesive tapes, for example, are 2 mm, 5 mm, 10 mm, 20 mm, or 50 mm wide. Adhesive tapes can be supplied wound on rolls.

[0063] For the purposes of this invention, the general term "adhesive tape" includes all planar structures such as films or film sections extended in two dimensions, tapes with extended length and limited width, tape sections, die-cut pieces, labels and the like.

[0064] Adhesive products are typically supplied on a release liner (preferably silicone-coated paper or film). The liner can be single-sided. In this case, a second layer of liner is advantageously used to cover the second surface (especially with die-cut parts). Alternatively, the liner can be double-sided. In this case, a single liner layer is sufficient (especially with adhesive tapes).

[0065] The adhesives can be manufactured using either solvent-based or solvent-free processes. Solvent-free production is preferred because it is cheaper and faster, although there may be applications where solvent-based production is preferred. This is the case, for example, when there are specific requirements regarding the optical properties.

[0066] For solvent-free production, the use of either a hot melt kneader or an extruder is particularly preferred.

[0067] Additional layers of the adhesive tape can be incorporated into the product structure by laminating.

[0068] Accordingly, the invention also relates to a double-sided adhesive tape for fastening large surface structures for transport and / or assembly protection on substrates such as automotive paint, comprising a first adhesive side A made of an adhesive compound according to the invention and a second adhesive side B made of an adhesive compound B, wherein the adhesive compound B is self-adhesive and suitable for reversible bonding to automotive paint.

[0069] Alternatively, the invention relates to a double-sided adhesive tape for fastening large surface structures for transport and / or assembly protection on substrates such as automotive paint, consisting of a first adhesive side A made of an adhesive compound according to the invention and a second adhesive side B made of an adhesive compound B comprising isobutyl rubber or its derivatives or mixtures.

[0070] When used, the side of the adhesive tape containing the adhesive compound according to the invention faces the large surface structure and serves to fasten it. EP 2 036 961 A1 describes such applications.

[0071] In general, the invention consists of an adhesive tape with two adhesive layers. In an advantageous embodiment, these are supported by a carrier material. This can be a woven fabric, knitted fabric, nonwoven fabric, film, paper, and their composite materials and combination products, which are based on natural or synthetic materials or their combination or mixture.

[0072] Accordingly, polymeric films, nonwovens, or fabrics made of polypropylene, polyester, polyamide, polyurethane, or polyethylene, as well as combinations with mineral fibers such as glass fibers or carbon fibers, or products such as woven, non-woven, and knitted fabrics with cellulose or cotton fibers, and also of metallic origin, are advantageously used. For special applications, blended products such as compounds or blended fiber products, optionally as blended fiber threads, yarns, or threads, can also be used. These can be partially dyed or otherwise finished to impart optical or mechanical characteristics and properties to the substrate. In alternative versions, fibers of natural origin such as cotton, silk, flax, or rayon can also be used.

[0073] In an alternative embodiment of the invention, a nonwoven fabric is used as a carrier material for masking surfaces. The nonwoven fabric is reinforced by the formation of seams created by loops made from the fibers of the nonwoven fabric, advantageously having a seam count of at least 3 / cm, preferably 5 / cm to 50 / cm.

[0074] In a further advantageous embodiment, the invention can be torn by hand perpendicular to its orientation and / or in the direction of the seams. This is frequently used when the product according to the invention is wound onto itself to form a roll.

[0075] In another embodiment, this tearability is not necessary. This could involve die-cut products for gluing onto the large surface structure.

[0076] The adhesive compound according to the invention advantageously has the following property profile: Characteristic Physical quantity Unit Value (range) Cohesion (Test I) Shear life at 40°C Min ≥ 1,000 min; preferably ≥ 10,000 min Adhesion (Test II) PE adhesive strength N / cm ≥ 1.5 N / cm preferably ≥ 3 N / cm Testing methods Test method I - Static shear test at 40°C

[0077] Shear strength at 40°C is a measure of the internal strength of the adhesive at elevated temperature and is tested in the so-called static shear test as follows: The test is performed according to PSTC-7 at 40°C using a 1 kg weight. A 1.3 cm wide strip of this sample is bonded to a polished steel plate over a length of 2 cm using a 2 kg roller by double rolling over it twice. The plates are equilibrated for 30 minutes under test conditions (40°C) but without a load. Then the test weight (1 kg) is attached so that a shear stress is applied parallel to the bonded area, and the time until the bond fails is measured. The measurement result is given in minutes, and if failure occurs, the failure mode (cohesive failure or adhesive failure) is specified. The median of three individual measurements is reported. Test method II - Adhesion 180°

[0078] The adhesive strength on polyethylene (PE) was determined under a test climate of 23 °C ± 1 °C and 50% ± 5% relative humidity. The samples were cut to a width of 20 mm and adhered to a PE plate. The test plate was cleaned and conditioned before measurement. For this purpose, the PE plate was cleaned with isopropanol and cellulose and then left to air dry for 2 hours to allow the solvent to evaporate. The test sample was then rolled onto the test substrate. For this, the tape was rolled back and forth five times with a 4 kg roller at a rolling speed of 10 m / min. The adhesive strength was measured using a Zwick tensile testing machine at an angle of 180° and a speed of 300 mm / min. The measurement results are given in N / cm and are averaged from three individual measurements. Test Method III - Viscosity of soft resins

[0079] To determine the melt viscosity of the soft resins, a shear stress sweep was performed in a rotating, shear-stress-controlled DSR 200 N rheometer from Rheometrics Scientific. A cone / plate measuring system with a diameter of 25 mm (cone angle 0.1002 rad) was used; the measuring head was air-bearing and suitable for normal force measurements. The gap was 0.053 mm and the measuring temperature was 25 °C. The frequency was varied from 0.002 Hz to 200 Hz, and the melt viscosity was recorded at 1 Hz. Test Method IV - Molecular Weight, GPC

[0080] IVa: Adhesive Resins: The mean molecular weight (MW) of the adhesive resins – also called molar mass – is determined by gel permeation chromatography (GPC). THF is used as the eluent. The measurement is performed at 23 °C. A 10 µm PSS-SDV column with an ID of 8.0 mm x 50 mm is used as the guard column. PSS-SDV columns with an ID of 8.0 mm x 300 mm, 5 µm, 10³ < Å, and 10² < Å were used for separation. The sample concentration is approximately 2 g / L, and the flow rate is 1.0 mL per minute. Measurements are performed against PS standards. A refractive index detector is used.

[0081] IVb: Block Copolymers: The mean molecular weight (MW) of the block copolymers – also called molar mass – is determined by gel permeation chromatography (GPC). THF is used as the eluent. The measurement is performed at 23 °C. A 5 µm PSS-SDV backing column with an ID of 8.0 mm x 50 mm is used. For separation, PSS-SDV columns with an ID of 8.0 mm × 300 mm, 5 µm, 10⁻³ Å, 10⁻⁵ Å, and 10⁻⁶ Å, were used. The sample concentration is approximately 3 g / L, and the flow rate is 1.0 mL per minute. Measurements are performed against PS standards. A refractive index detector is used. Test method V - resin softening temperature

[0082] The adhesive resin softening temperature is determined according to the relevant method known as Ring & Ball, which is standardized according to ASTM E28-14.

[0083] To determine the softening temperature of the adhesive resins, a Herzog HRB 754 ring-sphere tester is used. Resin samples are first finely ground in a mortar. The resulting powder is filled into a brass cylinder with a bottom opening (inner diameter at the top of the cylinder 20 mm, diameter of the bottom opening 16 mm, cylinder height 6 mm) and melted on a heating table. The fill quantity is chosen so that the resin completely fills the cylinder after melting, without any overflow. The resulting sample, along with the cylinder, is placed in the sample holder of the HRB 754. Glycerin is used to fill the temperature control bath if the softening temperature of the adhesive resin is between 50 °C and 150 °C. For lower softening temperatures, a water bath can also be used. The test spheres have a diameter of 9.5 mm and weigh 3.5 g.According to the HRB 754 procedure, the sphere is positioned above the specimen in the temperature-controlled bath and placed on the specimen. A collection plate is located 25 mm below the bottom of the cylinder, and a photoelectric sensor is positioned 2 mm above this plate. During the measurement process, the temperature is increased at 5 °C / min. Within the temperature range of the adhesive resin softening temperature, the sphere begins to move through the opening in the bottom of the cylinder until it finally comes to rest on the collection plate. In this position, it is detected by the photoelectric sensor, and the temperature of the temperature-controlled bath is recorded at this point. A duplicate measurement is performed. The adhesive resin softening temperature is the average of the two individual measurements. Examples Sample preparation (from solution)

[0084] The raw materials were placed in a glass container in the appropriate proportions. A solvent mixture of toluene, gasoline, and acetone was added to achieve a solids content of 40% by weight. The mixture was then dissolved on a roller bench for two days. The dissolved adhesive solutions were coated onto a 23 µm etched PET film using a Zentner coating table, resulting in a layer thickness of 70 µm when dry. These samples were then dried in a Thermo Scientific oven at 120°C for 20 minutes. Raw materials used

[0085] Table 1: Raw materials used name type Manufacturer Elastomers Tuftec P1500 Polystyrene-poly(butadiene-co-butylene) block copolymer (SBBS), polystyrene content: 30 wt.% Asahi Kasei Adhesive resins Regalite R 1125 Fully hydrogenated hydrocarbon resin hydrogenated rosin ester Eastman Forest 105 Eastman Soft resins Wingtack 10 C5 resin, melt viscosity 22 Pa s Cray Valley Anti-aging agents Irganox 1010 Sterically hindered phenol BASF Examples

[0086] All values ​​in wt.%; all adhesives (100 parts) also contained an additional 1.5 parts of Irganox 1010 each. Table 2: Examples (from the solution): Raw materials Example E1 Example E2 Example E3 Example E4 Example E5 Elastomer 53,4 49,7 38,4 35,0 52,2 Tuftec P1500 [%] Adhesive resin 1 15,6 2,5 0,0 0,0 6,4 Regalite R1125 [%] Adhesive resin 2 29,5 46,3 41,4 38,5 14,9 Foral 105 [%] Soft resin 0,0 0,0 18,7 25,0 25,0 Wingtack 10 [%] Age protection [%] 1,5 1,5 1,5 1,5 1,5 Formulation concept A A A A A KK PE 180° [N / cm] 1,74 4,21 4,37 6,95 4,65 SSZ 40°C 1KG [min] 10000 10000 10000 1434 10000 Table 3: Raw materials Example E6 Example E7 Example E8 Elastomer 60,0 35,0 60,0 Tuftec P1500 [%] Adhesive resin 1 25,8 15,6 13,5 Regalite R1125 [%] Adhesive resin 2 12,7 25,1 0,0 Foral 105 [%] Soft resin 0,0 22,8 25,0 Wingtack 10 [%] Age protection [%] 1,5 1,5 1,5 Formulation concept A A B KK PE 180° [N / cm] 5,38 5,39 2,10 SSZ 40°C 1KG [min] 10000 3451 10000 Table 4 (comparative examples): Raw materials Example V1 Example V2 Example V3 Elastomer 37,0 47,7 60,0 Tuftec P1500 [%] Adhesive resin 1 28,8 38,5 29,4 Regalite R1125 [%] Adhesive resin 2 27,5 0,0 0,0 Foral 105 [%] Soft resin 5,2 12,3 9,1 Wingtack 10 [%] Age protection [%] 1,5 1,5 1,5 Formulation concept A AWAY B KK PE 180° [N / cm] 0,51 0,89 1,29 SSZ 40°C 1KG [min] 10000 10000 10000

[0087] Tables 2 and 3 show various adhesive compositions according to the invention, as per variant A (examples E1 to E8) and variant B (example E9), with their properties relating to bond strength and shear strength. The proportions of elastomer, optionally adhesive resin 1 and 2, and optionally plasticizer are varied within the ranges specified in the invention. As expected, the test results show that a higher elastomer content results in a longer shear life due to increased cohesion. Regarding adhesive strength, the test results show that the specified ranges for the different components—elastomer, adhesive resin 1 and 2, and plasticizer—in their combinations according to the invention lead to the desired properties. No single component has a predictably unambiguous influence; rather, certain combinations of compositions yield particularly favorable results.

[0088] The comparative examples shown in Table 4 demonstrate that it is not only the presence of a soft resin that ensures sufficient adhesive strength, but rather the amount of soft resin in combination with the amount of the other components must be considered.

Claims

1. An adhesive compound consisting of elastomer, at least one tackifier resin, an optional soft resin as well as at least one optional further additive, wherein the adhesive compound has one of the following two compositions A or B: composition A: Aa) 35% by weight to 60% by weight of an elastomer component which contains at least 80% by weight of at least one type of a vinyl aromatic block copolymer which contains at least one block consisting of conjugated dienes in which the terminal double bonds, formed by 1,2-addition, are more than 80% hydrogenated, while the double bonds in the main chain, formed by 1,4-addition, are less than 30% hydrogenated, Ab) 0% by weight to 40% by weight of at least one type of a first tackifier resin which is a partially or fully hydrogenated hydrocarbon resin with a degree of hydrogenation of at least 65%, Ac) 10% by weight to 50% by weight of at least one type of a second tackifier resin which is a rosin ester, Ad) 0% by weight to 25% by weight of a soft resin with a melt viscosity at 25°C and 1 Hz of at least 5 Pa s, Ae) 0% by weight to 5% by weight of at least one further additive, wherein the total proportion of tackifier resin is 20% by weight to 50% by weight; or composition B: Ba) 35% by weight to 60% by weight of an elastomer component which contains at least 80% by weight of at least one type of a vinyl aromatic block copolymer which contains at least one block consisting of conjugated dienes in which the terminal double bonds, formed by 1,2-addition, are more than 80% hydrogenated, while the double bonds in the main chain, formed by 1,4-addition, are less than 30% hydrogenated, Bb) 10% by weight to 50% by weight of at least one type of a first tackifier resin which is a partially or fully hydrogenated hydrocarbon resin with a degree of hydrogenation of at least 65%, Bc) 0% by weight to 10% by weight of at least one type of a second tackifier resin which is a rosin ester, Bd) 15% by weight to 25% by weight of a soft resin with a melt viscosity at 25°C and 1 Hz of at least 5 Pa s, Be) 0% by weight to 5% by weight of at least one further additive, wherein the total proportion of tackifier resin is 10% by weight to 50% by weight, wherein the proportion of low viscosity plasticizers in the adhesive compound is at most 1% by weight.

2. The adhesive compound as claimed in claim 1, characterized in that the vinyl aromatic block copolymer is a styrene block copolymer, preferably a polystyrene-poly(butadiene-co-butylene) block copolymer.

3. The adhesive compound as claimed in claim 1 or claim 2, characterized in that the partially or fully hydrogenated hydrocarbon resin has a degree of hydrogenation of at least 80%, and in particular is fully hydrogenated.

4. The adhesive compound as claimed in one of claims 1 to 3, characterized in that the soft resin has a melt viscosity at 25°C and 1 Hz of at least 25 Pa s.

5. The adhesive compound as claimed in one of claims 1 to 4, characterized in that the adhesive compound in accordance with composition A contains from 5% by weight to 20% by weight of a soft resin Ad) with a melt viscosity at 25°C and 1 Hz of at least 5 Pa s.

6. The adhesive compound as claimed in one of claims 1 to 5, characterized in that the soft resin is a rosin-based or a hydrocarbon-based soft resin.

7. The adhesive compound as claimed in one of claims 1 to 6, characterized in that it contains at least one UV stabilizer, in particular in a quantity of 0.5% by weight to 2% by weight, as the further additive.

8. The adhesive compound as claimed in one of claims 1 to 7, characterized in that it contains, as the further additive, at least one antioxidant, in particular in a quantity of 0.2% by weight to 0.8% by weight, in particular an anti-degradant selected from the group of monocyclic and / or polycyclic phenols which contains a benzylthioether group in the position ortho- and / or para- to the phenolic OH group.

9. An adhesive tape, in particular double-sided adhesive tape, comprising at least one adhesive compound as claimed in one of claims 1 to 8.

10. The adhesive tape as claimed in claim 9, characterized in that it contains a carrier.

11. The adhesive tape as claimed in claim 9 or claim 10, characterized in that it is a transfer tape.

12. Use of the adhesive tape as claimed in one of claims 9 to 11 for bonding to a porous, fibrous and / or rough, in particular flexible, substrate.