Pressure sensitive adhesive comprising liquid resin comprising oligoester composition

Abstract

The present invention relates to a pressure sensitive adhesive composition comprising at least one polymer, at least one liquid resin comprising an oligoester composition as described herein, and at least one further plasticizer wherein the at least one further plasticizer comprises an isobutylene / butylene copolymer. The invention also relates to the use of the pressure-sensitive adhesive composition according to the invention, to a method for producing the pressure-sensitive adhesive composition, and to a method for bonding at least two substrates. Finally, the invention relates to an article comprising a pressure sensitive adhesive composition according to the invention.

Description

[0001] The present invention relates to a pressure-sensitive adhesive composition comprising at least one polymer, at least one liquid resin containing an oligoester composition as described herein, and at least one other plasticizer, wherein the at least one other plasticizer comprises an isobutylene / butylene copolymer. The present invention also relates to the use of the pressure-sensitive adhesive composition according to the present invention, a method for preparing the pressure-sensitive adhesive composition, and a method for bonding at least two substrates. Finally, the present invention relates to an article comprising the pressure-sensitive adhesive composition according to the present invention.

[0002] For reasons of growing sustainability and environmental awareness, there is an increasing desire to replace mineral oil-based compounds with substances based on renewable raw materials.

[0003] Commercially available pressure-sensitive adhesive compositions often contain plasticizers based on mineral oils. It is advantageous to minimize or completely avoid the use of these substances, especially in food packaging, in hygiene products, and in many other areas, for example, to prevent the adhesive from migrating into the packaging material. Therefore, there is a need for alternatives that can partially or completely replace these plasticizers and are suitable and approved for use in contact with food.

[0004] Many available alternatives based on renewable raw materials are disadvantageous with regard to compatibility with the other components of the pressure-sensitive adhesive composition and / or lead to reduced performance with regard to the adhesive properties of the adhesive composition.

[0005] The object of the present invention is therefore to provide a pressure-sensitive adhesive composition which has as high a proportion of renewable resources as possible in the formulation, in particular by replacing the mineral oil-based plasticizers used previously in large quantities. At the same time, such a composition should have the same or even improved properties in terms of bond strength and stability compared to conventional systems and should also be suitable for the production of, for example, food packaging or hygiene products, i.e. should contain only ingredients approved for contact with food.

[0006] Surprisingly it has been found that this object is achieved by a pressure-sensitive adhesive composition which, in addition to at least one polymer, comprises a combination of at least one liquid resin and at least one further plasticizer, wherein the at least one further plasticizer comprises or consists of an isobutylene / butene copolymer, and the liquid resin comprises an oligoester composition, wherein the oligoester composition is the reaction product of a reaction mixture comprising:

[0007] ii) one or more monocarboxylic acids, optionally in an amount of at least 15 wt. %, based on the total weight of the reaction mixture;

[0008] iii) one or more polyols; and

[0009] iv) optionally one or more polycarboxylic acids,

[0010] The reaction mixture comprises one or more rosins.

[0011] The combination of the liquid resin and the isobutylene / butene copolymer at least partially, preferably even completely replaces the commonly used mineral oil-based plasticizers, especially naphthenic oil and / or paraffinic oil, in the pressure-sensitive adhesive composition, and is therefore a sustainable alternative to mineral oil-based plasticizers. Preferably, such pressure-sensitive adhesive compositions comprising the liquid resin and the isobutylene / butene copolymer described herein show improved bond strength and / or adhesion to various substrates.

[0012] Therefore, a first aspect of the present invention relates to a pressure-sensitive adhesive composition comprising:

[0013] a) at least one polymer;

[0014] b) at least one liquid resin comprising an oligomeric ester composition which is the reaction product of a reaction mixture comprising:

[0015] ii) one or more monocarboxylic acids, optionally in an amount of at least 15 wt. %, based on the total weight of the reaction mixture;

[0016] iii) one or more polyols; and

[0017] iv) optionally one or more polycarboxylic acids;

[0018] wherein the reaction mixture comprises one or more rosins;

[0019] c) at least one other plasticizer, wherein the at least one other plasticizer comprises an isobutylene / butene copolymer;

[0020] d) optionally at least one other resin; and

[0021] e) optionally at least one additive, preferably at least one stabilizer.

[0022] The pressure-sensitive adhesive composition according to the invention preferably comprises at least one polymer a) selected from the following group: polymers based on acrylates, polyesters, urethanes, ethylene acrylates, butyl rubbers and (synthetic) (natural) rubbers; ethylene-vinyl acetate copolymers (EVA), polyolefin (co)polymers (PO), polyamide (co)polymers (PA), ethylene-propylene copolymers or styrene copolymers, which are present alone or as a mixture, and the polymer is particularly preferably a styrene block copolymer, for example styrene and styrene-butadiene copolymers (SBC, SBS, SBR), styrene-isoprene copolymers (SIS), styrene-ethylene / butylene copolymers (SEBS), styrene-ethylene / propylene-styrene copolymers (SEPS) or styrene-isoprene-butylene copolymers (SIBS) or mixtures thereof.

[0023] Particularly preferably, the at least one polymer a) is a styrene-isoprene copolymer (SIS), a styrene-butadiene copolymer (SBC) and / or an ethylene-vinyl acetate copolymer (EVA) or a mixture thereof, in particular a styrene-butadiene copolymer (SBC).

[0024] Particularly preferably, the content of polymer a) in the pressure-sensitive adhesive composition is 10 to 70 wt %, preferably 15 to 70 wt %, more preferably 20 to 70 wt %, for example 20 to 50 wt %, 20 to 40 wt % or 25 to 60 wt %, based on the total weight of the pressure-sensitive adhesive composition.

[0025] Another essential component of the composition according to the invention is a liquid resin b), which comprises an oligoester composition as described herein. In various embodiments, the reaction mixture for preparing the oligoester composition comprises:

[0026] at least 15% by weight of one or more monocarboxylic acids;

[0027] one or more polyols; and

[0028] Optionally, greater than 0 wt% to less than 4 wt% of one or more polycarboxylic acids are present, wherein the reaction mixture comprises one or more rosins. However, in various embodiments, the one or more monocarboxylic acids may also be present in an amount of 14 wt%.

[0029] Preferably, the reaction mixture used to prepare the oligoester composition comprises:

[0030] 25 to 85 wt. % of one or more monocarboxylic acids;

[0031] 7 to 35 wt % of one or more polyols; and

[0032] More than 0 wt % to less than 4 wt % of one or more polycarboxylic acids are optionally present, wherein the reaction mixture preferably contains 5 wt % to 75 wt % rosin.

[0033] Typically, rosin comprises a mixture of rosin acids, preferably C 20 The tricyclic monocarboxylic acid and its isomers, more preferably the tricyclic diterpene carboxylic acid. Suitable abietic acid may be selected from the group consisting of abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid and palustric acid and their isomers, but is not limited thereto.

[0034] In various embodiments, the liquid resin b) consists of the oligoester composition. "Liquid resin" as used herein means that the ingredient is in liquid form under standard conditions, ie 20°C and 1013 mbar.

[0035] Particularly preferably, the at least one liquid resin b) is present in the pressure-sensitive adhesive composition in an amount of 1 to 50% by weight, more preferably 2 to 40% by weight, more preferably 5 to 40% by weight and in particular 5 to 30% by weight, based in each case on the total weight of the pressure-sensitive adhesive composition.

[0036] Suitable liquid resins are commercially available, for example, from Kraton Corporation. Detailed preparation instructions can be found, for example, in specification US2017 / 0190935 A1, but are not limited thereto. The liquid resin or oligoester composition described therein is suitable for use as component b) in the pressure-sensitive adhesive composition described herein. This document is incorporated herein by reference in its entirety.

[0037] According to the invention, the pressure-sensitive adhesive composition comprises a combination of at least one liquid resin b) as described herein and at least one further plasticizer c), wherein the at least one plasticizer comprises or consists of an isobutylene / butylene copolymer. Such a pressure-sensitive adhesive composition preferably has a comparable enhanced bond strength and / or adhesion to various substrates (e.g. steel, polyethylene, nonwovens, glass or cardboard) compared to a reference adhesive.

[0038] Preferably, the at least one further plasticizer c) or the isobutylene / butene copolymer is used in an amount of 0.1 to 30 wt. %, more preferably 1 to 15 wt. %, in particular 5 to 12 wt. %, based on the total weight of the pressure-sensitive adhesive composition. Also preferably, the number average molecular weight M of the further plasticizer c) or the isobutylene / butene copolymer measured by size exclusion chromatography (GPC: gel permeation chromatography) is n750-1450 g / mol, more preferably 850-1350 g / mol, in particular 900-1300 g / mol. In various embodiments, the glass transition temperature (Tg) of the at least one other plasticizer c) or the isobutylene / butene copolymer, preferably measured by dynamic differential thermal analysis (DSC: differential scanning calorimetry), may be -60 to -73 ° C, more preferably -63 to -73 ° C, in particular -66 to -70 ° C. Determined at 100 ° C by the method described in ASTM D445, the plasticizer c) or the copolymer may also have a temperature of 0.00018-0.0007 m 2 / s(180-700cSt), preferably 0.00019-0.00067m 2 / s(190-670cSt), especially 0.0002-0.000655m 2 / s (200-655cSt) kinematic viscosity.

[0039] Particularly preferably, the concentration of the at least one liquid resin b) and the at least one further plasticizer c) in the pressure-sensitive adhesive composition is 5 to 50% by weight, preferably 10 to 40% by weight, in particular 15 to 35% by weight, based on the total weight of the components of the pressure-sensitive adhesive composition.

[0040] Furthermore, it is particularly preferred that the pressure-sensitive adhesive composition according to the invention contains no further plasticizers besides the isobutylene / butylene copolymer.

[0041] Preferably, the liquid resin b) in combination with other plasticizers c) can partially or preferably completely replace conventional mineral oil-based plasticizers, in particular naphthenic oils and / or (white medical) paraffin oils.

[0042] Therefore, in preferred embodiments, the pressure-sensitive adhesive composition according to the present invention comprises mineral oil-based plasticizers, in particular naphthenic oil and / or paraffinic oil, in an amount of less than 10 wt. %, more preferably less than 9 wt. %, even more preferably less than 8 wt. %, even more preferably less than 7 wt. %, even more preferably less than 6 wt. %, even more preferably less than 5 wt. %, even more preferably less than 4 wt. %, even more preferably less than 3 wt. %, even more preferably less than 2 wt. %, even more preferably less than 1 wt. %, even more preferably less than 0.5 wt. %, even more preferably less than 0.1 wt. %, even more preferably less than 0.01 wt. %, and most preferably contains no such mineral oil-based plasticizers.

[0043] In a preferred embodiment, in the pressure-sensitive adhesive composition, the degree of replacement of the mineral oil-based plasticizer, more preferably naphthenic oil and / or paraffinic oil, by the combination of the liquid resin b) and the other plasticizer c) comprising the isobutylene-butene copolymer is at least 50%, more preferably at least 60%, even more preferably at least 70%, even more preferably at least 80%, even more preferably at least 90%, even more preferably at least 95%, even more preferably at least 98%, even more preferably at least 99%, most preferably 100%.

[0044] In addition, the pressure-sensitive adhesive composition may comprise at least one further resin d), which is preferably a natural resin or a hydrocarbon resin, more preferably a tall oil ester, a gum rosin (rosin ester), an optionally partially polymerized tall resin, a terpene or crude oil based aliphatic, aromatic or alicyclic hydrocarbon resin, having, for example, 1 to 30 carbon atoms in the case of aliphatic hydrocarbon resins and, for example, 6 to 30 carbon atoms in the case of aromatic and alicyclic hydrocarbon resins, wherein these resins and their modified or hydrogenated forms may be, for example, C5 aliphatic or C9 aromatic hydrocarbon resins or C5 / C9 monomer mixtures, wherein the resin is different from the liquid resin b), in particular is not a liquid resin, but a solid resin. Such a "solid resin" is solid under standard conditions.

[0045] In various embodiments, the at least one other resin d) may comprise at least two resins, wherein these resins are preferably selected from aliphatic (cycloaliphatic) hydrocarbons and / or rosin esters, such as pentaerythritol esters.

[0046] In various embodiments, the resin d) is a solid resin, for example in the form of granules or flakes. However, it can also be a solid resin provided in molten form, for example in a heated tank car.

[0047] In a particularly preferred embodiment, the content of the other resin d) in the pressure-sensitive adhesive composition is 10 to 70 wt %, preferably 15 to 60 wt %, for example 20 to 50 wt %, 15 to 45 wt %, 25 to 60 wt %, based on the total weight of the pressure-sensitive adhesive composition.

[0048] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention comprises at least one additive e), which is preferably selected from the group consisting of antioxidants such as stabilizers, waxes, UV protectants, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, fluorescent brighteners and fragrances, in particular stabilizers.

[0049] In various embodiments, the pressure-sensitive adhesive composition comprises 0.01 to 20 wt %, preferably 0.1 to 5 wt %, more preferably 0.5 to 3 wt % of at least one additive e), based on the total weight of the pressure-sensitive adhesive composition.

[0050] Also preferably, the pressure sensitive adhesive according to the invention has enhanced adhesion to various substrates such as steel or plastics. Thus, significantly less adhesive can be used to meet application requirements compared to reference adhesives, for example the application weight can be reduced.

[0051] In another aspect, the present invention relates to a process for preparing a pressure-sensitive adhesive composition according to the present invention, which comprises mixing in a suitable order at least one liquid resin b) comprising an oligoester composition as described herein and the other components of the pressure-sensitive adhesive composition, such as at least one polymer a), at least one plasticizer c) and optionally further components, such as at least one further resin d) and / or at least one additive e), preferably at a temperature of 100 to 200° C., more preferably at a temperature of 120 to 180° C., even more preferably at a temperature of 150 to 170° C.

[0052] In a further aspect, the present invention relates to the use of the pressure-sensitive adhesive composition according to the invention in: adhesive tapes; labels; multilayer films, for example for sealing; hygiene products, for example diapers; markings, for example markings of beverage bottles; flexible packaging; food packaging; cartons or envelopes; medical applications, for example in the packaging of medical materials and products; the assembly sector (high performance, such as in the automotive industry); and / or the graphic industry (such as books, magazines, brochures).

[0053] Other examples include coatings of self-adhesive films. In general, the compositions described herein are suitable for thin film applications, ie, self-adhesive films, tapes, or labels.

[0054] In another aspect, the present invention relates to an article comprising the pressure-sensitive adhesive composition according to the present invention.

[0055] The present invention finally relates to a method for bonding at least two substrates, wherein the pressure-sensitive composition according to the invention is applied to at least one substrate and the at least two substrates are subsequently bonded together.

[0056] In a preferred embodiment, the pressure-sensitive adhesive composition is applied in an amount of 1 to 200 g / m 2 , preferably 2 to 70 g / m 2 , more preferably 10 to 60 g / m 2 , for example 20 to 50 g / m 2 .

[0057] These and other embodiments, features and advantages of the present invention will become clear to those skilled in the art by studying the following detailed description and claims. In this case, each described feature or embodiment of the present invention may be combined with other features or embodiments of the present invention without describing them in combination within the scope of the present invention. It goes without saying that the examples herein are intended to describe and illustrate the present invention, but not to limit the present invention, and in particular the present invention is not limited to these examples.

[0058] As used herein, "at least one" refers to 1 or more, such as 2, 3, 4, 5, 6, 7, 8, 9 or more. With respect to the polymers described herein, the expression does not refer to the absolute amount of the molecule, but rather to the type of compound. Thus, "at least one polymer" means, for example, that only one type of polymer or multiple different types of polymers may be included without specifying the amount of a single compound.

[0059] Unless otherwise stated, all amounts related to the pressure-sensitive adhesive compositions described herein refer to % by weight, in each case based on the total weight of the composition. Furthermore, such quantitative specifications related to at least one ingredient always refer to the total amount of such ingredient contained in the composition, unless expressly stated otherwise. This means that these amounts, for example in the case of "at least one polymer", refer to the total amount of polymers contained in the composition, unless expressly stated otherwise.

[0060] Numerical values ​​specified herein without decimal points refer in each case to the full specified value with a decimal point. For example, "99%" means "99.0%".

[0061] Numerical ranges expressed in the format "from x to y" include the values ​​recited. If several preferred numerical ranges are specified in this format, it is readily understood that any range resulting from a combination of the individual endpoints is also contemplated.

[0062] "About" in connection with numerical values ​​herein means ±10%, preferably ±5%, in particular ±1% of the respective value.

[0063] When referring to molar mass in this article, it means the number-average molar mass M n , unless explicitly stated otherwise. The number-average molar mass can be determined, for example, by gel permeation chromatography (GPC) according to DIN 55672-1:2007-08 with THF as eluent. The weight-average molar mass M w Also can be as M n As described, measured by GPC. For example, US2017 / 0190935 A1 also describes a method for measuring M n or M w The appropriate method.

[0064] In a first aspect, the present invention relates to a pressure-sensitive adhesive composition comprising:

[0065] a) at least one polymer;

[0066] b) at least one liquid resin comprising an oligomeric ester composition which is the reaction product of a reaction mixture comprising:

[0067] ii) one or more monocarboxylic acids, optionally in an amount of at least 15 wt. %, based on the total weight of the reaction mixture;

[0068] iii) one or more polyols; and

[0069] iv) optionally one or more polycarboxylic acids;

[0070] wherein the reaction mixture comprises one or more rosins;

[0071] c) at least one further plasticizer, wherein the at least one further plasticizer comprises or consists of an isobutylene / butene copolymer;

[0072] d) optionally at least one other resin; and

[0073] e) optionally at least one additive, preferably at least one stabilizer.

[0074] The pressure-sensitive adhesive composition is preferably a hot melt pressure-sensitive adhesive composition (HMPSA). More preferably, the pressure-sensitive adhesive composition is a non-reactive pressure-sensitive adhesive composition, in particular a non-reactive hot melt pressure-sensitive adhesive composition.

[0075] "Pressure-sensitive adhesives" are typical representatives of non-curing adhesives. "Hot-melt pressure-sensitive adhesives" (HMPSA) are generally understood to be adhesives that are solid at room temperature, in particular water-free and solvent-free. They are usually applied to the parts to be bonded in a molten state and physically solidify when cooled and solidified after bonding. Such hot-melt pressure-sensitive adhesives preferably remain permanently tacky when cooled and adhere immediately to almost all substrates under slight contact pressure.

[0076] In this context, "non-reactive" or "physical cure" generally means that solidification occurs in a physical process (eg, hardening by cooling, or by evaporation of a solvent or water).

[0077] The pressure-sensitive adhesive composition according to the invention comprises at least one polymer a) which may be a homopolymer or a copolymer.

[0078] Examples of such polymers include, but are not limited to, polymers based on acrylates, polyesters, urethanes, ethylene acrylates, butyl rubbers and (synthetic) natural rubbers; ethylene-vinyl acetate copolymers (EVA), polyolefin (co) polymers (PO), polyamide (co) polymers (PA), ethylene-propylene copolymers or styrene copolymers, either alone or as a mixture, these copolymers are typically random copolymers, alternating graft copolymers or block copolymers. Thermoplastic elastomers are preferably selected from the following group: styrene block copolymers, such as styrene and styrene-butadiene copolymers (SBC or SBS, SBR), styrene-isoprene copolymers (SIS), styrene-ethylene / butylene copolymers (SEBS), styrene-ethylene / propylene-styrene copolymers (SEPS) or styrene-isoprene-butylene copolymers (SIBS). These products are known to those skilled in the art and are commercially available.

[0079] Particularly preferably, the at least one polymer a) is a styrene block copolymer, for example styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS) or styrene-ethylene-butadiene-styrene (SEBS), more preferably a styrene-isoprene-styrene triblock copolymer or a styrene-butadiene copolymer (SBC) or a mixture thereof.

[0080] In various embodiments, the pressure-sensitive adhesive composition according to the present invention may further include ethylene-vinyl acetate copolymer (EVA), and EVA may be used in addition to those described above.

[0081] In a preferred embodiment, the at least one polymer a) is present in the pressure-sensitive adhesive composition in an amount of 10 to 70% by weight, preferably 15 to 70% by weight, more preferably 20 to 70% by weight, for example 20 to 50% by weight, 20 to 40% by weight, 25 to 60% by weight, 30 to 60% by weight or 28 to 40% by weight, based on the total weight of the pressure-sensitive adhesive composition.

[0082] Furthermore, the pressure-sensitive adhesive composition comprises at least one liquid resin b) comprising an oligomeric ester composition which is the reaction product of a reaction mixture comprising:

[0083] ii) one or more monocarboxylic acids;

[0084] iii) one or more polyols; and

[0085] iv) optionally one or more polycarboxylic acids,

[0086] The reaction mixture comprises one or more rosins.

[0087] In various embodiments, the reaction mixture used to prepare the oligoester composition comprises at least 15 wt % of one or more monocarboxylic acids, based on the total weight of the reaction mixture. However, in other embodiments, the amount of the one or more monocarboxylic acids may also be 14 wt %.

[0088] "Liquid resin" is understood to mean any resin composition which can be prepared from the above reaction mixture and which is liquid, ie flowable, at 20° C. and 1013 mbar. The liquid resin may also comprise, in particular, (high) viscous resin compositions.

[0089] The oligoester composition of the liquid resin b) may include the oligoesters described herein, or consist of or consist essentially of the oligoesters described herein. In one embodiment, the oligoester composition comprises 1 wt % to 100 wt % of one or more oligoesters of the type described herein, such as 10 wt % to 100 wt %, 20 wt % to 80 wt % or 30 wt % to 70 wt %, based on the total weight of the oligoester composition. In some embodiments, the oligoester composition comprises equal to or less than 20 wt % of non-oligoesters, such as less than 10 wt % or less than 5 wt %, based on the total weight of the oligoester composition. The oligoester composition may have improved color (e.g., the pure Gardner chroma of the oligoester may be 7 or less), improved oxidative stability (e.g., at 110° C., the oxidative induction time of the oligoester composition may be at least 30 minutes), improved color stability (e.g., when heated to a temperature of 160° C. for three hours, the pure Gardner chroma of the oligoester may change by less than 10%), or a combination thereof.

[0090] In the context of the present invention, "essentially" means that the composition may contain other substances or compounds, but these substances or compounds are not actively added to the oligoester composition, but are included due to, for example, impurities or undesired side reactions. These additional ingredients beyond the "essential" ingredients may preferably constitute a weight proportion of less than 1% by weight, preferably less than 0.1% by weight or less than 0.01% by weight, in each case based on the total weight of the oligoester composition.

[0091] The oligoester composition of the liquid resin b) described herein may be derived from at least one rosin.

[0092] Rosin, also known as rosin or Greek resin (Pix ), is a solid hydrocarbon secretion of plants, usually conifers, such as pines (such as longleaf pine (Pinus palustris) and Caribbean pine (Pinus caribaea)). Rosin can contain a mixture of rosin acids, but the exact composition of the rosin depends on the species of the plant. Rosin acid is a C20 fused-ring monocarboxylic acid whose core consists of three fused six-carbon rings containing double bonds of varying numbers and positions.

[0093] Suitable rosin acids are, for example but not limited to, abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid and palustric acid and isomers thereof. In various embodiments, the natural rosin comprises mainly a mixture of abietic acid, abietic acid and / or pimaric acid.

[0094] Rosin is commercially available and can be obtained from pine trees by distilling oleoresins (gum colophony is the residue of distillation), by extraction from pine stumps (wood rosin), or by fractionating tall oil (tall oil rosin). Any type of rosin can be used to prepare the oligoester compositions described herein, including tall oil rosin, gum rosin, and wood rosin, and mixtures thereof. If desired, the rosin can be subjected to one or more purification steps (e.g., vacuum distillation, extraction, and / or crystallization) prior to use as the rosin in the esterification step described herein. Hydrogenated rosin resins and partially hydrogenated rosin resins can also be used as a rosin source. An example of a commercially available hydrogenated rosin suitable for use in the present invention is FORAL® sold by Eastman Chemical Company. TM AX-E. Examples of commercially available hydrogenated rosins include STAYBELITE sold by Eastman Chemical Company. TM HYDROGAL for sale by Resin-E and DRT (Dérivés Résiniques et Terpéniques) TM .

[0095] In various embodiments, the oligoesters are obtained from tall oil rosin (TOR). Non-limiting examples of commercially available TOR include SYLVAROS TM 90S、SYLVAROS TM HYR, SYLVAROS TM NCY, SYLVAROS TM 85S、SYLVAROS TM 90F and SYLVAROS TM R Type S, these are commercially available from Arizona Chemical, a subsidiary of Kraton Corporation.

[0096] Crude tall oil (CTO) obtained from the kraft pulping process contains large amounts of TOR and tall oil fatty acids (TOFA). Distilled tall oil (DTO) is an industrial refinery product obtained by fractionation of crude tall oil. DTO contains primarily TOR and TOFA (a mixture of several monocarboxylic acids). In some embodiments, DTO can be used as a starting point for preparing the oligoester composition. Several commercial DTO grades with different rosin contents are marketed by Arizona Chemical, a subsidiary of Kraton Corporation, as SYLVATAL TM Product lines for sale, including SYLVATAL TM 10S, SYLVATAL TM 20 / 25S, SYLVATAL TM 20S, SYLVATAL TM 25 / 30S、SYLVATAL TM D25 LR, SYLVATAL TM D30 LR and SYLVATAL TM D40LR.

[0097] In a preferred embodiment, the oligoester composition is derived from 5 to 80 wt %, such as 10 to 70 wt % or 30 to 60 wt % of rosin, based on the total weight of the components used to prepare the oligoester composition.

[0098] As mentioned above, rosin comprises a mixture of abietic acids (e.g. abietadienoic acid), which may contain conjugated double bonds in the ring system. These conjugated double bonds may be the cause of oxidative instability. Therefore, in some embodiments, rosin, oligoesters or a combination thereof are treated to reduce the proportion of components containing conjugated double bonds. The term "PAN value" as used herein refers in particular to the sum of the weight percentages of the palustric acid, abietic acid and neoabietic acid components obtained by hydrolysis of the oligoesters, as determined according to the method described in ASTM D5974-00 (2010).

[0099] In some embodiments, the oligoesters may be derived from rosin with a low PAN value. In some embodiments, the rosin obtained by hydrolyzing the oligoesters may have a PAN value of 25 or less, such as 15 or less or 5 or less, as determined by the method described in ASTM D5974-00 (2010). The rosin obtained by hydrolyzing the oligoesters may contain 30% by weight or more of dehydroabietic acid, such as 30 to 60% by weight or 40 to 55% by weight, based on the total weight of the rosin. In some embodiments, the weight ratio of dehydroabietic acid to dihydroabietic acid in the rosin obtained by hydrolyzing the oligoesters is 1:0.80 to 1:0.25, such as 1:0.70 to 1:0.35, or 1:0.55 to 1:0.40.

[0100] The oligoester compositions described herein may also be derived from one or more polyols.

[0101] In various embodiments, the oligoester composition is derived from 5 to 40 wt %, eg, 5 to 30 wt %, or 9 to 18 wt %, or 9.7 to 12.7 wt % of the polyol, based on the total weight of the components used to prepare the oligoester composition.

[0102] The at least one polyol may include all suitable polyols. In various embodiments, the one or more polyols may have an average hydroxyl functionality of 2 to 10, such as 2 to 7 or 3 to 5.

[0103] In particular embodiments, the one or more polyols contain 2 to 36, such as 2 to 20 or 2 to 8 carbon atoms.For example, the one or more polyols may have a boiling point in excess of 240°C at about 1013 mbar (1 atm).

[0104] The polyols may contain a combination of linear, branched, cyclic aliphatic, partially unsaturated or aromatic chemical units and may optionally contain one or more additional functional groups, such as alkyl (e.g. C 1-3 The one or more polyols may be substituted with alkyl, aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or keto groups. In aromatic polyols, the aromatic ring may optionally contain one or more ring substituents, such as fluorine, chlorine, alkyl (e.g., methyl or ethyl), methoxy, or trifluoromethyl. If desired, the one or more polyols may also contain one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the molecular structure, such as ether groups in the case of oxygen atoms and thioethers in the case of sulfur atoms. In various embodiments, the one or more polyols include aliphatic alcohols, such as alicyclic alcohols.

[0105] In some embodiments, the one or more polyols may include a polyol containing a first hydroxyl group and a second hydroxyl group separated by 2 to 10 carbon atoms, or by 2 to 7 carbon atoms, or by 3 to 5 carbon atoms. In some embodiments, the one or more polyols include a polyol wherein each hydroxyl group of the polyol is separated from another hydroxyl group of the polyol by at least 2 carbon atoms, e.g., at least 3 carbon atoms or at least 6 carbon atoms.

[0106] Examples of suitable polyols include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, neopentyl glycol, trimethylene glycol, glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, technical grade pentaerythritol, dipentaerythritol, tripentaerythritol, 1,4-cyclohexanediol, polyethylene glycol, polyglycerol, technical grade polyglycerol, polyglycerol-3, polyglycerol-4, cyclohexane-1,4-dimethanol, tricyclo[5.2.1.0(2.6)]decane-4,8-dimethanol, hydrogenated bisphenol A (4,4'-isopropyldicyclohexanol), mannitol, sorbitol, xylitol, maltitol, and lactitol. In a particular embodiment, the one or more polyols can be selected from diethylene glycol, triethylene glycol, glycerol, trimethylolpropane, pentaerythritol, technical grade pentaerythritol, dipentaerythritol, polyglycerol, polyglycerol-4, tricyclo[5.2.1.0(2.6)]decane-4,8-dimethanol, cyclohexane 1,4-dimethanol, hydrogenated bisphenol A (4,4'-isopropylidene dicyclohexanol) and combinations thereof.

[0107] The oligoester compositions described herein may be derived from one or more monocarboxylic acids.

[0108] In various embodiments, the oligoester composition may be derived from 15 to 90 wt %, eg, 30 to 80 wt %, or 40 to 75 wt %, of one or more monocarboxylic acids, based on the total weight of the components used to prepare the oligoester composition.

[0109] It can be any suitable carboxylic acid. Non-limiting examples of suitable monocarboxylic acids include aromatic monofunctional carboxylic acids, heteroaromatic monofunctional carboxylic acids, aliphatic monofunctional carboxylic acids, unsaturated straight or branched monofunctional carboxylic acids, partially unsaturated straight or branched monofunctional carboxylic acids, alicyclic monofunctional carboxylic acids, partially unsaturated cyclic monofunctional carboxylic acids, natural fatty acids, synthetic fatty acids, fatty acids derived from vegetable oils and animal oils, and combinations thereof.

[0110] In some embodiments, the at least one monocarboxylic acid may contain at least six carbon atoms, such as 6-36 carbon atoms, 6-32 carbon atoms, 6-25 carbon atoms, 6-22 carbon atoms, 6-18 carbon atoms, or 6-12 carbon atoms. The monocarboxylic acid may contain a combination of linear, branched, cyclic aliphatic (alicyclic), partially unsaturated, or aromatic or heteroaromatic chemical groups, and in addition to the carboxylic acid group, may optionally contain one or more additional functional groups, such as hydroxyl, alkyl (e.g., C 1-3 The aromatic monocarboxylic acids may be substituted with halogenated alkyl, aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or keto groups. In aromatic monocarboxylic acids, the aromatic ring may optionally contain one or more ring substituents, such as fluorine, chlorine, alkyl (e.g., methyl or ethyl), methoxy, or trifluoromethyl groups. If desired, the one or more monocarboxylic acids may also contain one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the carboxylic acid molecular structure, such as ether groups in the case of oxygen atoms and thioethers in the case of sulfur atoms.

[0111] Examples of suitable aliphatic monocarboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acetic acid, caprylic acid, nonanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and cerotic acid. Examples of suitable aromatic monocarboxylic acids are benzoic acid. Non-limiting examples of suitable alicyclic monocarboxylic acids are cyclopropanecarboxylic acid, cyclopentanecarboxylic acid and cyclohexanecarboxylic acid. Non-limiting examples of suitable unsaturated straight or branched monocarboxylic acids are linoleic acid, α-linolenic acid, elaidic acid, sapienic acid, arachidonic acid, myristic acid, palmitoleic acid and oleic acid. Suitable fatty acids obtained from vegetable oils (such as triglyceride vegetable oils) and animal fats and oils include palm oil, linseed oil, rapeseed oil, sunflower seed oil, olive oil, tung oil, peanut oil, cottonseed oil, palm kernel oil, soybean oil, corn oil, grape seed oil, hazelnut oil, rice bran oil, safflower oil, sesame oil, butterfat and coconut oil. These fatty acids include linoleic acid, alpha-linolenic acid, palmitic acid, stearic acid, myristic acid and oleic acid. The limiting examples of natural fatty acids are tall oil fatty acids and commercial products thereof, such as isostearic acid.

[0112] In various embodiments, the at least one monocarboxylic acid may include oleic acid, linoleic acid, α-linolenic acid, palmitic acid, stearic acid, or a combination thereof. In particular embodiments, the at least one monocarboxylic acid may contain tall oil fatty acid (TOFA). Suitable commercially available TOFA-derived monocarboxylic acids include, but are not limited to, CENTURY FA sold by Arizona Chemical, a subsidiary of Kraton Corporation. TM Part of a product line, such as CENTURY TM D1, CENTURYTM MO5, CENTURY TM MO5N, and isostearic acid products such as CENTURY TM 1105 and CENTURY TM 1107.

[0113] Carboxylic acids and derivatives thereof may be characterized by their iodine values. In particular embodiments, the at least one monocarboxylic acid may have an iodine value of less than 275 mg / g, optionally less than 180 mg / g, or less than 115 mg / g, or less than 80 mg / g, or optionally from 55 mg / g to 270 mg / g, or from 60 mg / g to 250 mg / g, or from 70 mg / g to 200 mg / g, as determined by the method described in ASTM D5768-02 (2014).

[0114] Particularly preferably, the at least one monocarboxylic acid is a fatty acid, tall oil fatty acid or a mixture thereof.

[0115] In various embodiments, the oligoester composition may optionally also be derived from one or more polycarboxylic acids.

[0116] The oligoester composition may be derived from less than Q weight percent of one or more polycarboxylic acids, wherein Q is defined by the formula:

[0117]

[0118] Wherein ∑ represents the mathematical sum of the product of X and Y for each of the one or more polycarboxylic acids; X is the carboxylic acid functionality of the polycarboxylic acid and is an integer from 2 to 4; Y is the polycarboxylic acid weight fraction of the polycarboxylic acid and is from 0 to 1, wherein the sum of the weight fractions of the one or more polycarboxylic acids is equal to 1. In other words, the Q value refers to the percentage of the polycarboxylic acid in the total ester composition. For example, using 50 weight percent of a dicarboxylic acid and 50 weight percent of a tricarboxylic acid will result in a Q value of 10-2(2×0.5+3×0.5)=10-2(1+1.5)=10-2×2.5=5%. Similarly, using only dicarboxylic acids will result in a Q value of 6%. In some embodiments, Q may be defined by the following formula

[0119]

[0120] wherein Σ represents the mathematical sum of the product of X and Y for each of the one or more polycarboxylic acids; X is the carboxylic acid functionality of the polycarboxylic acid and is an integer from 2 to 4; and Y is the polycarboxylic acid weight fraction of the polycarboxylic acid and is from 0 to 1, wherein the sum of the weight fractions of the one or more polycarboxylic acids is equal to 1.

[0121] In various embodiments, the oligoester composition may be derived from 0 to 4 wt %, e.g., 0 to 3 wt % or 0 to 2 wt % polycarboxylic acid (i.e., having a carboxylic acid functionality of 2 or more), based on the total weight of the components used to prepare the oligoester composition.

[0122] In certain embodiments, the oligoesters may be derived from 0 to 6 wt%, optionally 0 to 4 wt% or 0 to 2 wt% of one or more dicarboxylic acids, based on the total weight of the components used to form the liquid resin b). In various embodiments, the oligoester composition is not derived from any polycarboxylic acid.

[0123] The at least one polycarboxylic acid may include all suitable polycarboxylic acids. In some embodiments, the one or more polycarboxylic acids may include dicarboxylic acids; In some embodiments, the one or more polycarboxylic acids may include tricarboxylic acids. In some embodiments, the one or more polycarboxylic acids may be tetracarboxylic acids. In some embodiments, the one or more polycarboxylic acids include 2 to 54 carbon atoms, such as 4-35 carbon atoms or 6-12 carbon atoms.

[0124] Polycarboxylic acids may comprise a combination of linear, branched, cyclic aliphatic (alicyclic), unsaturated, partially unsaturated, heteroaromatic or aromatic chemical units and, in addition to comprising two or more carboxylic acid units, may optionally comprise one or more additional functional groups, such as hydroxyl, alkyl (e.g. C1-3 alkyl), aryl (e.g. benzyl), alkoxy (e.g. methoxy), haloalkyl (e.g. trifluoromethyl) or keto groups. In aromatic polycarboxylic acids, the aromatic ring may optionally comprise one or more ring substituents, such as fluorine, chlorine, alkyl (e.g. methyl or ethyl), methoxy or trifluoromethyl groups. If desired, the one or more polycarboxylic acids may also contain one or more heteroatoms (e.g., one or more oxygen, sulfur or nitrogen atoms) incorporated into the molecular structure, such as ether groups in the case of oxygen atoms incorporated and thioethers in the case of sulfur atoms incorporated.

[0125] Non-limiting examples of suitable polycarboxylic acids include adipic acid, 3-methyladipic acid, succinic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, rosin dimer, isophthalic acid, terephthalic acid, phthalic acid, TOFA dimer, hydrogenated TOFA dimer, 2-(2-carboxyphenyl)benzoic acid, 2,5-furandicarboxylic acid, camphoric acid, cis-norbornene-endo-2,3-dicarboxylic acid, trimellitic acid, and combinations thereof. TM 30 is an example of a commercially available dimeric TOFA derivative suitable for use in the present invention.

[0126] The ratio of the weight of the one or more polycarboxylic acids to the weight of the rosin and the one or more monocarboxylic acids may be less than 1:20, such as less than 1:50 or less than 1:100. In various embodiments, the weight ratio between the rosin and the one or more monocarboxylic acids may be from 60:40 to 10:85. The ratio of the weight of the rosin and the one or more monocarboxylic acids to the weight of the one or more polycarboxylic acids may be at least 6.5:1 or at least 15:1. In particular embodiments, the oligoester composition may be derived from, for example, 30% to 75% by weight of rosin, or 25% to 60% by weight of one or more monocarboxylic acids, or 5% to 18% by weight of one or more polyols; or 0% to less than 4% by weight of one or more polycarboxylic acids.

[0127] In one embodiment, the oligoester composition may be derived from 5 to 75% by weight of rosin, 15 to 85% by weight of one or more monocarboxylic acids, or 7 to 40% by weight of one or more polyols, or 0 to less than 4% by weight of one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 15 to 75% by weight of rosin, 36 to 80% by weight of one or more monocarboxylic acids, 9 to 35% by weight of one or more polyols, and 0 to less than 4% by weight of one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 30 to 75% by weight of rosin, 25 to 60% by weight of one or more monocarboxylic acids, 3 to 18% by weight of one or more polyols, and 0 to less than 4% by weight of one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 5 to 75% by weight of rosin, 15 to 85% by weight of one or more monocarboxylic acids, 7 to 40% by weight of one or more polyols, and 0 to less than 6% by weight of one or more dicarboxylic acids containing 2 to 35 carbon atoms.

[0128] Particularly preferably, the reaction mixture for preparing the oligoester composition comprises, based on the total weight of the reactants used in the reaction mixture:

[0129] ii) 25 to 85% by weight of one or more monocarboxylic acids;

[0130] iii) 7 to 35 wt% of one or more polyols; and

[0131] iv) optionally more than 0% to less than 4% by weight of one or more polycarboxylic acids,

[0132] The reaction mixture preferably contains 5 to 75 wt % of rosin.

[0133] In various embodiments, the weight average molecular weight, M, of the oligoester compositions described herein, as measured by gel permeation chromatography (GPC) according to ASTM D5296-05 is w In certain embodiments, the oligoester composition has a molecular weight of less than 1000 g / mol, for example, less than 35 wt %, for example, less than 20 wt %, or less than 13 wt %, as measured by gel permeation chromatography (GPC).

[0134] In various embodiments, the individual oligoesters may be liquids, such as viscous liquids, at 20°C and 1013 mbar (1 atm). The oligoester composition itself is preferably also a liquid.

[0135] The oligoester composition described herein can be characterized by its glass transition temperature (Tg). Dynamic mechanical analysis (DMA) and dynamic differential thermal analysis (DSC: differential scanning calorimetry) can be used to determine the Tg value. Preferably, the Tg of the oligoester (composition) can be about 50°C lower than the softening point of the oligoester (composition).

[0136] In particular embodiments, the oligoester ester composition may have a Tg of -80°C to 100°C, such as -60°C to 80°C, or -50°C to 40°C, or less than about 20°C, as measured by DSC.

[0137] The oligoester composition can exhibit improved Gardner color. In some embodiments, the oligoester has a neat Gardner color of 8 or less, such as 6 or less, or 4 or less, as measured by the method described in ASTM D1544-04 (2010).

[0138] The oligoester composition may exhibit improved color stability. In some embodiments, when heated to a temperature of 160° C. for three hours, the oligoester composition may exhibit less than a 10% change in neat Gardner color, such as less than an 8% change or less than a 5% change, as measured according to the method described in ASTM D1544-04 (2010). In a specific embodiment, when the oligoester composition is heated to a temperature of 160° C. for three hours, the neat Gardner color of the oligoester composition remains substantially unchanged (i.e., the change in neat Gardner color is less than 0.5%) as measured according to the method described in ASTM D1544-04 (2010).

[0139] The oligoester composition can exhibit improved oxidative stability. For example, in some embodiments, when there is no antioxidant combined with the oligoester composition, the oligoester composition has an onset of oxidative induction time of 30 to 200 minutes, such as 70 to 150 minutes at 110°C, as measured using the method specified in ASTM D5483-05 (2010).

[0140] Optionally, the oligoester composition may have a low hydroxyl value. In some embodiments, the hydroxyl value of the oligoester composition is less than 200 mg KOH / g, for example less than 30 mg KOH / g, less than 20 mg KOH / g or less than 6 mg KOH / g, measured using a modified version of the standard method provided in DIN 53240-2 (using a different solvent, tetrahydrofuran). The hydroxyl value is represented by mgKOH / g of oligoester or oligoester composition sample.

[0141] Optionally, the oligoester composition may have a low acid number. In some embodiments, the acid number of the oligoester composition is 30 mg KOH / g or less, such as 15 mg KOH / g or less, or 6 mg KOH / g or less, as measured by the method described in ASTM D465-05 (2010). The acid number is represented by mg KOH / g of oligoester or oligoester composition sample.

[0142] Suitable oligoester compositions and their properties are described, for example, in US 2017 / 0190935 A1.

[0143] Various methods can be used to prepare the oligoester composition. For example, the oligoester composition described herein can be prepared by an esterification method, in which the carboxylic acid-containing component of the oligoester is esterified with one or more polyols. This type of esterification reaction is a balanced reaction. Removing the water formed during the reaction can change the reaction equilibrium, which is conducive to product formation, so that the reaction is completed. Therefore, in some embodiments, the method for preparing the oligoester may include esterifying a mixture containing one or more rosins, one or more monocarboxylic acids and one or more polycarboxylic acids that are optionally present with one or more polyols to form the oligoester composition. The esterification step may be to react the mixture with the one or more polyols under appropriate conditions for a specific time to form the oligoester. Optionally, the esterification step may also include removing water produced as a by-product of the esterification reaction. Optionally, the esterification step may include contacting the mixture and one or more polyols with an esterification catalyst (e.g., bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)ethyl calcium phosphate)). In other embodiments, the esterification step may include contacting the mixture with one or more polyols in the absence of an esterification catalyst.

[0144] For example, oligoester compositions described herein can also be prepared by transesterification methods, in which the ester containing the carboxylic acid component of the oligoester is reacted with one or more polyols. In the polyol reacted with the carboxylic acid, some free, unreacted hydroxyl groups of the polyol may be retained, which can react with the ester in the transesterification reaction and cause its alkoxy groups to exchange. This transesterification reaction is a kind of equilibrium reaction, in which new oligoester compositions can be formed. Therefore, in some embodiments, the method for preparing the oligoester compositions can include reacting one or more rosin esters having a hydroxyl value greater than zero with one or more esters derived from monocarboxylic acids and optionally one or more polycarboxylic acids. In some embodiments, alcohol or polyol can be added to initiate or accelerate this transesterification reaction. Optionally, the transesterification step may include contacting the mixture and one or more polyols with an esterification catalyst (e.g., calcium bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methylphosphate)). In other embodiments, the transesterification step may include contacting the mixture with one or more polyols in the absence of an esterification catalyst. Non-limiting examples of esters of the carboxylic acid component of the oligoesters useful in this transesterification process are vegetable oils (e.g., triglyceride vegetable oils) and animal fats and oils, including oils such as palm oil, linseed oil, rapeseed oil, sunflower seed oil, olive oil, tung oil, peanut oil, cottonseed oil, palm kernel oil, soybean oil, corn oil, grapeseed oil, hazelnut oil, rice bran oil, safflower oil, sesame oil, milk fat, and coconut oil; as well as hydrogenated and deodorized oils. Other esters useful in this transesterification process are rosin esters. Such esters may also be used in the interesterification process described below.

[0145] The oligoester compositions described herein can also be prepared by an interesterification process that is mechanistically related to esterification and transesterification. The interesterification process can be performed by mixing different esters in the presence of a catalyst, such as an esterification catalyst, followed by rearrangement of the carboxylic acid groups on the polyol scaffold. The interesterification reaction is an equilibrium reaction. For example, a rosin ester can be reacted with a triglyceride such as rapeseed oil. This interesterification reaction will produce an oligoester in which the fatty acid component of the triglyceride is partially replaced by the rosin acid component, and the rosin acid component of the rosin ester is partially replaced by the fatty acid component.

[0146] The oligoester compositions described herein can also be prepared by a combination of the above-described esterification, transesterification and interesterification methods, wherein the esters can react with each other in the presence of one or more polyols and one or more monocarboxylic acids and optionally one or more polycarboxylic acids or partial esters or half esters thereof. Examples of partial esters are partial glycerides, i.e., glycerides with fatty acids in which not all hydroxyl groups are esterified. Cis-HOOC-CH═CH-COOCH3 is an example of a maleic acid half ester. Monomethyl adipate and monoethyl adipate are examples of half esters derived from adipic acid. As with the above methods, removal of water or volatile monoalcohols formed during the reaction can shift the reaction equilibrium in favor of product formation, thereby driving the reaction to completion.

[0147] For example, in certain embodiments, the preparation method may include esterifying a mixture comprising one or more rosins, one or more monocarboxylic acids, and optionally one or more polycarboxylic acids with one or more polyols to form an oligoester composition. In some embodiments, the esterification step may include thermally reacting the mixture with the one or more polyols. For example, the esterification may include contacting the mixture with the one or more polyols at an elevated temperature (e.g., at a temperature of 30° C. to 300° C. or 150° C. to 285° C.). Optionally, the esterification step may also include removing water formed as a byproduct during the esterification process.

[0148] In various embodiments, catalysts, co-catalysts, solvents, bleaching agents, stabilizers, and / or antioxidants may be added during the esterification, transesterification, and interesterification reactions.

[0149] The pressure-sensitive adhesive composition according to the present invention comprises 1 to 50 wt.-%, more preferably 2 to 40 wt.-%, even more preferably 5 to 40 wt.-%, even more preferably 5 to 30 wt.-%, in particular 10 to 30 wt.-%, for example 15 to 30 wt.-%, 10 to 25 wt.-% or 15 to 20 wt.-% of at least one liquid resin b), based on the total weight of the pressure-sensitive adhesive composition, the at least one liquid resin comprising or consisting of the oligoester composition as described herein, or a combination thereof.

[0150] Commercially available pressure-sensitive adhesive compositions usually contain plasticizers. These plasticizers are used, for example, to reduce the viscosity of the pressure-sensitive adhesive composition and to improve wettability. The common plasticizers used in this case are, for example, medical white oil, naphthenic mineral oil, adipic acid esters, polypropylene, polybutene and polyisoprene oligomers, hydrogenated polyisoprene and / or polybutadiene oligomers, benzoates, phthalates, vegetable or animal oils and derivatives thereof, sulfonic acid esters, monohydric or polyhydric alcohols and polyalkylene glycols, such as polypropylene glycol, polybutylene glycol or polymethylene glycol. Polybutene oligomers should have a molecular weight of 200 to 6000 g / mol, and polyolefins should have a molecular weight of up to about 2000 g / mol, particularly up to 1000 g / mol. w .

[0151] Oily plasticizer components are usually used. Examples of plasticizer components are liquid at room temperature, such as hydrocarbon oils, polybutene / polyisoprene oligomers, (hydrogenated) naphthenic oils, paraffin oils or vegetable oils.

[0152] Pressure-sensitive adhesive composition according to the present invention comprises the combination of the liquid resin b) and at least one other plasticizer c), and this plasticizer comprises isobutylene / butylene copolymer.These components are used together, to partially, mainly or completely replace traditional plasticizers such as those mentioned above.Based on the gross weight of pressure-sensitive adhesive composition, the content of this at least one other plasticizer c) in pressure-sensitive adhesive composition is preferably 0.1 to 30 wt %, more preferably 1 to 15 wt %, for example 2 to 12 wt % or 5 to 10 wt %.Particularly preferably, based on the gross weight of each component of pressure-sensitive adhesive composition, the concentration of at least one liquid resin b) and at least one other plasticizer c) in pressure-sensitive adhesive composition together is 5 to 50 wt %, preferably 10 to 40 wt %, particularly 15 to 35 wt %.

[0153] The isobutylene / butene copolymer used herein is a synthetic hydrocarbon obtained by polymerization of a C4 fraction. By varying the polymerization parameters, polymers with different chain lengths are produced. This variation in chain length affects the physical properties.

[0154] The at least one further plasticizer c) or the isobutylene / butene copolymer can be characterized by its molecular weight. Size exclusion chromatography (GPC: gel permeation chromatography) can be used to determine the molecular weight of the n In various embodiments, the number average molecular weight M of the plasticizer c) or the isobutylene / butene copolymer is n 750-1450 g / mol, preferably 850-1350 g / mol, in particular 900-1300 g / mol. This distinguishes the plasticizer c) used according to the invention from, for example, plasticizing oils such as polybutene oils. Oils generally have a lower number average molecular weight, for example 480 g / mol.

[0155] In addition, the at least one plasticizer c) or isobutylene / butene copolymer can be characterized by its glass transition temperature (Tg). Dynamic differential thermal analysis (DSC: differential scanning calorimetry) can be used to determine the Tg value. Tg can be determined according to DIN EN ISO11357-1:2017-02, -2:2014-07 or -3:2018-07. The glass transition temperature Tg is preferably determined by differential scanning calorimetry (DSC), preferably using a heating rate of 10K / min. In various embodiments, the glass transition temperature of the plasticizer c) or isobutylene / butene copolymer is from -60 to -73°C, more preferably from -63 to -73°C, in particular from -66 to -70°C.

[0156] In various embodiments, the at least one plasticizer c) or isobutylene / butene copolymer has a kinematic viscosity of 0.00018 to 0.0007 m / s as measured at 100° C. according to ASTM D445. 2 / s (180-700 cSt), preferably 0.00019 to 0.00067 m 2 / s (190-670cSt), especially 0.0002 to 0.000655m 2 / s(200-655cSt).

[0157] Suitable isobutylene / butene copolymers are commercially available, for example, under the name Polybutene (PB) 1300 from Daelim Industrial or Indopol H300 from Ineos.

[0158] Preferably, the pressure sensitive adhesive composition contains no other plasticizers besides the combination of the liquid resin b) and other plasticizers c).Such a pressure sensitive adhesive composition preferably exhibits improved bond strength and / or adhesion to various substrates.

[0159] In particular, the combination of the liquid resin b) and at least one other plasticizer c) in the pressure-sensitive adhesive composition according to the invention partially or completely replaces conventional mineral oil-based plasticizers (eg naphthenic oil and / or paraffin oil).

[0160] Mineral oils are generally produced by distillation of crude oil and optionally other raw fossil materials. Mineral oils include, for example, paraffinic, cycloparaffinic and aromatic hydrocarbons, olefins and sulfur- and nitrogen-containing or organic compounds. The term "cycloparaffinic oil" refers specifically to saturated cyclic hydrocarbons herein. "Paraffinic oil" refers specifically to saturated chain hydrocarbons.

[0161] In various embodiments, the pressure-sensitive adhesive composition comprises less than 20 wt. %, preferably less than 15 wt. %, more preferably less than 10 wt. %, even more preferably less than 9 wt. %, even more preferably less than 8 wt. %, even more preferably less than 7 wt. %, even more preferably less than 6 wt. %, even more preferably less than 5 wt. %, even more preferably less than 4 wt. %, even more preferably less than 3 wt. %, even more preferably less than 2 wt. %, even more preferably less than 1 wt. %, even more preferably less than 0.5 wt. %, even more preferably less than 0.1 wt. %, even more preferably less than 0.01 wt. %, based on the total weight of the pressure-sensitive adhesive composition, and most preferably contains no such plasticizers.

[0162] In a preferred embodiment, in the pressure-sensitive adhesive composition, at least one mineral oil-based plasticizer, preferably naphthenic oil and / or paraffinic oil (or the required amount of plasticizer) is replaced by the at least one liquid resin b) and the at least one other plasticizer c) to an extent of at least 50%, more preferably at least 60%, even more preferably at least 70%, even more preferably at least 80%, even more preferably at least 90%, even more preferably at least 95%, even more preferably at least 98%, even more preferably at least 99%, most preferably 100%.

[0163] In another preferred embodiment, the pressure-sensitive adhesive composition has a proportion of renewable resources of 20 to 100% by weight, preferably 50 to 100% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, even more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, most preferably at least 99% by weight, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0164] Besides the at least one liquid resin b), the pressure-sensitive adhesive composition according to the invention may also comprise at least one further resin d).

[0165] Resins are generally used to modify, preferably reduce, the viscosity of the pressure-sensitive adhesive composition according to the invention and to influence the odor, the (initial) color and the color stability of the composition, as well as the viscosity and polarity of any polymers present.

[0166] They are in particular resins having a softening point of 35 to 160° C. or up to 130° C. (ring and ball method, DIN 52011). Suitable resins include, but are not limited to, aromatic, aliphatic or cycloaliphatic hydrocarbon resins, and modified or hydrogenated forms thereof. Specific examples are: aliphatic or cycloaliphatic petroleum hydrocarbon resins and hydrogenated derivatives thereof. Other resins that can be used within the scope of the present invention are, for example, hydrogenated abietyl alcohol and its esters, in particular esters with aromatic carboxylic acids such as terephthalic acid and phthalic acid; modified natural resins, for example resin acids from balsamic resins, tall resins or root resins, for example fully saponified balsamic resins; alkyl esters of optionally partially hydrogenated rosins with low softening points, for example methyl esters, diethylene glycol esters, glycerol esters and pentaerythritol esters; terpene resins, in particular terpolymers or copolymers of terpenes, for example styrene terpene, α-methylstyrene terpene, phenol-modified terpene resins and hydrogenated derivatives thereof; acrylic copolymers, preferably styrene-acrylic copolymers and resins based on functional hydrocarbon resins, for example resins having 3 to 8 carbon atoms, in particular 5 carbon atoms, the at least one resin d) being different from the liquid resin b) described herein, in particular not being a liquid resin. Particularly preferably, the at least one resin d) is a solid resin. "Solid" as used in this context means that the resin is solid at 20°C and 1013 mbar, ie it is not flowable nor exists in the form of a liquid having a yield point, but exists in the form of a solid.

[0167] The at least one resin d) is preferably a natural resin or a hydrogenated and / or non-hydrogenated hydrocarbon resin, more preferably tall oil esters, gum rosin (rosin esters), optionally partially polymerized tall resins, terpene or crude oil based aliphatic, aromatic or alicyclic hydrocarbon resins and modified or hydrogenated forms thereof, for example C5 aliphatic or C9 aromatic hydrocarbon resins or C5 / C9 monomer mixtures, the at least one resin d) being different from the liquid resin b) described herein, in particular not a liquid resin, but for example a solid resin.

[0168] Particularly preferably, the pressure-sensitive adhesive composition comprises at least one resin d), preferably two resins, in particular selected from rosin esters, such as pentaerythritol esters (from tall oil rosin) and / or aliphatic (cycloaliphatic) hydrocarbons, for example having 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), for example 10 to 25 carbon atoms. In various embodiments, the aliphatic (cycloaliphatic) hydrocarbons may contain a combination of linear, branched, cyclic aliphatic (cycloaliphatic), partially unsaturated or aromatic or heteroaromatic chemical groups, and may optionally contain one or more functional groups, such as, but not limited to, hydroxyl, alkyl, aryl, alkoxy, haloalkyl or keto groups. Resins with low coloration and good color stability are particularly suitable.

[0169] The solid resins used preferably differ from liquid resins in that they are solid at room temperature (20° C.) and 1013 mbar and have a softening range of 70 to 110° C., preferably 85 to 106° C., for example 85 to 100° C. (ring and ball method, ASTM D36, glycerol).

[0170] In a specific embodiment, the at least one resin d) is present in an amount of 10 to 70 wt %, preferably 15 to 60 wt %, for example 15 to 70 wt %, 20 to 50 wt %, 15 to 45 wt % or 25 to 60 wt %, based on the total weight of the pressure-sensitive adhesive composition.

[0171] According to the invention both solid resins and liquid resins can be used. In a preferred embodiment, however, in addition to the liquid resins b) described herein, at least one resin d) is a solid resin.

[0172] The pressure-sensitive adhesive composition according to the present invention may further comprise at least one additive. Suitable additives include, but are not limited to, components selected from the following group: antioxidants (particularly stabilizers), waxes, UV protectants, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, fluorescent brighteners and fragrances.

[0173] The at least one additive e) is preferably contained in the pressure-sensitive adhesive composition in an amount of 0.01 to 20 wt %, more preferably 0.1 to 5 wt %, even more preferably 0.5 to 3 wt %, based on the total weight of the pressure-sensitive adhesive composition.

[0174] Antioxidants, such as stabilizers, are particularly preferably used in the pressure-sensitive adhesive composition according to the invention in an amount of preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, even more preferably 0.5 to 2% by weight. For example, they are used to resist thermal and oxidative degradation caused by oxygen and ultraviolet radiation. In addition, antioxidants can improve thermal stability and / or color stability.

[0175] When stabilizers are used, it must be ensured that they are compatible with the pressure-sensitive adhesive composition. For example, the trade name Antioxidants obtained from BASF SE can be used as stabilizers, preferably in an amount of 0.5 to 1.5% by weight, for example 1% by weight, based on the total weight of the composition.

[0176] In various embodiments, wax can be optionally added to the pressure-sensitive adhesive composition in an amount of 0.5 to 5% by weight. In this case, the amount is measured so that the viscosity is reduced to the desired range without negatively affecting adhesion. The wax can be of natural origin, chemically modified form, or synthetic origin. Vegetable wax, animal wax, mineral wax or petrochemical wax can be used as natural wax. Hard wax, such as montan ester wax, sasol wax, etc., can be used as chemically modified wax. Polyalkylene wax and polyethylene glycol wax are used as synthetic wax. Preferably, petrochemical waxes are used, such as vaseline, paraffin, microcrystalline wax and synthetic wax. Particularly preferred are paraffin and / or microcrystalline wax and / or hydrogenated forms thereof, particularly polypropylene or polyethylene wax having a dropping point of 50°C to 170°C as determined according to ASTM D-3954.

[0177] The consistency of the pressure-sensitive adhesive composition according to the invention can be adjusted according to specific requirements, for example by adding a suitable solvent. In various embodiments, the pressure-sensitive adhesive composition according to the invention further comprises one or more solvents.

[0178] However, considering the considerable environmental and economic requirements associated with the use of organic solvents in particular, it is advantageous to avoid the use of solvents. Therefore, embodiments in which the pressure-sensitive adhesive composition according to the invention is solvent-free are preferred. When the amount of liquid resin b) is appropriately selected, the use of solvents can be completely or partially avoided.

[0179] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention is solvent-containing, solvent-free or a dispersion.

[0180] In a particularly preferred embodiment, the pressure-sensitive adhesive composition comprises:

[0181] a) at least one polymer, preferably a SBC and / or SIS polymer;

[0182] b) at least one liquid resin comprising an oligomeric ester composition which is the reaction product of a reaction mixture comprising:

[0183] ii) one or more monocarboxylic acids;

[0184] iii) one or more polyols; and

[0185] iv) optionally one or more polycarboxylic acids,

[0186] wherein the reaction mixture comprises one or more rosins;

[0187] c) at least one other plasticizer, wherein the at least one other plasticizer comprises an isobutylene / butene copolymer; and

[0188] d) at least one resin, preferably two resins, more preferably rosin esters, such as pentaerythritol resin esters, and / or aliphatic (cycloaliphatic) hydrocarbon resins, for example having 1 to 30 or 6 to 30 carbon atoms, which resin is different from the liquid resin b) described herein, in particular is not a liquid resin, and more preferably is a solid resin;

[0189] e) at least one additive, preferably a stabilizer;

[0190] Wherein, each component is preferably used in the pressure-sensitive adhesive composition as follows, based on the total weight of the pressure-sensitive adhesive composition:

[0191] a) 10 to 70 wt%, preferably 15 to 70 wt%, more preferably 20 to 70 wt%, for example 20 to 50 wt%, 20 to 40 wt%, 25 to 60 wt%, 30 to 60 wt% or 28 to 40 wt%; and / or

[0192] b) 1 to 50 wt %, preferably 2 to 40 wt %, more preferably 5 to 40 wt %, even more preferably 5 to 30 wt %, in particular 10 to 30 wt %, for example 15 to 30 wt %, 10 to 25 wt % or 15 to 20 wt %; and / or

[0193] c) 0.1 to 30 wt%, more preferably 1 to 15 wt%, for example 2 to 12 wt% or 5 to 10 wt%; and / or

[0194] d) 10 to 70 wt%, preferably 15 to 60 wt%, more preferably 20 to 60 wt%, for example 15 to 70 wt%, 15 to 45 wt%, 20 to 50 wt%, 40 to 60 wt% or 25 to 60 wt%; and / or

[0195] e) 0.01 to 20% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight.

[0196] In various embodiments, the pressure-sensitive adhesive composition according to the invention does not contain betulin-based polyester polyols as described, for example, in EP 3 878 883 A1.

[0197] Especially high requirements are put forward for food packaging and the materials used to produce these packaging. In addition to mechanical properties, the focus is also particularly on health aspects. Within the scope of the present invention, it is surprisingly found that by using liquid resin b) as described herein and at least one plasticizer c) as described herein, the formation of so-called key migratable substances can be prevented. Key migratable substances should be understood to refer to compounds that can migrate from adhesives to packaging materials or packaged products such as food, and therefore may be harmful to health. Therefore, one embodiment of the pressure-sensitive adhesive composition according to the present invention is preferred, wherein the proportion of key migratable components in the pressure-sensitive adhesive composition is less than 300ppm, preferably less than 200ppm, and particularly preferably less than 50ppm, and ppm represents the weight ratio and amount related to the total weight of the pressure-sensitive adhesive composition.

[0198] In a preferred embodiment, the liquid resins b) and / or plasticizers c) described herein have a molecular weight such that they exhibit only a low volatility and thus a low migration capacity.

[0199] It is particularly preferred that the liquid resin b) and / or the plasticizer c) described herein contain only ingredients which are approved for contact with foods.

[0200] In a preferred embodiment of the pressure-sensitive adhesive composition according to the present invention, the combination of the liquid resin b) described herein and the other plasticizer c) described herein partially or completely replaces the mineral oil such as the migratable naphthenic oil. The liquid resin preferably comprises or is composed of the oligoester composition described herein. Due to the described properties of the oligoester composition, compared with migratable naphthenic oil or white medical paraffin oil, using the liquid resin described herein, preferably no component migrates from the adhesive to the material, for example, to the packaging material or to the packaged product, or the migration amount is greatly reduced. This preferably also applies to at least one plasticizer described herein.

[0201] Furthermore, the replacement of mineral oils, such as naphthenic and / or paraffinic oils, by the liquid resins b) described herein increases the proportion of renewable resources in the formulation.

[0202] Compared with other adhesive compositions, the pressure-sensitive adhesive composition according to the present invention preferably has a lower viscosity and can therefore be applied at a lower temperature, which saves energy and costs for the customer.

[0203] In a preferred embodiment, the pressure sensitive adhesive according to the present invention has a Brookfield viscosity at 160° C. (eg measured with spindle 27 at 20 RPM) of 5000 to 160000 mPas, preferably 8000 to 30000 mPas, for example 9000 to 20000 mPas or 10000 to 15000 mPas.

[0204] In a preferred embodiment, the pressure-sensitive adhesive according to the invention has a softening point above 90° C. (ring and ball method, ASTM D36, glycerol).

[0205] The glass transition temperature Tg of the pressure-sensitive adhesive composition according to the present invention is preferably -50 to 80°C, more preferably -10 to 30°C, in particular -5 to 20°C, for example 0 to 10°C (measurement: DMA).

[0206] Preferably, the pressure-sensitive adhesive composition according to the invention has a reduced glass transition temperature, in particular compared to compositions with betulin-based polyester polyols.

[0207] In a preferred embodiment, the pressure-sensitive adhesive compositions according to the invention also exhibit improved adhesion to various substrates, such as plastics, glass, nonwovens, cardboard or steel, and therefore require reduced amounts compared to known pressure-sensitive adhesive compositions.

[0208] In order to test the adhesion of the pressure-sensitive adhesive composition according to the present invention, a peel test can be performed. The peel force is generally the average force required to separate two materials that are stuck together. The test is generally performed at an angle of 90° or 180°, depending on the material.

[0209] In a preferred embodiment, the pressure-sensitive adhesive composition has a peeling force of at least 10 Newtons (N) based on a 25 mm wide PET coating, using an angle of 180 °, measured by the FINAT-FTM1 test method. In other embodiments, the peeling force of the pressure-sensitive adhesive composition according to the present invention on highly branched (LD) polyethylene is at least 15N / 25mm PET coating, preferably at least 18N / 25mm PET coating, more preferably at least 20N / 25mm PET coating, particularly at least 21N / 25mm PET coating, for example at least 22N / 25mm PET coating. In a preferred embodiment, the peeling force of the pressure-sensitive adhesive composition according to the present invention on nonwoven fabrics is at least 10N / 25mm PET coating, preferably at least 12N / 25mm PET coating. In other preferred embodiments, the peeling force of the pressure-sensitive adhesive composition on cardboard is at least 15N / 25mm PET coating, preferably at least 18N / 25mm PET coating. These measurements all refer to the use of an angle of 180 °, using the FINAT FTM1 test method to measure.

[0210] Furthermore, the adhesive strength of the pressure-sensitive adhesive composition according to the present invention can be measured by a loop tack test. The measured value refers to a 25 mm x 25 mm PET coating.

[0211] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention has an adhesive strength on steel (loop quick tack) of at least 40 N, preferably at least 43 N, more preferably at least 45 N, even more preferably at least 46 N, in particular at least 47 N. The pressure-sensitive adhesive composition according to the invention has an adhesive strength on glass of preferably at least 38 N, more preferably at least 40 N, even more preferably at least 42 N, in particular at least 43 N. In a preferred embodiment, the composition has an adhesive strength on LD polyethylene of at least 20 N, preferably at least 22 N, in particular at least 23 N.

[0212] The present invention also relates to a process for preparing a pressure-sensitive adhesive composition according to the invention, which comprises mixing in a suitable order at least one liquid resin b) as described herein and the other components of the pressure-sensitive adhesive composition, such as at least one polymer a) and at least one other plasticizer c), and optionally other components such as at least one resin d) and / or at least one additive e), preferably at a temperature of 100 to 200° C., more preferably at a temperature of 120 to 180° C., even more preferably at a temperature of 150 to 170° C.

[0213] In a preferred embodiment, the other components of the pressure-sensitive adhesive composition, such as polymer a) and resin d), are provided and mixed before the liquid resin b) is added. Subsequently, plasticizer c) or additive e) may be added.

[0214] The preferred mixing sequence for the process for preparing the pressure-sensitive adhesive composition according to the present invention is:

[0215] 1. Providing at least one polymer a);

[0216] 2. optionally adding at least one resin d), preferably two resins;

[0217] 3. Adding at least one liquid resin b) as described herein;

[0218] 4. Adding at least one plasticizer c);

[0219] 5. Optionally adding at least one additive, such as at least one stabilizer, preferably at a temperature of 100 to 200°C, more preferably at a temperature of 120 to 180°C, even more preferably at a temperature of 150 to 170°C.

[0220] Preferably, the individual components used to prepare the pressure-sensitive adhesive composition according to the present invention are as described herein.

[0221] The invention further relates to the use of the pressure-sensitive adhesive composition according to the invention in adhesive tapes, labels, hygiene articles (e.g. diapers), markings (e.g. markings for beverage bottles), flexible packaging, films, food packaging, the assembly sector (high performance, e.g. the automotive industry), medical applications (e.g. packaging of medical materials and products) and / or the graphic industry (e.g. books, magazines, brochures).

[0222] The pressure-sensitive adhesive according to the present invention is used, for example, for bonding substrates such as glass, metals (e.g. steel), fabrics, nonwovens, coated or uncoated paper, cardboard and plastic materials (e.g. PET, PEN, PE, PP, PVC and PS). The flexible thin substrate made of film, multilayer film or paper is then bonded to a solid substrate of this type. The flexible thin substrate is, for example, a label, an outer packaging, a bag, etc., and can be, for example, made of a plastic material, for example, made of polyethylene, polypropylene, polystyrene, polyvinyl chloride or cellophane, in particular made of PE film. However, labels can also be paper-based, optionally in combination with polymer films. The hot-melt pressure-sensitive adhesive according to the present invention is particularly characterized in that it has very good adhesion to the above-mentioned plastic materials, but they can also be removed from the substrate surface again.

[0223] For example, international patent publication WO 2016 / 062797 A1, in particular on pages 10-11, describes other application areas.

[0224] In a preferred embodiment, the pressure-sensitive adhesive composition is applied in an amount of 1 to 200 g / m 2 , preferably 2 to 70 g / m 2 , more preferably 10 to 60 g / m 2 , for example 20 to 50 g / m 2 .

[0225] In a preferred embodiment, the substrates may optionally be pretreated, and / or the two substrates may be joined together under pressure.

[0226] The present invention also relates to an article comprising a pressure-sensitive adhesive composition according to the invention. In a preferred embodiment, the article can be obtained using the method according to the invention. The article is preferably a multilayer substrate, in particular for use in food and pharmaceutical packaging, hygiene products, "labels" and "marking" fields, and can also be used in the automotive industry or the graphics industry.

[0227] All aspects, purposes and embodiments of the pressure-sensitive adhesive composition according to the invention can also be applied to the method according to the invention, to the article according to the invention and to the use according to the invention. Therefore, explicit reference is made here to the disclosure of the corresponding points, wherein it is pointed out that the present disclosure also applies to the use according to the invention, to the article according to the invention and to the method according to the invention.

[0228] The present invention is described below with reference to Examples, but the present invention is not limited to these Examples. Example

[0229] Example 1

[0230] The preparation of a pressure sensitive adhesive having a liquid resin comprising the oligoester composition described herein is as follows:

[0231] The raw materials listed were formulated at the specified temperatures in the mixing order listed in the table below. The adhesive was mixed with a propeller mixer at a speed of 50-500 rpm.

[0232] Table 1: Recipe 1

[0233]

[0234] 1: Radial styrene block copolymer with narrow molecular weight distribution, available from TSRC Corporation, USA

[0235] 2: Stabilized pentaerythritol ester of tall oil rosin, available from Kraton Corporation, USA 3: Cycloaliphatic hydrocarbon resin, available from ExxonMobil, USA

[0236] 4: Phenolic antioxidants ( 1010) and secondary phosphite antioxidants ( 168), available from BASF, Germany.

[0237] The adhesive according to the invention has improved adhesion to various substrates while reducing the application weight. This means that significantly less adhesive can be used to meet the application requirements compared to reference adhesive 1. This saves energy and costs for the customer.

[0238] Table 2: Physical properties

[0239]

[0240] The coatings required for the adhesion tests are produced on a laboratory-scale, heatable coating table. The table has a heated, movable scraper that can be used to spread the adhesive onto the table. Two adjustment screws are used for coarse adjustment and two adjustment screws for fine adjustment to set the layer thickness. The gap width between the scraper and the heated plate is displayed by two pressure gauges, which are located on the scraper above the adjustment screws. Here, the gap width in micrometers can be read from the scale. The adhesive is applied on silicone paper, which is fixed to the plate by vacuum. After the adhesive layer has been applied, it is rolled onto a PET film. The application weight is checked with a maximum deviation of ±10% and after a rest period of 24 hours, the finished coating can be used for the tests. The coatings were made from 50 μm thick PET film with an application weight of 40 g / m 2 .

[0241] The following table provides the values ​​of 180° peel force and loop quick tack on various substrates. The mineral oil-free adhesive according to the invention having a liquid resin comprising an oligoester composition as described herein shows improved performance compared to a mineral oil-free pressure sensitive adhesive having a polyester polyol based on betulin (EP3878883A1) and is comparable to good label and omnidirectional pressure sensitive adhesives (reference 1).

[0242] Table 3: Adhesion properties

[0243]

Claims

1. A pressure-sensitive adhesive composition comprising: a) at least one polymer; b) at least one liquid resin comprising an oligomeric ester composition which is the reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids; iii) one or more polyols; and iv) optionally one or more polycarboxylic acids, wherein the reaction mixture comprises one or more rosins; c) at least one other plasticizer, wherein the at least one other plasticizer comprises an isobutylene / butene copolymer; d) optionally at least one other resin; and e) optionally at least one additive, preferably at least one stabilizer.

2. A pressure-sensitive adhesive composition according to claim 1, wherein the at least one polymer a) is selected from the group consisting of polymers based on acrylates, polyesters, urethanes, ethylene acrylates, butyl rubbers and (synthetic) natural rubbers; ethylene-vinyl acetate copolymers (EVA), polyolefin (co)polymers (PO), polyamide (co)polymers (PA), ethylene-propylene copolymers or styrene copolymers, either alone or as a mixture, the polymer being particularly preferably a styrene block copolymer, for example styrene and styrene-butadiene copolymers (SBC or SBS, SBR), styrene -isoprene copolymers (SIS), styrene-ethylene / butylene copolymers (SEBS), styrene-ethylene / propylene-styrene copolymers (SEPS) or styrene-isoprene-butylene copolymers (SIBS), most preferably styrene-isoprene-styrene triblock copolymers, styrene-butadiene copolymers (SBC) and / or ethylene-vinyl acetate copolymers (EVA) or mixtures thereof, wherein the polymer a) is present in the composition in an amount of 10 to 70% by weight, preferably 15 to 70% by weight, more preferably 20 to 70% by weight, based on the total weight of the composition.

3. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the reaction mixture for preparing the oligoester composition comprises: 25 to 85 wt. % of one or more monocarboxylic acids; 7 to 35 wt % of one or more polyols; and the optional presence of greater than 0% to less than 4% by weight of one or more polycarboxylic acids, The reaction mixture comprises 5 to 75 wt % of rosin.

4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the rosin comprises a mixture of rosin acids, preferably C 20 Tricyclic monocarboxylic acids and isomers thereof, the rosin acid being in particular selected from the group consisting of abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid and palustric acid and isomers thereof.

5. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the at least one liquid resin b) is present in the pressure-sensitive adhesive composition in an amount of 1 to 50 wt %, more preferably 2 to 40 wt %, even more preferably 5 to 40 wt %, in particular 5 to 30 wt %, based on the total weight of the pressure-sensitive adhesive composition.

6. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the at least one other plasticizer c) is: i) 0.1 to 30 wt %, preferably 1 to 15 wt %, based on the total weight of the pressure-sensitive adhesive composition; and / or iii) its number average molecular weight M measured by size exclusion chromatography (GPC: gel permeation chromatography) n 750-1450 g / mol, preferably 850-1350 g / mol, in particular 900-1300 g / mol; and / or iv) its glass transition temperature (Tg) measured by dynamic differential thermal analysis (DSC: Differential Scanning Calorimetry) is from -60 to -73°C, more preferably from -63 to -73°C, in particular from -66 to -70°C; and / or v) Its kinematic viscosity measured at 100°C according to ASTM D445 is 0.00018-0.0007m 2 / s (180-700 cSt), preferably 0.00019 to 0.00067 m 2 / s (190-670cSt), especially 0.0002 to 0.000655m 2 / s(200-655cSt). 7 . The pressure-sensitive adhesive composition according to claim 1 , wherein the pressure-sensitive adhesive composition contains no other plasticizer besides the isobutylene / butylene copolymer plasticizer c).

8. A pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the at least one other resin d) comprises a natural resin or a hydrocarbon resin, more preferably tall oil esters, gum rosin (rosin esters), optionally partially polymerized tall resins, terpene or crude oil based aliphatic, aromatic or alicyclic hydrocarbon resins, and modified or hydrogenated forms thereof, such as C5 aliphatic or C9 aromatic hydrocarbon resins or C5 / C9 monomer mixtures, wherein the resin is different from the liquid resin, is preferably a solid resin, and is preferably present in the pressure-sensitive adhesive composition in an amount of 10 to 70% by weight, more preferably 15 to 60% by weight, based on the total weight of the pressure-sensitive adhesive composition.

9. The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the at least one further resin d) comprises at least two further resins, wherein the resins are preferably selected from aliphatic (cycloaliphatic) hydrocarbons having, for example, 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), and / or rosin esters, such as pentaerythritol esters, wherein the at least one further resin d) is preferably a solid resin.

10. The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the at least one additive e) comprises at least one substance selected from the following group: antioxidants such as stabilizers, waxes, UV protectants, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, fluorescent brighteners and fragrances, wherein the at least one additive e) is present in the pressure-sensitive adhesive composition in an amount of 0.01 to 20% by weight, preferably 0.1 to 5% by weight, based on the total weight of the pressure-sensitive adhesive composition.

11. A method for preparing a pressure-sensitive adhesive composition according to any one of claims 1 to 10, the method comprising: Preferably at a temperature of 100 to 200° C., more preferably at a temperature of 120 to 180° C., even more preferably at a temperature of 150 to 170° C., at least one liquid resin b) according to any of the preceding claims and the other components of the pressure-sensitive adhesive composition, such as the at least one polymer a) and the at least one other plasticizer c) and optionally further components, such as at least one other resin d) and / or at least one additive e) are mixed in a suitable order.

12. Use of the pressure-sensitive adhesive composition according to any one of claims 1 to 10 in adhesive tapes, labels, hygiene articles such as diapers, markings such as beverage bottles, flexible packaging, food packaging, cartons or envelopes, packaging for medical materials and products, in the assembly sector (high performance, such as the automotive industry) and / or in the graphic industry (such as books, magazines, brochures).

13. An article comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 10.

14. A method for bonding at least two substrates, wherein the pressure-sensitive composition according to any one of claims 1 to 10 is applied to at least one substrate and the at least two substrates are subsequently bonded together.

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