Pressure-sensitive adhesive containing a liquid resin comprising an 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, said at least one further plasticizer comprising an isobutene / butene copolymer. The present invention also relates to the use of the pressure-sensitive adhesive composition according to the invention, to a method for preparing the pressure-sensitive adhesive composition, and to 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 invention.

Description

[Technical field]

[0001] 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, said at least one further plasticizer comprising an isobutene / butene copolymer.

[0002] The present invention also relates to the use of the pressure-sensitive adhesive composition according to the invention, to a method for preparing the pressure-sensitive adhesive composition and to 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 invention.

[0003] Due to increased sustainability and environmental awareness, there is an increasing desire to replace mineral oil based compounds with materials based on renewable raw materials.

[0004] Commercially available pressure-sensitive adhesive compositions usually contain plasticizers based on mineral oils. It is particularly advantageous in food packaging, but also in hygiene articles, for example, and in many other areas, for example to prevent migration from the adhesive into the packaging material, to reduce the use of these substances as much as possible or to avoid them altogether. There is therefore a need for alternatives that can replace some or all of these plasticizers and that are suitable and approved for contact with food.

[0005] Many of the available alternatives based on renewable raw materials have disadvantages in terms of compatibility with the other components of the pressure-sensitive adhesive composition and / or result in reduced performance in terms of the cohesive properties of the adhesive composition. Summary of the Invention [Problem to be solved by the invention]

[0006] 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 its formulation, in particular by largely replacing the mineral oil-based plasticizers previously used. At the same time, such a composition should have the same or even improved performance in terms of adhesive strength and stability compared to conventional systems, and should also be suitable, for example, for the manufacture of food packaging or hygiene articles, i.e. it should only contain ingredients approved for contact with food. [Means for solving the problem]

[0007] Surprisingly, this object is achieved by a method comprising the combination of at least one liquid resin and at least one further plasticizer in addition to the at least one polymer, said at least one further plasticizer comprising or consisting of an isobutene / butene copolymer, said liquid resin comprising an oligoester composition, said oligoester composition being ii) one or more monocarboxylic acids, optionally in an amount of at least 15% by weight, based on the total weight of the reaction mixture; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; wherein the reaction mixture comprises one or more colophons It has been found that this can be accomplished by a pressure sensitive adhesive composition that is the reaction product of a reaction mixture comprising: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The described liquid resins, in combination with isobutene / butene copolymers, at least partially, preferably even completely replace the mineral oil-based plasticizers, in particular naphthenic and / or paraffinic oils, typically used in pressure-sensitive adhesive compositions and are therefore sustainable alternatives to mineral oil-based plasticizers. Preferably, such pressure-sensitive adhesive compositions comprising the liquid resins and isobutene / butene copolymers described herein exhibit improved adhesive strength and / or adhesion to various substrates.

[0009] Thus, a first aspect of the present invention relates to a pressure sensitive adhesive composition comprising: a) at least one polymer; b) at least one liquid resin comprising an oligoester composition that is the reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids, optionally in an amount of at least 15% by weight based on the total weight of the reaction mixture; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; wherein the reaction mixture comprises one or more colophons; c) at least one additional plasticizer, wherein the at least one additional plasticizer comprises an isobutene / butene copolymer; d) optionally at least one additional resin; and e) optionally at least one additive, preferably at least one stabilizer.

[0010] The pressure-sensitive adhesive composition according to the invention preferably comprises at least one polymer a) selected from the group of acrylates, polyesters, urethanes, ethylene acrylates, butyl rubber, polymers based on (synthetic) or (natural) rubber; ethylene-vinyl acetate copolymers (EVA), polyolefin (co)polymers (PO), polyamide (co)polymers (PA), ethylene-propylene copolymers or styrene copolymers, either alone or in a mixture, particularly preferably said polymer is a styrene block copolymer, such as styrene and styrene-butadiene copolymer (SBC, SBS, SBR), styrene-isoprene copolymer (SIS), styrene-ethylene / butylene copolymer (SEBS), styrene-ethylene / propylene-styrene copolymer (SEPS) or styrene-isoprene-butylene copolymer (SIBS), or a mixture thereof.

[0011] 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).

[0012] Particularly preferably, the 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 or 25 to 60% by weight, based on the total weight of the pressure-sensitive adhesive composition.

[0013] Another essential component of the composition according to the invention is the liquid resin b), which comprises the oligoester composition described herein. In various embodiments, the reaction mixture for preparing the oligoester composition comprises: at least 15% by weight of one or more monocarboxylic acids; one or more polyhydric alcohols, and Optionally, greater than 0% to less than 4% by weight of one or more polycarboxylic acids, where the reaction mixture includes one or more colophons. However, in various embodiments, the one or more monocarboxylic acids may be used in an amount of up to 14% by weight.

[0014] Preferably, the reaction mixture for preparing the oligoester composition comprises: 25% to 85% by weight of one or more monocarboxylic acids, 7% to 35% by weight of one or more polyhydric alcohols, and Optionally, greater than 0% to less than 4% by weight of one or more polycarboxylic acids wherein the reaction mixture preferably comprises 5% to 75% by weight of colophony.

[0015] Typically, colophony is made from colophony acid, preferably C 20The colophonylic acid comprises a mixture of tricyclic monocarboxylic acids and their isomers, more preferably tricyclic diterpene carboxylic acids. Suitable colophonylic acids may be selected from the group consisting of, but are not limited to, abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid and palustric acid, and their isomers. In various embodiments, the liquid resin b) consists of the described oligoester composition. As used herein, "liquid resin" means that this component is liquid at standard conditions, i.e., 20° C. and 1013 mbar.

[0016] Particularly preferably, the at least one liquid resin b) is present in the pressure-sensitive adhesive composition in an amount of in each case 1 to 50% by weight, more preferably 2 to 40% by weight, even more preferably 5 to 40% by weight and in particular 5 to 30% by weight, based on the total weight of the pressure-sensitive adhesive composition.

[0017] Suitable liquid resins are commercially available, for example from Kraton. Detailed manufacturing specifications are described, for example, but not limited to, in US 2017 / 0190935 A1. The liquid resin or oligoester compositions described therein are suitable for use as component B) of the pressure-sensitive adhesive compositions described herein. This document is incorporated herein in its entirety by reference.

[0018] According to the invention, a pressure-sensitive adhesive composition comprises at least one liquid resin b) as described herein in combination with at least one further plasticizer c), said at least one plasticizer comprising or consisting of an isobutene / butene copolymer. This type of pressure-sensitive adhesive composition preferably exhibits a comparable increase in adhesion and / or cohesion to various substrates (e.g. steel, polyethylene, nonwovens, glass or cardboard) compared to a reference adhesive.

[0019] Preferably, the at least one further plasticizer c) or isobutene / butene copolymer is used in an amount of 0.1 to 30% by weight, more preferably 1 to 15% by weight, in particular 5 to 12% by weight, based on the total weight of the pressure-sensitive adhesive composition. Further preferably, this further plasticizer c) or isobutene / butene copolymer has a number average molecular weight M of 750 to 1450 g / mol, more preferably 850 to 1350 g / mol, in particular 900 to 1300 g / mol, measured by size exclusion chromatography (GPC: gel permeation chromatography). n In various embodiments, the at least one further plasticizer c) or isobutene / butene copolymer may have a glass transition temperature (Tg) of -60 to -73°C, more preferably -63 to -73°C, in particular -66 to -70°C, preferably measured by dynamic differential thermal analysis (DSC: differential scanning calorimetry). The plasticizer c) or copolymer may also have a glass transition temperature (Tg) of 0.00018 to 0.0007 m, determined at 100°C according to the method described in ASTM D445. 2 / s (180 to 700 cSt), preferably 0.00019 to 0.00067 m 2 / s (190-670 cSt), especially 0.0002-0.000655 m 2 / s (200 cSt to 655 cSt).

[0020] Particularly preferably, the at least one liquid resin b) and the at least one further plasticizer c) together have a concentration in the pressure-sensitive adhesive composition of 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.

[0021] Furthermore, it is particularly preferred that the pressure-sensitive adhesive composition according to the invention does not comprise any further plasticizers besides the isobutene / butene copolymer, i.e. it is free of further plasticizers.

[0022] Preferably, the described liquid resins b) in combination with further plasticizers c) can partially or preferably completely replace conventional mineral oil-based plasticizers, in particular naphthenic oils and / or (white medical) paraffinic oils.

[0023] As a result, in various preferred embodiments, the pressure-sensitive adhesive composition according to the present invention comprises 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 no mineral oil-based plasticizers, based on the total weight of the composition.

[0024] In a preferred embodiment, the mineral oil-based plasticizer or plasticizers, more preferably naphthenic and / or paraffinic oils, are replaced in the pressure-sensitive adhesive composition 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% and most preferably 100%, by the described liquid resins b) in combination with a further plasticizer c) comprising an isobutylene-butene copolymer.

[0025] Furthermore, 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, gum rosin (colophony ester), optionally partially polymerized tall oil resin, terpene or an aliphatic, aromatic or cycloaliphatic hydrocarbon resin based on crude oil, for example having 1 to 30 carbon atoms in the case of aliphatic, for example having 6 to 30 carbon atoms in the case of aromatic and cycloaliphatic hydrocarbon resins, where the resins, as well as modified or hydrogenated versions thereof, may be, for example, C5-aliphatic or C9-aromatic hydrocarbon resins or C5 / C9 monomer mixtures, which resins, unlike the liquid resins b), are in particular not liquid resins but solid resins. Such "solid resins" are solid under standard conditions.

[0026] In various embodiments, the at least one further resin d) may comprise at least two resins, where the resins are preferably selected from (cyclo)aliphatic hydrocarbons and / or colophonyl esters, such as pentaerythritol esters.

[0027] In various embodiments, the resin d) is a solid resin, for example in pellet or pastille form, but it can also be a solid resin delivered in molten form, for example in a heated tanker truck.

[0028] In a particularly preferred embodiment, the further resin d) is present in the pressure-sensitive adhesive composition in an amount of 10 to 70% by weight, preferably 15 to 60% by weight, for example 20 to 50% by weight, 15 to 45% by weight or 25 to 60% by weight, based on the total weight of the composition.

[0029] 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, e.g. stabilizers, waxes, UV protection agents, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners and fragrances, in particular stabilizers.

[0030] In various embodiments, the pressure-sensitive adhesive composition comprises at least one additive e) in an amount of 0.01 to 20 wt. %, preferably 0.1 to 5 wt. %, more preferably 0.5 to 3 wt. %, based on the total weight of the composition.

[0031] More preferably, the pressure sensitive adhesives according to the invention have improved adhesion to a variety of substrates, such as steel and plastics, such that a significant reduction in the amount of adhesive used to meet the requirements of an application can be achieved, e.g., reducing the weight of the application, as compared to a reference adhesive.

[0032] In a further embodiment, the present invention relates to a method for preparing a pressure-sensitive adhesive composition according to the invention, which comprises mixing at least one liquid resin b) comprising the oligoester composition as described herein with further 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), in any suitable order; preferably at a temperature of 100-200°C, more preferably 120-180°C, even more preferably 150-170°C.

[0033] In a further aspect, the present invention relates to the following uses of the pressure sensitive adhesive composition according to the invention: Adhesive tape, label, Multilayer films, e.g. for sealing, Hygiene articles, such as diapers, Labelling, e.g. for beverage bottles, Flexible packaging, food packaging, A cardboard box or envelope, Medical applications, such as packaging of medical materials and supplies; Assembly sector (high performance, e.g. automotive industry), and / or Graphic industry (books, magazines, brochures, etc.).

[0034] A further example is the coating of self-adhesive films.Generally, the compositions described herein are suitable for film applications, i.e., self-adhesive films, tapes or labels.

[0035] In a further aspect, the present invention relates to an article comprising a pressure sensitive adhesive composition according to the present invention.

[0036] The invention finally relates to a method for joining at least two substrates, comprising applying a pressure sensitive composition according to the invention to at least one substrate and then joining the at least two substrates.

[0037] In a preferred embodiment, the coating amount of the pressure-sensitive adhesive composition is 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 It is.

[0038] These and other embodiments, features and advantages of the present invention will become apparent to those skilled in the art upon review of the following detailed description and claims. In this case, each described feature or embodiment of the present invention can be combined with other features or embodiments of the present invention even if they are not described in combination within the scope of the present invention. It is self-evident that the examples herein are intended to explain and illustrate the present invention, but are not intended to limit the present invention, and in particular the present invention is not limited to the examples.

[0039] As used herein, "at least one" refers to one or more, for example, two, three, four, five, six, seven, eight, nine or more. With respect to the polymers described herein, this description does not refer to the absolute amount of molecules, but rather to the type of compound. Thus, "at least one polymer" means, for example, that it can include only one type of polymer, or multiple different types of polymers, without specifying the amount of each compound.

[0040] Unless otherwise indicated, all amounts shown in relation to the pressure-sensitive adhesive composition described herein refer in each case to weight percent based on the total weight of the composition.Furthermore, the designation of such amount with respect to at least one component always refers to the total amount of such component contained in the composition, unless otherwise expressly indicated.This means that, for example, these amounts in the context of "at least one polymer" relate to the total amount of polymer contained in the composition, unless otherwise expressly indicated.

[0041] Numerical values ​​specified in this specification excluding decimal places refer in each case to the full specified value to one decimal place, e.g., "99%" means "99.0%".

[0042] Numerical ranges expressed in the format "in / from x to y" are inclusive of the recited values. When multiple preferred numerical ranges are specified in this format, it will be readily understood that the ranges resulting from combining the various endpoints are also included.

[0043] As used herein, "about" or "approximately" in relation to numerical values ​​means ±10%, preferably ±5%, especially ±1% of the corresponding value.

[0044] When referring to molar mass in this specification, unless otherwise specified, it refers to the number average molar mass M n 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 the eluent. The weight-average molar mass M w Also, M n It can be determined by GPC as described above for M n or M w Suitable methods for determining are also described, for example, in US 2017 / 0190935 A1.

[0045] In a first aspect, the present invention relates to a pressure sensitive adhesive composition comprising: a) at least one polymer; b) ii) one or more monocarboxylic acids, optionally in an amount of at least 15% by weight based on the total weight of the reaction mixture; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; wherein the reaction mixture comprises one or more colophons at least one liquid resin comprising an oligoester composition that is a reaction product of a reaction mixture comprising: c) at least one further plasticizer, wherein said at least one further plasticizer comprises or consists of an isobutene / butene copolymer; d) optionally at least one additional resin; and e) optionally at least one additive, preferably at least one stabilizer.

[0046] 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.

[0047] "Pressure sensitive adhesives" are representative of non-curing adhesives. "Hot melt pressure sensitive adhesives" (HMPSAs) are generally understood to be adhesives that are solid at room temperature and, in particular, do not contain water or solvents. They are usually applied from a molten state to the parts to be joined, and physically solidify as they cool and harden after joining. Such hot melt pressure sensitive adhesives preferably remain tacky and adhesive permanently, even when cooled, and bond immediately to almost any substrate with minimal contact pressure.

[0048] "Non-reactive" or "physically set" in this context usually means that solidification occurs by a physical process (e.g., solidifying upon cooling or by evaporation of a solvent or water).

[0049] The pressure-sensitive adhesive composition according to the invention contains at least one polymer a), which may be a homopolymer or a copolymer.

[0050] Examples of such polymers include, but are not limited to, acrylates, polyesters, urethanes, ethylene acrylates, polymers based on butyl rubber and (synthetic) natural rubber; ethylene-vinyl acetate copolymers (EVA), polyolefin (co)polymers (PO), polyamide (co)polymers (PA), ethylene-propylene copolymers or styrene copolymers, alone or in mixtures, the copolymers typically being random, alternating graft or block copolymers. The thermoplastic elastomer is preferably selected from the group of 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). Such products are known to those skilled in the art and are commercially available.

[0051] Particularly preferably, the at least one polymer a) is a styrene block copolymer, such as styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS) or styrene-ethylene-butadiene-styrene (SEBS), preferably a triblock copolymer of styrene-isoprene-styrene or a styrene-butadiene copolymer (SBC) or a mixture thereof.

[0052] In various embodiments, pressure sensitive adhesive compositions according to the present invention can also contain ethylene-vinyl acetate copolymers (EVA), which can also be used in addition to those mentioned above.

[0053] 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 composition.

[0054] Furthermore, the pressure-sensitive adhesive composition comprises at least one liquid resin B) consisting of an oligoester composition, which is the reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; Here, the reaction mixture includes one or more colophons.

[0055] In various embodiments, the reaction mixture for preparing the oligoester composition comprises at least 15% by weight of one or more monocarboxylic acids, based on the total weight of the reaction mixture, although in other embodiments, the one or more monocarboxylic acids can be used in an amount of up to 14% by weight.

[0056] "Liquid resin" refers to any resin composition that can be prepared from the reaction mixture described above and that is liquid, i.e. flowable, at 20° C. and 1013 mbar. Liquid resins may in particular include (highly) viscous resin compositions.

[0057] The oligoester composition of the liquid resin b) described can comprise, consist of, or consist essentially of the oligoesters described herein. In one embodiment, the oligoester composition comprises 1 weight percent (wt.%) to 100 wt.%, such as 10 wt.% to 100 wt.%, 20 wt.% to 80 wt.%, or 30 wt.% to 70 wt.%, of one or more oligoesters of the type described herein, based on the total weight of the composition. In some embodiments, the oligoester composition comprises equal to or less than 20 wt.%, such as less than 10 wt.% or less than 5 wt.%, based on the weight of the oligoester composition. The oligoester composition may have improved color (e.g., the oligoester may have a Pure Gardner Color of 7 or less), improved oxidative stability (e.g., the oligoester composition may have an oxidative induction time of at least 30 minutes at 110° C.), improved color stability (e.g., the oligoester may have less than a 10% change in Pure Gardner Color when heated at a temperature of 160° C. for 3 hours), or a combination thereof.

[0058] In the context of the present invention, "substantially" means that the composition may contain further substances or compounds that are not actively added to the oligoester composition, but are included, for example, as impurities or due to undesired side reactions. These additional components beyond the "substantial" components may preferably account for a weight percentage of less than 1 wt.%, preferably less than 0.1 wt.% or less than 0.01 wt.%, in each case based on the total weight of the oligoester composition.

[0059] The oligoester compositions of the liquid resins b) described herein can be derived from at least one colophony.

[0060] Colophony, also called colophony or Greek pitch (Pix graeca), is a solid hydrocarbon exudation of plants, typically coniferous trees such as pine (e.g., Pinus palustris and Pinus caribaea). Colophony may contain a mixture of colophonic acids, although the exact composition of colophony varies in part depending on the plant species. Colophony acid is a C20 fused-ring monocarboxylic acid whose core consists of three fused six-carbon rings containing double bonds that vary in number and position.

[0061] Suitable colophony acids include, but are not limited to, abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid, palustric acid, and isomers thereof. In various embodiments, natural colophony contains a mixture of predominantly colophony acids, abietic acid and / or pimaric acid.

[0062] Colophony is commercially available and can be obtained from pine trees by distillation of oleoresin (colophony gum is the residue of distillation), extraction from pine stumps (wood colophony), or fractionation of tall oil (tall oil colophony). Any type of colophony can be used to prepare the oligoester compositions described herein, including tall oil colophony, gum colophony, wood colophony, and mixtures thereof. If desired, the colophony can be subjected to one or more purification steps (e.g., distillation under reduced pressure, extraction, and / or crystallization) before being used as colophony in the esterification step described herein. Hydrogenated and partially hydrogenated colophony resins can also be used as a source of colophony. An example of a commercially available hydrogenated colophony suitable for use in the present disclosure is FORAL®, available from Eastman Chemical Company. TM AX-E. A commercially available example of hydrogenated colophony is STAYBELITE® from Eastman Chemical Company. TMResin-E and HYDROGAL sold by DRT (Derives Resiniques et Terpeniques) TM There is.

[0063] In various embodiments, the described oligoesters are obtained from tall oil colophony (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, which are commercially available from Arizona Chemical Company, a subsidiary of Kraton Corporation.

[0064] Crude tall oil (CTO) obtained from the kraft paper pulping process contains significant amounts of TOR and tall oil fatty acids (TOFA). Distilled tall oil (DTO) is an industrial refinery product obtained by fractional distillation 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 to prepare the described oligoester compositions. Several commercially available DTO grades with different colophony content are available from Arizona Chemical Company, a subsidiary of Kraton, under the trade name SYLVATAL. TM It is sold as a product line, which includes SYLVATAL TM 10S, SYLVATAL TM 20 / 25S, SYLVATAL TM 20S, SYLVATAL TM 25 / 30S, SYLVATAL TM D25 LR, SYLVATAL TM D30 LR, SYLVATAL TM Includes D40 LR.

[0065] In a preferred embodiment, the oligoester composition is derived from 5 wt.% to 80 wt.%, such as 10 wt.% to 70 wt.%, or 30 wt.% to 60 wt.%, of colophony, based on the total weight of the ingredients used to prepare the oligoester composition.

[0066] As mentioned above, colophony contains a mixture of colophonic acids (e.g., abietadienoic acids), which may contain conjugated double bonds in their ring systems. These conjugated double bonds may be a source of oxidative instability. Thus, in some embodiments, colophony, oligoesters, or combinations thereof are treated to reduce the proportion of components containing conjugated double bonds. The term "PA number" as used herein refers to the sum of the weight percent of palustric, abietic, and neoabietic acid components obtained by hydrolysis from oligoesters, as determined in accordance with the method described in ASTM D5974-00 (2010), among others.

[0067] In some embodiments, the oligoesters may be derived from colophony having a low PAN number. In some embodiments, the colophony obtained from the oligoesters by hydrolysis may have a PAN number of 25 or less, e.g., 15 or less or 5 or less, determined according to the method described in ASTM D5974-00 (2010). The colophony obtained from the oligoesters by hydrolysis may contain 30 wt% or more dehydroabietic acid, e.g., 30-60 wt% or 40-55 wt%, based on the total weight of the colophony. In some embodiments, the weight ratio of dehydroabietic acid to dihydroabietic acid in the colophony obtained from the oligoesters by hydrolysis is between 1:0.80 and 1:0.25, e.g., between 1:0.70 and 1:0.35, or between 1:0.55 and 1:0.40.

[0068] The oligoester compositions described herein can further be derived from one or more polyhydric alcohols.

[0069] In various embodiments, the oligoester composition is derived from 5 to 40 wt.%, for example 5 to 30 wt.%, or 9 to 18 wt.%, or 9.7 to 12.7 wt.%, of a polyhydric alcohol, based on the total weight of the components used to prepare the oligoester composition.

[0070] The at least one polyhydric alcohol can include any suitable polyhydric alcohol. In various embodiments, the one or more polyhydric alcohols can have an average hydroxyl functionality of 2 to 10, such as 2 to 7 or 3 to 5.

[0071] In specific embodiments, the one or more polyhydric alcohols contain 2 to 36 carbon atoms, such as 2 to 20 or 2 to 8 carbon atoms. For example, the one or more polyhydric alcohols may have a boiling point of 240° C. or greater at about 1013 mbar (1 atmosphere).

[0072] The polyhydric alcohols may include combinations of linear, branched, cyclic, aliphatic, partially unsaturated, or aromatic chemical units, and may optionally include, in addition to two or more hydroxyl units, one or more additional functional groups, such as alkyl (e.g., C1-3 alkyl), aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or keto groups. In aromatic polyhydric alcohols, the aromatic rings may optionally include one or more ring substituents, such as fluoro, chloro, alkyl (e.g., methyl or ethyl), methoxy, or trifluoromethyl groups. Optionally, the one or more polyhydric alcohols may further include one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the molecular structure, such as ether groups when oxygen atoms are incorporated, and thioethers when sulfur atoms are incorporated. In various embodiments, the one or more polyhydric alcohols include aliphatic alcohols, such as cycloaliphatic alcohols.

[0073] In some embodiments, the one or more polyhydric alcohols can include a polyol that includes a first hydroxyl group separated from a second hydroxyl group by 2 to 10 carbon atoms, alternatively 2 to 7 carbon atoms, or alternatively 3 to 5 carbon atoms. In some embodiments, the one or more polyhydric alcohols include a polyol in which each hydroxyl group of the polyol is separated from the other hydroxyl groups of the polyol by at least 2 carbon atoms, e.g., at least 3 carbon atoms or at least 6 carbon atoms.

[0074] Examples of suitable polyhydric alcohols 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, polyglycerin, technical grade polyglycerin, polyglycerin-3, polyglycerin-4, cyclohexane-1,4-dimethanol, tricyclo[5.2.1.0(2.6)]decane-4,8-dimethanol, hydrogenated bisphenol A (4,4'-isopropylidenedicyclohexanol), mannitol, sorbitol, xylitol, maltitol, lactitol. In specific embodiments, the one or more polyhydric alcohols may be selected from diethylene glycol, triethylene glycol, glycerol, trimethylolpropane, pentaerythritol, technical grade pentaerythritol, dipentaerythritol, polyglycerin, polyglycerin-4, tricyclo[5.2.1.0(2.6)]decane-4,8-dimethanol, cyclohexane-1,4-dimethanol, hydrogenated bisphenol A (4,4'-isopropylidenedicyclohexanol), and combinations thereof.

[0075] The oligoester compositions described herein can be derived from one or more monocarboxylic acids.

[0076] In various embodiments, the oligoester composition can be derived from 15 to 90 wt %, for example 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.

[0077] This 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 linear or branched monofunctional carboxylic acids, partially unsaturated linear or branched monofunctional carboxylic acids, cycloaliphatic monofunctional carboxylic acids, partially unsaturated cyclic monofunctional carboxylic acids, natural fatty acids, synthetic fatty acids, fatty acids derived from vegetable and animal oils, and combinations thereof.

[0078] In some embodiments, the at least one monocarboxylic acid can contain at least 6 carbon atoms, e.g., 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 can contain a combination of linear, branched, cyclic aliphatic (cycloaliphatic), partially unsaturated, or aromatic or heteroaromatic chemical groups, and can optionally contain, in addition to the carboxylic acid group, one or more additional functional groups, such as hydroxyl groups, alkyl groups (e.g., C1-3 alkyl), aryl groups (e.g., benzyl), alkoxy groups (e.g., methoxy), haloalkyl groups (e.g., trifluoromethyl), or keto groups. In aromatic monocarboxylic acids, the aromatic ring can optionally contain one or more ring substituents, such as fluoro groups, chloro groups, alkyl groups (e.g., methyl or ethyl groups), methoxy groups, or trifluoromethyl groups. Optionally, the one or more monocarboxylic acids can further include one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the molecular structure of the carboxylic acid, such as ether groups when an oxygen atom is incorporated, and thioethers when a sulfur atom is incorporated.

[0079] Examples of suitable aliphatic monocarboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, ethanoic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, cerotic acid, and the like. An example of a suitable aromatic monocarboxylic acid is benzoic acid. Non-limiting examples of suitable cycloaliphatic monocarboxylic acids are cyclopropane carboxylic acid, cyclopentane carboxylic acid, and cyclohexane carboxylic acid. Non-limiting examples of suitable unsaturated straight-chain or branched monocarboxylic acids are linoleic acid, alpha-linolenic acid, elaidic acid, sapienic acid, arachidonic acid, myristoleic acid, palmitoleic acid, and oleic acid. Suitable fatty acids obtained from vegetable oils (e.g., triglyceride vegetable oils) and animal fats include palm oil, linseed oil, rapeseed oil, sunflower seed oil, olive oil, tuna oil, peanut oil, cottonseed oil, palm kernel oil, soybean oil, corn oil, grapeseed oil, hazelnut oil, rice bran oil, safflower oil, sesame oil, butterfat and coconut oil. These fatty acids include linoleic acid, α-linolenic acid, palmitic acid, stearic acid, myristic acid, oleic acid, etc. Non-limiting examples of natural fatty acids are tall oil fatty acids and their commercial products, such as isostearic acid.

[0080] 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 certain embodiments, the at least one monocarboxylic acid may include tall oil fatty acid (TOFA). Suitable commercially available TOFA-derived monocarboxylic acids include CENTURY ET AL. FA, available from Arizona Chemical Company, a subsidiary of Kraton, Inc. TM Part of a product line, e.g. CENTURY TM D1, CENTURY TM MO5, CENTURY TM MO5N, and isostearic acid products, such as CENTURY TM 1105 and CENTURY TM1107, but are not limited to these.

[0081] Carboxylic acid and its derivatives can be characterized by iodine value.In certain embodiments, the at least one monocarboxylic acid can have an iodine value of less than 275mg / g, optionally less than 180mg / g, or less than 115mg / g, or less than 80mg / g, or optionally between 55mg / g and 270mg / g, or between 60mg / g and 250mg / g, or between 70mg / g and 200mg / g, as determined by the method described in ASTM D5768-02(2014).

[0082] Particularly preferably, said at least one monocarboxylic acid is a fatty acid, a tall oil fatty acid or a mixture thereof.

[0083] In various embodiments, the oligoester compositions may optionally be further derived from one or more polycarboxylic acids.

[0084] The oligoester composition may be derived from less than Q weight percent of one or more polycarboxylic acids, where Q is defined by the formula: TIFF2025515822000001.tif20158 where Σ denotes 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, an integer ranging from 2 to 4; Y is the polycarboxylic acid weight fraction of the polycarboxylic acid, ranging from 0 to 1, and 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 proportion of polycarboxylic acid in the total ester composition. For example, when 50% by weight of dicarboxylic acid and 50% by weight of tricarboxylic acid are used, the Q value is 10-2(2×0.5+3×0.5)=10-2(1+1.5)=10-2×2.5=5%. Similarly, when only dicarboxylic acid is used, the Q value is 6%. In some embodiments, Q may be defined by the following formula: TIFF2025515822000002.tif20159 where 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 ranging from 2 to 4; and Y is the polycarboxylic acid weight fraction of the polycarboxylic acid and is ranging from 0 to 1, and the sum of the weight fractions of the one or more polycarboxylic acids is equal to 1.

[0085] In various embodiments, the oligoester composition can be derived from 0-4 wt %, e.g., 0-3 wt %, or 0-2 wt % polycarboxylic acid (i.e., two or more carboxylic acid functional groups), based on the total weight of the components used to prepare the oligoester composition.

[0086] In specific embodiments, the oligoester may be derived from 0-6 wt %, optionally 0-4 wt %, or 0-2 wt % of one or more dicarboxylic acids (i.e., two carboxylic acid functional groups), 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 acids.

[0087] The at least one polycarboxylic acid can include any suitable polycarboxylic acid. In some embodiments, the one or more polycarboxylic acids can include dicarboxylic acids; in some embodiments, the one or more polycarboxylic acids can include tricarboxylic acids. In some embodiments, the one or more polycarboxylic acids can be tetracarboxylic acids. In some embodiments, the one or more polycarboxylic acids include 2 to 54 carbon atoms, such as 4 to 35 carbon atoms or 6 to 12 carbon atoms.

[0088] Polycarboxylic acids can include linear, branched, cyclic aliphatic (cycloaliphatic), unsaturated, partially unsaturated, heteroaromatic or combinations of aromatic chemical units, and in addition to two or more carboxylic acid units, 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 rings can optionally include one or more ring substituents, such as fluoro, chloro, alkyl (e.g., methyl or ethyl), methoxy or trifluoromethyl groups. Optionally, the one or more polycarboxylic acids can further include one or more heteroatoms (e.g., one or more oxygen, sulfur or nitrogen atoms) incorporated into the molecular structure, such as ether groups when oxygen atoms are incorporated, and thioethers when sulfur atoms are incorporated.

[0089] 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, colophony 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 dimerized TOFA derivative suitable for use in the present disclosure.

[0090] The ratio of the weight of the one or more polycarboxylic acids to the weight of the colophony and the one or more monocarboxylic acids can be less than 1:20, such as less than 1:50 or less than 1:100. In various embodiments, the ratio of the weight of the colophony and the one or more monocarboxylic acids to the weight of the one or more polycarboxylic acids can be from 60:40 to 10:85. The ratio of the weight of the colophony and the one or more monocarboxylic acids to the weight of the one or more polycarboxylic acids can be at least 6.5:1 or at least 15:1. In certain embodiments, the oligoester composition can be derived, for example, from 30 wt.% to 75 wt.% of colophony, or from 25 wt.% to 60 wt.% of one or more monocarboxylic acids, or from 5 wt.% to 18 wt.% of one or more polyhydric alcohols, or from 0 wt.% to less than 4 wt.% of one or more polycarboxylic acids.

[0091] In one embodiment, the oligoester composition may be derived from 5-75 wt% colophony, 15-85 wt% one or more monocarboxylic acids, or alternatively 7 wt% to 40 wt% one or more polyhydric alcohols, or 0-less than 4 wt% one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 15-75 wt% colophony, 36-80 wt% one or more monocarboxylic acids, 9-35 wt% one or more polyhydric alcohols, and 0-less than 4 wt% one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 30-75 wt% colophony, 25-60 wt% one or more monocarboxylic acids, 3-18 wt% one or more polyhydric alcohols, and 0-less than 4 wt% one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 5-75 wt.% colophony, 15-85 wt.% of one or more monocarboxylic acids, 7-40 wt.% of one or more polyhydric alcohols, and 0-less than 6 wt.% of one or more dicarboxylic acids, wherein the dicarboxylic acids contain from 2 to 35 carbon atoms.

[0092] Particularly preferably, the reaction mixture for preparing the oligoester composition comprises:

[0093] ii) 25% to 85% by weight of one or more monocarboxylic acids;

[0094] iii) 7% to 35% by weight of one or more polyhydric alcohols, and

[0095] iv) optionally, greater than 0 wt % and less than 4 wt %, based on the total weight of reactants used in the reaction mixture, of one or more polycarboxylic acids;

[0096] Here, the reaction mixture preferably contains 5 wt.% to 75 wt.% colophony.

[0097] In various embodiments, the oligoester compositions described herein have a weight average molecular weight M of 500 g / mol to 8000 g / mol, e.g., 700 g / mol to 8000 g / mol, 1000 to 5000 g / mol, or 1100 g / mol to 3000 g / mol, as measured by gel permeation chromatography (GPC) according to ASTM D5296-05. w In specific embodiments, less than 35 wt.%, such as less than 20 wt.%, or less than 13 wt.%, of the oligoester composition has a molecular weight of less than 1000 g / mol as measured by gel permeation chromatography (GPC).

[0098] In various embodiments, the single oligoester can be a liquid, e.g., a viscous liquid, at 20° C. and 1013 mbar (1 atm). The oligoester composition itself is also preferably a liquid.

[0099] The oligoester compositions described herein can be characterized by their 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).

[0100] In specific embodiments, the oligoester composition can have a Tg of from −80° C. to 100° C., such as from −60° C. to 80° C., or from −50° C. to 40° C., or less than about 20° C., as measured by DSC.

[0101] The oligoester compositions may exhibit improved Gardner color. In some embodiments, the oligoester has a pure Gardner color of 8 or less, such as 6 or less, or 4 or less, as determined by the method described in ASTM D1544-04(2010).

[0102] The oligoester composition may exhibit improved color stability. In some embodiments, the oligoester composition may exhibit less than 10% change, such as less than 8% change or less than 5% change in Pure Gardner Color as determined according to the method described in ASTM D1544-04(2010) when heated to a temperature of 160° C. for 3 hours. In certain embodiments, the Pure Gardner Color of the oligoester composition as determined according to the method described in ASTM D1544-04(2010) does not change substantially (i.e., exhibits less than 0.5% change in Pure Gardner Color) when the oligoester composition is heated to a temperature of 160° C. for 3 hours.

[0103] The oligoester compositions may also exhibit improved oxidative stability. For example, in some embodiments, when no antioxidant is present in combination with the oligoester composition, the oligoester composition may have an onset of oxidative induction at 110° C. of 30 to 200 minutes, e.g., 70 to 150 minutes, as measured using the method set forth in ASTM D5483-05(2010).

[0104] Optionally, the oligoester composition may have a low hydroxyl value. In some embodiments, the oligoester composition has a hydroxyl value of less than 200 mg KOH / gram, for example less than 30 mg KOH / gram, less than 20 mg KOH / gram, or less than 6 mg KOH / gram, measured using a modified version of the standard method set forth in DIN 53240-2 (using a different solvent, tetrahydrofuran). The hydroxyl value is expressed in mg KOH per gram of the oligoester or oligoester composition sample.

[0105] Optionally, the oligoester composition may have a low acid number. In some embodiments, the oligoester composition has an acid number of 30 mg KOH / gram or less, such as 15 mg KOH / gram or less, or 6 mg KOH / gram or less, as determined by the method described in ASTM D465-05 (2010). The acid number is expressed as mg KOH per gram of the oligoester or oligoester composition sample.

[0106] Suitable oligoester compositions and their properties are described, for example, in US 2017 / 0190935 A1.

[0107] Various methods can be used to prepare the oligoester composition. For example, the oligoester composition described herein can be prepared by an esterification process in which the carboxylic acid-containing component of the oligoester is esterified with one or more polyhydric alcohols. This type of esterification reaction is an equilibrium reaction. Removal of the water produced during the reaction shifts the reaction equilibrium in favor of the production of the product, thereby driving the reaction to completion. Thus, in some embodiments, a method for preparing an oligoester can include esterifying a mixture comprising one or more colophons, one or more monocarboxylic acids, and optionally one or more polycarboxylic acids with one or more polyhydric alcohols to form an oligoester composition. The esterification step can consist of reacting the mixture with the one or more polyhydric alcohols for a specific time under suitable conditions to form an oligoester. Optionally, the esterification step can also include removal of water produced as a by-product of the esterification reaction. Optionally, the esterification step may include contacting the mixture and said one or more polyhydric alcohols with an esterification catalyst (e.g., calcium bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)ethylphosphonate). In other embodiments, the esterification step may consist of contacting the mixture with said one or more polyhydric alcohols in the absence of an esterification catalyst.

[0108] The oligoester compositions described herein can also be prepared by a transesterification process in which an ester of a carboxylic acid-containing component of an oligoester is reacted with one or more polyhydric alcohols. The polyhydric alcohol reacted with a carboxylic acid may leave free, unreacted hydroxyl groups of the polyhydric alcohol that may react with an ester in a transesterification reaction, leading to an exchange of alkoxy groups. Such transesterification reactions are equilibrium reactions in which new oligoester compositions may be formed. Thus, in some embodiments, a method for preparing an oligoester composition may include reacting one or more colophony esters having a hydroxyl number greater than zero with one or more esters derived from a monocarboxylic acid and optionally one or more polycarboxylic acids. In some embodiments, an alcohol or polyhydric alcohol may be added to initiate or accelerate such transesterification reactions. Optionally, the transesterification step may include contacting the mixture and said one or more polyhydric alcohols with an esterification catalyst (e.g., calcium bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methylphosphonate). In other embodiments, the transesterification step may include contacting the mixture with said one or more polyhydric alcohols in the absence of an esterification catalyst. Non-limiting examples of esters of the carboxylic acid-containing components of the oligoesters that can be used in such a transesterification step include vegetable oils (e.g., 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, butterfat, coconut oil, and the like oils, as well as hydrogenated and deodorized oils. Other esters that can be used in such a transesterification step are colophony esters. Such esters can also be used in the transesterification step described below.

[0109] The oligoester compositions described herein can also be prepared by a transesterification process, which is mechanically related to esterification and transesterification. Transesterification can be carried out by mixing different esters and then rearranging the carboxylic acid groups on the polyhydric alcohol scaffold used in the presence of a catalyst, such as an esterification catalyst. Transesterification is an equilibrium reaction. For example, colophony esters can be reacted with triglyceride esters such as rapeseed oil. Such transesterification reactions result in oligoesters in which some of the fatty acid moieties in the triglyceride esters are replaced with colophonyl acid moieties, and in which some of the colophonyl acid moieties in the colophonyl esters are replaced with fatty acid moieties.

[0110] The oligoester compositions described herein can also be prepared by a combination of the above esterification, transesterification and transesterification steps, where the esters can be reacted with one another in the presence of one or more polyhydric alcohols and one or more monocarboxylic acids, and optionally one or more polycarboxylic acids or partial esters or semiesters thereof. Examples of partial esters include partial glycerides, i.e., esters of glycerol and fatty acids in which not all hydroxyl groups are esterified. cis-HOOC-CH=CH-COOCH 3 is an example of a semi-ester of maleic acid. Monomethyl adipic acid ester and monoethyl adipic acid ester are examples of semi-esters derived from adipic acid. As with the above process, removing water or volatile monoalcohol produced during the reaction can shift the reaction equilibrium in favor of product formation, thereby driving the reaction to completion.

[0111] For example, in certain embodiments, the preparation method may include esterifying a mixture comprising one or more colophonies, one or more monocarboxylic acids, and optionally one or more polycarboxylic acids with one or more polyhydric alcohols to form an oligoester composition. In some embodiments, the esterification step may include a thermal reaction of the mixture with said one or more polyhydric alcohols. For example, the esterification may include contacting the mixture with said one or more polyhydric alcohols at an elevated temperature (e.g., a temperature between 30°C and 300°C or between 150°C and 285°C). Optionally, the esterification step may further include removing water formed as a by-product during esterification.

[0112] In various embodiments, catalysts, cocatalysts, solvents, bleaches, stabilizers and / or antioxidants can be added during the esterification, transesterification and transesterification reactions.

[0113] The pressure-sensitive adhesive composition according to the invention preferably contains 1 to 50 wt. %, more preferably 2 to 40 wt. %, even more preferably 5 to 40 wt. %, even more preferably 5 to 30 wt. %, particularly preferably 10 to 30 wt. %, for example 15 to 30 wt. %, 10 to 25 wt. % or 15 to 20 wt. % of said at least one liquid resin b) which comprises or consists of or consists of an oligoester composition as described herein, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0114] Commercially available pressure-sensitive adhesive compositions usually contain plasticizers. These are used, for example, to reduce the viscosity of the pressure-sensitive adhesive composition and to improve its wettability. Common plasticizers used in this context are, for example, medical white oils, naphthenic mineral oils, adipates, polypropylene, polybutylene and polyisoprene oligomers, hydrogenated polyisoprene and / or polybutadiene oligomers, benzoic acid esters, phthalic acid esters, animal and vegetable oils and their derivatives, sulfonic acid esters, monohydric or polyhydric alcohols, polyalkylene glycols such as polypropylene glycol, polybutylene glycol, polymethylene glycol, etc. The polybutylene oligomers should have a molecular weight of 200 to 6,000 g / mol, while the polyolefins should have a molecular weight M of up to about 2,000 g / mol, in particular up to 1,000 g / mol. w should have.

[0115] Oil-based plasticizer components are often used. Examples of plasticizer components are liquid at room temperature, such as hydrocarbon oils, polybutylene / polyisoprene oligomers, (hydrogenated) naphthenic oils, paraffinic oils or vegetable oils.

[0116] The pressure-sensitive adhesive composition according to the invention contains a combination of the described liquid resin B) and at least one further plasticizer C) comprising an isobutene / butene copolymer. These components are used in combination to partially, mainly or completely replace conventional plasticizers as described above. The at least one further plasticizer c) is preferably present in the pressure-sensitive adhesive composition in an amount of 0.1 to 30 wt%, more preferably 1 to 15 wt%, for example 2 to 12 wt% or 5 to 10 wt%, based on the total weight of the pressure-sensitive adhesive composition. Particularly preferably, the at least one liquid resin b) and the at least one further plasticizer c) together have a concentration in the pressure-sensitive adhesive composition of 5 to 50 wt%, preferably 10 to 40 wt%, in particular 15 to 35 wt%, based on the total weight of the components of the pressure-sensitive adhesive composition.

[0117] The isobutene / butene copolymers used here are synthetic hydrocarbons obtained by polymerization of C4 fractions. By varying the polymerization parameters, polymers with different chain lengths are produced. This change in chain length affects the physical properties.

[0118] The at least one further plasticizer c) or isobutene / 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 isobutene / butene copolymer. n In various embodiments, the plasticizer c) or isobutene / butene copolymer has a number average molecular weight M of 750 to 1450 g / mol, preferably 850 to 1350 g / mol, in particular 900 to 1300 g / mol. n This distinguishes the plasticizers c) used according to the invention from, for example, plasticizer oils, such as polybutene oils. The oils generally have a low number average molecular weight, for example 480 g / mol.

[0119] Furthermore, the at least one plasticizer c) or isobutene / 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 ISO 11357-1:2017-02, -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 10 K / min. In various embodiments, the plasticizer c) or isobutene / butene copolymer has a glass transition temperature of -60 to -73 °C, more preferably -63 to -73 °C, in particular -66 to -70 °C.

[0120] In various embodiments, the at least one plasticizer c) or isobutene / butene copolymer has a viscosity of 0.00018 to 0.0007 m 2 / s (180 to 700 cSt), preferably 0.00019 to 0.00067 m 2 / s (190-670 cSt), especially 0.0002-0.000655 m2 / s (200cSt to 655cSt).

[0121] Suitable isobutene / butene copolymers can be purchased, for example, under the designation Polybutene (PB) 1300 from Daelim Industrial or Indopol H300 from Ineos.

[0122] The pressure-sensitive adhesive composition preferably does not contain any further plasticizers other than the described combination of liquid resin b) and further plasticizer c), such pressure-sensitive adhesive compositions preferably exhibit improved adhesion and / or cohesion to various substrates.

[0123] In particular, the described liquid resins B) in combination with said at least one further plasticizer C) partially or completely replace conventional mineral oil-based plasticizers (e.g. naphthenic and / or paraffinic oils) in the pressure-sensitive adhesive compositions according to the invention.

[0124] Mineral oils are typically produced by distillation of crude oil and optionally other fossil feedstocks. Mineral oils include, for example, paraffinic, naphthenic, aromatic hydrocarbons, alkenes, sulfur-containing compounds, nitrogen-containing compounds, organic compounds, etc. "Naphthenic oil" herein refers specifically to saturated cyclic hydrocarbons. "Paraffinic oil" refers specifically to saturated chain hydrocarbons.

[0125] 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.%, and most preferably is free of mineral oil-based plasticizers, in particular naphthenic and / or paraffinic oils, based on the total weight of the pressure-sensitive adhesive composition.

[0126] In a preferred embodiment, the at least one mineral oil-based plasticizer, preferably naphthenic and / or paraffinic oil (or the required amount of plasticizer) is replaced in the pressure-sensitive adhesive composition by the at least one liquid resin b) and the at least one further 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% and most preferably 100%.

[0127] In a further preferred embodiment, the pressure-sensitive adhesive composition has a proportion of renewable resources of 20 to 100 wt.%, preferably 50 to 100 wt.%, more preferably at least 50 wt.%, more preferably at least 60 wt.%, even more preferably at least 70 wt.%, even more preferably at least 80 wt.%, even more preferably at least 90 wt.%, even more preferably at least 95 wt.% and most preferably at least 99 wt.%, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0128] The pressure-sensitive adhesive composition according to the invention can further comprise, in addition to said at least one liquid resin b), at least one further resin d).

[0129] Resins are typically used to modify, preferably reduce, the viscosity of the pressure-sensitive adhesive composition according to the invention, to influence the odor, the (initial) color and color stability of the composition, as well as the tack and polarity of any polymers present.

[0130] In particular, resins with 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 their modifications or hydrogenations. Specific examples include aliphatic or cycloaliphatic petroleum hydrocarbon resins and their hydrogenated derivatives. Other resins which can be used within the scope of the present invention are, for example, hydroabietyl 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 resin, tall resin or root resin, for example fully saponified balsamic resin; alkyl esters of optionally partially hydrogenated colophony with low softening points, for example methyl, diethylene glycol, glycerol and pentaerythritol esters; terpene resins, in particular terpene terpolymers or copolymers, for example styrene terpene, α-methylstyrene terpene, phenol-modified terpene resins and their hydrogenated derivatives; acrylic acid copolymers, preferably styrene-acrylic acid copolymers and resins based on functional hydrocarbon resins, for example resins having 3 to 8 carbon atoms, in particular 5 carbon atoms, said at least one resin d) being different from the liquid resins b) described herein, in particular not a liquid resin. Particularly preferably, said 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, i.e. it is not flowable and does not exist as a liquid with a yield point, but exists as a solid.

[0131] 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 (colophony esters), optionally partially polymerized tall resin, terpene, or crude oil-based aliphatic, aromatic or cycloaliphatic hydrocarbon resins, and modified or hydrogenated versions thereof, such as C5 aliphatic or C9 aromatic hydrocarbon resins or C5 / C9 monomer mixtures, and the at least one resin d) is different from the liquid resins b) described herein, in particular is not a liquid resin, but rather for example a solid resin.

[0132] Particularly preferably, the pressure-sensitive adhesive composition comprises at least one resin d), preferably two resins, in particular selected from colophony esters, such as pentaerythritol esters (from tall oil colophony) and / or (cyclo)aliphatic hydrocarbons, such as those having 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), for example 10 to 25 carbon atoms. The (cyclo)aliphatic hydrocarbons may in various embodiments comprise a combination of linear, branched, cyclic aliphatic (cycloaliphatic), partially unsaturated or aromatic or heteroaromatic chemical groups, optionally containing one or more functional groups, such as, but not limited to, hydroxyl groups, alkyl groups, aryl groups, alkoxy groups, haloalkyl groups or keto groups. Resins with low coloration and good color stability are particularly suitable.

[0133] The solid resins used are preferably distinguished from the liquid resins in that they are solid at room temperature (20°C) and 1013 mbar and have a softening range of 70-110°C, preferably 85-106°C, e.g. 85-100°C (ring and ball method, ASTM D36, glycerol).

[0134] In certain embodiments, the at least one resin d) is present in the pressure-sensitive adhesive composition 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 composition.

[0135] According to the invention, both solid and liquid resins can be used, however in a preferred embodiment, at least one resin d) is a solid resin in addition to the liquid resin b) described herein.

[0136] The pressure-sensitive adhesive composition according to the invention may also comprise at least one additive e). Suitable additives include, but are not limited to, components from the group consisting of antioxidants, especially stabilizers, waxes, UV protection agents, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners and fragrances.

[0137] 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 %, and even more preferably 0.5 to 3 wt %, based on the total weight of the pressure-sensitive adhesive composition.

[0138] Antioxidants such as stabilizers are particularly preferably used in the pressure-sensitive adhesive composition according to the present invention, preferably in an amount of 0.01 to 10 wt%, more preferably 0.1 to 5 wt%, and even more preferably 0.5 to 2 wt%. For example, they are used against thermal degradation or oxidative degradation caused by oxygen or ultraviolet light. Furthermore, the antioxidant can improve the thermal stability and / or color stability.

[0139] If a stabilizer is used, it must be ensured that it is compatible with the pressure-sensitive adhesive composition. For example, antioxidants available under the trade name Irganox® (BASF SE) can be used as stabilizers, preferably in an amount of 0.5 to 1.5 wt %, for example 1 wt %, based on the total weight of the composition.

[0140] In various embodiments, the wax can be optionally added to the pressure-sensitive adhesive composition in an amount of 0.5 to 5 wt.%. In this case, the amount is measured so that the viscosity is reduced to the desired range without adversely affecting the adhesive properties. The wax can be of natural origin, optionally chemically modified, or synthetic origin. As natural waxes, vegetable waxes, animal waxes, mineral waxes, petrochemical waxes, etc. can be used. As chemically modified waxes, hard waxes such as montan ester waxes and sazol waxes can be used. As synthetic waxes, polyalkylene waxes and polyethylene glycol waxes are used. Petrochemical waxes, such as petrolatum, paraffin wax, microcrystalline wax, and synthetic waxes are preferably used. Paraffin wax and / or microcrystalline wax and / or their hydrogenated products are particularly preferred, and in particular polypropylene or polyethylene waxes having a dropping point of 50°C to 170°C as determined according to ASTM D-3954 are preferred.

[0141] 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 also comprises one or more solvents.

[0142] However, in particular in view of the environmental and economic demands associated with the use of organic solvents, it is advantageous not to use a solvent. Therefore, embodiments in which the pressure-sensitive adhesive composition according to the present invention does not contain a solvent are preferred. By appropriately selecting the amount of liquid resin b) used, the use of a solvent can be omitted in whole or in part.

[0143] In preferred embodiments, the pressure sensitive adhesive compositions according to the present invention are solvent-containing, solvent-free or dispersions.

[0144] In a particularly preferred embodiment, the pressure sensitive adhesive composition comprises: a) at least one polymer, preferably an SBC and / or SIS polymer; b) at least one liquid resin comprising an oligoester composition that is the reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; wherein the reaction mixture comprises one or more colophons; c) at least one additional plasticizer, wherein the at least one additional plasticizer comprises an isobutene / butene copolymer; and d) at least one resin, preferably two resins, more preferably colophonyl esters, such as pentaerythritol resin esters, and / or (cyclo)aliphatic hydrocarbon resins, such as resins having 1 to 30 or 6 to 30 carbon atoms, which resins are different from the liquid resins b) described herein, in particular are not liquid resins, but rather are preferably solid resins; e) at least one additive, preferably a stabilizer; The components herein are preferably used in the pressure-sensitive adhesive composition as described below: Based on the total weight of the pressure sensitive adhesive composition, 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 b) 1 to 50 wt%, preferably 2 to 40 wt%, more preferably 5 to 40 wt%, even more preferably 5 to 30 wt%, particularly preferably 10 to 30 wt%, for example 15 to 30 wt%, 10 to 25 wt% or 15 to 20 wt%; and / or 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 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 e) 0.01 to 20 wt%, preferably 0.1 to 5 wt%, and more preferably 0.5 to 3 wt%.

[0145] In various embodiments, the pressure sensitive adhesive composition according to the invention does not include betulin-based polyester polyols, such as those described in EP 3878883 A1.

[0146] High demands are placed on food packaging in particular and on the materials used for its production. Not only mechanical properties but also health aspects in particular are the focus. Surprisingly, within the scope of the present invention, it has been found that the use of the liquid resins b) described herein together with at least one plasticizer c) described herein makes it possible to prevent the formation of what are called critical migration cycles. Critical migration cycles are understood to mean compounds that can migrate from the adhesive into the packaging material or into the packaged product, e.g. food, and thus be harmful to health. Thus, preferred embodiments of the pressure-sensitive adhesive composition according to the present invention are those in which the proportion of critical migration components in the pressure-sensitive adhesive composition is less than 300 ppm, preferably less than 200 ppm, particularly preferably less than 50 ppm, ppm indicating the proportion by weight and the amount relating to the total weight of the pressure-sensitive adhesive composition.

[0147] In a preferred embodiment, the liquid resin b) and / or the plasticizer c) described herein have a molecular weight such that they exhibit low volatility and therefore low migration.

[0148] Particularly preferably, the liquid resins b) and / or plasticizers c) described herein contain only ingredients which are approved for contact with food.

[0149] In a preferred embodiment of the pressure-sensitive adhesive composition according to the invention, the combination of the liquid resin b) described herein with the further plasticizer c) described herein partially or completely replaces the migrating naphthenic or other mineral oils. The liquid resin preferably comprises or consists of the oligoester composition described herein. Due to the described properties of the oligoester composition, there is preferably no or a significantly reduced migration of components from the adhesive into the material, for example into the packaging material or into the packaged product, with the liquid resin described herein, compared to the migrating naphthenic or white paraffinic oils. This also preferably applies to the at least one plasticizer described herein.

[0150] Furthermore, by replacing mineral oils such as naphthenic and / or paraffinic oils with the liquid resins b) described herein, the proportion of renewable resources in the formulation is increased.

[0151] The pressure sensitive adhesive compositions according to the present invention preferably have a lower viscosity than other adhesive compositions and, as a result, can be applied at lower temperatures, which translates into energy and cost savings for the customer.

[0152] In a preferred embodiment, the pressure sensitive adhesive according to the invention has a Brookfield viscosity at 160° C. (measurable, for example, with spindle 27 at 20 RPM) of 5,000 to 160,000 mPas, preferably 8,000 to 30,000 mPas, for example 9,000 to 20,000 mPas or 10,000 to 15,000 mPas.

[0153] In a preferred embodiment, the pressure sensitive adhesive according to the invention has a softening point of 90° C. or higher (ring and ball method, ASTM D36, glycerol).

[0154] The pressure-sensitive adhesive composition according to the present invention preferably has a glass transition temperature Tg of -50 to 80°C, more preferably -10 to 30°C, particularly -5 to 20°C, for example 0 to 10°C (measured by DMA).

[0155] Preferably, the pressure sensitive adhesive compositions according to the invention have a reduced glass transition temperature, especially compared to compositions using betulin-based polyester polyols.

[0156] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention further exhibits improved adhesion to various substrates, such as plastics, glass, nonwovens, cardboard or steel, so that preferably less pressure-sensitive adhesive composition is required compared to known pressure-sensitive adhesive compositions.

[0157] To check the adhesion of the pressure-sensitive adhesive composition according to the invention, a peel test can be carried out. The peel force is generally the average force required to separate two joined materials. This test is usually carried out at an angle of 90° or 180° depending on the materials.

[0158] In a preferred embodiment, the pressure-sensitive adhesive composition has a peel force of at least 10 Newtons (N) based on a 25 mm wide PET coating using an angle of 180° measured according to the FINAT-FTM1 test method. In another embodiment, the pressure-sensitive adhesive composition according to the invention has a peel force against highly branched (LD) polyethylene of at least 15 N / 25 mm PET coating, preferably at least 18 N / 25 mm PET coating, more preferably at least 20 N / 25 mm PET coating, in particular at least 21 N / 25 mm PET coating, for example at least 22 N / 25 mm PET coating. In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention has a peel force against nonwoven fabric of at least 10 N / 25 mm PET coating, preferably at least 12 N / 25 mm PET coating. In a further preferred embodiment, the pressure-sensitive adhesive composition has a peel force against cardboard of at least 15 N / 25 mm PET coating, preferably at least 18 N / 25 mm PET coating. All these measurements use an angle of 180° measured using the FINAT FTM1 test method.

[0159] Furthermore, the adhesive strength of the pressure sensitive adhesive composition according to the invention can be determined by a loop tack test, the measurements being taken on a 25 mm x 25 mm PET coating.

[0160] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention has an adhesive strength (loop tack) on steel of at least 40 N, preferably at least 43 N, more preferably at least 45 N, even more preferably at least 46 N, particularly preferably at least 47 N. On glass, the pressure-sensitive adhesive composition according to the invention preferably has an adhesive strength of at least 38 N, more preferably at least 40 N, even more preferably at least 42 N, particularly preferably 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, particularly preferably at least 23 N.

[0161] The invention further relates to a method for preparing a pressure-sensitive adhesive composition according to the invention, which comprises mixing at least one liquid resin b) as described herein with further components of the pressure-sensitive adhesive composition, such as at least one polymer a) and at least one further plasticizer c), and optionally further components, such as at least one resin d) and / or at least one additive e), in the appropriate order;

[0162] The temperature is preferably 100 to 200°C, more preferably 120 to 180°C, and further preferably 150 to 170°C.

[0163] In a preferred embodiment, the further components of the pressure-sensitive adhesive composition, such as the polymer a) and the resin d), are first fed and mixed before adding the liquid resin b), after which the plasticizer c) and additives e) can be added.

[0164] A preferred mixing sequence for the process for preparing the pressure sensitive adhesive composition according to the present invention is as follows: 1. Providing at least one polymer a), 2. Optionally adding at least one resin d), preferably two resins; 3. Adding at least one liquid resin b) as described herein; 4. Adding at least one plasticizer c); 5. Optionally adding at least one additive, such as at least one stabilizer; The temperature is preferably 100 to 200°C, more preferably 120 to 180°C, and further preferably 150 to 170°C.

[0165] Preferably, the individual components for preparing a pressure sensitive adhesive composition according to the present invention are as described herein.

[0166] The invention also relates to the use of the pressure-sensitive adhesive compositions according to the invention in tapes, labels, hygiene articles such as diapers, labelling, e.g. for beverage bottles, flexible packaging, films, food packaging, in the assembly field (high performance, e.g. in the automotive industry), medical applications (e.g. packaging of medical materials and products) and / or in the graphic industry (books, magazines, brochures, etc.).

[0167] The pressure-sensitive adhesives according to the invention are used, for example, to bond substrates such as glass, metals, e.g. steel, wovens, nonwovens, coated or uncoated paper, cardboard, plastic materials, e.g. PET, PEN, PE, PP, PVC, PS, etc. A thin flexible substrate, e.g. made of film, multilayer film or paper, is then bonded to this type of solid substrate. Said thin flexible substrates are, for example, labels, outer packaging, bags, etc., and can be made, for example, of plastic materials, e.g. polyethylene, polypropylene, polystyrene, polyvinyl chloride or cellophane, in particular PE film. However, the labels can also be based on paper, optionally in combination with a polymer film. The hot-melt pressure-sensitive adhesives according to the invention are distinguished in particular by a very good adhesion to the aforementioned plastic materials, but can also be removed again from the substrate surface.

[0168] Further fields of application are described, for example, in International Patent Publication WO 2016 / 062797 A1, in particular on pages 10-11.

[0169] In a preferred embodiment, the coating amount of the pressure-sensitive adhesive composition is 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 It is.

[0170] In a preferred embodiment, the substrates may optionally be pretreated and / or the two substrates are joined under pressure.

[0171] The present invention further relates to an article comprising the pressure-sensitive adhesive composition according to the invention. In a preferred embodiment, the article is obtainable using the method according to the invention. The article is preferably a multi-layer substrate, in particular for packaging food and medicines, for hygiene articles, used in the field of "labels" and "labeling", but also in the automotive or graphic industry.

[0172] All aspects, objects and embodiments described for the pressure-sensitive adhesive composition according to the invention are also applicable to the method according to the invention, the article according to the invention and the use according to the invention, and therefore, at this point, explicit reference is made to the disclosure at the corresponding point where it is indicated that the present disclosure also applies to the use according to the invention, the article according to the invention and the method according to the invention.

[0173] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. EXAMPLES

[0174] Working Example Example 1 Preparation of a pressure sensitive adhesive having a liquid resin comprising the oligoester composition described herein: The ingredients listed were prepared at the specified temperatures and according to the mixing sequence listed in the table below. The adhesive was mixed with a propeller mixer at speeds of 50-500 rpm.

[0175] [Table 1]

[0176] The adhesive according to the invention increases adhesion to a variety of substrates while at the same time reducing the application weight. This means that significantly less adhesive is available to meet the application requirements compared to Reference Adhesive 1. This translates into energy and cost savings for the customer.

[0177] [Table 2]

[0178] The coatings required to carry out the adhesion tests are produced on a laboratory scale on a heatable coating table. This table has a heated and movable doctor blade, with which the adhesive can be drawn across the table. The layer thickness is set by means of two adjusting screws for coarse adjustment and two for fine adjustment. The gap width between the doctor blade and the heating plate is displayed by two manometers above the doctor blade on the adjusting screws. Here the gap width in micrometers can be read off on a scale. The adhesive is applied to silicone paper and fixed to the plate by vacuum. After the adhesive layer has been applied it is wound up on a PET film. After checking the application weight with a maximum deviation of ±10% and after a rest period of 24 hours the finished coating is ready for testing. The coating is a 50 μm thick PET film with an application weight of 40 g / m 2 It was.

[0179] The following table shows the 180° peel and loop tack adhesion values ​​on various substrates. The mineral oil-free adhesives according to the invention using liquid resins comprising the oligoester compositions described herein show improved values ​​compared to the mineral oil-free pressure sensitive adhesives using betulin-based polyester polyols (EP3878883A1) and are comparable to good label and all-rounder pressure sensitive adhesives (Reference 1).

[0180] [Table 3]

Claims

1. a) at least one polymer; b) at least one liquid resin comprising an oligoester composition that is the reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids; iii) one or more polyhydric alcohols; and iv) optionally one or more polycarboxylic acids; wherein the reaction mixture comprises one or more colophons; c) at least one additional plasticizer, wherein the at least one additional plasticizer comprises an isobutene / butene copolymer; d) optionally at least one additional resin; and e) optionally, at least one additive, preferably at least one stabilizer; A pressure sensitive adhesive composition comprising:

2. 2. The pressure-sensitive adhesive composition according to claim 1, wherein the at least one polymer a) is selected from the group of polymers based on acrylates, polyesters, urethanes, ethylene acrylates, butyl rubber and (synthetic) natural rubber; ethylene-vinyl acetate copolymers (EVA), polyolefin (co)polymers (PO), polyamide (co)polymers (PA), ethylene-propylene copolymers or styrene copolymers, individually or in mixtures, where the polymer is particularly preferably styrene and styrene-butadiene copolymers (SBC or SBS, SBR), styrene-isoprene copolymers ( %.

3. The reaction mixture for preparing the oligoester composition comprises: 25% to 85% by weight of one or more monocarboxylic acids, 7% to 35% by weight of one or more polyhydric alcohols, and Optionally, greater than 0% to less than 4% by weight of one or more polycarboxylic acids; wherein the reaction mixture comprises 5% to 75% by weight of colophony 3. The pressure sensitive adhesive composition of claim 1 or 2, comprising:

4. Colophony is preferably made from colophonic acid, preferably C ２０ 4. The pressure-sensitive adhesive composition according to claim 1, comprising a mixture of tricyclic monocarboxylic acids and their isomers, in particular colophonic acid, 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.

5. 5. The pressure-sensitive adhesive composition according to claim 1 , wherein 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, even more preferably 5 to 40% by weight, in particular 5 to 30% by weight, based on the total weight of the pressure-sensitive adhesive composition.

6. In the at least one further plasticizer c), i) is present in an amount of 0.1 to 30 wt. %, preferably 1 to 15 wt. %, based on the total weight of the pressure-sensitive adhesive composition; and / or iii) is the number average molecular weight M measured by size exclusion chromatography (GPC, gel permeation chromatography) ｎ is from 750 to 1450 g / mol, preferably from 850 to 1350 g / mol, in particular from 900 to 1300 g / mol; and / or iv) has a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of from −60 to −73° C., more preferably from −63 to −73° C., in particular from −66 to −70° C.; and / or v) has a kinematic viscosity of 0.00018 to 0.0007 m, measured at 100°C according to ASTM D445 ２ / s (180 to 700 cSt), preferably 0.00019 to 0.00067 m ２ / s (190 to 670 cSt), especially 0.0002 to 0.000655 m ２ / s (200 cSt to 655 cSt), The pressure-sensitive adhesive composition according to any one of claims 1 to 5.

7. 7. The pressure sensitive adhesive composition according to claim 1, which does not contain any plasticizer other than the isobutene / butene copolymer plasticizer c).

8. 8. The pressure-sensitive adhesive composition according to claim 1 , wherein the at least one further resin d) comprises a natural resin or a hydrocarbon resin, more preferably tall oil esters, gum rosin (colophony esters), optionally partially polymerized tall resins, terpene or crude oil-based aliphatic, aromatic or cycloaliphatic hydrocarbon resins and modified or hydrogenated versions thereof, e.g. C5 aliphatic or C9 aromatic hydrocarbon resins or C5 / C9 monomer mixtures, wherein the resins are different from liquid resins and are preferably solid resins, preferably the at least one further resin d) comprises at least two further resins, preferably selected from (cyclic)aliphatic hydrocarbons having, for example, 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), and / or colophony esters, e.g. pentaerythritol esters, and the at least one further resin d) is preferably a solid resin and is preferably contained 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 pressure-sensitive adhesive composition.

9. 9. The pressure-sensitive adhesive composition according to any of the preceding claims, wherein the at least one further resin d) comprises at least two further resins, said resins being preferably selected from (cyclo)aliphatic hydrocarbons, e.g. having 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), and / or colophony esters, e.g. pentaerythritol esters, and wherein the at least one further resin d) is preferably a solid resin.

10. 10. The pressure-sensitive adhesive composition according to claim 1 , wherein the at least one additive e) comprises at least one substance from the group consisting of antioxidants, such as stabilizers, waxes, UV protection agents, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners and fragrances, the at least one additive e) being contained in the pressure-sensitive adhesive composition in particular 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 producing a pressure sensitive adhesive composition according to any of claims 1 to 10, comprising mixing at least one liquid resin b) according to any of claims 1 to 10 with further components of the pressure sensitive adhesive composition, such as at least one polymer a) and at least one further plasticizer c) and optionally further components, such as at least one further resin d) and / or at least one additive e), in the appropriate order, preferably at a temperature of 100 to 200°C, more preferably 120 to 180°C, even more preferably 150 to 170°C.

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

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

14. A method for bonding at least two substrates, comprising applying a pressure sensitive composition according to any one of claims 1 to 10 to at least one substrate, and then bonding the at least two substrates.

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