Pressure sensitive adhesive containing 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, wherein the at least one further plasticizer comprises an isobutene / butene copolymer. The invention also relates to a use of the pressure-sensitive adhesive composition according to the invention, as well as to a process for preparing the pressure-sensitive adhesive composition and to a process for bonding at least two substrates. The invention further relates to an article comprising the claimed pressure-sensitive adhesive composition.

Description

[0001] 2022P00047EP_P84045

[0002] Pressure-sensitive adhesive containing liquid resin comprising an oligoester composition

[0003] The present invention relates to a pressure-sensitive adhesive composition comprising at least one polymer, at least one liquid resin comprising an oligoester composition as described herein, and at least one further plasticizer, wherein the at least one further plasticizer comprises an isobutene / butene copolymer. Furthermore, the invention relates to a use of the pressure-sensitive adhesive composition according to the invention, as well as to a process for producing the pressure-sensitive adhesive composition and a process for bonding at least two substrates. Finally, the invention relates to an article comprising the pressure-sensitive adhesive composition according to the invention.

[0004] For reasons of sustainability and growing environmental awareness, it is desirable to increasingly replace mineral oil-based compounds with substances based on renewable raw materials.

[0005] Commercially available pressure-sensitive adhesive compositions typically contain mineral oil-based plasticizers. It is advantageous to reduce or completely avoid the use of these substances, especially in food packaging, but also in hygiene products, and in many other areas, to prevent, for example, migration from the adhesive into the packaging material. Therefore, there is a need for substitutes that can partially or completely replace these plasticizers and are suitable and approved for contact with food.

[0006] Many of the available alternatives based on renewable raw materials are disadvantageous in terms of compatibility with the other components of the pressure-sensitive adhesive composition and / or lead to a reduction in the performance of the adhesive composition.

[0007] The object of the present invention is therefore to provide a pressure-sensitive adhesive composition that contains the highest possible proportion of renewable raw materials in its formulation, in particular by largely replacing the mineral oil-based plasticizers previously used. At the same time, such a composition should exhibit consistent or even improved performance in terms of adhesive strength and stability compared to conventional systems and be suitable, for example, for the production of food packaging or hygiene articles, i.e., it should contain only components approved for contact with food.

[0008] Surprisingly, it has been found that this object is achieved by a pressure-sensitive adhesive composition which, in addition to at least one polymer, comprises a combination of at least one liquid resin and at least one further plasticizer, wherein the at least one further plasticizer comprises or consists of an isobutene / butene copolymer and the liquid resin comprises an oligoester composition, wherein the oligoester composition is a reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids, optionally in an amount of at least 15 wt.% 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 rosins.

[0009] The described liquid resin, in combination with the isobutene / butene copolymer, at least partially, preferably even completely, replaces the typically used mineral oil-based plasticizers, especially naphthenic oils and / or paraffinic oils, in the pressure-sensitive adhesive composition and is thus a sustainable alternative to mineral oil-based plasticizers. Such pressure-sensitive adhesive compositions comprising the liquid resin described herein and the isobutene / butene copolymer preferably exhibit improved bond strength and / or adhesion to various substrates.

[0010] A first aspect of the invention therefore relates to a pressure-sensitive adhesive composition comprising a) at least one polymer; b) at least one liquid resin comprising an oligoester composition which is a reaction product of a reaction mixture comprising: ii) one or more monocarboxylic acids, optionally in an amount of at least 15 wt.% 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 rosins; c) at least one further plasticizer, wherein the at least one further plasticizer comprises an isobutene / butene copolymer; d) optionally at least one further resin; and e) optionally at least one additive, preferably at least one stabilizer.

[0011] The pressure-sensitive adhesive composition according to the invention preferably comprises at least one polymer a) selected from the group of polymers based on acrylate, polyester, urethane, ethylene-acrylate, 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 a mixture, particularly preferably it is a styrene block copolymer such as a styrene and styrene-butadiene copolymer (SBC, SBS, SBR), a styrene-isoprene copolymer (SIS), a styrene-ethylene / butylene copolymer (SEBS), a styrene-ethylene / propylene-styrene copolymer (SEPS) or a styrene-isoprene-butylene copolymer (SIBS) or a mixture thereof.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] The polymer a) is particularly preferably present in the pressure-sensitive adhesive composition in an amount of 10 to 70 wt.%, preferably 15 to 70 wt.%, more preferably 20 to 70 wt.%, for example 20 to 50 wt.%, 20 to 40 wt.% or 25 to 60 wt.%, based on the total weight of the pressure-sensitive adhesive composition.

[0013] A further essential component of the compositions according to the invention is the liquid resin b), which comprises an oligoester composition as described herein. In various embodiments, the reaction mixture for preparing the oligoester composition comprises at least 15 wt.% of one or more monocarboxylic acids, one or more polyhydric alcohols, and optionally more than 0 wt.% to less than 4 wt.% of one or more polycarboxylic acids, wherein the reaction mixture comprises one or more rosins. In various embodiments, however, the one or more monocarboxylic acids can also be used in an amount of 14 wt.%.

[0014] Preferably, the reaction mixture for preparing the oligoester composition comprises

[0015] 25 wt.% to 85 wt.% of one or more monocarboxylic acids,

[0016] 7 wt.% to 35 wt.% of one or more polyhydric alcohols, and optionally more than 0 wt.% to less than 4 wt.% of one or more polycarboxylic acids, wherein the reaction mixture preferably comprises 5 wt.% to 75 wt.% rosin.

[0017] Typically, rosin comprises a mixture of rosin acids, preferably C20 tricyclic monocarboxylic acids and isomers thereof, more preferably tricyclic diterpene carboxylic acids. Suitable rosin acids can be selected from the group consisting of, but not limited to, abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid, and palustric acid, as well as their isomers.

[0018] In various embodiments, the liquid resin b) consists of the described oligoester composition. "Liquid resin," as used herein, means that this component is in liquid form under standard conditions, i.e., 20°C and 1013 mbar.

[0019] It is particularly preferred that the at least one liquid resin b) is present in the pressure-sensitive adhesive composition in an amount of 1 to 50 wt. %, more preferably 2 to 40 wt. %, even more preferably 5 to 40 wt. %, in particular 5 to 30 wt. %, based in each case on the total weight of the pressure-sensitive adhesive composition. Suitable liquid resins are commercially available, for example from Kraton Corporation. A detailed preparation procedure, without being limited thereto, can be found, for example, in patent US 2017 / 0190935 A1. The liquid resins or oligoester compositions described therein are suitable for use as component b) in the pressure-sensitive adhesive composition described herein. This document is hereby incorporated by reference in its entirety.

[0020] According to the invention, the pressure-sensitive adhesive composition comprises a combination of at least one liquid resin b) as described herein and at least one further plasticizer c), wherein the at least one plasticizer comprises or consists of an isobutene / butene copolymer. Such a pressure-sensitive adhesive composition preferably exhibits comparable to enhanced adhesive strength and / or adhesion on various substrates (e.g., steel, polyethylene, nonwoven fabric, glass, or cardboard) compared to reference adhesives.

[0021] Preferably, the at least one further plasticizer c) or the isobutene / butene copolymer is used in an amount of 0.1 to 30 wt.%, more preferably 1 to 15 wt.%, in particular 5 to 12 wt.%, based on the total weight of the pressure-sensitive adhesive composition. It is further preferred that this further plasticizer c) or the isobutene / butene copolymer has a number-average molecular weight M nof 750-1450 g / mol, more preferably 850-1350 g / mol, in particular 900-1300 g / mol, measured by size exclusion chromatography (GPC, gel permeation chromatography). In various embodiments, the at least one further plasticizer c) or the isobutene / butene copolymer can 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 differential scanning calorimetry (DSC). The plasticizer c) or the copolymer can furthermore have a kinematic viscosity of 0.00018 - 0.0007 m 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-655 cSt) determined according to the method described in ASTM D445 at 100 °C.

[0022] 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.

[0023] 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, ie is free from further plasticizers.

[0024] Preferably, the described liquid resin b) in combination with the further plasticizer c) can partially or preferably completely replace conventional mineral oil-based plasticizers, in particular naphthenic oils and / or (white medicinal) paraffinic oils. As a result, in various preferred embodiments, the pressure-sensitive adhesive composition according to the invention comprises mineral oil-based plasticizers, in particular naphthenic oils and / or paraffinic oils, in 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.%, more preferably less than 0.01% by weight, most preferably it is free of these, based on the total weight of the composition.

[0025] In a preferred embodiment, the mineral oil-based plasticizer or plasticizers, more preferably naphthenic oils and / or paraffinic oils, in the pressure-sensitive adhesive composition are replaced by the described liquid resin b) in combination with the further plasticizer c), which comprises an isobutylene-butene copolymer, to 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%.

[0026] 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), an optionally partially polymerized tall oil resin, a terpene, or a crude oil-based aliphatic, aromatic, or cycloaliphatic hydrocarbon resin having, for example, 1 to 30 carbon atoms for aliphatic and, for example, 6 to 30 carbon atoms for aromatic and cycloaliphatic hydrocarbon resins. The resins, as well as modified or hydrogenated versions thereof, may be, for example, a C5-aliphatic or C9-aromatic hydrocarbon resin or a C5 / C9 monomer mixture. The resin differs from the liquid resin b), in particular is not a liquid resin, but a solid resin. Such a "solid resin" is solid under standard conditions.

[0027] In various embodiments, the at least one further resin d) may comprise at least two resins, wherein the resins are preferably selected from (cyclo)aliphatic hydrocarbons and / or rosin esters, for example pentaerythritol esters.

[0028] In various embodiments, resin d) is a solid resin, for example, in pellet or pastille form. However, it can also be a solid resin, which is then provided, for example, in molten form in a heated tanker truck.

[0029] In particularly preferred embodiments, the further resin d) is present in an amount of 10 to 70

[0030] Wt.%, preferably 15 to 60 wt.%, for example from 20 to 50 wt.%, 15 to 45 wt.% or 25 to 60 wt.%, in the pressure-sensitive adhesive composition, based on the total weight of the composition.

[0031] In preferred embodiments, the pressure-sensitive adhesive composition according to the invention contains at least one additive e), which is preferably selected from the group consisting of antioxidants such as stabilizers, waxes, UV protectors, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners and fragrances, in particular stabilizers.

[0032] In various embodiments, the pressure-sensitive adhesive composition contains the 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.

[0033] It is further preferred that the pressure-sensitive adhesive according to the invention exhibits increased adhesion to various substrates, for example, steel or plastic. This allows, for example, significantly less adhesive to be used to meet the application requirements compared to reference adhesives; for example, the application weight can be reduced.

[0034] In a further aspect, the invention relates to a process for producing the pressure-sensitive adhesive composition according to the invention, comprising mixing at least one liquid resin b) comprising an oligoester composition as described herein with further components of the pressure-sensitive adhesive composition, such as the at least one polymer a), the 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 a suitable order; preferably at a temperature of 100 to 200°C, more preferably at 120 to 180°C, even more preferably 150 to 170°C.

[0035] In a further aspect, the invention relates to a use of the pressure-sensitive adhesive composition according to the invention in tapes / adhesive tapes, labels / labels,

[0036] Multilayer films, e.g. for sealing devices

[0037] Hygiene products, e.g. diapers,

[0038] Labelling, e.g. of beverage bottles, flexible packaging,

[0039] food packaging,

[0040] Cardboard boxes or shipping bags; in medical applications, e.g., in packaging for medical materials and products; in assembly (high-performance, e.g., in the automotive industry); and / or in the graphics industry (e.g., books, magazines, brochures). Further examples include the coating of self-adhesive films. In general, the compositions described herein are suitable for film applications, e.g., self-adhesive films, tapes, or labels.

[0041] In a further aspect, the invention relates to an article comprising the pressure-sensitive adhesive composition according to the invention.

[0042] Finally, the invention relates to a method for bonding at least two substrates, wherein the pressure-sensitive adhesive composition according to the invention is applied to at least one substrate and then the at least two substrates are joined together.

[0043] In a preferred embodiment, the amount of pressure-sensitive adhesive composition applied 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 .

[0044] These and other embodiments, features, and advantages of the invention will become apparent to those skilled in the art from studying the following detailed description and the claims. Individual features or embodiments of the invention described may be combined with other features or embodiments of the invention without necessarily being described in combination within the scope of the invention. It is to be understood that the examples contained herein are intended to describe and illustrate the invention, but not to limit it, and in particular, the invention is not limited to the examples.

[0045] "At least one," as used herein, refers to 1 or more, for example, 2, 3, 4, 5, 6, 7, 8, 9, or more. In the context of the polymers described herein, this statement does not refer to the absolute amount of molecules, but rather to the type of compound. "At least one polymer" therefore means, for example, that only one type of polymer or several different types of polymer may be present, without specifying the amount of the individual compounds.

[0046] Unless otherwise stated, all quantities stated in connection with the pressure-sensitive adhesive composition described herein refer to wt. %, in each case based on the total weight of the composition. Furthermore, such quantities relating to at least one component always refer to the total amount of that component contained in the composition, unless explicitly stated otherwise. This means that such quantities, for example in connection with "at least one polymer," refer to the total amount of polymer contained in the composition, unless explicitly stated otherwise.

[0047] Numerical values ​​stated herein without decimal places refer to the full specified value with one decimal place. For example, "99%" represents "99.0%." Numerical ranges stated in the format "in / from x to y" include the stated values. If multiple preferred numerical ranges are specified in this format, it is understood that all ranges resulting from the combination of the various endpoints are also included.

[0048] “Approximately” or “about”, as used herein with reference to numerical values, means the corresponding value ±10%, preferably ±5%, especially ±1%.

[0049] When reference is made to molecular weights, these data refer to the number-average molecular weight M n, unless explicitly stated otherwise. The number-average molar mass can be determined, for example, by gel permeation chromatography (GPC) according to DIN 55672-1:2007-08 using THF as eluent. The weight-average molar mass Mw can also be determined by GPC, as for M n Suitable methods for determining M n or Mw are also described, for example, in US 2017 / 0190935 A1.

[0050] In a first aspect, the invention relates to a pressure-sensitive adhesive composition comprising a) at least one polymer; b) at least one liquid resin comprising an oligoester composition which is a 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 rosins; c) at least one further plasticizer, wherein the at least one further plasticizer comprises or consists of an isobutene / butene copolymer; d) optionally at least one further resin; and e) optionally at least one additive, preferably at least one stabilizer.

[0051] Preferably, the pressure-sensitive adhesive composition is a hotmelt pressure-sensitive adhesive (HMPSA) composition. More preferably, the pressure-sensitive adhesive composition is a non-reactive pressure-sensitive adhesive composition, in particular a non-reactive hotmelt pressure-sensitive adhesive composition.

[0052] A "pressure-sensitive adhesive" is a typical non-curing adhesive. "Hotmelt pressure-sensitive adhesives" (HMPSAs) are generally understood to be solid at room temperature, particularly water- and solvent-free adhesives. They are typically applied from the melt to the parts to be bonded and, after joining, physically cure upon cooling and solidify. Such hotmelt pressure-sensitive adhesives preferably remain permanently tacky and adhesive upon cooling and adhere immediately to almost all substrates under light contact pressure.

[0053] In this context, “non-reactive” or “physically setting” typically means that solidification occurs through a physical process (e.g., by solidification upon cooling, or by evaporation of solvents or water).

[0054] The pressure-sensitive adhesive composition according to the invention contains at least one polymer a). This can be a homopolymer or a copolymer.

[0055] Examples of such polymers include, but are not limited to, polymers based on acrylate, polyester, urethane, ethylene acrylate, 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, wherein the copolymers are typically random, alternating, graft, or block copolymers. Preferred thermoplastic elastomers are selected from the group of styrene block copolymers, for example styrene and styrene-butadiene copolymers (SBC or SBS, SBR), styrene-isoprene copolymers (SIS), styrene-ethylene / butylene copolymers (SEBS), styrene-ethylene / propylene-styrene copolymers (SEPS), or styrene-isoprene-butylene copolymers (SIBS). Such products are known to those skilled in the art and are commercially available.

[0056] 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), more preferably a styrene-isoprene-styrene triblock copolymer or a styrene-butadiene copolymer (SBC) or a mixture thereof.

[0057] In various embodiments, the pressure-sensitive adhesive composition according to the invention may also contain an ethylene-vinyl acetate copolymer (EVA), which may also be used in addition to those mentioned above.

[0058] 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 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.%, based on the total weight of the composition.

[0059] The pressure-sensitive adhesive composition further contains at least one liquid resin b) comprising an oligoester composition which is a 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 rosins.

[0060] In various embodiments, the reaction mixture for preparing the oligoester composition comprises at least 15 wt.% of one or more monocarboxylic acids, based on the total weight of the reaction mixture. In other embodiments, however, the one or more monocarboxylic acids can also be used in an amount of 14 wt.%.

[0061] "Liquid resin" describes any resin composition that can be prepared from the reaction mixture described above and is liquid, i.e., flowable, at 20°C and 1013 mbar. The liquid resin can, in particular, also include (highly) viscous resin compositions.

[0062] An oligoester composition of the described liquid resin b) may comprise, consist of, or consist essentially of the oligoesters described herein. In one embodiment, the oligoester composition comprises from 1 weight percent (wt%) to 100 wt% of one or more oligoesters of the type described herein, based on the total weight of the composition, for example, from 10 wt% to 100 wt%, from 20 wt% to 80 wt%, or from 30 wt% to 70 wt%. In some embodiments, the oligoester composition comprises equal to or less than 20 wt% of a non-oligoester, based on the weight of the oligoester composition, for example, less than 10 wt% or less than 5 wt%. The oligoester compositions 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 oxidation induction time at 110°C of at least 30 minutes), improved color stability (e.g., the oligoester may have less than a 10% change in pure Gardner color when heated to a temperature of 160°C for a period of three hours), or combinations thereof.

[0063] In the context of the present invention, "essentially" means that the compositions may contain additional substances or compounds that are not actively added to the oligoester composition, but are present due to, for example, impurities or undesirable side reactions. These additional components, which go beyond the "essential" components, may preferably constitute a weight fraction 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.

[0064] The oligoester composition of the liquid resin b) described herein may be derived from at least one rosin.

[0065] Rosin, also called colophony or Greek pitch (Pix graeca), is a solid hydrocarbon secretion from plants, typically from conifers such as pines (e.g., Pinus palustris and Pinus caribaea). Rosin can contain a mixture of rosin acids, with the exact composition depending partly on the plant species. Rosin acids are C20 monocarboxylic acids with condensed rings, the core of which consists of three condensed six-carbon rings containing double bonds that vary in number and location.

[0066] Suitable rosin acids include, but are not limited to, abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid, and palustric acid, as well as their isomers. In various embodiments, natural rosin primarily comprises a mixture of the rosin acids abietic acid and / or pimaric acid.

[0067] Rosin is commercially available and can be obtained from pine trees by distillation of oleoresin (gum rosin is the residue of distillation), by extraction from pine stumps (wood rosin), or by fractionation of tall oil (tall oil rosin). Any type of rosin can be used to prepare the oligoester compositions described herein, including tall oil rosin, gum rosin, and wood rosin, as well as mixtures thereof. If desired, the rosin can be subjected to one or more purification steps (e.g., reduced-pressure distillation, extraction, and / or crystallization) prior to its use as rosin in the esterification steps described herein. Hydrogenated rosins and partially hydrogenated rosins can also be used as a rosin source.An example of a commercially available hydrogenated rosin suitable for use in the present disclosure is FORAL™ AX-E, marketed by Eastman Chemical Company. Examples of commercially available hydrogenated rosins include STAYBELITE™ Resin-E, marketed by Eastman Chemical Company, and HYDROGAL™, marketed by DRT (Derives Resiniques et Terpeniques).

[0068] In various embodiments, the described oligoester is derived from tall oil rosin (TOR). Non-limiting examples of commercially available TOR are SYLVAROS™ 90S, SYLVAROS™ HYR, SYLVAROS™ NCY, SYLVAROS™ 85S, SYLVAROS™ 90F, and SYLVAROS™ R Type S, which are commercially available from Arizona Chemical, a subsidiary of Kraton Corporation.

[0069] Crude tall oil (CTO), as obtained from the kraft pulping process, contains significant amounts of TOR and tall oil fatty acid (TOFA). Distilled tall oil (DTO) is an industrial refinery product obtained from the fractional distillation of crude tall oil. DTO primarily contains TOR and TOFA (a mixture of several monocarboxylic acids). In some embodiments, DTO can be used as a starting point for preparing the described oligoester composition. Several commercial DTO grades with varying rosin contents are marketed as the SYLVATAL™ product line by Arizona Chemical, a subsidiary of Kraton Corporation, including SYLVATAL™ 10S, SYLVATAL™ 20 / 25S, SYLVATAL™ 20S, SYLVATAL™ 25 / 30S, SYLVATAL™ D25 LR, SYLVATAL™ D30 LR, and SYLVATAL™ D40 LR.

[0070] In preferred embodiments, the oligoester composition is derived from 5 wt% to 80 wt%, for example 10 to 70 wt% or 30 to 60 wt% rosin, based on the total weight of the components used to prepare the oligoester composition.

[0071] As described above, rosin contains a mixture of rosin acids (e.g., abietadienoic acids), which may contain conjugated double bonds in their ring systems. These conjugated double bonds can be a source of oxidative instability. Accordingly, in some embodiments, the rosin, oligoester, or combinations thereof are processed to reduce the percentage of components containing conjugated double bonds. The term "PAN Number," as used herein, refers specifically to the sum of the weight percentages of the palustric acid, abietic acid, and neoabietic acid moieties as obtained by hydrolysis from the oligoester, determined according to the method described in ASTM D5974-00 (2010).

[0072] In some embodiments, the oligoester may be derived from a rosin with a low PAN number. In some embodiments, the rosin obtained by hydrolysis from the oligoester may have a PAN number, determined according to the method described in ASTM D5974-00 (2010), of equal to or less than 25, for example, equal to or less than 15 or equal to or less than 5. The rosin obtained by hydrolysis from the oligoester may contain equal to or more than 30 wt.% dehydroabietic acid, for example, 30 to 60 wt.% or 40 to 55 wt.%, based on the total weight of the rosin. In some embodiments, the weight ratio of dehydroabietic acid to dihydroabietic acid in the rosin as obtained by hydrolysis from the oligoester is between 1:0.80 and 1:0.25, for example between 1:0.70 and 1:0.35, or alternatively between 1:0.55 and 1:0.40.

[0073] The oligoester composition described herein may further be derived from one or more polyhydric alcohols.

[0074] 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 polyhydric alcohols, based on the total weight of the components used to prepare the oligoester composition.

[0075] The at least one polyhydric alcohol may include any suitable polyhydric alcohols. In various embodiments, the one or more polyhydric alcohols may have an average hydroxyl functionality of 2 to 10, for example, from 2 to 7 or from 3 to 5. In certain embodiments, the one or more polyhydric alcohols comprise 2 to 36, for example, from 2 to 20 or from 2 to 8, carbon atoms. For example, the one or more polyhydric alcohols may have a boiling point of greater than 240°C at approximately 1013 mbar (1 atm).

[0076] Polyhydric alcohols may contain a combination of linear, branched, cyclic, aliphatic, partially unsaturated, or aromatic chemical moieties and may optionally contain one or more additional functional groups in addition to the two or more hydroxyl moieties, such as an alkyl (e.g., C1-3 alkyl), aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or keto group. In aromatic polyhydric alcohols, the aromatic ring may optionally contain one or more ring substituents, such as a fluoro, chloro, alkyl (e.g., methyl or ethyl), methoxy, or trifluoromethyl group. If desired, the one or more polyhydric alcohols may also contain one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the molecular structure, such asan ether group in the case of incorporation of an oxygen atom, or a thioether in the case of incorporation of a sulfur atom. In various embodiments, the one or more polyhydric alcohols comprise an aliphatic alcohol, e.g., a cycloaliphatic alcohol.

[0077] In some embodiments, the one or more polyhydric alcohols may comprise a polyol comprising a first hydroxyl group separated from a second hydroxyl group by 2 to 10 carbon atoms, alternatively by 2 to 7 carbon atoms, or alternatively by 3 to 5 carbon atoms. In some embodiments, the one or more polyhydric alcohols comprise a polyol wherein each hydroxyl group of the polyol is separated from the other hydroxyl group of the polyol by at least 2 carbon atoms, for example, by at least 3 carbon atoms or at least 6 carbon atoms.

[0078] 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, glycerin, 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, and lactitol. In certain embodiments, the one or more polyhydric alcohols can be selected from diethylene glycol, triethylene glycol, glycerin, trimethylolpropane, pentaerythritol, technical grade pentaerythritol, dipentaerythritol, polyglycerin, polyglycerol-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.

[0079] The oligoester composition described herein may be derived from one or more monocarboxylic acids. In various embodiments, the oligoester composition may 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.

[0080] 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 oils and animal oils, and combinations thereof.

[0081] In some embodiments, the at least one monocarboxylic acid(s) may contain at least six carbon atoms, for example, 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. Monocarboxylic acids may contain a combination of linear, branched, cyclic, aliphatic (cycloaliphatic), partially unsaturated, or aromatic or heteroaromatic chemical moieties and may optionally contain one or more additional functional groups in addition to the carboxylic acid moiety, such as a hydroxyl, alkyl (e.g., C1-3 alkyl), aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or keto group. In aromatic monocarboxylic acids, the aromatic ring may optionally contain one or more ring substituents, such as a fluoro, chloro, alkyl (e.g. methyl or ethyl), methoxy or trifluoromethyl group.If desired, the one or more monocarboxylic acids may further contain 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 an ether group in the case of incorporation of an oxygen atom or a thioether in the case of incorporation of a sulfur atom.

[0082] 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, and cerotic acid. An example of a suitable aromatic monocarboxylic acid is benzoic acid. Non-limiting examples of suitable cycloaliphatic monocarboxylic acids include cyclopropanecarboxylic acid, cyclopentanecarboxylic acid, and cyclohexanecarboxylic acid. Non-limiting examples of suitable unsaturated linear or branched monocarboxylic acids include linoleic acid, alpha-linolenic acid, elaidic acid, sapienic acid, arachidonic acid, myristoleic acid, palmitoleic acid, and oleic acid. Suitable fatty acids derived from vegetable oils (e.g., triglyceride vegetable oils) and animal fats and oils include:Palm oil, linseed oil, rapeseed oil, sunflower seed oil, olive oil, tung oil, peanut oil, cottonseed oil, palm kernel oil, soybean oil, corn oil, grapeseed oil, hazelnut oil, rice bran oil, safflower oil, sesame oil, butterfat, and coconut oil. These fatty acids include, for example, linoleic acid, alpha-linolenic acid, palmitic acid, stearic acid, myristic acid, and oleic acid. Non-limiting examples of natural fatty acids are tall oil fatty acid and its commercial products, such as isostearic acid.

[0083] In various embodiments, the at least one monocarboxylic acid may comprise oleic acid, linoleic acid, alpha-linolenic acid, palmitic acid, stearic acid, or combinations thereof. In certain embodiments, the at least one monocarboxylic acid may include a tall oil fatty acid (TOFA). Suitable TOFA-derived commercially available monocarboxylic acids include, but are not limited to, the CENTURY™ product line sold by Arizona Chemical, a subsidiary of Kraton Corporation, such as CENTURY™ D1, CENTURY™ MO5, CENTURY™ MO5N, and isostearic acid products such as CENTURY™ 1105 and CENTURY™ 1107.

[0084] Carboxylic acids and their derivatives can be characterized by their iodine value. In certain embodiments, the at least one monocarboxylic acid(s) can have an iodine value of less than 275 mg / g, optionally less than 180 mg / g, or less than 115 mg / g, or less than 80 mg / g, or optionally from 55 mg / g to 270 mg / g, or from 60 mg / g to 250 mg / g, or from 70 mg / g to 200 mg / g, as determined according to the method described in ASTM D5768-02 (2014).

[0085] Particularly preferably, the at least one monocarboxylic acid is a fatty acid, a tall oil fatty acid or a mixture thereof.

[0086] In various embodiments, the oligoester composition may optionally be further derived from one or more polycarboxylic acids.

[0087] The oligoester compositions may contain less than Q wt.% of one or more

[0088] Polycarboxylic acids, where Q is defined by the following formula

[0089] Polycarbon acids where Z denotes the mathematical summation 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 in the range of 2 to 4; and Y is the polycarboxylic acid weight fraction of the polycarboxylic acid and ranges from 0 to 1, with the sum of the weight fractions for the one or more polycarboxylic acids equal to 1. In other words, the Q value refers to the percentage of polycarboxylic acids in the total ester composition. For example, using 50 wt% of a dicarboxylic acid and 50 wt% of a tricarboxylic acid would result in a Q value of 10-2(2*0.5+3*0.5)=10-2(1+1.5)=10-2*2.5=5%. Similarly, using only dicarboxylic acid would result in a Q value of 6%. In some embodiments, Q can be defined by the following formula:

[0090] Polycarbon acids where Z denotes the mathematical summation 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 in the range of 2 to 4; and Y is the polycarboxylic acid weight fraction of the polycarboxylic acid and is in the range of 0 to 1, the sum of the weight fractions for the one or more polycarboxylic acids being equal to 1.

[0091] In various embodiments, the oligoester may be derived from 0 to 4 wt.%, for example from 0 to 3 wt.% or from 0 to 2 wt.% of polycarboxylic acids (i.e., 2 or more carboxylic acid functionalities), based on the total weight of the components used to prepare the oligoester composition.

[0092] In certain embodiments, the oligoester may be derived from 0 to 6 wt.%, optionally from 0 to 4 wt.%, or from 0 to 2 wt.% of one or more dicarboxylic acids (i.e., 2 carboxylic acid functionalities), based on the total weight of the components used to form the liquid resin b). In various embodiments, the oligoester composition is not derived from any polycarboxylic acid.

[0093] The at least one polycarboxylic acid may comprise any suitable polycarboxylic acids. In some embodiments, the one or more polycarboxylic acids may comprise a dicarboxylic acid; in some embodiments, the one or more polycarboxylic acids may comprise a tricarboxylic acid. In some embodiments, the one or more polycarboxylic acids may be a tetracarboxylic acid. In some embodiments, the one or more polycarboxylic acids comprise 2 to 54 carbon atoms, for example, 4-35 carbon atoms or 6-12 carbon atoms.

[0094] Polycarboxylic acids may contain a combination of linear, branched, cyclic, aliphatic (cycloaliphatic), unsaturated, partially unsaturated, heteroaromatic, or aromatic chemical units and may optionally contain one or more additional functional groups in addition to the two or more carboxylic acid units, such as a hydroxyl, alkyl (e.g., C1-3 alkyl), aryl (e.g., benzyl), alkoxy (e.g., methoxy), haloalkyl (e.g., trifluoromethyl), or a keto group. In aromatic polycarboxylic acids, the aromatic ring may optionally contain one or more ring substituents, such as a fluoro, chloro, alkyl (e.g., methyl or ethyl), methoxy, or trifluoromethyl group. If desired, the one or more polycarboxylic acids may also contain one or more heteroatoms (e.g., one or more oxygen, sulfur, or nitrogen atoms) incorporated into the molecular structure, such asan ether group in case of incorporation of an oxygen atom or a thioether in case of incorporation of a sulfur atom.

[0095] Non-limiting examples of suitable polycarboxylic acids include adipic acid, 3-methyladipic acid, succinic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, rosin dimer, isophthalic acid, terephthalic acid, phthalic acid, TOFA dimer, hydrogenated TOFA dimer, 2-(2-carboxyphenyl)benzoic acid, 2,5-furandicarboxylic acid, camphoric acid, cis-norbornene-endo-2,3-dicarboxylic acid, trimellitic acid, and combinations thereof. UNIDYME™ 30 is an example of a commercially available dimerized TOFA derivative suitable for use in the present disclosure.

[0096] The ratio of the weight of one or more polycarboxylic acids to the weight of the rosin and the one or more monocarboxylic acids may be less than 1:20, for example less than 1:50 or less than 1:100. In various embodiments, the weight ratio between the rosin and the one or more monocarboxylic acids may be between 60:40 and 10:85. The ratio of the weight of the rosin and the one or more monocarboxylic acids to the weight of the one or more polycarboxylic acids may be at least 6.5:1 or at least 15:1. In certain embodiments, the oligoester composition may, for example, contain from 30 wt% to 75 wt% of rosin, 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.

[0097] In one embodiment, the oligoester composition may be derived from 5 to 75 wt.% rosin, 15 to 85 wt.% of one or more monocarboxylic acids, or alternatively, from 7 to 40 wt.% of one or more polyhydric alcohols or from 0 to less than 4 wt.% of one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 15 to 75 wt.% rosin, from 36 to 80 wt.% of one or more monocarboxylic acids, from 9 to 35 wt.% of one or more polyhydric alcohols, and from 0 to less than 4 wt.% of one or more polycarboxylic acids. In one embodiment, the oligoester composition may be derived from 30 to 75 wt.% rosin, 25 to 60 wt.% of one or more monocarboxylic acids, 3 to 18 wt.% of one or more polyhydric alcohols, and 0 to less than 4 wt.% of one or more polycarboxylic acids. In one embodiment, the oligoester composition may contain from 5 to 75 wt.% rosin, from 15 to 85 wt.% of one or more monocarboxylic acids, from 7 to 40 wt.% of one or more polyhydric alcohols and from 0 to less than 6 wt.% of one or more dicarboxylic acids, wherein the dicarboxylic acid contains 2 to 35 carbon atoms.

[0098] More preferably, the reaction mixture for preparing the oligoester composition comprises ii) 25 wt% to 85 wt% of one or more monocarboxylic acids, iii) 7 wt% to 35 wt% of one or more polyhydric alcohols, and iv) optionally from more than 0 wt% to less than 4 wt% of one or more polycarboxylic acids, based on the total weight of the reactants used in the reaction mixture, wherein the reaction mixture preferably comprises 5 wt% to 75 wt% rosin.

[0099] In various embodiments, the oligoester composition described herein has a weight-average molecular weight Mw of 500 g / mol to 8000 g / mol, for example, from 700 g / mol to 8000 g / mol, from 1000 to 5000 g / mol, or from 1100 g / mol to 3000 g / mol, measured by gel permeation chromatography (GPC) according to ASTM D5296-05. In certain embodiments, less than 35 wt.%, for example, less than 20 wt.% or less than 13 wt.% of the oligoester composition has a molecular weight of less than 1000 g / mol, measured by gel permeation chromatography (GPC).

[0100] In various embodiments, the individual oligoester may be liquid, e.g., a viscous liquid, at 20°C and 1013 mbar (1 atm). The oligoester composition itself is preferably also liquid.

[0101] The oligoester composition described herein can be characterized by its glass transition temperature (Tg). Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) can be used to determine Tg values. Preferably, the Tg of the oligoester (composition) can be about 50°C lower than the softening point of the oligoester(s) (composition).

[0102] In certain embodiments, the oligoester composition may have a Tg value between -80°C and 100°C, for example -60°C and 80°C, or between -50°C and 40°C, or less than about 20°C as measured by DSC.

[0103] The oligoester composition may exhibit an improved Gardner color. In some embodiments, the oligoester has a pure Gardner color, determined by the method described in ASTM D1544-04 (2010), of 8 or less, for example, 6 or less, or 4 or less.

[0104] The oligoester composition may exhibit improved color stability. In some embodiments, the oligoester composition may exhibit less than a 10% change, for example, less than an 8% change, or less than a 5% change, in pure Gardner color, as determined according to the method described in ASTM D1544-04 (2010), when heated at a temperature of 160°C for a period of three hours. In certain embodiments, the pure Gardner color of the oligoester composition, as determined according to the method described in ASTM D1544-04 (2010), remains substantially unchanged (i.e., exhibits less than a 0.5% change in pure Gardner color) when the oligoester composition is heated at a temperature of 160°C for three hours.

[0105] The oligoester composition 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 exhibit an onset time of oxidation induction at 110°C, as measured using the methods specified in ASTM D5483-05(2010), ranging between 30 and 200 minutes, for example, between 70 and 150 minutes.

[0106] Optionally, the oligoester composition may have a low hydroxyl number. In some embodiments, the oligoester composition has a hydroxyl number 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 specified in DIN 53240-2 (a different solvent, tetrahydrofuran, was used). The hydroxyl number is expressed in mg KOH per gram of sample of the oligoester or oligoester composition.

[0107] Optionally, the oligoester composition may have a low acid number. In some embodiments, the oligoester composition has an acid number, determined according to the method described in ASTM D465-05 (2010), of 30 mg KOH / gram or less, for example, 15 mg KOH / gram or less, or 6 mg KOH / gram or less. The acid number is expressed in mg KOH per gram of sample of the oligoester or oligoester composition.

[0108] Suitable oligoester compositions and their properties are described, for example, in US 2017 / 0190935 A1.

[0109] Various methods can be used to prepare oligoester compositions. For example, the oligoester compositions described herein can be prepared by an esterification process in which the carboxylic acid-containing components of the oligoester are esterified with one or more polyhydric alcohols. An esterification reaction of this type is an equilibrium reaction. Removal of the water formed during the reaction can shift the reaction equilibrium in favor of product formation, thereby driving the reaction to completion. Accordingly, in some embodiments, processes for preparing oligoesters can comprise esterifying a mixture comprising one or more rosins, one or more monocarboxylic acids, and optionally one or more polycarboxylic acids with one or more polyhydric alcohols to form the oligoester composition.The esterification step may consist of reacting the mixture and the one or more polyhydric alcohols for a certain period of time and under suitable conditions to form the oligoester. Optionally, the esterification step may also comprise removing water formed as a by-product of the esterification reaction. Optionally, the esterification step may comprise contacting the mixture and the 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 comprise contacting the mixture and the one or more polyhydric alcohols in the absence of an esterification catalyst.

[0110] The oligoester compositions described herein can also be prepared by a transesterification process in which esters of the carboxylic acid-containing components of the oligoester are reacted with one or more polyhydric alcohols. In polyhydric alcohols that have reacted with carboxylic acids, some free, unreacted hydroxyl groups of the polyhydric alcohol may remain, which can react with the esters in a transesterification reaction, leading to an exchange of their alkoxy groups. Such a transesterification reaction is an equilibrium reaction in which new oligoester compositions can be formed.Accordingly, in some embodiments, methods for preparing oligoester compositions may comprise reacting one or more rosin esters having a hydroxyl value greater than zero with one or more esters derived from monocarboxylic acids and optionally one or more polycarboxylic acids. In some embodiments, an alcohol or a polyhydric alcohol may be added to initiate or accelerate such a transesterification reaction. Optionally, the transesterification step may comprise contacting the mixture and the 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 comprise contacting the mixture and the 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 oligoester that can be used in such a transesterification process are vegetable oils (e.g., triglyceride vegetable oils) and animal fats and oils, including oils such as palm oil, linseed oil, rapeseed oil, sunflower seed oil, olive oil, tung oil, peanut oil, cottonseed oil, palm kernel oil, soybean oil, corn oil, grapeseed oil, hazelnut oil, rice bran oil, safflower oil, sesame oil, butterfat, and coconut oil, as well as hydrogenated and deodorized oils. Other esters that can be used in such a transesterification process are rosin esters. Such esters can also be used in the interesterification process described below.

[0111] The oligoester compositions described here can also be prepared by an interesterification process that is mechanistically related to esterification and transesterification. Interesterification can be carried out by mixing different esters and subsequent rearrangement of the carboxylic acid residues over the polyhydric alcohol backbones used in the presence of a catalyst, e.g., an esterification catalyst. Interesterifications are equilibrium reactions. For example, a rosin ester can be reacted with a triglyceride ester, such as rapeseed oil. Such an interesterification reaction would yield an oligoester in which the fatty acid moieties in the triglyceride ester are partially substituted by rosin acid moieties and in which the rosin acid moieties in the rosin ester are partially substituted by fatty acid moieties.

[0112] The oligoester compositions described here can also be prepared by a combination of the esterification, transesterification, and interesterification processes described above, wherein 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 their partial esters or half-esters. An example of partial esters are partial glycerides, i.e., esters of glycerol with fatty acids in which not all hydroxyl groups are esterified. cis-HOOC-CH=CH-COOCH3 is an example of a half-ester of maleic acid. Adipic acid monomethyl ester and adipic acid monoethyl ester are examples of half-esters derived from adipic acid.As with the above methods, removal of water or volatile monoalcohols formed during the reaction can shift the reaction equilibrium in favor of product formation and thereby bring the reaction to completion.

[0113] For example, in certain embodiments, the manufacturing methods may comprise esterifying a mixture comprising one or more rosins, one or more monocarboxylic acids, and optionally one or more polycarboxylic acids with one or more polyhydric alcohols to form the oligoester composition. In some embodiments, the esterification step may comprise a thermal reaction of the mixture with the one or more polyhydric alcohols. For example, the esterification may comprise contacting the mixture with the one or more polyhydric alcohols at an elevated temperature (e.g., at a temperature of from 30°C to 300°C or from 150°C to 285°C). Optionally, the esterification step may further comprise removing water formed as a by-product of the esterification.

[0114] In various embodiments, catalysts, co-catalysts, solvents, bleaching agents, stabilizers and / or antioxidants may be added during the esterification, transesterification and interesterification reactions.

[0115] The pressure-sensitive adhesive composition according to the invention contains the at least one liquid resin b) which comprises or consists of the oligoester composition, or a combination of those as described herein, preferably in an amount of 1 to 50 wt.%, more preferably 2 to 40 wt.%, even more preferably 5 to 40 wt.%, even more preferably 5 to 30 wt.%, in particular 10 to 30 wt.%, for example 15 to 30 wt.%, 10 to 25 wt.% or 15 to 20 wt.%, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0116] 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 improve wetting. Common plasticizers used in this context include medicinal white oils, naphthenic mineral oils, adipates, polypropylene, polybutylene, and polyisoprene oligomers, hydrogenated polyisoprene and / or polybutadiene oligomers, benzoate esters, phthalates, vegetable or animal oils and their derivatives, sulfonic acid esters, mono- or polyhydric alcohols, and polyalkylene glycols, such as polypropylene glycol, polybutylene glycol, or polymethylene glycol. Polybutylene oligomers should have a molecular weight of 200 to 6,000 g / mol, while polyolefins should have a molecular weight Mw of up to approximately 2,000 g / mol, in particular up to 1,000 g / mol.

[0117] 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, paraffin oils, or vegetable oils.

[0118] 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), which comprises an isobutene / butene copolymer. These components are used together to partially, predominantly, or completely replace conventional plasticizers, such as those mentioned 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.

[0119] The isobutene / butene copolymers used here are synthetic hydrocarbons derived from the polymerization of the C4 fraction. By varying the polymerization parameters, polymers with different chain lengths are created. This variation in chain length influences the physical properties.

[0120] The at least one further plasticizer c) or the isobutene / butene copolymer can be characterized by its molecular weight. To determine the M n size exclusion chromatography (GPC, gel permeation chromatography) can be used. In various embodiments, the plasticizer c) or the isobutene / butene copolymer has a number-average molecular weight M nof 750-1450 g / mol, preferably 850-1350 g / mol, in particular 900-1300 g / mol. This distinguishes the plasticizer c) used according to the invention, for example, from plasticizer oils, e.g., polybutene oil. Oils typically have a lower number-average molecular weight of, for example, 480 g / mol.

[0121] Furthermore, the at least one plasticizer c) or the isobutene / butene copolymer can be characterized by its glass transition temperature (Tg). Differential scanning calorimetry (DSC) can be used to determine the Tg values. The 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 the 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.

[0122] In various embodiments, the at least one plasticizer c) or the isobutene / butene copolymer has a kinematic viscosity of 0.00018 - 0.0007 m 2 / s (180 to 700 cSt), preferably 0.00019 to 0.00067 m2 / s (190 to 670 cSt), especially 0.0002 to 0.000655 m 2 / s (200 cSt-655 cSt) determined according to ASTM D445 at 100 °C.

[0123] Suitable isobutene / butene copolymers are available for purchase, for example, under the names Polybutene (PB) 1300 from Daelim Industrial or Indopol H300 from Ineos.

[0124] It is preferred that the pressure-sensitive adhesive composition contains no further plasticizers besides the described combination of liquid resin b) and further plasticizer c). Such pressure-sensitive adhesive compositions preferably exhibit improved adhesive strength and / or adhesion to various substrates.

[0125] In particular, the described liquid resin b) in combination with the at least one further plasticizer c) partially or completely replaces conventional mineral oil-based plasticizers (e.g. naphthenic oil and / or paraffinic oil) in the pressure-sensitive adhesive composition according to the invention.

[0126] Mineral oils are typically produced by distilling crude oil and, if necessary, other fossil fuels. Mineral oils include, for example, paraffinic, naphthenic, and aromatic hydrocarbons, alkenes, as well as sulfur- and nitrogen-containing or organic compounds. The term "naphthenic oil" refers specifically to saturated cyclic hydrocarbons. "Paraffinic oil" refers specifically to saturated chain hydrocarbons.

[0127] 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.%, of mineral oil-based plasticizers, in particular naphthenic and / or paraffinic oils, and most preferably it is free of these, based on the total weight of the pressure-sensitive adhesive composition.

[0128] In a preferred embodiment, the at least one mineral oil-based plasticizer, preferably the naphthenic and / or paraffinic oil (or the required amount of plasticizer) is replaced to at least 50%, more preferably to at least 60%, even more preferably to at least 70%, even more preferably to at least 80%, even more preferably to at least 90%, even more preferably to at least 95%, even more preferably to at least 98%, even more preferably to at least 99% and most preferably to 100% in the pressure-sensitive adhesive composition by the at least one liquid resin b) and the at least one further plasticizer c), as described herein.

[0129] In a further preferred embodiment, the pressure-sensitive adhesive composition has a proportion of renewable raw materials 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.%, most preferably at least 99 wt.%, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0130] The pressure-sensitive adhesive composition according to the invention may, in addition to the at least one liquid resin b), further contain at least one further resin d).

[0131] Resins are typically used to change, preferably lower, the viscosity of the pressure-sensitive adhesive composition according to the invention and to influence the odor, the (initial) color and the color stability of the composition, as well as the tackiness and polarity of the polymers optionally present.

[0132] These are, in particular, resins that have a softening point of 35 to 160°C or up to 130°C (ring-ball method, DIN 52011). Suitable resins include, but are not limited to, aromatic, aliphatic, or cycloaliphatic hydrocarbon resins, as well as modified or hydrogenated versions thereof. Specific examples are: aliphatic or alicyclic petroleum hydrocarbon resins and hydrogenated derivatives thereof. Other resins that can be used within the scope of the 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 such as resin acids from balsam resin, tall oil resin, or wood resin, e.g., fully saponified balsam resin; alkyl esters of optionally partially hydrogenated rosin with low softening points, such as, for example,Methyl, diethylene glycol, glycerol, and pentaerythritol esters; terpene resins, in particular terpolymers or copolymers of terpenes, such as styrene terpenes, α-methyl styrene terpenes, phenol-modified terpene resins, and hydrogenated derivatives thereof; acrylic acid copolymers, preferably styrene-acrylic acid copolymers, and resins based on functional hydrocarbon resins, for example having 3 to 8 carbon atoms, in particular 5 carbon atoms, wherein the at least one resin d) differs from the liquid resin b) described herein, in particular is not a liquid resin. Particularly preferably, the at least one resin d) is a solid resin. "Solid," as used in this context, means that the resin is solid at 20°C and 1013 mbar, i.e., it is not flowable and is not present as a liquid with a yield point, but rather as a solid.

[0133] Preferably, the at least one resin d) is a natural resin or a hydrogenated and / or non-hydrogenated hydrocarbon resin, more preferably a tall oil ester, gum rosin (colophony ester), an optionally partially polymerized tall oil resin, a terpene or a crude oil-based aliphatic, aromatic or cycloaliphatic hydrocarbon resin, as well as modified or hydrogenated versions thereof, for example C5-aliphatic or C9-aromatic hydrocarbon resin or a C5 / C9 monomer mixture, wherein the at least one resin d) differs from the liquid resin b) described herein, in particular is not a liquid resin, but for example a solid resin.

[0134] The pressure-sensitive adhesive composition particularly preferably comprises at least one resin d), preferably two resins, in particular selected from rosin esters, for example pentaerythritol esters (from tall oil rosin), and / or (cyclo)aliphatic hydrocarbons, for example having 1 to 30 carbon atoms (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), e.g. 10 to 25 carbon atoms. The (cyclo)aliphatic hydrocarbons can, in various embodiments, contain a combination of linear, branched, cyclic aliphatic (cycloaliphatic), partially unsaturated or aromatic or heteroaromatic chemical radicals and can optionally contain one or more functional groups, such as, for example, a hydroxyl, alkyl, aryl, alkoxy, haloalkyl, or a keto group, without being limited thereto. Resins with low coloration and good color stability are particularly suitable.

[0135] 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 (ring-ball method, ASTM D36, glycerol) between 70 and 110°C, preferably between 85 and 106°C, for example 85 to 100°C.

[0136] In a particular embodiment, 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.

[0137] Both solid and liquid resins can be used in accordance with the invention. In preferred embodiments, however, at least one resin d) is a solid resin in addition to the liquid resin b) described herein.

[0138] The pressure-sensitive adhesive composition according to the invention may further comprise at least one additive e). Suitable additives include, but are not limited to, components from the group consisting of antioxidants, in particular stabilizers, waxes, UV protectors, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners, and fragrances.

[0139] Preferably, the at least one additive e) is present in the pressure-sensitive adhesive composition in an amount of 0.01 to 20 wt.%, more preferably in 0.1 to 5 wt.%, even more preferably in 0.5 to 3 wt.%, based on the total weight of the pressure-sensitive adhesive composition.

[0140] Antioxidants such as stabilizers are particularly preferably used in the pressure-sensitive adhesive composition according to the 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.%. They are used, for example, to protect against thermal and oxidative degradation caused by oxygen and UV radiation. Furthermore, antioxidants can improve thermal stability and / or color stability.

[0141] When using stabilizers, it is important to ensure compatibility with the pressure-sensitive adhesive composition. For example, antioxidants available under the trade name Irganox® (BASF SE) can be used as stabilizers, preferably in amounts of 0.5 to 1.5 wt.%, for example 1 wt.%, based on the total weight of the composition.

[0142] In various embodiments, waxes can optionally be added to the pressure-sensitive adhesive composition in amounts of 0.5 to 5 wt.%. The amount is calculated such that, on the one hand, the viscosity is reduced to the desired range, but on the other hand, adhesion is not negatively affected. The wax can be natural, optionally also in chemically modified form, or of synthetic origin. Natural waxes can be vegetable waxes, animal waxes, mineral waxes, or petrochemical waxes. Chemically modified waxes can be hard waxes such as montan ester waxes, Sasol waxes, etc. Polyalkylene waxes and polyethylene glycol waxes are used as synthetic waxes. Petrochemical waxes such as petrolatum, paraffin waxes, microcrystalline waxes, and synthetic waxes are preferably used.Particularly preferred are paraffinic and / or microcrystalline waxes and / or hydrogenated versions thereof, in particular polypropylene or polyethylene wax with a dropping point determined according to ASTM D-3954 of 50°C to 170°C.

[0143] The consistency of the pressure-sensitive adhesive composition according to the invention can be adjusted according to the respective requirements, for example by adding suitable solvents. In various embodiments, the pressure-sensitive adhesive composition according to the invention further comprises one or more solvents.

[0144] However, given the considerable ecological and economic requirements associated with the use of organic solvents in particular, it is advantageous to avoid the use of solvents. Therefore, an embodiment in which the pressure-sensitive adhesive composition according to the invention is free of solvents is preferred. The use of solvents can be dispensed with entirely or partially if the amount of liquid resin b) used is selected accordingly.

[0145] In a preferred embodiment, the pressure-sensitive adhesive composition according to the invention is solvent-containing, solvent-free or a dispersion.

[0146] 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 which is a 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 rosins; c) at least one further plasticizer, wherein the at least one further plasticizer comprises an isobutene / butene copolymer;and d) at least one resin, preferably two resins, more preferably a rosin ester such as, for example, pentaerythritol resin ester, and / or a (cyclo)aliphatic hydrocarbon resin, for example having 1 to 30 or 6 to 30 carbon atoms, wherein this resin differs from the liquid resin b) described herein, in particular is not a liquid resin, but preferably is a solid resin; e) at least one additive, preferably a stabilizer; wherein the components are preferably used in the pressure-sensitive adhesive composition as described below: 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%, in particular 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 from 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.%, more preferably 0.5 to 3 wt.%; based on the total weight of the pressure-sensitive adhesive composition.;

[0147] In various embodiments, the pressure-sensitive adhesive composition according to the invention does not contain a betulin-based polyester polyol, as described, for example, in EP3878883A1. High demands are placed on food packaging in particular, as well as on the substances used in its production. In addition to mechanical properties, health aspects are particularly important. Within the scope of the present invention, it was surprisingly found that the use of a liquid resin b), as described herein, together with at least one plasticizer c), as described herein, can prevent the formation of so-called critical migratory cycles. Critical migratory cycles are understood to mean compounds that are capable of migrating from the adhesive into the packaging material or the packaged product, for example a foodstuff, and that thus have a potential to be harmful to health.Therefore, an embodiment of the pressure-sensitive adhesive composition according to the invention is preferred in which the proportion of critical migratable constituents in the pressure-sensitive adhesive composition is less than 300 ppm, preferably less than 200 ppm and particularly preferably less than 50 ppm, where the ppm denotes proportions by weight and the data relate to the total weight of the pressure-sensitive adhesive composition.

[0148] In preferred embodiments, the liquid resin b) and / or the plasticizer c) described herein have a molecular weight such that they exhibit only low volatility and thus low migration capacity.

[0149] Particularly preferably, the liquid resin b) and / or the plasticizer c) described herein contain only components that are approved for contact with food.

[0150] In preferred embodiments of the pressure-sensitive adhesive composition according to the invention, the liquid resin b) described herein, in combination with the further plasticizers c) described herein, partially or completely replaces migratable naphthenic oils or other mineral oils. The liquid resin preferably comprises or consists of an oligoester composition as described herein. Due to the described property of the oligoester composition, with the liquid resin described herein, preferably no or greatly reduced migration of components from the adhesive into materials, such as, for example, packaging materials or into the packaged product, occurs compared to migratable naphthenic or white medicinal paraffinic oils. This preferably also applies to the at least one plasticizer as described herein.

[0151] Furthermore, by replacing mineral oils, such as naphthenic oils and / or paraffinic oils, with the liquid resin b) described herein, the proportion of renewable raw materials in the formulation is increased.

[0152] The pressure-sensitive adhesive composition of the invention preferably has a lower viscosity compared to other adhesive compositions, allowing it to be applied at lower temperatures. This leads to energy and cost savings for the customer. In a preferred embodiment, the pressure-sensitive adhesive of the invention has a Brookfield viscosity (e.g., measurable at 20 RPM with spindle 27) at 160°C 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 softening point of the pressure-sensitive adhesive according to the invention is above 90°C (ring-ball method, ASTM D36, glycerin).

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

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

[0156] In preferred embodiments, the pressure-sensitive adhesive composition according to the invention further exhibits improved adhesion to various substrates, for example plastic, glass, nonwoven fabric, cardboard or steel, whereby preferably a smaller amount of the pressure-sensitive adhesive composition is required compared to known pressure-sensitive adhesive compositions.

[0157] To test the adhesive strength of the pressure-sensitive adhesive composition according to the invention, a peel test can be performed. The peel force is typically the average force required to separate two adhered materials. The test is generally performed at a 90° or 180° angle, depending on the material.

[0158] In preferred embodiments, 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 using the FINAT FTM1 test method. In other embodiments, the pressure-sensitive adhesive composition according to the invention has a peel force on highly branched (LD) polyethylene of at least 15 N / 25 mm PET coating, preferably of at least 18 N / 25 mm PET coating, more preferably of at least 20 N / 25 mm PET coating, in particular of at least 21 N / 25 mm PET coating, for example of at least 22 N / 25 mm PET coating. In preferred embodiments, the pressure-sensitive adhesive composition according to the invention has a peel force on nonwoven fabric of at least 10 N / 25 mm PET coating, preferably of at least 12 N / 125 mm PET coating.In further preferred embodiments, the pressure-sensitive adhesive composition has a peel force on cardboard of at least 15 N / 25 mm PET coating, preferably of at least 18 N / 25 mm PET coating. These measurements all refer to the use of an angle of 180°, measured by the FINAT FTM1 test method. Furthermore, the adhesive strength of the pressure-sensitive adhesive composition according to the invention can be determined by means of the loop tack test. The determined values ​​refer to a 25 mm x 25 mm PET coating. In preferred embodiments, the pressure-sensitive adhesive composition according to the invention has an adhesive strength (loop tack) on steel of at least 40 N, preferably of at least 43 N, more preferably of at least 45 N, even more preferably of at least 46 N, in particular of 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 of at least 40 N, even more preferably of at least 42 N, and in particular of at least 43 N. In preferred embodiments, the composition has an adhesive strength on LD polyethylene of at least 20 N, preferably of at least 22 N, in particular of at least 23 N.

[0159] The present invention further provides a process for producing the pressure-sensitive adhesive composition according to the invention, comprising mixing the at least one liquid resin b), as described herein, with further components of the pressure-sensitive adhesive composition, such as the at least one polymer a) and the at least one plasticizer c) and optionally further components such as at least one resin d) and / or at least one additive e), in a suitable order; preferably at a temperature of 100 to 200°C, more preferably at 120 to 180°C, even more preferably at 150 to 170°C.

[0160] In a preferred embodiment, the other components of the pressure-sensitive adhesive composition, such as polymer a) and resin d), are first prepared and mixed before the liquid resin b) is added. The plasticizer c) or additive e) can then be added.

[0161] A preferred mixing sequence for the process for preparing the pressure-sensitive adhesive composition according to the invention is:

[0162] 1 . Presenting at least one polymer a),

[0163] 2. if necessary, adding at least one resin d), preferably two resins,

[0164] 3. Adding the at least one liquid resin b) as described herein,

[0165] 4. Adding at least one plasticizer c),

[0166] 5. optionally adding at least one additive, for example at least one stabilizer, preferably at a temperature of 100 to 200°C, more preferably at 120 to 180°C, even more preferably at 150 to 170°C.

[0167] Preferably, the individual components for preparing the pressure-sensitive adhesive composition according to the invention are as described herein.

[0168] A further object of the present invention is the use of the pressure-sensitive adhesive composition according to the invention in tapes, labels, hygiene articles such as diapers, labeling, e.g. of beverage bottles, flexible packaging, films, food packaging, in the field of assembly (high performance, such as in the automotive industry), medical applications (e.g. in packaging for medical materials and products) and / or in the graphic industry (e.g. books, magazines, brochures).

[0169] The pressure-sensitive adhesives according to the invention are used, for example, for bonding substrates such as glass, metal, e.g. steel, fabrics, non-wovens, coated or uncoated paper, cardboard and plastics, such as e.g. PET, PEN, PE, PP, PVC and PS. Thin, flexible substrates, for example made of films, multilayer films or paper, are then bonded to such solid substrates. These are, for example, labels, outer packaging, bags, etc. These can be made, for example, from plastics, e.g. polyethylene, polypropylene, polystyrene, polyvinyl chloride or cellophane, in particular from PE films. Furthermore, the labels can also be paper-based, optionally in combination with polymer films. The hotmelt pressure-sensitive adhesives according to the invention are notable in particular for very good adhesion to the aforementioned plastics, and these can also be removed again from the substrate surfaces.

[0170] Further fields of application are described, for example, in the international patent publication WO 2016 / 062797 A1 , in particular pages 10-11 .

[0171] In a preferred embodiment, the amount of pressure-sensitive adhesive composition applied 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 .

[0172] In a preferred embodiment, the substrates may optionally be subjected to a pretreatment and / or the two substrates may be joined together under pressure.

[0173] The present invention further provides an article comprising the pressure-sensitive adhesive composition of the invention. In a preferred embodiment, the article is obtainable by the process of the invention. The article is preferably a multilayer substrate, in particular for packaging for food and pharmaceutical products, for hygiene articles, in the label and labeling sector, but also for use in the automotive industry or the graphic arts industry.

[0174] All facts, subject matter, and embodiments described for the pressure-sensitive adhesive composition of the invention also apply to the processes of the invention, the article of the invention, and the use of the invention. Therefore, express reference is made here to the disclosure at the appropriate point, with the note that this disclosure also applies to the use of the invention, the article of the invention, and the processes of the invention.

[0175] The invention is illustrated below by examples, but is not limited to them. Examples

[0176] Example 1

[0177] The preparation of a liquid resin pressure sensitive adhesive comprising an oligoester composition as described herein:

[0178] The listed raw materials were formulated according to the mixing sequence listed in the table below at the specified temperature. The adhesive was mixed using a propeller mixer at a rotation speed of 50–500 rpm.

[0179] Table 1 : Formulation 1

[0180] 1 : radial styrenic block copolymer with narrow molecular weight distribution, available from TSRC Corporation, USA

[0181] 2: stabilized pentaerythritol ester of tall oil rosin, available from Kraton Corporation, USA

[0182] 3: cycloaliphatic hydrocarbon resin, available from ExxonMobil, USA

[0183] 4: Mixture of phenolic antioxidant (Irganox® 1010) and a secondary phosphite antioxidant (Irgafos® 168), available from BASF, Germany.

[0184] The adhesive of the invention exhibits increased adhesion to various substrates with a reduced application weight. As a result, significantly less adhesive can be used to meet application requirements compared to Reference Adhesive 1. This leads to energy and cost savings for the customer. Table 2: Physical Properties

[0185] The coatings required for adhesion tests are produced on a laboratory scale on a heated coating table. This table is equipped with a heated and movable squeegee with which the adhesive can be drawn across the table. The layer thickness is adjusted using two adjusting screws for coarse adjustment and two more for fine adjustment. The gap width between the squeegee and the heating plate is displayed using two pressure gauges, which rest on the squeegee above the adjusting screws. The gap width can be read in micrometers on a scale. The coating is applied to silicone paper, which is vacuum-sealed to the plate. Once the adhesive layer has been applied, it is rolled onto a PET film. After checking the application weight with a maximum deviation of ±10% and allowing it to rest for 24 hours, the produced coating can be used for testing.The coatings were applied with a 50 pm thick PET film and a coating weight of 40 g / m. 2 made.

[0186] The following table shows 180° peel and loop tack bond strengths on various substrates. The mineral oil-free adhesive with a liquid resin comprising an oligoester composition, as described herein, shows improved values ​​compared to the mineral oil-free pressure-sensitive adhesive with a polyester polyol based on betulin (EP3878883A1) and is comparable to a good labeling and all-rounder pressure-sensitive adhesive (Reference 1). Table 3: Pressure-sensitive adhesive properties

Claims

Patent claims 1. Pressure-sensitive adhesive composition comprising a) at least one polymer; b) at least one liquid resin comprising an oligoester composition that is a 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 rosins; c) at least one further plasticizer, wherein the at least one further plasticizer comprises an isobutene / butene copolymer; d) optionally at least one further resin; and e) optionally at least one additive, preferably at least one stabilizer.

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 acrylate, polyester, urethane, ethylene acrylate, 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, particularly preferably a styrene block copolymer such as a styrene and styrene-butadiene copolymer (SBC or SBS, SBR), a styrene-isoprene copolymer (SIS), a styrene-ethylene / butylene copolymer (SEBS), a styrene-ethylene / propylene-styrene copolymer (SEPS) or a styrene-isoprene-butylene copolymer (SIBS), most preferably a styrene-isoprene-styrene triblock copolymer, a styrene-butadiene copolymer (SBC) and / or an ethylene-vinyl acetate copolymer (EVA) or a mixture thereof, wherein the polymer a) is particularly in an amount of 10 to 70 kg%, preferably 15 to 70 wt.%, more preferably 20 to 70 wt.%, is contained in the composition, based on the total weight of the composition.

3. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the reaction mixture for producing the oligoester composition 25 wt.% to 85 wt.% of one or more monocarboxylic acids, comprising 7 wt.% to 35 wt.% of one or more polyhydric alcohols, and optionally more than 0 wt.% to less than 4 wt.% of one or more polycarboxylic acids, wherein the reaction mixture comprises 5 wt.% to 75 wt.% rosin.

4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein rosin comprises a mixture of rosin acids, preferably C20 tricyclic monocarboxylic acids and isomers thereof, in particular the rosin acids are selected from the group consisting abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid, and palustric acid, as well as their isomers. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the at least one liquid resin b) is contained in the pressure-sensitive adhesive composition in an amount of 1 to 50 wt.%, more preferably 2 to 40 wt.%, and even more preferably 5 to 40 wt.%, in particular 5 to 30 wt.%, based on the total weight of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the at least one further plasticizer c) i) is contained 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) a number-average molecular weight M nhas a viscosity of 750–1450 g / mol, preferably 850–1350 g / mol, particularly 900–1300 g / mol, as measured by size exclusion chromatography (GPC, gel permeation chromatography); and / or iv) has a glass transition temperature (Tg) of -60 to -73°C, more preferably -63 to -73°C, particularly -66 to -70°C, as measured by differential scanning calorimetry (DSC); and / or v) has a kinematic viscosity of 0.00018–0.0007 m 2 / s (180 to 700 cSt) has, preferably 0.00019 to 0.00067 m 2 / s (190 to 670 cSt), in particular 0.0002 to 0.000655 m 2 / s (200 cSt-655 cSt), determined according to ASTM D445 at 100 °C. The pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive composition comprises no other plasticizers besides the isobutene / butene copolymer plasticizer c). The pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the at least one further resin d) comprises a natural resin or a hydrocarbon resin, more preferably a tall oil ester, gum rosin (rosin ester), a tall resin, optionally partially polymerized, a terpene or a crude oil-based aliphatic, aromatic or cycloaliphatic hydrocarbon resin, as well as modified or hydrogenated versions thereof, for example a C5 aliphatic or C9 aromatic hydrocarbon resin or a C5 / C9 monomer mixture, wherein the resin differs from the liquid resin, is preferably a solid resin, and is preferably in an amount of 10 to 70 wt.%, more preferably 15 to 60 wt.%.%, contained in the pressure-sensitive adhesive composition, based on the total weight of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the at least one further resin d) comprises at least two further resins, the resins preferably being (cyclo)aliphatic hydrocarbons with, for example, 1 to 30 carbon atoms. (aliphatic) or 6 to 30 carbon atoms (cycloaliphatic), and / or rosin esters, for example pentaerythritol esters, are selected, wherein the at least one further resin d) is preferably a solid resin. The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the at least one additive e) comprises at least one substance from the group consisting of antioxidants such as stabilizers, waxes, UV protectors, solvents, adhesion promoters, fillers, pigments, flame retardants, UV absorbers, optical brighteners and perfumes, in particular the at least one additive e) is contained in an amount of 0.01 to 20 wt.%, preferably 0.1 to 5 wt.%, in the pressure-sensitive adhesive composition, based on the total weight of the pressure-sensitive adhesive composition.A method for producing the pressure-sensitive adhesive composition according to any one of claims 1 to 10, comprising mixing at least one liquid resin b) according to any one of the preceding claims with further components of the pressure-sensitive adhesive composition, such as the at least one polymer a) and the 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 a suitable sequence; preferably at a temperature of 100 to 200°C, more preferably at 120 to 180°C, and even more preferably at 150 to 170°C. Use of the pressure-sensitive adhesive composition according to any one of claims 1 to 10 in tapes, labels, hygiene articles such as diapers, labeling, e.g., of beverage bottles, flexible packaging, food packaging, cardboard boxes or shipping bags, in packaging for medical materials and products, in the field of assembly (high performance, e.g.,in the automotive industry), and / or in the graphic arts industry (e.g., books, magazines, brochures). Article comprising an adhesive composition according to one or more of claims 1 to 10. Method for bonding at least two substrates, wherein the adhesive composition according to one of claims 1 to 10 is applied to at least one substrate and the at least two substrates are then joined together.

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