Biobased, eco-friendly hotmelt adhesive

Abstract

To provide an eco-friendly hotmelt adhesive based on renewable raw materials.SOLUTION: A hotmelt adhesive formulation of the present embodiment is made up of biobased polyesters (specifically a combination of polylactide and polybutylene succinate) and also of resins, plasticizers and stabilizers. Further additives may be added as well as necessary (for example waxes, fumed silica, lime or color pigments). The raw materials used are sustainable, biodegradable and unhazardous to nature. The adhesive of the present embodiment exhibits very good adhesion to wood, paper, cardboard and certain, predominantly non-polar plastics (such as PMMA, ABS, PC, PLA or PET) and can be applied with the commonplace systems.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The use of renewable raw materials is becoming increasingly important. Driving forces for this development include climate change and the need to use petroleum-independent resources. The present invention describes environmentally friendly hot melt adhesives based on the bio-based polyesters polylactide (PLA) and polybutylene succinate (PBS). [Background technology]

[0002] German Utility Model No. 202006001693 (U1) discloses an adhesive tape based on renewable raw materials. The tape comprises a film composed of a blend of polylactic acid (PLA) and at least one aliphatic-aromatic copolyester. A layer of a pumpable, water-containing adhesive compound is applied to the film. This layer is then dried. Specifically, a pressure-sensitive adhesive containing polylactic acid, epoxidized soybean oil, polybutylene succinate, and citric acid is disclosed, which is fluidized before application. In contrast, hot melt adhesives are solvent-free and water-free adhesives based on thermoplastic polymers. These polymers are solid at room temperature and soften upon heating to form a viscous fluid, which allows them to be applied as a melt. Upon cooling to room temperature, the hot melt adhesive undergoes reversible solidification while simultaneously developing adhesive strength. Further components of conventional hot melt adhesives are resins, waxes, plasticizers, stabilizers, and fillers. The most common areas of use for conventional hot melt adhesives are the packaging industry, the hygiene industry, the bookbinding industry, the wood and furniture industry and the do-it-yourself sector.

[0003] Currently commercially available semi-bio-based hot melt adhesives contain a high proportion of bio-based resins and waxes. The use of bio-based resins and waxes has been state of the art for decades. However, the base polymers used are almost exclusively petroleum-based.

[0004] Intercol BV sells a bio-based hot melt adhesive made from 70% natural ingredients.

[0005] Jowat SE sells a bio-based hot melt adhesive made from 50% natural ingredients under the trade name Jowatherm® GROW.

[0006] Henkel sells bio-based hot melt adhesives under the trade name Technomelt® Supra ECO. Despite the high proportion of renewable raw materials, the base polymer is synthetic.

[0007] WO 2015 / 153226 describes a bio-based hot melt adhesive. The base polymer is PLA. Apart from this, no additional bio-based polymers, nor bio-based rosin or terpene resins, are used as tackifiers or bio-based plasticizers.

[0008] WO 2013 / 162058 describes environmentally friendly hot melt adhesives. In addition to bio-based raw materials, petroleum-based raw materials are also described in this case.

[0009] WO 2002 / 053376 describes a PLA-based biodegradable and compostable hot melt adhesive, but no further bio-based polymers or bio-based rosin or terpene resins are used as tackifiers.

[0010] US Patent No. 9,428,645 describes environmentally friendly hot melt adhesives based on bio- and petroleum-based raw materials.

[0011] US Patent Application Publication No. 2014 / 0329065 relates to a biodegradable film having a print layer, a resin layer, an adhesive layer, and optionally a carrier layer. The carrier layer preferably consists of paper, cotton fabric, or a fiber web. Polylactide (PLA) is part of the resin layer and / or adhesive layer. The polylactide may be blended with a number of natural or synthetic polymers, including polybutylene succinate (PBS). A plasticizer (e.g., citric acid, citric acid esters, epoxidized vegetable oils, fatty acid esters, polyethylene glycol esters, or glycerol esters) may also be present. The adhesive layer forms the outer surface of the biodegradable film.

[0012] Bio-based polyesters (such as PLA or PBS) generally lack sufficient compatibility with commercially used resins. Furthermore, compared to commonly used polymers (such as EVA or PO), bio-based polyesters are brittle and have high viscosity, meaning that commercially equivalent hot melt adhesives based on bio-based polyesters have not been successfully developed to date.

[0013] PLA and PBS are not currently used for formulating hot melt adhesives and pressure sensitive hot melt adhesives. The base polymers used are exclusively ethylene-vinyl acetate (EVA), certain polyolefins (PO), and styrene-butadiene copolymers (SBC). These polymers have been optimized for hot melt adhesives for the last few decades.

[0014] PLA and PBS are currently primarily used for injection-molded parts and flexible packaging. In contrast to the amount of commercially available types of these polymers, only a few different types of PBS and some types of PLA are available. Poor flexibility compared to conventional polymers, high melting points, and high melt viscosities are problems, all of which are of great importance for hot-melt adhesives. Furthermore, compatibility with other components (resins, waxes) presents an additional challenge. Compatibility with polymers must be considered, as must the associated effects on curing, flow, and solidification properties, as well as the interactions of polymer components at phase boundaries. These factors have a substantial impact on the morphology that occurs during manufacturing. The number, size, and morphology of the phases present, as well as their interactions with each other, exert reliable constraints on macroscopic properties. Formulations suitable for use as hot-melt adhesives are only those with good compatibility—in other words, no phase separation or demixing of the individual components.

[0015] Moreover, bio-based polyesters are susceptible to hydrolytic chain degradation, which occurs particularly at relatively high temperatures over relatively long periods of time. Summary of the Invention

[0016] It is an object of the present invention to produce a PLA and PBS based hot melt adhesive that overcomes the drawbacks described in the prior art (such as low flexibility and high melting point) and that will nevertheless be fully biodegradable.

[0017] The object of the present invention is achieved by utilizing a combination of PLA and PBS as base polymer for hot melt adhesives, which is processed with correspondingly adapted resins, plasticizers and stabilizers to give a completely bio-based hot melt adhesive. Optionally, the addition of further fillers (such as waxes, fumed silica, lime or color pigments) is possible.

[0018] The subject of the present invention is therefore a hot melt adhesive formulation comprising the following components: A glass transition temperature greater than 50°C, a melt flow index greater than 25 g / 10 min measured at a temperature of 210°C using a load of 2.16 kg, and a weight average molecular weight M in the range of 120,000 to 280,000 g / mol. W , and 19.2 to 21.1 (J / cm 3 ) 0.5 at least one polylactide having a Hansen solubility parameter of 0.05 to 0.15 wt. % relative to the total weight of the hot melt adhesive formulation; Melt flow index of 3 to 26 g / 10 min, measured at 190°C with a load of 2.16 kg, and weight average molecular weight M in the range of 60,000 to 190,000 g / mol W , and 20.1 to 21.2 (J / cm 3 ) 0.5 at least one polybutylene succinate having a Hansen solubility parameter of 10 to 55% by weight relative to the total weight of the hot melt adhesive formulation; Melt temperature between 60 and 150°C, melt viscosity at 140°C between 80 and 24,000 mPa·s, and 16.0 to 21 (J / cm 3 ) 0.5 at least one naturally occurring resin having a Hansen solubility parameter between 0.01 and 0.1, and in a proportion of 30 to 55% by weight relative to the total weight of the hot melt adhesive formulation; at least one tri(C2-C8) alkyl ester of citric acid or tri(C2-C8) alkyl ester of acetylcitric acid as plasticizer, in a proportion of 5 to 15% by weight relative to the total weight of the hot melt adhesive formulation; and At least one epoxidized vegetable oil as stabilizer, in a proportion of 0.5 to 1.5% by weight relative to the total weight of the hot melt adhesive formulation. DETAILED DESCRIPTION OF THE INVENTION

[0019] Unless otherwise indicated, all percentages in this patent are by weight based on the total mass of the respective formulation.

[0020] The first priority for formulating PLA and PBS-based hot melt adhesives is compatibility with the other adhesive ingredients. Compatibility is sometimes measured as Hansen Solubility Parameters, which are based on the basic idea that like dissolves like and are expressed as a function of the viscosity (J / cm 3 ) 0.5 Therefore, the materials selected are preferably those with the same or similar solubility parameters. Two components can be simply selected such that their solubility parameters are 1.0 (J / cm 3 ) 0.5 They are fully miscible with each other, even at high temperatures, provided they differ by the following difference:

[0021] In practice, compatibility is assessed visually in the melt and in the solid state: if phase separation of the materials is visible, the mixture is rated as incompatible.

[0022] The base polymer of a hot melt adhesive formulation determines essential properties of the hot melt adhesive, such as processing temperature, adhesion, chemical stability, hydrolytic stability, softening range, and solidification mechanism. A combination of PLA and PBS is used as the base polymer for the adhesive formulation of the present invention. This combination combines the properties of these two polymers, thereby overcoming the shortcomings of the individual polymers and highlighting their positive features. The base polymer is used in a proportion of 40-65%.

[0023] Polylactide (PLA) is a semi-crystalline to completely amorphous, bio-based, biodegradable polymer. Commercially available PLA has a glass transition temperature (Tg) of 53-64°C, a melting range of 150-180°C, and a melt flow rate (MFR) of 6-80 g / 10 min [210°C / 2.16 kg]. Its Hansen solubility parameter is 19.2-21.1 (J / cm). 3 )0.5 The PLA suitable for the present invention has a very high glass transition temperature, preferably above 50°C, and a very high MFR, preferably above 25g / 10min [210°C / 2.16kg]. For the present invention, the average molecular weight M W PLA having a molecular weight in the range of 120,000 to 280,000 g / mol has proven to be particularly suitable.

[0024] Polybutylene succinate (PBS) is a crystalline, biobased, biodegradable plastic. PBS has a glass transition temperature of -40°C to -31°C, a melting range of 85-115°C, and a melt flow rate of 3-26 g / 10 min [190°C / 2.16 kg]. Its Hansen solubility parameter is 20.9 (J / cm). 3 ) 0.5 In the present invention, the weight average molar mass M W PBS having a pH in the range of 60,000 to 190,000 g / mol is preferred.

[0025] PBS-based hot melt adhesives have high thermal stability but poor adhesive properties. In contrast, PLA-based hot melt adhesives have good adhesive properties but only a low heat distortion temperature. By combining these two polymers according to the present invention, it is possible to produce hot melt adhesives that not only have high dimensional stability under heat, but also have excellent adhesive properties.

[0026] A combination of 50-75% low-melting PBS (85°C) and 25-50% high-melting PBS (115°C) has proven particularly advantageous, as it allows the high thermal stability of the high-melting PBS to be optimally combined with the better adhesive properties of the low-melting PBS.

[0027] For the adhesive formulations of the present invention, resins specifically adapted for PLA and PBS are used. These bio-based resins are added to increase tack, adhesion, and thermal stability, and to reduce processing viscosity. Rosin- and terpene-based resins have proven particularly suitable.

[0028] Rosin is a product obtained from tree resin. Due to its amorphous structure, rosin does not have a distinct melting point and is very brittle. It ranges from liquid to solid resins with an average melting temperature between 60 and 150 °C and a viscosity at 140 °C of 80 to 24,000 mPa·s. The solubility parameters of commercial rosins are generally 17.0 to 19.5 (J / cm 3 ) 0.5 However, in the present invention, the solubility parameter is between 19.0 (J / cm 3 ) 0.5 More than 19.2 to 21.1 (J / cm 3 ) 0.5 A specific formulation is used to ensure good compatibility with the biopolyester. Furthermore, for the majority of applications, the resin contributes to the flexibility of the adhesive formulation. This is due to the resin's particularly flexible structure and softening point of approximately 25°C to 35°C, which therefore optimizes the overall formulation for various applications in this temperature range.

[0029] Terpenes are hydrocarbon compounds that occur almost exclusively as secondary constituents in plants. Representative examples of the most important terpenes for resins in hot melt adhesives are α-pinene, β-pinene, and D-limonene. Polyterpenes or terpene resins are composed of multiple isoprene units (C5H8) n Terpenes are converted to resins via a thermo-oxidative process. Terpene resins are amorphous with a melting range of 60°C to 170°C. Commercial terpene resins have solubility parameters ranging from 16.2 to 20.9 (J / cm). 3 ) 0.5The preferred terpene resins for the present invention have a Hansen solubility parameter of 20.0 (J / cm 3 ) 0.5 It's super.

[0030] In the present invention, resins that are solid at room temperature and have a melting temperature of less than 120°C and a melt viscosity of less than 1000 mPa·s at 160°C are preferred. Such resins are preferably designed to exhibit high impact toughness and relatively high flexibility at room temperature. Furthermore, preferred resins are notable for their excellent hot tack, thus allowing high thermal stability to be achieved despite a low softening temperature. In the adhesive formulation of the present invention, the bio-based resin accounts for 30-65% of the total mass, preferably 40-55% of the total mass.

[0031] Various suitable plasticizers are used to soften the biopolyester, which helps soften the adhesive and lower the processing temperature. The plasticizers can be premixed with the PLA and PBS or incorporated directly into the hot melt adhesive during production.

[0032] Bioplasticizers suitable for this invention are certain citrate esters. These include triethyl citrate; however, relatively long-chain citrate esters, such as acetyl tributyl citrate and tributyl citrate, are particularly preferred due to their greater temperature stability and lower tendency to migrate. The plasticizer is preferably premixed with the PLA. Ratios of 10 to 25% of the plasticizer relative to the PLA in the adhesive formulation have been shown to be particularly effective. The addition of a plasticizer can reduce the modulus, tensile strength, and Shore hardness, allowing the modified PLA to achieve the mechanical properties of commercial EVA. Tensile elongation, in particular, is significantly increased. This leads to significant softening of otherwise very stiff polylactide-based hot-melt adhesives.

[0033] The addition of plasticizers to PBS causes a deterioration in adhesive and cohesive properties without significant softening. However, surprisingly, it was found that the combination of PLA / plasticizer blends with PBS does not cause a deterioration in these properties; instead, the positive properties of the plasticized PLA are preserved and further improved by those of PBS. Thus, the formulations are strongly softened with a concomitant increase in impact toughness and a simultaneous decrease in viscosity, thus making the adhesive practically processable in the intended application area.

[0034] Epoxidized vegetable oils are used to stabilize against hydrolytic degradation. Particularly preferred are epoxidized linseed oil or epoxidized soybean oil, which are added in proportions of less than 1.5% and serve as both a plasticizer and a stabilizer, or to protect against hydrolysis. The preferred oils used in this invention are epoxidized vegetable oils with an epoxy oxygen content of 8.5 to 9.5%, an acid value of 0.1 to 1.0 mgKOH / g, and a viscosity of approximately 500 to 1500 mPa·s at 25°C. In industrial operations, hot melt adhesives are often exposed to relatively high temperatures for relatively long periods of time. A stable viscosity is an important property in the processing of hot melt adhesives. The addition of stabilizers can reduce the viscosity loss at a temperature load of 160°C for 24 hours by up to 50%.

[0035] To formulate a hot melt adhesive from PLA and PBS, the plasticizer, resin, and stabilizer must all be compatible with each other, so that there is no phase separation. The adhesive properties and heat distortion temperature should not be reduced as a result of the addition of additives; ideally, they should even be improved.

[0036] The hot melt adhesive formulation of the present invention consists of 5-45% PLA, 10-55% PBS, 30-55% resin, up to 15% plasticizer, and 0.5-1.5% stabilizer.

[0037] Hot melt adhesives are typically produced in a batch process in a stirred reactor. Extrusion is currently only used in exceptional cases. However, a stirred reactor requires a relatively long residence time, which represents a relatively long temperature load for the raw materials used. The biopolymers used are substantially more susceptible to thermal degradation processes under prolonged temperature loads, which means that an extrusion process is appropriate when formulating hot melt bioadhesives. Such a process, firstly, significantly reduces residence times and, secondly, allows for the use of lower temperatures. Regarding hot melt adhesives, underwater pelletization poses additional challenges. Their stickiness poses problems when producing uniformly shaped pellets at room temperature (RT). Therefore, in this process, the water bath is additionally cooled to 5-10°C via an external heat exchanger. In the production of adhesive formulations, PLA and PBS are metered into pellets at 20-30°C in the intake section. The resin is supplied in molten form at approximately 140-170°C in the compression section. Through further liquid metering, a mixture of plasticizers and stabilizers is introduced in the compression section. Alternatively, the PLA may be pre-mixed with the plasticizer in a first step at 140-160°C and pelletized together with the plasticizer.

[0038] The formulation of the present invention contains 5-45% PLA, 10-55% PBS, 30-55% resin, 0.5-1.5% epoxidized vegetable oil, and 5% to 15% plasticizer. Various additives may be added for cost reduction and / or coloring. These additives may account for up to 20% by weight of the total formulation. Examples of additives include fillers, lime, color pigments, or fumed silica. The additives are preferably particles having an equivalent spherical diameter of 150 μm or less, more preferably particles having an equivalent spherical diameter of 0.1-100 μm, and more specifically particles having an equivalent spherical diameter of 1-25 μm.

[0039] To further improve the properties of hot melt adhesives, bio-based waxes can sometimes be incorporated. These mainly serve to reduce viscosity and shorten open time and hardening time. Carnauba wax, Cadelilla wax and stearin wax have proven to be particularly suitable.

[0040] Carnauba wax is a wax obtained from the leaves of the carnauba palm. It has a pale yellowish to greenish color and is the hardest natural wax. Its melting point is relatively high for a wax, at 80-87°C.

[0041] Candelilla wax is obtained from the leaves and stems of the candelilla shrub. It is hard, brittle, yellow-brown, opaque to translucent, and has a melting point of 67-79°C.

[0042] Stearin is a mixture of stearic and palmitic acids obtained from the corresponding triglycerides by saponification and acidification of soapy liquids. The melting range of stearin is between 55 and 70 °C, depending on the composition.

[0043] In the present invention, waxes that are solid at room temperature, have a softening temperature of less than 90°C, and a melt viscosity of less than 1000 mPa·s at 100°C are preferred. Waxes having these properties are preferably carnauba wax, candelilla wax, or stearin wax. In the adhesive formulation of the present invention, the bio-based wax preferably accounts for 0 to 20% of the total mass.

[0044] Hot melt adhesives are used as pellets or blocks, or as glue sticks. For rapid operations, such as those in the packaging or hygiene industries, hot melt adhesives with low viscosity and rapid curing properties are particularly preferred. Therefore, preferred formulations have relatively low proportions of PLA and PBS (less than 50%) and relatively high proportions of resin and plasticizer (more than 50%). A particular role in this case is also played by tailing, which must be as low as possible to facilitate accurate application and minimize system contamination. Very low tailing can be achieved by combining PLA and PBS in a ratio of 2:8 to 8:2.

[0045] Adhesive properties and thermal stability play a secondary role in these applications, as products made with them are usually short-lived. In this case, formulations with a relatively high plasticizer content (greater than 10%) and a relatively high PLA content (greater than 40%) are preferred. The high proportion of PLA compared to PBS ensures shorter curing times, and a low viscosity can be achieved as a result of the plasticizer content.

[0046] In the bookbinding sector, or in the woodworking and furniture industries, thermal stability and strength play a significant role in adhesive bonding. Low viscosity is not essential. Therefore, for this application, only a low proportion of plasticizer (less than 5%) and a high proportion of polymer (more than 55%) and resin (more than 40%) are used. In the DIY sector as well, viscosity plays a minor role, for example in glue sticks. What is important here is a low melting point and good adhesive properties to ensure good handling. [Example]

[0047] The present invention will be described below with reference to examples.

[0048] Raw materials used (A1) Base polymer: polylactide, CAS number: 26100-51-6, "Ingeo 4060D" (Natureworks LLC), melting point: 160°C, MFR (210°C / 2.16 kg) (A2) Base polymer: polybutylene succinate, CAS number: 25777-14-4, "Bio-PBS FZ91PM" (Mitsubishi Chemical), melting point: 115°C, MFR (190°C / 2.16 kg) (A3) Base polymer: polybutylene succinate, CAS number: 25777-14-4, "Bio-PBS FD92PM" (Mitsubishi Chemical), melting point: 84°C, MFR (190°C / 2.16 kg) (A4) Base polymer: polyhydroxyalkanoate PHACT a1000p (Helian Polymers BV); melt flow index (MFI) (160°C and 5 kg load): 5 g / 10 min; amorphous poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] (P3HB4HB) (B1) Tackifier: rosin, "Bremar (registered trademark) PP 1181" (Robert Kraemer), softening range: 60°C to 80°C (B2) Tackifier: rosin, "Bremar PP 1071" (Robert Kraemer), softening range: 80°C to 100°C (B3) Tackifier: terpene resin, "Dertophene (registered trademark) H150" (DRT), softening range: 80°C to 120°C (B4) Tackifier: terpene resin, "Sylvares (registered trademark) TP 300" (Kraton), 100°C to 130°C (B5) Tackifier: terpene resin, "Sylvares TP 2040" (Kraton), 110°C to 140°C (B6) Tackifier: rosin, Bremar® RK 8133 (Robert Kraemer); liquid at room temperature, viscosity: about 9000 mPa·s at 60°C (B7) Tackifier: rosin, Rokrapol® RK 6898 (Robert Kraemer); solid at room temperature, melting point: 80°C, viscosity (160°C): less than 500 mPa·s (C1) Plasticizer: Acetyl tributyl citrate, CAS number: 77-90-7 (C2) Plasticizer: Tributyl citrate, CAS number: 77-94-1 (D1) Wax: Carnauba wax, CAS number: 8015-86-9, "Carnaubwachs LT 124" (TH.C.TROMM), solidification point: 80°C to 87°C (D2) Wax: Candelilla wax, CAS number: 8006-44-8, "Candelillawachs LT 281 BI" (TH.C.TROMM), solidification point: 65°C to 73°C (D3) Wax: Stearin wax, CAS number: 22610-63-5, "TeCe-Stearin I" (TH.C.TROMM), solidification point: 55°C to 59°C (E1) Stabilizer: Epoxidized linseed oil, "Merginat® ELO" (Hobum Oleochemicals), CAS number: 8016-11-3, viscosity: 700 mPa·s to 1300 mPa·s at 25°C (E2) Stabilizer: Epoxidized soybean oil, "Merginat ESBO" (Hobum Oleochemicals), CAS number: 8013-07-8, viscosity: 400 mPa·s to 600 mPa·s at 20°C

[0049] method (M1) Determination of lap shear strength [MPa] according to DIN EN 1465: Two steel sheets are glued together with an overlap area of ​​12.5 x 25 mm and pulled apart using a tensile tester. The lap shear strength obtained represents the adhesive strength (adhesion, cohesion) of the adhesive.

[0050] (M2) Shear Adhesion Failure Temperature (SAFT) [°C] according to ASTM D4498: Two steel sheets are glued together with an overlap area of ​​25 x 25 mm. The adhesive sheet is suspended and loaded with a 200 g weight. The adhesive sheet is then heated in a drying cabinet at a rate of 2°C / min. The temperature at which the bond breaks is called SAFT. This provides information about the thermal stability of the adhesive.

[0051] (M3) Melting point according to DIN EN ISO 11357 [°C]: The melting point is determined by DSC (differential scanning calorimetry). The measurement range is -50°C to 200°C. The heating rate is 20 K / min.

[0052] (M4) Viscosity measurement at 160°C according to DIN EN ISO 3219 [mPa·s]: The viscosity is determined using a plate / plate rheometer. This provides information on the deformation and flow properties of the adhesive at a specific temperature. During the measurement, the sample is sheared between a rotating or oscillating part of the device and a stationary part. The shear rate is the product of the geometry of the measuring device and the speed of the moving part. The torque required to maintain the movement is measured and can then be used to determine the shear stress and therefore the viscosity and other rheological parameters.

[0053] (M5) Open time [s]: The open time is defined by the time that elapses until the adhesive is no longer tacky. At regular time intervals, a wooden pick is pressed into a drop of adhesive (applied at 160°C) and pulled away. As soon as the pick sticks and does not come off (cohesive failure), the hot melt adhesive is rated as "open" (open [usable]). When the pick no longer sticks to the drop of hot melt adhesive, the hot melt adhesive is no longer usable.

[0054] (M6) Setting time [s]: Setting time represents the time that elapses until the adhesive develops significant adhesion. A small amount of adhesive is applied to the end of a wooden pick. An identical pick is immediately pressed down at a 90° angle, thereby creating an overlap and joint area. At the same time, the time measurement begins. At regular intervals, attempt to twist the pick by hand (not too forcefully) and determine when the pick can no longer be moved.

[0055] Example 1 Typical hot melt adhesives were pre-dried: PLA at 45 °C for 4 h and the two PBS types at 60 °C for 4 h. Compounding was carried out in a twin-screw extruder (Leistritz, model ZSE 27 MAXX) with a screw length of 1.12 m and a screw diameter of 28 mm at 125–160 °C, a total throughput of 8–10 kg / h, a screw speed of 80–150 rpm, and a set-point pressure of 5 bar.

[0056] The two types of PBS were premixed in a pellet mixer, and then PLA and the two types of PBS were metered into the intake section at 20-30°C via their respective single-screw feeders (Brabender, model DS28). The resin was fed into the compression section at 150°C via a heated liquid feeder. The plasticizer was metered into the compression section at room temperature via a liquid feeder (Brabender, model FDDW-MP). The melt was discharged through an underwater pelletizer at an outlet temperature of 120-130°C, with a cutting blade speed of 500-1500 rpm and a water temperature of 5-20°C. Compounds R1-R4, R13, and R14 were produced in this way. Due to their high adhesive strength and high thermal stability, these compounds are particularly suitable for the textile, footwear, and automotive industries.

[0057] Example 2 The formulations were prepared in a manner similar to that of Example 1. To achieve a relatively low melting point, the relatively high-melting PBS FZ91 was omitted. Therefore, premixing as in Example 1 was not necessary. Furthermore, in formulations R7 and R8, a terpene resin was used to improve adhesion to the specified substrate. This resin was fed at 170°C via a heated liquid feeder in the compression section. Formulations R5 and R8 were prepared in this manner. Due to their relatively low melting points, these formulations are particularly suitable for glue stick applications.

[0058] Example 3 The formulation was prepared in much the same manner as in Example 1. To achieve relatively high thermal stability, the low melting point PBS FD92 was omitted, so premixing as in Example 1 was not necessary.

[0059] The rosin in R9 was fed at 150°C, and the terpene resins in R9 to R11 at 170°C, via a heated liquid feeder in the compression section. Formulations R9 to R12 were produced in this way. Due to their high thermal stability and viscosity, these formulations are particularly suitable for patch bonding in the wood and furniture sectors.

[0060] Example 4 The formulations were prepared in much the same way as in Example 1. The various waxes were metered into the intake section at 20-30°C via a twin-screw feeder (model DDSR20, Brabender). The resin was fed into the compression section at 150°C via a heated liquid feeder. Formulations R15 to R20 were prepared in this way. The use of waxes reduces the viscosity of these adhesive systems and also shortens the processing time. These formulations are therefore particularly suitable for rapid operations of the kind customary in the packaging sector.

[0061] Complex [Table 1] JPEG2025078091000002.jpg129170

[0062] [Table 2] JPEG2025078091000004.jpg91170

[0063] [Table 3] JPEG2025078091000006.jpg86170

[0064] [Table 4] JPEG2025078091000008.jpg84170

[0065] A1: PLA, type Ingeo 4060D A2: Bio-PBS, Type FZ91PM A3: Bio-PBS, Type FZ92PM A4: Amorphous poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate (PHACT)] B1: Rosin, type Bremar® PP 1181 B2: Rosin, type Bremar PP 1017 B3: Terpene resin, type Dertophene® H150 B4: Terpene resin, type Sylvares® TP 300 B5: Terpene resin, type Sylvares TP 2040 type B6: Rosin, type Bremar RK 8133 B7: Rosin, type Rokrapol RK 6898 C1: Acetyl tributyl citrate (ATBC) C2: Tributyl citrate D1: Wax, Carnauba wax, type Carnauba wax LT 124 D2: Wax, candelilla wax, type Candelillawachs LT 281 BI D3: Wax, stearin wax, type Stearinwachs TeCe-Stearin I E1: Epoxidized linseed oil, type Merginat® ELO E2: Epoxidized soybean oil, type Merginat ESBO M1: Lap shear strength [MPa] M2: Thermal stability [°C] M3: Melting point [°C] M4: Viscosity [mPa·s] M5: Open time [s] M6: Curing time [s]

[0066] Comparative Example Following the details for the layer identified as the "resin layer" in the examples of US Patent Application Publication No. 2014 / 0329065, the following formulations were investigated.

[0067] [Table 5]

[0068] All ingredients except for the calcium carbonate were mixed in an anchor blade mixer at 180°C for approximately 120 minutes. After the calcium carbonate was added, the formulation became very viscous. The stearin wax was not compatible with the polylactide, resulting in separation.

[0069] Due to the poor homogeneity and compatibility of the components, it was not possible to carry out any investigations aimed at characterizing the mixture. In the absence of tackifier, the adhesive properties were poor.

Claims

1. A hot melt adhesive formulation comprising the following components: A glass transition temperature of greater than 50° C., a melt flow index of greater than 25 g / 10 min, measured at a temperature of 210° C. with a load of 2.16 kg, and a weight average molecular weight M in the range of 120,000 to 280,000 g / mol. Ｗ , and 19.2 to 21.1 (J / cm ３ ) ０．５ at least one polylactide having a Hansen solubility parameter of 0.01 to 0.05, the proportion being between 5 and 45% by weight relative to the total weight of the hot melt adhesive formulation; 2. A melt flow index of 3 to 26 g / 10 min, measured at 190° C. with a load of 16 kg, and a weight average molecular weight M in the range of 60,000 to 190,000 g / mol Ｗ , and 20.1 to 21.2 (J / cm ３ ) ０．５ at least one polybutylene succinate having a Hansen solubility parameter of 10 to 55% by weight relative to the total weight of the hot melt adhesive formulation; A melting temperature between 60 and 150°C, a melt viscosity at 140°C of 80 to 24,000 mPa·s, and a viscosity of 16.0 to 21 (J / cm ３ ) ０．５ at least one naturally occurring resin having a Hansen solubility parameter between 0.01 and 0.15, and a proportion of 30 to 55% by weight relative to the total weight of the hot melt adhesive formulation; At least one tri(C2-C8) alkyl ester of citric acid or acetyl tri(C2-C8) alkyl ester of acetyl citrate as plasticizer, in a proportion of 5 to 15% by weight relative to the total weight of the hot melt adhesive formulation; and At least one epoxidized vegetable oil as stabilizer, in a proportion of 0.5 to 1.5% by weight relative to the total weight of the hot melt adhesive formulation.

2. 2. The hot melt adhesive formulation according to claim 1, containing up to 20% by weight of additives, preferably fillers, lime, colour pigments or fumed silica, relative to the total weight of the hot melt adhesive formulation, said additives being preferably particles with an equivalent spherical diameter of up to 150 μm (more preferably 0.1-100 μm, more particularly 1-25 μm).

3. 3. The hot melt adhesive formulation according to claim 2, wherein the additive is a bio-based wax (preferably carnauba wax, cadellila wax or stearin wax) having a softening temperature below 90°C and a melt viscosity below 1000 mPa.s at 100°C.

4. 4. The hot melt adhesive formulation according to claim 1, wherein the epoxidized vegetable oil is an epoxidized linseed oil or an epoxidized soybean oil having in each case an epoxy oxygen content of 8.5 to 9.5% by weight, an acid number of 0.1 to 1.0 [mg KOH / g] and a viscosity at 25° C. of 500 to 1500 mPa·s.

5. A hot melt adhesive formulation according to any one of claims 1 to 4, wherein said citric acid ester is triethyl citrate, tributyl citrate or acetyl tributyl citrate.

6. 6. The hot melt adhesive formulation of any one of claims 1 to 5, comprising a combination of 50 to 75 wt. % of a polybutylene succinate having a melting point or melting range of 60 to 90°C and 50 to 25 wt. % of a polybutylene succinate having a melting point or melting range of 110 to 125°C.

7. The naturally occurring resins have a Hansen solubility parameter of 20 (J / cm ３ ) ０．５ The hot melt adhesive formulation according to any one of claims 1 to 6, wherein the resin is a rosin or terpene based resin having a viscosity of 100°C or less.

8. The component according to claim 1 has a Hansen solubility parameter of 1.0 (J / cm ３ ) ０．５ or less (preferably 0.5 (J / cm ３ ) ０．５ The hot melt adhesive formulations according to any one of claims 1 to 7, which differ from each other by a difference of 0.01 to 0.01% by mass (I) of 0.01 to 0.01% by mass (II) of 0.01 to 0.01% by mass (III) of 0.01 to 0.01% by mass (IV ...

9. Use of the hot melt adhesive formulation according to any one of claims 1 to 8 as a bookbinding adhesive, furniture adhesive or for bonding paper, cardboard or non-polar plastics such as PMMA, ABS, PC or PET.

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