Polyolefin-based hot melt adhesive composition

Abstract

Provided in the present disclosure is a hot melt adhesive composition comprising: (A) from 25 to 50 wt% of a copolymer of butene-1 and at least one comonomer selected from the group consisting of ethylene, propylene, C5-C10 alpha-olefins, and combinations thereof, the copolymer has a copolymerized comonomer content of 0.5 to 8.0 wt% and a melt flow rate MFR (A) (ISO 1133: 2011, 190 DEG C / 2.16 kg) of equal to or greater than 200 g / 10 min; (B) 30 to 60 wt% of a tackifier; and (C) 5 to 30 wt% of a polypropylene wax, wherein the amounts of (A), (B) and (C) are based on the total weight of (A) + (B) + (C). Also provided is an article comprising the HMA composition.

Description

Technical Field

[0001] This disclosure relates to polyolefin-based hot melt adhesive (HMA) compositions, particularly HMA compositions comprising high melt flow polybutene-1, a tackifier, and a specific class of waxes (i.e., polypropylene-based waxes). Background Technology

[0002] Thermoplastic adhesives are thermoplastic adhesives applied in a molten state and cured upon cooling. They are widely used in various industries and fields, such as packaging, woodworking, product assembly, crafts, and textiles, due to their rapid setting, ease of use, and strong bonding properties.

[0003] Hot-melt adhesive compositions containing high-flowability butene-1 homopolymers or copolymers are known in the art, for example, according to European patent application EP671431 (Himont Inc.) or EP314495 (Shell Oil Company). These documents disclose the use of peroxides to reduce viscosity of butene-1 polymers to achieve low viscosity values. However, it is known that peroxide degradation introduces some disadvantages (such as unpleasant odor and high yellow index), which may hinder the use of peroxide-degraded compositions in some technical fields, such as food packaging.

[0004] It is also known that high-flowability polybutene-1 outside the reactor is suitable for use in hot melt adhesive compositions.

[0005] US2008190541A1 discloses a hot melt adhesive composition comprising at least two butene-1 copolymers with different melt flow indices, prepared using a metallocene catalyst. The low melt flow index component is essential for achieving a balance of properties in the hot melt adhesive.

[0006] According to international patent application WO2015 / 074830A1, butene-1 copolymers with an MFR ranging from 200 to 1500 g / 10 min are known for use in HMA compositions. International patent application WO2020 / 016143A1 discloses HMA compositions comprising a combination of polybutene-1 with an MFR of 200 to 1500 g / 10 min, a tackifier, and Fischer-Tropsch wax. These compositions are known to exhibit a good trade-off between rheological and thermal properties.

[0007] In this context, there remains a need for polyolefin-based hot melt adhesive compositions that achieve a good balance between adhesive and mechanical properties. Summary of the Invention

[0008] This disclosure relates to a hot melt adhesive composition comprising:

[0009] (A) A copolymer of 25% to 50% by weight of butene-1 and at least one comonomer selected from ethylene, propylene, C5-C10 α-olefins and combinations thereof, the copolymer having a total polymeric comonomer content of 0.5% to 8.0% by weight as determined by IR spectroscopy using the method described in the Examples section, and a melt flow rate (MFR) equal to or greater than 200 g / 10 min as measured according to ISO 1133-1:2011 (190°C, 2.16 kg);

[0010] (B) 30% to 60% by weight of tackifier; and

[0011] (C) 5% to 30% polypropylene wax by weight

[0012] The quantities of (A), (B), and (C) are based on the total weight of (A) + (B) + (C).

[0013] The polyolefin-based hot melt adhesive compositions disclosed herein have a good balance of properties, such as good mechanical properties, SAFT, open and set times, and softening properties, as indicated by the values ​​of the ring and ball test.

[0014] In another aspect, this disclosure relates to an article comprising a first substrate and a second substrate, wherein the first substrate is bonded to the second substrate by a hot melt adhesive composition of this disclosure, the hot melt adhesive composition being inserted between the first substrate and the second substrate.

[0015] While several embodiments have been disclosed, other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments disclosed herein can be modified in various obvious respects without departing from the spirit and scope of the claims presented herein. Therefore, the following detailed description should be considered illustrative rather than restrictive in nature. Detailed Implementation

[0016] In the context of this disclosure:

[0017] - Unless otherwise stated, percentages are expressed by weight;

[0018] - Unless otherwise stated, the total weight of the polymer composition is 100% by weight.

[0019] - The term "comprising / including" in relation to polymers or polymer compositions, mixtures or blends shall be interpreted as meaning "comprising / including or substantially consisting of";

[0020] The term "consistently made up of" means that other components, besides those that are mandatory, may also be present in the material, provided that the fundamental properties of the material are not substantially affected by their presence. Examples of components that, when present in conventional amounts, do not substantially affect the properties of polymers or polyolefin compositions, mixtures, or blends are catalyst residues, antistatic agents, and processing aids;

[0021] - The term "copolymer" refers to a polymer derived from at least two different comonomers through intentional polymerization; that is, the term "copolymer" includes terpolymers.

[0022] - The term "film" refers to a thin layer of material with a thickness of 2,000 micrometers or less;

[0023] - The term "sheet" refers to a layer of material that is more than 2,000 micrometers thick.

[0024] Therefore, the object of this disclosure is a hot melt adhesive (HMA) composition comprising:

[0025] (A) A copolymer of 25% to 50% by weight of butene-1 and at least one comonomer selected from ethylene, propylene, C5-C10 α-olefins and combinations thereof, the copolymer having a comonomer content of 0.5% to 8.0% by weight and a melt flow rate (MFR) equal to or greater than 200 g / 10 min as measured according to ISO 1133-1:2011 (190°C, 2.16 kg);

[0026] (B) 30% to 60% by weight of tackifier; and

[0027] (C) 5% to 30% by weight, preferably 15% to 30% by weight, of polypropylene wax.

[0028] The quantities of (A), (B), and (C) are based on the total weight of (A) + (B) + (C).

[0029] The components (A), (B), and (C) of the HMA composition are defined in more detail below. The components may be included in the HMA composition in any combination.

[0030] Preferably, the butene-1 copolymer (A) has a melt flow rate (MFR) of 200 to 3,000 g / 10 min, more preferably 400 to 1,700 g / 10 min, and still preferably 500 to 1,600 g / 10 min, as measured according to ISO 1133-1:2011 (190°C / 2.16 kg).

[0031] The butene-1 copolymer (A) preferably has a total comonomer content of 0.7% to 7.0% by weight based on the total weight of the butene-1 copolymer (A).

[0032] The butene-1 copolymer (A) preferably contains a comonomer selected from ethylene, propylene, hexene-1, octene-1, and combinations thereof, with ethylene being particularly preferred.

[0033] In a preferred embodiment, the butene-1 copolymer (A) comprises:

[0034] - Fraction (A1) comprising butene-1 homopolymer or butene-1 copolymer with a comonomer of less than 3% by weight based on fraction (A1), the comonomer being selected from ethylene, propylene, C5-C10 α-olefins and combinations thereof;

[0035] - Fraction (A2), comprising butene-1 and a copolymer of 3% to 10% by weight of a comonomer based on fraction (A2), wherein the comonomer is selected from ethylene, propylene, C5-C10 α-olefins, and combinations thereof.

[0036] The butene-1 copolymer (A) has the following characteristics:

[0037] - The total content of polymeric comonomers based on the total weight of fractions (A1) and (A2) is 0.5% to 8.0% by weight, preferably 0.7% to 7.0% by weight;

[0038] - Melt flow rate (MFR(I)) equal to or greater than 200 g / 10 min, as measured according to ISO 1133-1:2011 (190 °C, 2.16 kg); and

[0039] - The content of the fraction soluble in xylene at 0°C, determined by the method described in the Examples section based on the total weight of fractions (A1) and (A2), equal to or less than 80% by weight, preferably ranging from 20% to 80% by weight.

[0040] The content of the comonomer was determined by IR spectroscopy using the method described in the Examples section.

[0041] Preferably, the butene-1 copolymer (A) comprises 15% to 70% by weight, particularly 20% to 65% by weight, fraction (A1), and 30% to 85% by weight, particularly 35% to 80% by weight, fraction (A2), wherein the amounts of fractions (A1) and (A) are based on the total weight of fractions (A1) and (A2).

[0042] Preferably, the comonomer optionally included in the butene-1 copolymer fraction (A1) and the butene-1 copolymer fraction (A2) is ethylene.

[0043] Preferably, the butene-1 copolymer (A) has at least one of the following additional features, more preferably all of the following additional features:

[0044] (a) A molecular weight distribution (Mw / Mn) of less than 4, preferably less than 3, more preferably less than 2.5, with a lower limit of 1.5 in all cases, wherein this molecular weight distribution is determined by NMR using the method described in the Examples section; and / or

[0045] (b) Having one or more melting peaks Tm(II) at temperatures equal to or below 110°C, preferably equal to or below 105°C, more preferably ranging from 80°C to 103°C, wherein Tm(II) is measured by DSC using the method described in the Examples section; and / or

[0046] (c) The glass transition temperature (Tg) in the range of -40°C to -10°C, preferably -30°C to -10°C, wherein Tg is measured by DSC using the method described in the Examples section; and / or

[0047] (d) Brinell viscosity at 190°C below 15,000 mPa·s, preferably in the range of 3,000 to 15,000 mPa·s; and / or

[0048] (e) X-ray crystallinity in the range of 20% to 60%, preferably in the range of 25% to 50%;

[0049] (f) Between 0.89 and 0.91 g / cm³ 3 Density within the range; and / or

[0050] (g) Yellowness index less than 0, specifically ranging from -1 to -5.

[0051] In one embodiment, the butene-1 copolymer (A) may have all of the features (a) to (g).

[0052] Butene-1 copolymer (A) can be obtained by copolymerizing butene-1 and comonomer in the presence of a catalyst system, which can be obtained by contacting the following substances:

[0053] -Stereorigid metallocene compounds;

[0054] -Aluminoxanes or compounds capable of forming alkyl metallocene cations; and optionally,

[0055] - Organoaluminum compounds.

[0056] Patent applications WO2004 / 099269, WO2006 / 045687, WO2015 / 074830, WO2018 / 007279 and WO2022 / 0084081 (incorporated herein by reference) describe processes and catalyst systems suitable for the production of butene-1 copolymer (A).

[0057] The butene-1 copolymer (A) can be obtained by polymerization in one or more reactors connected in series. In the latter case, the catalyst may be added only in the first reactor or in more than one reactor. As explained in WO2004 / 099269, polymerization can be carried out in the liquid phase (optionally in the presence of an inert hydrocarbon solvent) or in the gas phase using a fluidized bed or mechanically stirred gas-phase reactor. Preferably, the polymerization process is carried out using liquid butene-1 as the polymerization medium. The polymerization temperature range is typically from 20°C to 150°C, preferably from 50°C to 90°C, and more preferably from 65°C to 82°C.

[0058] As explained in WO2006 / 045687, hydrogen can be advantageously used to adjust the molecular weight of butene-1 copolymers. During polymerization reactions in the liquid phase, the concentration of hydrogen is above 1,800 mol ppm and below 6,000 mol ppm, preferably in the range of 2,000 mol ppm to 6,000 mol ppm.

[0059] A low-melting-point butene-1 copolymer can be obtained by appropriately selecting the content of the comonomer (particularly the ethylene content). Therefore, the butene-1 copolymer (A) can be obtained by a polymerization process, wherein the amount of comonomer (particularly the ethylene content) in the liquid phase ranges from 0.1% to 8% by weight, preferably from 0.2% to 6% by weight, relative to the total weight of the butene-1 monomers present in the polymerization reactor.

[0060] When the butene-1 copolymer (A) is a butene-1 copolymer composition (I) comprising components (A1) and (A2), the butene-1 copolymer composition (I) is obtained by melt blending components (A1) and (A2) in appropriate amounts. Alternatively and preferably, the butene-1 copolymer composition (I) is obtained by a polymerization process comprising at least two polymerization stages carried out in at least two reactors connected in series. When component (A1) is a copolymer, the amount of comonomer in the liquid phase for the preparation of component (A1) can range from 0% to 1.2% by weight, while the amount of comonomer in the liquid phase in the second stage for the preparation of component (A2) can range from 1% to 10% by weight.

[0061] The hot melt adhesive composition disclosed herein comprises at least one tackifier (B). The tackifier (B) is preferably solid at a temperature of 25°C ± 1°C.

[0062] The tackifier (B) is preferably selected from hydrogenated hydrocarbon resins and their derivatives, such as aliphatic hydrocarbon resins, aromatic hydrocarbon resins, and aliphatic / aromatic hydrocarbon resins; terpene-derived resins, such as polyterpenes and terpene / phenolic resins; natural resins and natural resin esters, such as rosin, rosin esters, and tall oil rosin esters; and mixtures thereof. Preferably, the tackifier (B) is a hydrogenated hydrocarbon resin, more preferably alicyclic hydrocarbon resin.

[0063] In a preferred embodiment, the tackifier (B) has a softening point greater than 100°C.

[0064] Tackifiers suitable for use as component (B) in the HMA compositions of this disclosure are known in the art, and are, for example, produced by ExxonMobil under the trade name Escorez. TM (e.g., Escorez) TM Sales of 5400.

[0065] The HMA compositions disclosed herein further comprise polypropylene wax (C). In a preferred embodiment, the HMA compositions disclosed herein do not contain any wax other than polypropylene wax (C). More preferably, the HMA compositions do not contain Fischer-Tropsch wax.

[0066] Polypropylene wax (C) can be a modified polypropylene wax, such as maleic anhydride-grafted polypropylene wax.

[0067] The polypropylene wax (C) preferably has a weight average molecular weight Mw of 10,000 g / mol or less, preferably 8,000 g / mol or less, more preferably in the range of 3,000 to 7,000 g / mol, as measured by GPC, and / or a molecular weight distribution Mw / Mn in the range of 3.0 to 6.0, as measured by GPC.

[0068] The polypropylene wax (C) preferably also has a dropping point of 140°C to 157°C, more preferably 145°C to 155°C (DGF M-III 3, similar to DIN 51801).

[0069] Polypropylene wax (C) preferably also has a penetration range of 2 to 7 d mm (DIN 51579:2010).

[0070] Optionally, the HMA compositions of this disclosure comprise additional components (D) selected from the following: plasticizers, such as plasticizing oils (e.g., mineral oils); olefin oligomers or low molecular weight polyolefins (e.g., liquid polybutene); amorphous polyalphaolefins different from polybutene-1 component (A); thermoplastic polyurethanes; ethylene / (meth)acrylate copolymers; ethylene / vinyl acetate copolymers; and combinations thereof. The amount of additional component (D) ranges from 0% to 15% by weight based on the total weight of the HMA composition (including the additional component).

[0071] Optionally but preferably, the HMA composition comprises 0.05% to 5.0% by weight of an additive (E) based on the total weight of the HMA composition, the additive being selected from commonly used additives in HMA compositions, such as antioxidants, light stabilizers, and combinations thereof.

[0072] The viscosity of the hot melt adhesive composition disclosed herein can be customized, thereby optimizing the composition for different applications. Therefore, the hot melt adhesive composition disclosed herein is suitable for use in wood processing, packaging, and general assembly; particularly suitable for assembling components of electrical appliances, ceramics, furniture, textiles, furniture upholstery materials, leather, plastics, paper, and cardboard.

[0073] Therefore, in another aspect, this disclosure relates to the use of hot melt adhesive compositions for bonding articles in the fields of wood processing, packaging, and general assembly; particularly for the use of assembling components of electrical appliances, ceramics, furniture, textiles, furniture trim, leather, plastics, paper, and cardboard.

[0074] In another aspect, this disclosure relates to an article comprising a first substrate and a second substrate, wherein the first substrate is bonded to the second substrate by a hot melt adhesive composition of this disclosure, the hot melt adhesive composition being inserted between the first substrate and the second substrate.

[0075] Preferably, the first substrate and the second substrate are made of materials independently selected from the following: wood, paper, cardboard, natural leather, plastic materials, natural fibers such as cotton or linen, and combinations thereof.

[0076] Preferably, the first substrate and the second substrate are independently selected from the following: film, sheet, panel, woven fabric and nonwoven fabric.

[0077] In one embodiment, the hot melt adhesive composition of this disclosure preferably has a rotational (Bruch's) viscosity at 180°C equal to or less than 7,000 mPa·s, more preferably less than 5,000 mPa·s, and still more preferably less than 2,000 mPa·s. In one embodiment, for each upper limit, the lower limit is 500 mPa·s. HMA compositions having viscosities within these ranges are particularly suitable for use in the packaging field for assembling paper, paperboard, etc.

[0078] The hot melt adhesive compositions disclosed herein exhibit very good thermal stability.

[0079] The compositions of the present invention can be prepared by known methods and apparatus, such as melt blending components in a stirred tank or in a single-screw extruder or twin-screw extruder.

[0080] The features describing the subject matter of this disclosure are not inextricably linked to each other. Therefore, a preferred range of a feature can be combined with more or less preferred ranges of different features, regardless of their level of preference.

[0081] The following examples are merely illustrative and are not intended to limit the scope of the invention in any way.

[0082] Example

[0083] Characterization methods: The following methods are used to determine the characteristics indicated in the specification, claims and examples.

[0084] Melt flow rate (MFR) is measured according to ISO 1133-1:2011 (190°C, 2.16 kg, except for cases where different loads and temperatures are specified).

[0085] The comonomer content (wt.%) was measured by IR spectroscopy.

[0086] Absorbance versus wavenumber (cm) -1 Record the spectrum of the polymer pressed film. The following measurements were used to calculate the ethylene content: a) between 4482 and 3950 cm⁻¹ -1 The area (At) of the combined absorption bands between the two is used for spectral normalization of the film thickness;

[0087] b) The subtraction factor (FCR) of the digital subtraction between the polymer sample spectrum and the absorption bands of the sequences BEE and BEB (B: 1-butene unit, E: ethylene unit) due to the methylene group (CH2 rocking vibration). C2 );

[0088] c) The area of ​​the remaining band after subtracting the C2PB spectrum (A) C2，块 Its sequence originates from the methylene group, EEE (CH2 rocking vibration).

[0089] equipment

[0090] The spectral measurements reported above can be provided using a Fourier transform infrared spectrometer (FTIR). A hydraulic press (engraver or equivalent) with a pressure plate that can be heated to 200°C can also be used.

[0091] method

[0092] Calibration of (BEB + BEE) sequences

[0093] By plotting %(BEB+BEE)wt against FCR C2 / A t To obtain the calibration line, the slope Gr and intercept Ir are calculated using linear regression.

[0094] Calibration of EEE sequences

[0095] By plotting %(EEE)wt on A C2，块 / A t To obtain the calibration line. Slope G H and intercept I H Calculated by linear regression.

[0096] Sample preparation

[0097] Using a hydraulic press, a thick sheet is obtained by pressing approximately 1.5 g of sample between two aluminum foils. If uniformity issues exist, at least two pressing operations are recommended. A small portion is cut from this sheet to mold a film. The recommended film thickness range is between 0.1 and -0.3 mm. The pressing temperature is 140 ± 10 °C. Crystalline phase modification occurs over time; therefore, it is recommended to collect the IR spectrum of the sample film once it has been molded.

[0098] Procedure

[0099] The instrument data acquisition parameters are as follows:

[0100] Purging time: minimum 30 seconds.

[0101] Collection time: minimum 3 minutes.

[0102] Happ-Genzel.

[0103] Resolution: 2cm -1 .

[0104] Collect the IR spectrum of the sample relative to the air background.

[0105] calculate

[0106] Calculate the weight-based concentration of the BEE+BEB sequence of the ethylene unit:

[0107]

[0108] Using the baseline between the shoulders of the remaining strip, calculate the remaining area (AC2, block) after the subtraction described above.

[0109] Calculate the weight-based concentration of the EEE sequence of the ethylene unit:

[0110]

[0111] Calculate the total weight percentage of ethylene:

[0112]

[0113] Mw / Mn was determined. Measurements were performed in 1,2,4-trichlorobenzene (TCB) by gel permeation chromatography (GPC). Molecular weight parameters (Mn, Mw, Mz) and molecular weight distributions (Mw / Mn) for all samples were measured using a PolymerChar GPC-IR instrument equipped with four PLgel Olexis mixed-bed columns (Polymer Lab) and an IR5 infrared detector (PolymerChar). Column dimensions were 300 × 7.5 mm with a particle size of 13 µm. The mobile phase flow rate was maintained at 1.0 mL / min. All measurements were performed at 150 °C. The solution concentration was 2.0 mg / mL (at 150 °C) with 0.3 g / L of 2,6-di-tert-butyl-p-cresol added to prevent degradation. For GPC calculations, universal calibration curves were obtained using 12 polystyrene (PS) standard samples (peak molecular weights from 266 to 1,220,000) provided by PolymerChar. The experimental data were interpolated using cubic polynomial fitting to obtain the corresponding calibration curves. Data acquisition and processing were performed using Empower 3 (Waters Corporation). The molecular weight distribution and associated average molecular weight were determined using the Mark-Houwink relation: the K values ​​for PS and polybutene (PB) were KPS = 1.21 × 10⁻⁶. -4 dL / g and KPB = 1.78 × 10 -4 dL / g, with the Mark-Howwink index α=0.706 for PS and the Mark-Howwink index α=0.725 for PB.

[0114] For butene / ethylene copolymers, for data evaluation purposes, it is assumed that the composition of each sample is constant across the entire molecular weight range, and the K-value of the Mark-Howwink relationship is calculated using the linear combination reported below:

[0115]

[0116] Where K EB K is the constant of the copolymer. PE (4.06×10) -4 (dL / g) and K PB (1.78×10) -4 dL / g) is a constant for polyethylene (PE) and PB. and It is the relative weight of ethylene and butene, where For all butene / ethylene copolymers, the Mark-Howwink index α = 0.725 was used independently on their composition. Final processing data for all samples were fixed to include fractions with molecular weight equivalents up to 1000. Fractions below 1000 were studied by GC.

[0117] Thermal properties were determined using differential scanning calorimetry (DSC) on a Perkin Elmer DSC-7 instrument. The melting temperature of the butene-1 copolymer and HMA composition was determined according to the following method:

[0118] -TmII (Melting Temperature Measured in the Second Heating Run): A weighted sample (5 to 10 mg) obtained from the polymerization (or a weighted sample of the HMA composition) is sealed in an aluminum disk and heated at 200 °C at a scan rate corresponding to 10 °C / min. The sample is held at 200 °C for 5 minutes to allow all crystallites to melt completely, thus eliminating the thermal history of the sample. Then, after cooling to -20 °C at a scan rate corresponding to 10 °C / min, the peak temperature is taken as the crystallization temperature (Tc). After standing at -20 °C for 5 minutes, the sample is heated a second time at 200 °C at a scan rate corresponding to 10 °C / min. In this second heating run, the measured peak temperature is labeled as (TmII). If more than one peak exists, the highest (strongest) peak is taken as TmII. The area under the peak (or multiple peaks) is taken as the total enthalpy of fusion (DH TmII).

[0119] - Even after aging (without eliminating the thermal history of the sample), the enthalpy of fusion and melting temperature were measured on a Perkin Elmer DSC-7 instrument using differential scanning calorimetry (DSC). A weighted sample (5 to 10 mg) obtained from the polymerization (or a weighted sample of the HMA composition) was sealed in an aluminum dish and heated at 200 °C with a scan rate corresponding to 10 °C / min. The sample was held at 200 °C for 5 minutes to allow all crystallites to completely melt and then cooled to 20 °C at a cooling rate of 10 °C / min. The sample was then stored at room temperature for 10 days. After 10 days, the sample was subjected to DSC, cooled to -20 °C, and then heated to 200 °C with a scan rate corresponding to 10 °C / min. During this heating run, the peak temperature was recorded as the melting temperature (TmI). If more than one peak was present, the highest (strongest) peak was taken as TmI. The area under the peak (or multiple peaks) was taken as the total enthalpy of fusion (DH TmI) after 10 days.

[0120] The glass transition temperature (Tg) was determined by dynamic mechanical thermal analysis (DMTA). A 76mm × 13mm × 1mm molded specimen was fixed to a DMTA machine for tensile stress testing. The tension and frequency dependence of the specimen were fixed at 1Hz. DMTA converted the elastic response of the specimen from -100℃ to 130℃. In this way, a graph of the elastic response versus temperature can be plotted. The elastic modulus of a viscoelastic material is defined as E = E' + iE''. DMTA can separate the two components E' and E'' through their resonance and the graphs E' versus temperature and E / E'' = tan(δ) versus temperature. The glass transition temperature Tg is assumed to be the temperature at which the curve E / E'' = tan(δ) reaches its maximum value.

[0121] The Brinell viscosity of the butene-1 copolymer was measured at 190°C using a cylindrical mandrel rotational viscometer, HA Ametek / Benelux Scientific Model DV2T, equipped with a drive motor capable of variable test speed and a set of mandrels capable of achieving and maintaining approximately 80% of the torque. The selected mandrel / chamber combination was SC4-27 / SC4-13R / RP. The sample was subjected to gradual increases in rotation until approximately 80% of the torque value was reached and maintained. Rotation was started at 10 rpm, then gradually increased by 2 rpm every 5 seconds. The Brinell viscosity [mPa*s] was calculated as the ratio of shear stress (mPa) to shear rate (sec⁻¹) and determined by averaging the results obtained during the last 20 minutes of acquisition (1 data point / min).

[0122] Brinell viscosity of HMA: Measured at 180°C using a cylindrical mandrel rotational viscometer, HA Ametek Model DV2T, equipped with a drive motor capable of variable test speed and a set of mandrels capable of achieving and maintaining approximately 50% torque. The selected mandrel / chamber combination was SC4 / 27. The sample (10.5 g) was subjected to gradual increases in rotation until approximately 50% torque was reached and maintained. Rotation began at 5 rpm and continued up to 20 rpm, maintaining rotation for 20 min when it stabilized. Brinell viscosity [mPa*s] was calculated as the shear stress (mPa) / shear rate (sec⁻¹) ratio and determined by averaging the results obtained during the last 20 minutes of acquisition (1 data point / min).

[0123] Crystallinity was measured by X-ray diffraction using an X-ray powder diffractometer (XDPD). The XDPD used Cu-Kα1 radiation with a fixed slit and was able to collect spectra between diffraction angles 2Θ=5° and 2Θ=35° in steps of 0.1° every 6 seconds.

[0124] The samples were prepared by compression molding, consisting of discs approximately 1.5 to 2.5 mm thick and 2.5 to 4.0 cm in diameter. The discs were then aged at 23°C for 96 hours.

[0125] Following this preparation, the sample is inserted into the XDPD sample holder. The XRPD instrument is set to collect the XRPD spectrum of the sample from the diffraction angle 2Θ=5° to 2Θ=35° using a counting time of 6 seconds in steps of 0.1°, with the final spectrum collected at the end.

[0126] Ta is defined as the total area between the spectral curve and the baseline, expressed in counts / second • 2Θ; and Aa is defined as the total amorphous area, expressed in counts / second • 2Θ. Ca is the total crystalline area, expressed in counts / second • 2Θ.

[0127] Analyze the spectrum or diffraction pattern using the following steps:

[0128] 1) Define a suitable linear baseline for the entire spectrum and calculate the total area (Ta) between the spectral curve and the baseline;

[0129] 2) Define a suitable amorphous curve along the entire spectrum, which separates the amorphous region from the crystalline region according to the two-phase model;

[0130] 3) Calculate the amorphous area (Aa) as the area between the amorphous curve and the baseline;

[0131] 4) The crystallization area (Ca) is calculated as the area between the spectral curve and the amorphous curve, such as Ca = Ta - Aa; and

[0132] 5) Calculate the crystallinity of the sample using the following formula:

[0133] %Cr = 100 × Ca / Ta

[0134] Density: Determined according to ISO 1183-1, Method A, Part 1: Immersion method. Test specimens were obtained by compressing a molded substrate. The density of polybutene-1 was measured after 10 days of conditioning.

[0135] Fractions soluble in xylene and insoluble at 0°C: 2.5 g of the polymer composition and 250 cm³ of... 3 o-Xylene was introduced into a glass flask equipped with a refrigeration unit and a magnetic stirrer. The temperature was raised to the boiling point of the solvent within 30 minutes. The resulting clear solution was then kept under reflux and stirred for another 30 minutes. The sealed flask was then cooled to 100°C with stirring in air for 10 to 15 minutes, and then held for 30 minutes, followed by 60 minutes in a constant-temperature water bath at 0°C. The solid thus formed was filtered through rapid filter paper at 0°C. 100 cm⁻¹ 3 The filtrate was poured into a pre-weighed aluminum container and heated on a hot plate under a nitrogen stream to remove the solvent by evaporation. Therefore, the fraction (by weight) of polymers (XS) soluble in xylene was calculated from the average weight of the residue. The fraction (XI) of polymers insoluble in o-xylene at 0°C was calculated as: XI (%) = 100 - XS (%).

[0136] Yellowness index measured according to ASTM method D1925.

[0137] Tensile stress and yield elongation. Sample preparation: Set the oven to 175°C. Place the adhesive to be tested into an aluminum cup and melt it in the oven for approximately 1 hour. Pour the molten adhesive onto silicone paper sheets and allow it to cool to 23±1°C. Cut approximately 10gr cubes from each sample. Turn on the hot press and set the plate temperature to 85°C. Place the pre-weighed adhesive cubes in the center of two silicone paper sheets, with two 0.5mm metal spacers on each side. Press for approximately 2 minutes, turn off the press, and check for a flat and uniform surface with a thickness of approximately 0.5mm±0.05mm; if not, repeat the operation with a new sample. Allow to cool to 23±1°C. After 24 hours, cut standard dumbbell-shaped test specimens with the following dimensions:

[0138]

[0139] The test specimen was conditioned at 23°C for at least 24 hours, and the thickness was reconfirmed using a micrometer. Test method: In the force gauge, a separation speed of 60 mm / min and an elongation limit of 300 mm were set. The test specimen was clamped in the force gauge clamp, and traction was initiated, and a stress-strain curve was plotted. The yield point is the first point on the stress-strain curve where strain increases without stress increase. The tensile stress at yield is the stress value at the yield point; the elongation at yield is the percentage deformation at the yield point.

[0140] Ring and Ball Softening Point. The softening point is defined as the temperature at which a sample pan held in a horizontal ring is forced to descend 25.4 mm under the weight of a steel ball (diameter: 9.5 mm; weight: 3.5 ± 0.05 g) when the sample is heated in a glycerol bath at 5 °C / min. This test method is intended for use with the HERZOG HRB 754 instrument to determine the softening point of hot-melt adhesives and hot-melt raw materials. The adhesive sample is melted in an oven and filled into the ring. Conditioning is performed at 23 ± 1 °C for at least 4 hours. The ring is accurately inserted into the retainer, the bead guide holder is positioned, and the bead is checked for free movement before immersing it in a glycerol bath. A beaker is placed on the instrument's heating plate, and the retainer with the ring and thermometer are immersed. Sample identification data (name and batch number) is set on the control panel, and the determination begins. After analysis, the instrument will indicate the detected temperature. Results are expressed in °C.

[0141] Cloud point. The cloud point is the temperature at which an HMA composition becomes cloudy upon cooling. The HMA composition is melted at 170°C. A thermometer is immersed in the molten adhesive material, and the material is allowed to cool. When the adhesive becomes cloudy, the temperature measured by the thermometer is recorded as the cloud point of the adhesive.

[0142] Open time. Open time is defined as the maximum time an adhesive material retains its bonding ability. It is the time during which a useful bond can form after the adhesive has been applied. (Using 400g / m²) 2 The test was conducted using 70×50mm single-sided coated paperboard. A uniform 10×50mm layer of molten adhesive at 180°C was applied to the first paperboard using a spray gun with a pressure of 1 bar. After a 1-second time span (holding time), a second paperboard was bonded to the first paperboard by pressing it with a pressure of 0.8 bar for 1 second. Immediately after pressing, the second substrate was pulled perpendicularly to the first paperboard at a speed of 3000 mm / min. If a useful bond is formed, 100% of the fibers in the bonded area will be torn. The test was repeated, with the holding time increasing in 1-second increments. The open time is the holding time when less than 100% of the paperboard fibers are torn. The average open time was taken from 5 tests performed on the same HMA composition.

[0143] Settling Time: Settling time is the time required to form an acceptable bond when two substrates are joined together with an adhesive. A uniform 10×50 mm layer of adhesive molten at 180°C is applied to the first cardboard using a spray gun at a pressure of 1 bar. After 1 second, the second cardboard is bonded to the first cardboard by pressing it at a pressure of 0.8 bar for 0.05 seconds. After pressing, the second substrate is pulled perpendicularly to the first cardboard at a speed of 3000 mm / min. The pressing time is increased in increments of 0.02 seconds until the cardboard fibers are completely torn (settling time). The average settling time is taken from 5 tests performed on the same HMA composition.

[0144] Shear-adhesive failure temperature (SAFT). This test method determines the temperature at which a specimen bonded with a hot-melt adhesive delaminates under static shear load. The test specimens are prepared as follows: at 400 g / m²... 2 A 10×50mm hot melt adhesive strip is applied to the first 70×50mm single-sided coated cardboard using a spray gun (operated at 1 bar pressure) at a temperature of 180°C; 400g / m² adhesive is then applied at a pressure of 0.8 bar. 2 A second 70×50mm single-sided coated paperboard was bonded to the first paperboard. At least five test specimens were prepared for each adhesive and conditioned at 23°C and 50% RH for 24 hours. The oven was preheated to 50°C, one end of the test specimen was hung in the oven, and a 500g weight was attached to the other end. The oven temperature was increased at a rate of 5°C per hour. The temperature at which the adhesive failed (delamination) was recorded as the shear adhesion failure temperature.

[0145] Flexural modulus was measured according to ISO 178. Test specimens for flexural testing were cut from compression molded substrates that had been pressed at 200°C and aged at 25°C ± 1°C for 10 days. The specimen thickness was 4 mm.

[0146] raw material

[0147] Tackifier Escorez TM 5400 is an alicyclic hydrocarbon resin sold by ExxonMobil, which has a softening point of 103.4°C and a melt viscosity of 800 mPa·s at 160°C.

[0148] PP wax Deurex® P 3815 M is a polypropylene wax marketed by Deurex AG, which has a dropping point of 150°C, a penetration of 3 dmm, a weight average molecular weight of 5,781 Mw, and a Mw / Mn ratio of 4.2.

[0149] FT wax (1)Sasolwax H1 is a high-melting-point Fischer wax marketed by Sasol, with a dropping point of 112°C, a penetration of 1 dmm, a weight-average molecular weight of 1,863 Mw, and a Mw / Mn ratio of 1.3.

[0150] FT wax (2) Sasolwax C80M is a low-melting-point Fischer wax marketed by Sasol, with a dropping point of 97°C, a penetration of 7 dmm, a weight-average molecular weight of 1,145, and a Mw / Mn ratio of 1.1.

[0151] Preparation of catalyst components: Dimethylsilyl{(2,4,7-trimethyl-1-indenyl)-7-(2,5-dimethyl-cyclopentano[1,2-b:4,3-b']-dithiophene)}zirconium dichloride (metallocene A-1) was prepared according to Example 32 of WO01 / 47939.

[0152] Preparation of the catalyst solution: Under a nitrogen atmosphere, 6400 g of a 33 g / L solution of triisobutylaluminum (TIBA) in isododecane and 567 g of a 30% wt / wt solution of methylaluminoxane (MAO) in toluene were loaded into a 20 L jacketed glass reactor. The reactor was stirred using an anchor stirrer and allowed to react at 25 °C for approximately 1 hour with stirring. After this time, 1.27 g of metallocene A-1 was added and dissolved with stirring for approximately 30 minutes. The final solution was discharged from the reactor into a cylinder through a filter to remove the final solid residue. The composition of the resulting solution was as follows:

[0153]

[0154] Preparation of butene-1 copolymer [component (A)]: Polymerization was carried out in two stirred reactors operating in series, with liquid butene-1 forming the liquid medium. The catalyst system described above was injected into both reactors and polymerization was continued.

[0155] PB(1) was prepared according to Example 1 of WO2020 / 016143A1, and PB(2) was prepared according to the preparation of butene-1 polymer B)-I described in WO2022 / 084081, Table 1. PB(3) was prepared according to the polymerization process described in WO2020 / 016143A1 under the following conditions:

[0156] Table 1

[0157]

[0158] The butene-1 copolymer was recovered from the solution as a melt and granulated. The copolymer was further characterized, and the data are reported in Table 2.

[0159] Table 2

[0160]

[0161] *BV: Brinell viscosity

[0162] Preparation of hot melt adhesive composition: The components were melted in an aluminum can in a melter at 175°C and the melted composition was mixed at 200 rpm for 2 hours at 175°C using a small mixer IKA RW20 with a stirring bar.

[0163] Examples E1 to E3

[0164] The hot melt adhesive compositions prepared according to this disclosure are as described above, and their formulations are indicated in Table 3. The results of tests performed on these compositions are summarized in the same Table 3.

[0165] Table 3

[0166]

[0167]

[0168] *BV: Brinell viscosity

[0169] Comparative Examples CE4 to CE9

[0170] For comparative purposes, hot-melt adhesive compositions containing Fischer-Tropsch wax were prepared according to the method described above. The formulations and test results are summarized in Table 4.

[0171] Table 4

[0172]

[0173] *BV: Brinell viscosity

[0174] The HMA compositions disclosed herein exhibit an optimal balance of properties, such as an improved combination of mechanical properties, SAFT, open and solidification times, and ring and ball softening points.

Claims

1. A hot melt adhesive composition, said hot melt adhesive composition comprising: (A) A copolymer of 25% to 50% by weight of butene-1 and at least one comonomer, said at least one comonomer being selected from ethylene, propylene, C5-C10 α-olefins and combinations thereof, said copolymer having a total polymeric comonomer content of 0.5% to 8.0% by weight as determined by IR spectroscopy and a melt flow rate (MFR) equal to or greater than 200 g / 10 min as measured according to ISO 1133-1:2011 (190 °C, 2.16 kg); (B) 30% to 60% by weight of tackifier; and (C) 5% to 30% polypropylene wax by weight The quantities of (A), (B), and (C) are based on the total weight of (A) + (B) + (C).

2. The hot melt adhesive composition according to claim 1, wherein the butene-1 copolymer (A) has a melt flow rate (MFR) of 200 to 3,000 g / 10 min, preferably 400 to 1,700 g / 10 min, more preferably 500 to 1,600 g / 10 min (ISO 1133-1:2011, 190°C / 2.16 kg).

3. The hot melt adhesive composition according to claim 1 or 2, wherein the butene-1 copolymer (A) has a total polymeric comonomer content of 0.7% to 7.0% by weight based on the total weight of the butene-1 copolymer (A), wherein the comonomer content is determined by IR spectroscopy.

4. The hot melt adhesive composition according to any one of the preceding claims, wherein the butene-1 copolymer (A) contains a comonomer selected from ethylene, propylene, hexene-1, octene-1, and combinations thereof, with ethylene being particularly preferred.

5. The hot melt adhesive composition according to any one of the preceding claims, wherein the butene-1 copolymer (A) comprises: - Fraction (A1) comprising butene-1 homopolymer or butene-1 copolymer with a comonomer of less than 3% by weight based on fraction (A1), wherein the comonomer is selected from ethylene, propylene, C5-C10 α-olefins and combinations thereof. - Fraction (A2), comprising a copolymer of butene-1 and 3% to 10% by weight of a comonomer based on fraction (A2), wherein the comonomer is selected from ethylene, propylene, C5-C10 α-olefins, and combinations thereof. The butene-1 copolymer (A) wherein the butene-1 copolymer has: - The total content of polymeric comonomers based on the total weight of fractions (A1) and (A2) is 0.5% to 8.0% by weight, preferably 0.7% to 7.0% by weight; - Melt flow rate (MFR(I)) equal to or greater than 200 g / 10 min, as measured according to ISO 1133-1:2011 (190 °C, 2.16 kg); and - The content of the fraction that is soluble in xylene at 0°C, determined by the total weight of fractions (A1) and (A2) and using the methods described in the Examples section, equal to or less than 80% by weight, preferably ranging from 20% to 80% by weight. Furthermore, the content of the comonomer was determined by IR spectroscopy.

6. The hot melt adhesive composition according to claim 5, wherein the butene-1 copolymer (A) comprises 15% to 70% by weight, particularly 20% to 65% by weight, fraction (A1), and 30% to 85% by weight, particularly 35% to 80% by weight, fraction (A2), wherein the amounts of fractions (A1) and (A) are based on the total weight of fractions (A1) and (A2).

7. The hot melt adhesive composition according to claim 5 or 6, wherein the comonomer is ethylene.

8. The hot melt adhesive composition according to any one of the preceding claims, wherein the butene-1 copolymer (A) has at least one of the following characteristics: (a) A molecular weight distribution Mw / Mn of less than 4, preferably less than 3, more preferably less than 2.5, with a lower limit of 1.5 in all cases, wherein the molecular weight distribution is determined by NMR; and / or (b) Having one or more melting peaks Tm(II) at temperatures equal to or below 110°C, preferably equal to or below 105°C, more preferably ranging from 80°C to 103°C, wherein Tm(II) is measured by DSC; and / or (c) Glass transition temperature (Tg) measured by DSC in the range of -40°C to -10°C, preferably -30°C to -10°C; and / or (d) Brinell viscosity at 190°C below 15,000 mPa·s, preferably in the range of 3,000 to 15,000 mPa·s; and / or (e) X-ray crystallinity in the range of 20% to 60%, preferably in the range of 25% to 50%; (f) Between 0.89 and 0.91 g / cm³ 3 Density within the range; and / or (g) Yellowness index less than 0, specifically ranging from -1 to -5.

9. The hot melt adhesive composition according to any one of the preceding claims, wherein the tackifier (B) is solid at a temperature of 25°C ± 1°C, and preferably has a softening point greater than 100°C.

10. The hot melt adhesive composition according to any one of the preceding claims, wherein the polypropylene wax (C) has a weight average molecular weight Mw of 10,000 g / mol or less, preferably 8,000 g / mol or less, more preferably in the range of 3,000 to 7,000 g / mol, as measured by GPC, and / or a molecular weight distribution Mw / Mn in the range of 3.0 to 6.0, as measured by GPC.

11. The hot melt adhesive composition according to any one of the preceding claims, wherein the polypropylene wax (C) has a dropping point of 140°C to 157°C, preferably 145°C to 155°C (DGF M-III 3, similar to DIN 51801).

12. The hot melt adhesive composition according to any one of the preceding claims, wherein the hot melt adhesive composition further comprises a component (D) selected from the group consisting of: a plasticizer; an olefin oligomer or a low molecular weight polyolefin; an amorphous polyα-olefin different from the polybutene-1 component (A); a thermoplastic polyurethane; an ethylene / (meth)acrylate copolymer; an ethylene / vinyl acetate copolymer; and combinations thereof.

13. The hot melt adhesive composition according to claim 12, wherein the amount of component (D) ranges from 0% to 15% by weight based on the total weight of the HMA composition.

14. The hot melt adhesive composition according to any one of the preceding claims, the hot melt adhesive composition further comprising 0.05% to 5.0% by weight of an additive (E) based on the total weight of the HMA composition, said additive preferably selected from antioxidants, light stabilizers, and combinations thereof.

15. An article comprising a first substrate and a second substrate, wherein the first substrate is bonded to the second substrate by a hot melt adhesive composition according to any one of claims 1 to 14, the hot melt adhesive composition being inserted between the first substrate and the second substrate.

16. The article of claim 15, wherein the first substrate and the second substrate are made of materials independently selected from the group consisting of wood, paper, cardboard, natural leather, plastic materials, natural fibers such as cotton or linen, and combinations thereof.

17. The article of claim 15 or 16, wherein the first substrate and the second substrate are independently selected from the group consisting of: film, sheet, panel, woven fabric and nonwoven fabric.

18. The article of claim 15, wherein the first substrate and the second substrate are made of paper or paperboard, and the hot melt adhesive composition of any one of claims 1 to 14, inserted between the first substrate and the second substrate, has a rotational (Bruch's) viscosity at 180°C equal to or less than 7,000 mPa·s, more preferably less than 5,000 mPa·s, and still more preferably less than 2,000 mPa·s.

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