Butene-1 polymer masterbatch composition for foaming applications

Abstract

A masterbatch composition is provided comprising: A) 25 wt% to 80 wt% of a butene-1 polymer composition comprising: a) a butene-1 homopolymer or copolymer having a copolymerized comonomer content (CA) of up to 5 mol%, and b) a butene-1 copolymer having a copolymerized comonomer content (CB) of greater than 5 mol% to 25 mol%, wherein the amount of polymer a) ranges from 5 wt% to 95 wt%, said butene-1 polymer composition having: i) a total copolymerized comonomer content of 4 mol% to 18 mol%, and ii) a fraction soluble in xylene at 0°C of 35 mol% to 90 mol%, iii) a melt flow rate value of 30 to 1000 g / 10 min; B) 20 wt% to 75 wt% of at least one endothermic chemical blowing agent; and C) 0 wt% to 50 wt% of at least one nucleating agent.

Description

Technical Field

[0001] This disclosure relates to a polymer masterbatch composition suitable for foaming applications, particularly for foaming propylene polymers. The masterbatch composition of this disclosure comprises a butene-1 polymer carrier and at least an endothermic chemical foaming agent. Optionally, the masterbatch composition further comprises a nucleating agent. Background Technology

[0002] Polymer compositions containing butene-1 polymers exhibit advantageous properties such as chemical inertness and moisture resistance over a wide temperature range, as well as high flexibility and good mechanical properties.

[0003] EP2864403A1 discloses a polymer foam based on butene and ethylene. The butene copolymer has a melt temperature ranging from 60°C to 120°C. The foam also contains sodium bicarbonate and talc additives as chemical foaming agents that promote foaming.

[0004] GB1277161A discloses a process for preparing molded polyolefin cellular foamed products. The olefin polymer can be polyethylene, polypropylene, or polybutene. Sodium bicarbonate can be used as a foaming agent.

[0005] US20030037633A1 discloses a steering wheel that includes a rim portion, a spoke portion, and a foam filler material. The foam filler material may include a thermoplastic polyolefin elastomer (such as polybutene) and 0.1% to 10% by weight of a vaporized chemical foaming agent (such as sodium bicarbonate).

[0006] It has now been found that masterbatch compositions with advantageous properties can be achieved by combining butene-1 polymer compositions having specific total copolymer comonomer content, fractions soluble in xylene at 0°C, and melt flow rates with chemical foaming agents and optionally nucleating agents. Summary of the Invention

[0007] In a first aspect, this disclosure provides a masterbatch composition comprising:

[0008] A) 25% to 80% by weight of a butene-1 polymer composition, the butene-1 polymer composition comprising:

[0009] (a) at least one butene-1 homopolymer, or a copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, the copolymer having a comonomer content (C) in the range of up to 5 mol%. A ),and

[0010] (b) A copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, wherein the at least one copolymer has a comonomer content in the range of greater than 5 mol% to 25 mol% (C B ),

[0011] The amount of polymer (a) is based on the total weight of polymers (a) and (b) ranging from 5% to 95% by weight.

[0012] The butene-1 polymer composition has the following characteristics:

[0013] i) The total content of polymeric comonomers, based on the total weight of polymers (a) and (b), ranging from 4 mol% to 18 mol%.

[0014] ii) A fraction of polymers (a) and (b) that is soluble in xylene at 0 °C, comprising 35% to 90% by weight of the total weight of the polymers.

[0015] iii) Melt flow rate values ​​in the range of 30 to 1000 g / 10 min, as measured according to ISO 1133 at 190 °C and a load of 2.16 kg;

[0016] B) At least one endothermic chemical foaming agent, ranging from 20% to 75% by weight;

[0017] C) At least one nucleating agent, ranging from 0% to 50% by weight.

[0018] The amounts of components A), B) and C) are based on the total weight of the masterbatch composition.

[0019] In a second aspect, this disclosure relates to a process for preparing a masterbatch composition.

[0020] In a third aspect, this disclosure relates to the use of a masterbatch composition in a method of foaming thermoplastic polyolefins.

[0021] In a fourth aspect, this disclosure relates to a process for preparing thermoplastic polyolefin foamed articles.

[0022] The masterbatch compositions disclosed herein exhibit ultra-low volatile matter content and have a clean emissions profile. Furthermore, the masterbatch compositions disclosed herein are highly compatible with thermoplastic polyolefins, particularly polypropylene, and can be used in a wide range of foaming applications.

[0023] The foamed articles obtained by adding the masterbatch composition of this disclosure to a thermoplastic polyolefin base resin exhibit a structure with finely distributed cells in a uniform manner. Attached Figure Description

[0024] Figure 1A schematic diagram of a foamed sample is provided, illustrating a method for determining the total thickness, skin thickness, unfoamed layer thickness, and foamed layer thickness of a foamed article.

[0025] Figure 2 SEM images of the foaming material of Example E1 are provided.

[0026] Figure 3 SEM images of the foaming material of Example E2 are provided.

[0027] Figure 4 SEM images of the foaming material of Example E3 are provided.

[0028] Figure 5 SEM images of the foaming material of Example CE4 are provided. Detailed Implementation

[0029] In the context of this disclosure;

[0030] - Unless otherwise stated, the total weight of the polymer composition or masterbatch is 100% by weight.

[0031] - The term “composed of” in relation to polymers or polymer compositions, mixtures or blends shall be interpreted as meaning “composed of or substantially composed of”;

[0032] The term "substantially composed of" means that other components, besides those mandatory ones, may also be present in the material, provided that the essential characteristics 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 polymer or polyolefin compositions, mixtures, or blends are catalyst residues, antistatic agents, and processing aids;

[0033] - The term "copolymer" refers to a polymer derived from at least two different comonomers through intentional polymerization; that is, the term "copolymer" includes terpolymers.

[0034] - The term "masterbatch" refers to a powdered, granular, or pelletized composition comprising a mixture of two or more components used to simplify the metering of at least one component of the composition into a base resin during the formation of the final product, such as a foamed product.

[0035] The masterbatch composition of the first aspect of this disclosure comprises:

[0036] A) 25% to 80% by weight of a butene-1 polymer composition, the butene-1 polymer composition comprising:

[0037] (a) at least one butene-1 homopolymer, or a copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, the copolymer having a comonomer content (C) in the range of up to 5 mol%. A ),and

[0038] (b) A copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, wherein the at least one copolymer has a comonomer content in the range of greater than 5 mol% to 25 mol% (C B ),

[0039] The amount of polymer (a) is based on the total weight of polymers (a) and (b) ranging from 5% to 95% by weight.

[0040] The butene-1 polymer composition has the following characteristics:

[0041] i) The total content of polymeric comonomers, based on the total weight of polymers (a) and (b), ranging from 4 mol% to 18 mol%.

[0042] ii) A fraction of polymers (a) and (b) in which 35% to 90% by weight of the total weight of the polymers is soluble in xylene at 0°C, and

[0043] iii) The melt flow rate value MFR(A) in the range of 30 to 1000 g / 10 min, as measured according to ISO 1133 at 190 °C and a load of 2.16 kg;

[0044] B) 20% to 75% by weight of at least one endothermic chemical foaming agent; and

[0045] C) At least one nucleating agent, ranging from 0% to 50% by weight.

[0046] The amounts of components A), B) and C) are based on the total weight of the masterbatch composition.

[0047] Preferably, component A) comprises:

[0048] 20% to 70% by weight, preferably 30% to 60% by weight of polymer (a), and

[0049] 80% to 30% by weight, preferably 70% to 40% by weight of polymer (b), each based on the total weight of polymers (a) and (b).

[0050] In one embodiment, component A) consists of the amounts of polymer (a) and polymer (b) disclosed above.

[0051] Preferably, i) the total content of the copolymerized comonomer is in the range of 5 mol% to 12 mol% based on the total weight of polymers (a) and (b).

[0052] Preferably, ii) the solubility in xylene at 0°C is in the range of 48% to 62% by weight based on the total weight of polymers (a) and (b).

[0053] Preferably, component A) has a melt flow rate value MFR(A) in the range of 40 to 800 g / 10 min, preferably 100 to 300 g / 10 min, as measured according to ISO 1133 at 190 °C and a load of 2.16 kg.

[0054] The specific melt flow rate values ​​of polymers (a) and (b) can be widely selected, provided that the melt flow rate value MFR(A) of the overall butene-1 polymer composition A) is obtained.

[0055] In this regard, it is well known that the logarithm of the melt flow rate value of polyolefin blends (and therefore blends of butene-1 polymers) is generally given by the sum of the product of the weight fraction of the melt flow rate value of the individual polymer and its logarithm.

[0056] Therefore, the melt flow rate value of the polymer composition made from the blend of polymers (a) and (b) is determined by the following relationship:

[0057] log MFR(a+b) = W A log MFR(a) + W B log MFR(b)

[0058] Where MFR(a+b) is the melt flow rate value of the blend of (a) and (b), MFR(a) and MFR(b) are the melt flow rate values ​​of polymers (a) and (b), respectively, and W A and W B This refers to the corresponding weight fraction. For example, when the blend is made of 40% by weight polymer (a) and 60% by weight polymer (b), W A and W B It is 0.4 and 0.6.

[0059] The butene-1 polymer composition has measurable crystallinity, as demonstrated by the presence of the melting temperature peak of the crystalline butene-1 polymer in differential scanning calorimetry (DSC) spectra.

[0060] Specifically, the butene-1 polymer composition A) exhibited one or more melting peaks in the measured second DSC heating scan, as described in the experimental section. These temperature peaks, or multiple temperature peaks, are attributed to the melting point (Tm(II)) of butene-1 polymer crystal form II, and the area under the peak (or multiple peaks) is taken as the total enthalpy of fusion (DH Tm(II)). If more than one peak exists, the highest (strongest) peak is taken as Tm(II).

[0061] Preferably, component A) has a Tm(II) value, as measured by DSC at a scan rate of 10°C / min, in the range of 70°C to 105°C, preferably 75°C to 100°C, more preferably 77°C to 90°C, and particularly in the range of 79°C to 85°C.

[0062] The specific total DH Tm(II) value of the butene-1 polymer composition A) was measured at a scanning speed of 10 °C / min and was equal to or less than 15 J / g, particularly 3 to 15 J / g.

[0063] Furthermore, in a DSC heating scan performed after aging, the butene-1 polymer composition A) exhibited one or more melting peaks that appeared at a temperature equal to or greater than the temperature Tm(II) attributed to the melting point of crystal form II. Such temperature peaks, or multiple temperature peaks, are attributed to the melting point (Tm(I)) of crystal form I of the butene-1 polymer. If more than one peak exists, the highest (strongest) peak is taken as Tm(I). Therefore, for the butene-1 polymer composition A), the equation Tm(I) ≥ Tm(II) is satisfied.

[0064] The area under the peak (or multiple peaks) is taken as the total enthalpy of fusion (DH Tm(I)). Measured at a scan rate of 10 °C / min, the specific total DH Tm(I) value of the butene-1 polymer composition A) is 50 J / g or less, particularly 25 to 50 J / g, and preferably 30 to 50 J / g.

[0065] The butene-1 polymer composition A) preferably also has a detectable amount of crystal form III. Crystal form III can be detected by X-ray diffraction, which is described in the following: Journal of Polymer Science, Part B: Polymer Letters, Vol. 1, No. 11, pp. 587-591, November 1963 or Macromolecules, Vol. 35, No. 7, 2002.

[0066] Preferably, the butene-1 polymer composition A) has a Brinell viscosity, measured at 190°C according to ASTM D3236-15 (2021), in the range of 10,000 to 270,000 mPa∙s, preferably in the range of 15,000 to 250,000 mPa∙s, more preferably in the range of 20,000 to 200,000 mPa∙s, particularly in the range of 25,000 to 150,000 mPa∙s, such as in the range of 30,000 to 100,000 mPa∙s, or 35,000 to 50,000 mPa∙s.

[0067] In a preferred embodiment, the polymer (a) in the butene-1 polymer composition A) has 1 mol% to 4 mol% of comonomer (C A ).

[0068] Preferably, the polymer (b) in component A) has 8 mol% to 20 mol% of comonomer (C) B ).

[0069] Preferably, when both (a) and (b) are copolymers, the difference between the percentage values ​​of the comonomer content of (a) and (b) satisfies the following relationship:

[0070] (C) B )–(C A )≥ 5; or preferably, (C B )–(C A ≥ 6.

[0071] Preferably, the comonomers in polymers (a) and (b) contained in component A) are ethylene.

[0072] Specific examples of higher α-olefins that can exist as comonomers in polymers (a) and (b), in addition to or as a substitute for ethylene, are α-olefins having the formula CH2=CHR (where R is methyl or an alkyl group containing 3 to 8 or 3 to 6 carbon atoms), such as propylene, hexene-1 and octene-1.

[0073] In a preferred embodiment, component A) has a concentration equal to or greater than 0.89 g / cm³. 3 Preferably, the concentration is between 0.89 and 0.92 g / cm³. 3 The density within the range.

[0074] Preferably, component A) has an Mw / Mn value that is equal to or less than 4, particularly equal to or less than 3, or equal to or less than 2.5, with a lower limit of 1.5 in all cases, where Mw is the weight-average molecular mass and Mn is the number-average molecular mass, both of which are measured by GPC.

[0075] Furthermore, the butene-1 polymer composition A) preferably has at least one of the following additional characteristics, more preferably all of the following additional characteristics:

[0076] - Mw equal to or greater than 50,000, particularly 50,000 to 180,000 g / mol, such as 70,000 to 150,000 g / mol; and / or

[0077] - Mz equal to or greater than 90,000 g / mol, particularly 90,000 to 200,000 g / mol, such as 100,000 to 190,000 g / mol; and / or

[0078] - An intrinsic viscosity (IV) equal to or less than 0.7 dl / g, particularly 0.2 dl / g to 0.7 dl / g, such as 0.5 dl / g to 0.6 dl / g, as measured by ASTM D2857-22 in tetrahydronaphthalene (THN) at 135°C; and / or

[0079] - For operation at 150.91MHz 13 C-NMR measurements of higher than 90%, particularly higher than 93%, such as higher than 95%, of isotactic pentavalents (mmmm); and / or

[0080] -Using at 150.91MHz 13 C-NMR could not detect the 4,1 insertion; and / or

[0081] - Shore hardness D values ​​equal to or less than 50, particularly 25 to 50, such as 25 to 45, as measured according to ISO 868:2003; and / or

[0082] - Tensile modulus from 30 MPa to 150 MPa, particularly from 50 MPa to 120 MPa, measured at 23 °C, according to ISO 527-1:2019 and ISO 527-2:2019.

[0083] Butene-1 polymers (a) and (b) are preferably obtained by polymerizing monomers in the presence of a metallocene catalyst system, which can be obtained by contacting the following substances:

[0084] -Stereorigid metallocene compounds;

[0085] -Aluminoxanes or compounds capable of forming alkyl metallocene cations; and optionally,

[0086] - Organoaluminum compounds.

[0087] Preferably, the stereolithic metallocene compound belongs to the following formula (I):

[0088]

[0089] in:

[0090] M is an atom selected from transition metals belonging to Group 4; preferably, M is zirconium;

[0091] X, which may be the same as or different from each other, is a hydrogen atom, a halogen atom, R, OR, OR'O, OSO2CF3, OCOR, SR, NR2, or PR2 group, wherein R is a straight-chain or branched, saturated or unsaturated C1-C group. 20 -alkyl, C3-C 20 -Cycloalkyl, C6-C 20 -Aryl, C7-C 20 -alkylaryl or C7-C 20 -Arylalkyl radical, optionally containing a heteroatom belonging to Groups 13 to 17 of the periodic table; and R' is C1-C 20 -alkylene, C6-C 20 -Asaryl, C7-C 20 -alkylarylene or C7-C 20 -Arylalkylene radical; preferably, X is a hydrogen atom, a halogen atom, an OR'O or an R group; more preferably, X is a chlorine or methyl radical;

[0092] R that are the same or different from each other 1 R 2 R 5 R 6 R 7 R 8 and R 9 It is a hydrogen atom, or a straight-chain or branched, saturated or unsaturated C1-C atom. 20 -alkyl, C3-C 20 -Cycloalkyl, C6-C 20 -Aryl, C7-C 20 -alkylaryl or C7-C 20 -Arylalkyl radical, optionally containing a heteroatom belonging to Groups 13 to 17 of the periodic table; or R 5 and R 6 , and / or R 8 and R 9 Optionally, saturated or unsaturated 5-membered or 6-membered rings are formed, wherein the rings optionally contain C1-C2. 20 Alkyl radicals are used as substituents; the condition is R. 6 Or R 7 At least one of them is a straight-chain or branched, saturated or unsaturated C1-C 20-alkyl radical, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably C1-C 10 -alkyl radical;

[0093] R that are the same or different from each other 3 and R 4 It is a straight-chain or branched, saturated or unsaturated C1-C 20 -alkyl radicals, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably, R atoms that are the same or different from each other. 3 and R 4 It is C1-C 10 -alkyl radical; more preferably, R 3 It is a methyl or ethyl radical; and R 4 It is a methyl, ethyl, or isopropyl free radical.

[0094] Preferably, the compound of formula (I) has formula (Ia):

[0095] (Ia)

[0096] in:

[0097] M, X, R 1 R 2 R 5 R 6 R 8 and R 9 As described above;

[0098] R 3 It is a straight-chain or branched, saturated or unsaturated C1-C 20 -alkyl radical, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably, R 3 It is C1-C 10 -alkyl radical; more preferably, R 3 It is a methyl or ethyl free radical.

[0099] Specific examples of metallocene compounds are dimethylsilyl{(2,4,7-trimethyl-1-indyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}zirconium dichloride; dimethylsilyl{(1-(2,4,7-trimethylindyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}zirconium dichloride; or dimethylsilyl{(1-(2,4,7-trimethylindyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}dimethylzirconium.

[0100] Preferred aluminum oxanes are methylaluminoxane (MAO), tetra-(isobutyl)aluminoxane (TIBAO), tetra-(2,4,4-trimethyl-pentyl)aluminoxane (TIOAO), tetra-(2,3-dimethylbutyl)aluminoxane (TDMBAO) and tetra-(2,3,3-trimethylbutyl)aluminoxane (TTMBAO).

[0101] An example of a compound capable of forming an alkyl metallocene cation is formula D. + E - Compound, in which D + It is a Brønsted acid, which can donate a proton and react irreversibly with the metallocene substituent X of formula (I), and E - It is a compatible anion that can stabilize the active catalyst derived from the reaction of the two compounds, and is sufficiently unstable to be removed by the olefin monomer. Preferably, the anion E - It includes one or more boron atoms.

[0102] Examples of organoaluminum compounds are trimethylaluminum (TMA), triisobutylaluminum (TIBA), tri(2,4,4-trimethyl-pentyl)aluminum (TIOA), tri(2,3-dimethylbutyl)aluminum (TDMBA), and tri(2,3,3-trimethylbutyl)aluminum (TTMBA).

[0103] Examples of catalyst systems and polymerization processes using such catalyst systems can be found in WO2004 / 099269 and WO2009 / 000637.

[0104] In one embodiment, polymers (a) and (b) are prepared separately by operating under known polymerization conditions and in the presence of the catalyst system described above, and then blended together in the molten state using known polymer processing equipment such as single-screw and twin-screw extruders.

[0105] Preferably, butene-1 polymer composition A is prepared directly in polymerization (reactor blend).

[0106] Therefore, the polymerization process for producing the composition includes at least two consecutive polymerization stages carried out in two or more reactors connected in series, wherein polymers (a) and (b) are prepared in separate subsequent stages, and in each stage except the first stage, the process is carried out in the presence of the polymer formed and the catalyst used in the previous stage.

[0107] When the butene-1 polymer composition A) is a reactor blend, the amounts of polymer (a) and polymer (b) in the butene-1 polymer composition A) correspond to the separation between polymerization stages.

[0108] The polymerization process is preferably 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. Liquid polymerization is preferred.

[0109] The catalyst is preferably added only in the first reactor, or less preferably in more than one reactor.

[0110] In liquid polymerization, when a hydrocarbon solvent is used, it is either aromatic (such as toluene) or aliphatic (such as propane, hexane, heptane, isobutane, cyclohexane, and 2,2,4-trimethylpentane and isododecane). Preferably, liquid butene-1 is used as the polymerization medium for the polymerization process.

[0111] The polymerization temperature is preferably between 20°C and 150°C, particularly between 50°C and 90°C, such as between 65°C and 82°C.

[0112] The concentration of hydrogen in the liquid phase during the polymerization reaction (mol ppm H2 / butene-1 monomer) is preferably from 1000 ppm to 6000 ppm, particularly from 1900 ppm to 5500 ppm, such as from 1100 to 1800 ppm.

[0113] When preparing copolymers, the amount of comonomer (especially ethylene) in the liquid phase is preferably 0.1% to 8% by weight, particularly 0.2% to 7% by weight, relative to the total weight of the comonomer and butene-1 monomer present in the polymerization reactor.

[0114] Preferably, component B) is selected from the group consisting of alkali metal citrates, alkali metal bicarbonates, and combinations thereof. In a preferred embodiment, B) is sodium citrate or a mixture of sodium citrate and sodium bicarbonate.

[0115] In one embodiment, the masterbatch composition comprises 1% to 50% by weight of component C). Preferably, component C is talc.

[0116] Preferably, the masterbatch composition comprises:

[0117] -35% to 65% by weight, more preferably 40% to 55% by weight, particularly 45% to 50% by weight of component A),

[0118] -20% to 40% by weight, preferably 25% to 35% by weight, particularly 27% to 33% by weight of component B), and

[0119] -10% to 45% by weight, preferably 15% to 35% by weight, particularly 17% to 30% by weight of component C),

[0120] Each is based on the total weight of the masterbatch composition.

[0121] The masterbatch composition optionally further comprises up to and including 15% by weight, preferably 1% to 15% by weight, more preferably 5% to 12% by weight, of at least one wax (D) based on the total weight of the masterbatch composition, wherein the wax is preferably a polyolefin wax, such as Licowax PE 520 sold by Clariant.

[0122] The masterbatch composition optionally further comprises up to and including 5% by weight, such as from 0.1% to 5% by weight, at least one additive (E) selected from the group consisting of antioxidants, light stabilizers, slip agents, acid stabilizers, melt stabilizers and combinations thereof, such as CaO.

[0123] In a second aspect, this disclosure relates to a process for preparing the masterbatch composition of the first aspect, the process comprising:

[0124] a) optionally obtaining a blend of component B) and component C); and

[0125] b) Mix component B) or the blend of step a) with component A);

[0126] Step b) is performed at a temperature ranging from 80°C to 150°C.

[0127] Optionally, the at least one wax (D) and / or the at least one additive (E) are blended with component B) and optional component C) from step a).

[0128] Preferably, the process of the second aspect includes step (c): granulating the compound of step (b).

[0129] The process for preparing the masterbatch composition is carried out using known compounding equipment (such as an extruder).

[0130] In a third aspect, this disclosure relates to the use of the masterbatch composition according to the first aspect in a method of foaming thermoplastic polyolefins.

[0131] In a fourth aspect, this disclosure relates to a process for preparing thermoplastic polyolefin foamed articles, the process comprising:

[0132] i) Providing a foamable blend by dispersing the masterbatch composition according to the first aspect into a base resin at a temperature of at least 150°C, preferably in the range of 150°C to 230°C, the base resin comprising at least one thermoplastic polyolefin.

[0133] ii) Fill the cavity of the mold with the foamable blend, and

[0134] iii) Preferably, the foamable blend is foamed by reducing the pressure in the mold.

[0135] In one implementation, the process of the fourth aspect is a foam injection molding process, wherein the foaming step iii) is performed by expanding the foamable blend under low holding pressure of the mold.

[0136] In a preferred embodiment, the process of the fourth aspect is a core-back foam injection molding process, wherein the foaming step iii) is performed by depressurizing the mold cavity.

[0137] Preferably, step i) is performed by dispersing a masterbatch composition of the first aspect, which is 1% to 10% by weight, preferably 2% to 7% by weight, of the total weight of the foamable blend into the base resin.

[0138] Preferably, the thermoplastic polyolefin of the base resin has a melting point in the range of 150°C to 230°C.

[0139] In a more preferred embodiment, the base resin comprises at least one propylene polymer, more preferably at least one propylene polymer having a melt temperature equal to or greater than 150°C, such as including at least one propylene polymer in the range of 150°C to 170°C.

[0140] The thermoplastic polyolefin foamed products obtained from the fourth aspect of the process have small cell size, uniform cell size distribution, and a high ratio of core layer thickness to total product thickness, resulting in lightweight foamed products with good mechanical properties.

[0141] Thermoplastic polyolefin foamed products obtained from the process in the fourth aspect, particularly polypropylene foamed products, are preferably used in the automotive field, such as in interior parts.

[0142] 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.

[0143] Example

[0144] The following embodiments are given to illustrate the invention and not to limit it.

[0145] Characterization methods: The following methods are used to determine the properties indicated in the specification, claims and examples.

[0146] Comonomer content of polybutene-1: determined by FT-IR. The sample was a pressed film. The film was obtained using a hydraulic press (Carver or equivalent) that can be heated up to 200°C. The spectrum of the sample relative to the air background was recorded and plotted as absorbance versus wavenumber (resolution 2 cm⁻¹). -1 The following measurements are used to calculate the ethylene content:

[0147] -between 4482 and 3950cm -1 The area (At) of the combined absorption bands between the two is used for spectral normalization of the film thickness;

[0148] - Subtraction factor (FCR) C2 ): The numerical subtraction between the spectrum of the polymer sample 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);

[0149] - The area of ​​the remaining band after subtracting the C2PB spectrum (AC) 2，块 Its sequence originates from the methylene group, EEE (CH2 rocking vibration).

[0150] Sample preparation

[0151] A sheet was obtained by pressing 1.5 g of polymer between two aluminum foils. At least two pressing operations are recommended. A small portion was cut from this sheet to form a molded film. The film thickness ranged from 0.1 to 0.3 mm. The pressing temperature was 140 ± 10 °C. The IR spectrum was recorded immediately after film preparation.

[0152] Calibration of (BEB+BEE) sequence

[0153] By plotting (BEB+BEE) weight % compared to FCR C2 The calibration line is obtained using / At. The slope Gr and intercept Ir are calculated by linear regression.

[0154] EEE sequence calibration

[0155] By plotting (EEE) weight % compared to A C2，块 Use / At to obtain the calibration line. Slope G H and intercept I H Calculated by linear regression.

[0156] calculate

[0157] Calculate the weight-based concentration of the BEE+BEB sequence of the ethylene unit:

[0158]

[0159] Using the baseline between the shoulders of the remaining frequency band, calculate the remaining area (AC2, block) after the above subtraction.

[0160] Calculate the weight-based concentration of the EEE sequence of the ethylene unit:

[0161]

[0162] Calculate the total weight percentage of ethylene:

[0163]

[0164] Fractions soluble in xylene at 0°C: 2.5 g of polymer and 250 cm³ 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. The percentage by weight of the polymer that could dissolve at 0°C (XS 0°C) was calculated relative to the initial weight of the sample.

[0165] Melt flow rate: MFR is determined according to ISO 1133-1:2011, for polybutene-1 at 190°C and 2.16 kg load, and for polypropylene at 230°C and 2.16 kg load.

[0166] Thermal properties (melting temperature and enthalpy): determined by 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:

[0167] -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).

[0168] - 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.

[0169] Brookfield viscosity: determined according to ASTM D3236-15 (2021) at 190°C. Test instrument: Cylindrical mandrel rotational viscometer, Brookfield HA or HB type; Ametek / Benelux Scientific model DV2T can be used as a reference. Test conditions: Mandrel SC4-27; software Rheocalc T 1.2.19. Preheat the sample chamber and mandrel to the test temperature for at least 15 minutes. Load 10.5 ± 0.1 g of the polymer to be tested into the sample chamber and insert the mandrel. Preheat for another 3 minutes. Start rotating at a low speed and maintain a constant speed for 3 minutes. Gradually increase the RPM according to the table below until 80% of the torque value is reached:

[0170]

[0171] The torque decreased during the test, and the viscosity value was the average of the last 20 minutes of the test.

[0172] Molecular weight distribution: Measured in 1,2,4-trichlorobenzene (TCB) by gel permeation chromatography. Molecular weight parameters (Mn, Mw, and Mz) and molecular weight distribution of all samples were measured using a PolymerChar GPC-IR instrument equipped with four PLgel Olexis mixed-bed columns (Polymer Laboratories) and an IR5 infrared detector (PolymerChar). The column size was 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-dibutyl-p-cresol added to prevent degradation. For GPC calculations, universal calibration curves were obtained using 12 polystyrene (PS) standard samples (peak molecular weight range 266 to 1,220,000) supplied by PolymerChar. Third-order polynomial fitting was used to interpolate the experimental data and obtain calibration curves. Data acquisition and processing were performed using Empower 3 (Waters). The Mark-Hawwink equation was used to determine the molecular weight distribution and average molecular weight. For butene / ethylene copolymers, it was assumed that the composition of each sample was constant across the entire molecular weight range, and the K-value of the Mark-Hawwink equation was calculated using linear combination.

[0173]

[0174] 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 xE and xB are the weight-relative amounts of ethylene and butene-1, where xE + xB = 1. The Mark-Howwink index α = 0.725 is used independently for the composition of all butene / ethylene copolymers. For polystyrene, K is used. PS = 1.21 × 10 -4 dl / g and α = 0.706.

[0175] Density: Measured according to ISO 1183-1:2019. Samples were taken from a press-molded sheet that had been treated at 25°C for 10 days prior to density measurement.

[0176] Intrinsic viscosity: determined according to ASTM D2857-22 in tetrahydronaphthalene (THN) at 135°C.

[0177] Shore hardness D: Measured according to ISO 868:2003 (15 seconds) 10 days after molding of the compression molded specimen.

[0178] Tensile modulus: Measured at 23°C 10 days after molding of the compression-molded specimen, according to ISO 527-1:2019 and ISO 527-2:2019.

[0179] Bubble layer thickness: Measured on magnified cross-sectional images of the specimens using a Zeiss Axio Zoom.V16 optical microscope equipped with an Axiocam 305 color camera. The following parameters were determined for each specimen:

[0180] -Total specimen thickness (L): The distance between the opposing surfaces of the specimen measured at two points, see [reference]. Figure 1 Lines (A) and (B) are shown in the diagram. The total thickness (L) is calculated as the arithmetic mean of the two measurements.

[0181] - Skin thickness, unfoamed layer (S): For each surface, measure the distance between that surface and the edge of the foam cells adjacent to said surface, such as... Figure 1 (s1) and (s2). The thickness (S) of each epidermal layer was calculated as the arithmetic mean of s1 and s2;

[0182] - Calculate the thickness of the foam layer F according to the formula F = L - 2S.

[0183] Average cell size: Measured on a magnified cross-sectional image of the specimen using a Zeiss Axio Zoom.V16 optical microscope equipped with an Axiocam 305 color camera. For each foam cell, the cell size was determined as the diameter of a representative sphere (i.e., a sphere with the same surface area as the foam cell). Five foam cells representing the cell group were selected; the average cell size was the arithmetic mean of the five cell sizes.

[0184] Odor: Measured according to standard PV 3900, VW Norm 50180:2019-04.

[0185] Materials used

[0186] Component A): Three different butene-1 polymer compositions were tested as carrier resins in masterbatch compositions:

[0187] - PB(A1) was prepared according to Example 1 of WO2019 / 025583.

[0188] - PB(A2) was prepared according to Example 1 of WO2019 / 025585, and

[0189] - PB(A3) was prepared according to Example 1 of WO2018 / 007279.

[0190] The properties of the three butene-1 polymer compositions are reported in Tables 1a and 1b.

[0191] Component B): Sodium citrate and / or sodium bicarbonate, as specified below.

[0192] Component C): Talc Luzenac A7 C

[0193] additive :CaO.

[0194] Table 1a

[0195]

[0196] Table 1b

[0197]

[0198] Examples E1-E3 and Comparative Example CE4

[0199] Blending: To prepare the polybutene-1 masterbatch compositions, compounding was performed under standard conditions (i.e., under water-quenched granulation). The compounding temperature was typically higher than the melting point Tm(II) of the polymer with the lowest melting point, for example, greater than 80°C, and more typically 81°C to 150°C. The nucleating agent, chemical foaming agent, and additives were first formulated into a blend, and then the blend was added to the polybutene-1 carrier. The masterbatch compositions are reported in Table 2.

[0200] foaming Chemical foaming experiments were conducted on a KraussMaffei KM 350 CX 2000 injection molding machine equipped with a single screw and a gravimetric dosing system. The screw diameter was 70 mm, and the L / D ratio was 20. The temperature profile was typically 200°C to 230°C. The panels were made from an initial wall thickness of 2 mm. The mold was opened to a final wall thickness of 3 mm, with a set expansion stroke of 1 mm. The masterbatch composition was added at 4 wt% to a foamable base resin containing polypropylene and 15 wt% talc. Expansion gases were generated by the thermal decomposition of the foaming agent. The decomposition reaction was typically carried out at 150°C to 230°C. Expansion began due to pressure drop after injection and mold opening. Layer thickness, average cell size, and odor are illustrated in Table 2.

[0201] The foaming properties of Examples E1-E3 and Comparative Example CE4 are illustrated in... Figures 2 to 5In the middle. Examples E1 and E2, Figure 2 and Figure 3 The foaming projects are shown to have fine cell distributions that are comparable to those of projects foamed with commercial foaming masterbatch ITP825.

[0202] Table 2

[0203]

[0204] Examples E5-E7

[0205] The compounding and foaming were performed as in Examples E1-E3. The masterbatch compositions and foaming test results are summarized in Table 3.

[0206] Table 3

[0207]

[0208]

[0209] Examples E8 and E9

[0210] The masterbatch compounding and foaming test were performed as in Examples E1-E3. The masterbatch composition and foaming test results are summarized in Table 4.

[0211] Table 4

[0212]

Claims

1. A masterbatch composition, the masterbatch composition comprising: A) 25% to 80% by weight of a butene-1 polymer composition, said butene-1 polymer composition comprising: a) at least one butene-1 homopolymer, or a copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, said copolymer having a comonomer content (CA) in the range of up to 5 mol%, and b) A copolymer of butene-1 with one or more comonomers selected from ethylene and higher α-olefins, said at least one copolymer having a comonomer content (CB) in the range of greater than 5 mol% to 25 mol%. The amount of polymer a) is based on the total weight of polymers a) and b) ranging from 5% to 95% by weight. The butene-1 polymer composition has the following characteristics: i) The total content of polymeric comonomers based on the total weight of polymers a) and b) in the range of 4 mol% to 18 mol%, preferably 5 mol% to 12 mol%, and ii) A fraction based on a total weight of polymers a) and b) of 35% to 90% by weight, preferably 48% to 62% by weight, that is soluble in xylene at 0°C. iii) Melt flow rate values ​​in the range of 30 to 1000 g / 10 min, as measured according to ISO 1133 at 190 °C and a load of 2.16 kg; B) At least one endothermic chemical foaming agent, ranging from 20% to 75% by weight; C) At least one nucleating agent, ranging from 0% to 50% by weight. The amounts of components A), B) and C) are based on the total weight of the masterbatch composition.

2. The masterbatch composition according to claim 1, wherein component A) comprises: 20% to 70% by weight, preferably 30% to 60% by weight of polymer a), and 80% to 30% by weight, preferably 70% to 40% by weight of polymer (b), Each is based on the total weight of polymers a) and b).

3. The masterbatch composition according to claim 1 or 2, wherein component A) has a melt flow rate in the range of 40 to 800 g / 10 min, preferably 100 to 300 g / 10 min, as measured according to ISO 1133 at 190 °C and a load of 2.16 kg.

4. The masterbatch composition according to any one of the preceding claims, wherein component A) has a Tm(II) value as measured by DSC at a scan rate of 10°C / min in the range of 70°C to 105°C, preferably in the range of 75°C to 100°C, more preferably in the range of 77°C to 90°C, and particularly in the range of 79°C to 85°C.

5. The masterbatch composition according to any one of the preceding claims, wherein component A) has a Brinell viscosity, measured at 190°C (ASTM D3236-15 (2021)), in the range of 10,000 to 270,000 mPa∙s, preferably in the range of 15,000 to 250,000 mPa∙s, more preferably in the range of 20,000 to 200,000 mPa∙s, particularly in the range of 25,000 to 150,000 mPa∙s, such as in the range of 30,000 to 100,000 mPa∙s, or 35,000 to 50,000 mPa∙s.

6. The masterbatch composition according to any one of the preceding claims, wherein the polymer a) in component A) has 1 mol% to 4 mol% of a comonomer (C A ).

7. The masterbatch composition according to any one of the preceding claims, wherein the polymer b) in component A) has 8 mol% to 20 mol% of a comonomer (C B ).

8. The masterbatch composition according to any one of the preceding claims, wherein polymers (a) and (b) are copolymers, and the difference between the percentage values ​​of the content of the comonomers in (a) and (b) satisfies the following relationship: (CB) - (CA) ≥ 5, or preferably, (CB) - (CA) ≥ 6.

9. The masterbatch composition according to any one of the preceding claims, wherein the comonomer contained in polymer (a) and polymer (b) is ethylene.

10. The masterbatch composition according to any one of the preceding claims, wherein component A) has a concentration equal to or greater than 0.89 g / cm³. 3 Preferably, the concentration is between 0.89 and 0.92 g / cm³. 3 The density within the range.

11. The masterbatch composition according to any one of the preceding claims, wherein component A) has a Mw / Mn value equal to or less than 4, particularly equal to or less than 3, or equal to or less than 2.5, with a lower limit of 1.5 in all cases, wherein Mw is the weight-average molecular weight and Mn is the number-average molecular weight, both measured by GPC.

12. The masterbatch composition according to any one of the preceding claims, wherein component A) has at least one, more preferably all, of the following characteristics: - Mw equal to or greater than 50,000, particularly 50,000 to 180,000 g / mol, such as 70,000 to 150,000 g / mol; and / or - Mz equal to or greater than 90,000 g / mol, particularly 90,000 to 200,000 g / mol, such as 100,000 to 190,000 g / mol; and / or - An intrinsic viscosity (IV) equal to or less than 0.7 dl / g, particularly 0.2 dl / g to 0.7 dl / g, such as 0.5 dl / g to 0.6 dl / g, as measured by ASTM D2857-22 in tetrahydronaphthalene (THN) at 135°C; and / or - Isopropyl pentavalents (mmmm) with a concentration greater than 90%, particularly greater than 93%, such as greater than 95%, as measured by 13C-NMR operating at 150.91 MHz; and / or - The 4,1 insertion could not be detected using 13C-NMR operating at 150.91 MHz; and / or - Shore hardness D values ​​equal to or less than 50, particularly 25 to 50, such as 25 to 45, as measured according to ISO 868:2003; and / or - Tensile modulus from 30 MPa to 150 MPa, particularly from 50 MPa to 120 MPa, measured at 23 °C, according to ISO 527-1:2019 and ISO 527-2:2019.

13. The masterbatch composition according to any one of the preceding claims, wherein component B) is selected from the group consisting of alkali metal citrates, alkali metal bicarbonates and combinations thereof.

14. The masterbatch composition according to any one of the preceding claims, wherein component B) is sodium citrate or a mixture of sodium citrate and sodium bicarbonate.

15. The masterbatch composition according to any one of the preceding claims, wherein component C) is talc.

16. The masterbatch composition according to any one of the preceding claims, wherein the masterbatch composition comprises: -35% to 65% by weight, preferably 40% to 55% by weight, particularly 45% to 50% by weight of component A), -20% to 40% by weight, preferably 25% to 35% by weight, particularly 27% to 33% by weight of component B), and -10% to 45% by weight, preferably 15% to 35% by weight, particularly 17% to 30% by weight of component C), Each is based on the total weight of the masterbatch composition.

17. The masterbatch composition according to any one of the preceding claims, wherein the masterbatch composition further comprises at most 15% by weight, preferably 1% to 15% by weight, more preferably 5% to 12% by weight, of the total weight of the masterbatch composition, wherein the wax is preferably a polyolefin wax.

18. The masterbatch composition according to any one of the preceding claims, the masterbatch composition further comprising, based on the total weight of the masterbatch composition, up to and including 5% by weight, preferably from 0.1% by weight to 5% by weight, said at least one additive (E) selected from the group consisting of: antioxidants, light stabilizers, slip agents, acid stabilizers, melt stabilizers, and combinations thereof.

19. A process for preparing a masterbatch composition according to any one of the preceding claims, the process comprising: a. Optionally obtain a blend of component B) and component C); b. Mix component B) or the blend from step a) with component A); Step b) is performed at a temperature ranging from 80°C to 150°C.

20. The process according to claim 19, wherein the process includes step c): granulating the compound of step (b).

21. Use of a masterbatch composition according to any one of claims 1 to 18 in a method of foaming a thermoplastic polyolefin.

22. A process for preparing thermoplastic polyolefin foamed articles, the process comprising: i) Providing a foamable blend by dispersing the masterbatch composition according to any one of claims 1 to 18 into a base resin at a temperature of at least 150°C, preferably in the range of 150°C to 230°C, said base resin comprising at least one thermoplastic polyolefin. ii) Fill the cavity of the mold with the foamable blend, and iii) Preferably, the foamable blend is foamed by reducing the pressure in the mold.

23. The process of claim 22, wherein the foaming step iii) is performed by expanding the foamable blend under a low holding pressure in the mold.

24. The process according to claim 22 or 23, wherein step i) is performed by dispersing the masterbatch composition, in an amount of 1% to 10% by weight, preferably 2% to 7% by weight, of the total weight of the foamable blend into the base resin.

25. The process according to any one of claims 22 to 24, wherein the base resin comprises at least one propylene polymer, more preferably having a melt temperature equal to or greater than 150°C, more preferably including at least one propylene polymer in the range of 150°C to 170°C.

26. A thermoplastic polyolefin foamed article obtained from the process according to any one of claims 22 to 25.

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