High MFR polypropylene for meltblown nonwoven applications

Abstract

The following properties: a melt flow rate of greater than about 900 g / 10 min; a molecular weight distribution (M w / M n ); Less than about 8 M z+1 / M w and a xylene solubles content of less than about 4.0 wt.%. Such polymers are useful in meltblown nonwoven applications.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 309,378, filed February 11, 2022, which is incorporated by reference in its entirety herein for all purposes. Field

[0002] The present technology relates generally to polyolefin polymers, such as polypropylene polymers. More specifically, the present technology relates to high melt flow rate (MFR) polypropylene polymers useful in meltblown nonwoven applications. [Background technology]

[0002]

[0003] Polyolefin polymers are used in many different applications and fields. For example, polyolefin polymers are thermoplastic polymers that can be easily processed. They can also be recycled and reused. Polyolefin polymers are formed from hydrocarbons such as ethylene and alpha-olefins, which are derived from petrochemicals and are abundantly available.

[0003]

[0004] Polypropylene polymers, a type of polyolefin polymer, generally have a linear structure based on propylene monomer. Polypropylene polymers can have a variety of different stereospecific structures. For example, polypropylene polymers can be isotactic, syndiotactic, and atactic. Isotactic polypropylene is perhaps the most common form and can be highly crystalline. Polypropylene polymers that can be produced include homopolymers, modified polypropylene polymers, and polypropylene copolymers, including polypropylene terpolymers. By modifying polypropylene or copolymerizing propylene with other monomers, a variety of different polymers can be produced with desired properties for specific applications.

[0004]

[0005] Currently, there is a special demand and need for polypropylene polymers with very high melt flow rates. The melt flow rate of a polymer generally indicates the amount of molten polymer that flows during a certain time at a particular temperature and load. A higher melt flow rate can indicate that the polymer can be easily processed, especially during extrusion, injection molding, and during the formation of fibers and films. High melt flow rate polypropylene polymers are particularly well suited to producing meltblown webs. Meltblown nonwoven webs are generally formed from molten thermoplastic polymers that are extruded as molten fibers through a plurality of fine, usually circular, die capillaries. As the fibers are formed, they come into contact with a high velocity gas, such as air, which weakens the fibers and reduces their diameter. The meltblown fibers are then deposited on a collecting surface, which forms a web of randomly distributed meltblown fibers. The meltblown fibers can be continuous or discontinuous. The meltblown webs are particularly well suited to be used in filtration applications.

[0005]

[0006] For example, the meltblown web can be incorporated into a face mask designed to cover the wearer's nose and mouth. When incorporated into a face mask, the meltblown web is well suited to protect the wearer by preventing the passage of microorganisms, such as viruses, and other contaminants. Due to the coronavirus pandemic, face masks are now worn in nearly all public settings, not only by medical professionals, but also by office workers, factory workers, students, and consumers.

[0006]

[0007] Traditionally, to produce polypropylene polymers having high melt flow rates for use in producing meltblown webs, the polymers have been formed using metallocene catalysts or the polymers have been subjected to peroxide cracking. When using metallocene catalysts, also referred to as single-site catalysts, the polymerization process can be relatively slow and somewhat inefficient in terms of low raw material utilization. Furthermore, it can be time-consuming and costly to transition equipment between using Ziegler-Natta and metallocene catalysts to produce the polymers. In addition, metallocene catalysts can be susceptible to reactor operability issues and are not compatible with all known activity limiting agents. Metallocene catalysts can also be sensitive to raw material impurities.

[0007]

[0008] The peroxide cracking technique for producing high melt flow rate polypropylene polymers also has various drawbacks. For example, peroxide can be expensive. Furthermore, the supply of peroxide in the process must be carefully controlled so that sufficient peroxide is supplied to achieve a steady production of high melt flow rate polymers. In addition, unreacted peroxide can remain in the final material, which can cause degradation over time and produce undesirable tastes, odors, and volatile components. Finally, peroxide cracking can result in unwanted volatiles that may need to be removed by a thermal oxidation process to comply with environmental regulations.

[0008]

[0009] In view of the above, there is currently a need for a more efficient process for producing high melt flow rate polypropylene polymers. There is also a need for polypropylene polymer compositions containing high melt flow rate polypropylene polymers that can be used to produce all different types of articles, including meltblown webs.

[0009]

[0010] The high melt flow rate polypropylene polymer described herein may have the following advantages in terms of multi-layer spun-melt-spun (SMS) fabrics: Compared with the reactor grade meltblown polypropylene polymer produced with metallocene catalyst, the reactor grade ultra-high MFR polypropylene polymer produced with Ziegler-Natta catalyst described herein may provide a wider operating temperature window in the multi-layer spunbond-meltblown-spunbond (SMS) fabric (SBNW-MB-SBNW layers; SBNW=spunbond nonwoven and MB=meltblown) calendaring / bonding step. Since most SBNW layers are produced with cracked grade Ziegler-Natta catalyst-based polypropylene polymer, the reactor grade polypropylene polymer for meltblown (MB) applications in the present invention has a wider molecular weight distribution (MWD) than its metallocene polypropylene polymer counterpart, which contributes to a wider bonding temperature window. Summary of the Invention

[0010]

[0011] The present disclosure generally relates to a method for producing high melt flow rate polyolefin polymers, and the polymers produced by the method. High melt flow rate polyolefin polymers can be used in many different applications. For example, the high melt flow rate polypropylene polymers described herein prepared using Ziegler-Natta catalysts have a broader molecular weight distribution than polypropylene polymers prepared using metallocene catalysts. This is particularly useful for producing multi-layer spunbond-meltblown-spunbond (SMS) fabrics, in which the meltblown layer comprises the high melt flow rate polypropylene polymers described herein, resulting in a wider operating temperature window in the bonding step.

[0011]

[0012] In one embodiment, the polymer has the following properties: a melt flow rate of greater than about 900 g / 10 min; a molecular weight distribution (M w / M n ) less than about 8; z+1 / M w A polymer composition is provided that includes a polypropylene polymer having a ratio of:

[0012]

[0013] In some embodiments, the polypropylene polymer exhibits a melt flow rate of greater than about 1300 g / 10 min. In some embodiments, the polypropylene polymer exhibits a melt flow rate of from about 1300 g / 10 min to about 4000 g / 10 min.

[0013]

[0014] In some embodiments, the polypropylene polymer has an M of greater than about 6. w / M n In some embodiments, the polypropylene polymer has a M of greater than about 7. w / M n In some embodiments, the polypropylene polymer has an M of about 6.0 to about 10.0. w / M n has.

[0014]

[0015] In some embodiments, the polypropylene polymer has an M of less than about 7. z+1 / M w In some embodiments, the polypropylene polymer has an M z+1 / M w The ratio is:

[0015]

[0016] In some embodiments, the polypropylene polymer has a xylene solubles content of about 1.5% by weight to about 4% by weight. In some embodiments, the polypropylene polymer exhibits a melting temperature greater than about 155° C. In some embodiments, the polypropylene polymer exhibits a melting temperature of about 155° C. to about 168° C.

[0016]

[0017] In some embodiments, the polypropylene polymer has a weight average molecular weight of less than about 80,000 g / mol.In some embodiments, the polypropylene polymer has a weight average molecular weight of about 55,000 to about 70,000 g / mol as measured by gel permeation chromatography (GPC).

[0017]

[0018] In some embodiments, the polypropylene polymer has a number average molecular weight of less than about 8,500 g / mol.In some embodiments, the polypropylene polymer has a number average molecular weight of about 7,000 to about 8,000 g / mol.

[0018]

[0019] In some embodiments, the polypropylene polymer is a polypropylene homopolymer. In some embodiments, the polypropylene polymer is catalyzed with a Ziegler-Natta catalyst. In some embodiments, the polypropylene polymer is catalyzed in the presence of a Ziegler-Natta catalyst comprising an internal electron donor, the internal electron donor comprising a substituted phenylene diester or phthalate compound.

[0019]

[0020] In some embodiments, the polypropylene polymer comprises a processing aid in combination with at least one other polymer exhibiting a lower melt flow rate, and the polypropylene polymer is present in the composition in an amount of less than about 50% by weight. In some embodiments, the polypropylene polymer comprises a wax, a lubricant, a release agent, or a flow aid.

[0020]

[0021] In some embodiments, the polypropylene polymer is catalyzed in the presence of a Ziegler-Natta catalyst, the Ziegler-Natta catalyst comprising a solid catalyst component, a selectively control agent, and optionally an activity limiting agent, the solid catalyst component comprising a magnesium moiety, a titanium moiety, and an internal electron donor. In some embodiments, the solid catalyst component further comprises an organosilicon compound and an epoxy compound. In some embodiments, the selective control agent comprises an organosilicon compound. In some embodiments, the selective control agent comprises propyltriethoxysilane, diisobutyldimethoxysilane, n-propyltrimethoxysilane, or a mixture thereof, and is used in combination with an activity limiting agent.

[0021]

[0022] In some embodiments, the polypropylene polymer does not contain any peroxide. In some embodiments, the composition is suitable for meltblown nonwoven applications.

[0023] In one embodiment, a meltblown web is provided that is comprised of nonwoven meltblown fibers, the meltblown fibers being made from any one of the polymer compositions described herein.

[0022]

[0024] In one embodiment, there is provided a meltblown fiber comprised of any one of the polymer compositions described herein, wherein the meltblown fiber has a diameter of less than about 5 microns.

[0023]

[0025] In some embodiments, the meltblown fibers have a diameter of less than about 3 microns, hi some embodiments, the meltblown fibers have a diameter of about 1.5 to about 3.0 microns.

[0024]

[0026] In one embodiment, a nonwoven web is provided that comprises a multi-layer structure that includes one or more meltblown layers that include any one of the meltblown fibers described herein.

[0027] In some embodiments, the nonwoven web comprises one meltblown layer. In some embodiments, the nonwoven web comprises two or more meltblown layers. In some embodiments, the two or more meltblown layers comprise the same meltblown layer. In some embodiments, the two or more meltblown layers comprise different meltblown layers.

[0025]

[0028] In some embodiments, the nonwoven web further comprises two or more spunbond layers comprising spunbond fibers. In some embodiments, the spunbond fibers exhibit the following properties: a melt flow rate of about 20 g / 10 min to about 70 g / 10 min; a molecular weight distribution (M w / M n ), and having a xylene solubles content of about 1.5% to about 4% by weight.

[0026]

[0029] In some embodiments, the polypropylene polymer has an M w / M n In some embodiments, the polypropylene polymer has a weight average molecular weight of less than about 300,000 g / mol. In some embodiments, the polypropylene polymer has a weight average molecular weight of about 150,000 to about 250,000 g / mol. In some embodiments, the polypropylene polymer has a number average molecular weight of less than about 60,000 g / mol. In some embodiments, the polypropylene polymer has a number average molecular weight of about 40,000 to about 55,000 g / mol. In some embodiments, the polypropylene polymer exhibits a melting temperature greater than 155° C. In some embodiments, the polypropylene polymer may be produced using a metallocene catalyst and exhibit a melting temperature of about 155° C. or less.

[0027]

[0030] In some embodiments, the nonwoven web comprises two or more spunblown layers. In some embodiments, the two or more spunblown layers comprise the same spunblown layer. In some embodiments, the two or more spunblown layers comprise different spunblown layers.

[0028]

[0031] In some embodiments, the nonwoven web has a multi-layer structure including a first spunbond layer, a meltblown layer, and a second spunbond layer. In some embodiments, the first spunbond layer and the second spunbond layer are the same. In some embodiments, the first spunbond layer and the second spunbond layer are different.

[0029]

[0032] In some embodiments, the nonwoven web has a thickness of about 100 l / m 2 In some embodiments, the nonwoven web has a breathability of from about 40 to about 80 l / m 2 In some embodiments, the nonwoven web has a machine direction (MD) tensile strength of from about 2500 g / 1 inch to about 3500 g / 1 inch.

[0030]

[0033] In another aspect, there is provided a method of producing any one of the nonwoven webs disclosed herein, comprising contacting one or more meltblown layers with two or more spunbond layers at a bonding temperature of from about 130°C to about 140°C.

[0031]

[0034] In some embodiments, the bonding temperature is about 135°C.

[0035] In one aspect, there is provided a method for producing a polypropylene polymer comprising polymerizing propylene monomer in the presence of a Ziegler-Natta catalyst, the Ziegler-Natta catalyst comprising a solid catalyst component, a selective control agent, and optionally an activity limiting agent, the solid catalyst component comprising a magnesium moiety, a titanium moiety and an internal electron donor, the selective control agent comprising an organosilicon compound, and a polypropylene polymer is formed exhibiting a melt flow rate of greater than about 900 g / 10 min, the method forming the polypropylene polymer without the use of peroxides in the method.

[0032]

[0036] In some embodiments, the solid catalyst component further comprises an organosilicon compound and an epoxy compound. In some embodiments, the internal electron donor comprises a substituted phenylene diester or phthalate compound. In some embodiments, the selective control agent comprises an organosilicon compound, and a polypropylene polymer is formed that exhibits a melt flow rate of greater than about 1000 g / 10 min.

[0033]

[0037] In some embodiments, the H2 / C3 molar ratio during polymerization is about 0.1 to about 0.3. In some embodiments, the cocatalyst and external electron donor are fed to the polymerization reactor in a molar ratio of about 1.5 to about 15. In some embodiments, the reactor temperature during polymerization is about 65° C. to about 95° C. In some embodiments, the temperature is increased to increase the melt flow rate. In some embodiments, the propylene partial pressure is decreased to increase the melt flow rate of the polypropylene polymer. [Brief description of the drawings]

[0034] [Figure 1]

[0038] FIG. 1 is a perspective view of a face mask that may be made from the polymer composition of the present disclosure. [Diagram 2]

[0039] 1 is a graphical representation of some of the results obtained in the Examples below, showing the relationship between melt flow rate and H2 / C3 molar ratio. [Diagram 3]

[0040] 1 is a graphical representation of some of the results obtained in the Examples below, showing the relationship between melt flow rate and xylene solubles. [Figure 4]

[0041] 1 is a graphical representation of some of the results obtained in the Examples below, showing the relationship between fines content and melt flow rate. [Diagram 5]

[0042] FIG. 1 shows the tensile test mold used in the machine direction (MD) tensile strength tests described in the Examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035]

[0043] Various embodiments are described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. An aspect described in connection with a particular embodiment is not necessarily limited to that embodiment and may be practiced in any other embodiment.

[0036]

[0044] As used herein, "about" is understood by those of ordinary skill in the art and will vary to some extent depending on the context in which it is used. If the usage of a term is not clear to persons of ordinary skill in the art, "about" will mean up to plus or minus 10% of the particular term, given the context in which it is used.

[0037]

[0045] The use of the terms "a" and "an" and "the" and similar referents in describing elements (particularly in the claims that follow) should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand notation for referring individually to each and every value falling within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "such as"), are intended merely to make the embodiments more clear and do not impose limitations on the scope of the claims unless otherwise stated. No language in this specification should be construed as indicating any element not recited in the claims as required.

[0038]

[0046] In general, "substituted" refers to an alkyl, alkenyl, aryl, or ether group (e.g., alkyl group) as defined below, in which one or more bonds to hydrogen atoms contained therein are replaced by bonds to non-hydrogen or non-carbon atoms. Substituted groups also include groups in which one or more bonds to carbon or hydrogen atoms are replaced by bonds, including double or triple bonds, to one or more heteroatoms. Thus, substituted groups are substituted with one or more substituents unless otherwise specified. In some embodiments, substituted groups are substituted with 1, 2, 3, 4, 5, or 6 substituents. Examples of substituents include halogens (i.e., F, Cl, Br, and I); hydroxyl; alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy, and heterocyclylalkoxy groups; carbonyl (oxo); carboxyl; ester; urethane; oxime; hydroxylamine; alkoxyamine; aralkoxyamine; thiol; sulfide; sulfoxide; sulfone; sulfonyl; sulfonamide; amine; N-oxide; hydrazine; hydrazide; hydrazone; azide; amide; urea; amidine; guanidine; enamine; imide; isocyanate; isothiocyanate; cyanate; thiocyanate; imine; nitro group; nitrile (i.e., CN), and the like.

[0039]

[0047] As used herein, "alkyl" groups include straight-chain and branched alkyl groups having 1 to about 20 carbon atoms, typically 1 to 12 carbons or, in some embodiments, 1 to 8 carbon atoms. As used herein, "alkyl group" includes cycloalkyl groups, as defined below. Alkyl groups can be substituted or unsubstituted. Alkyl groups can be mono- or multiply substituted. Alkyl groups can be di- or higher substituted. Examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branched alkyl groups include, but are not limited to, isopropyl, sec-butyl, t-butyl, neopentyl, isopentyl groups, and 1-cyclopentyl-4-methylpentyl. Representative substituted alkyl groups can be mono- or multiply substituted, for example, with amino, thio, hydroxy, cyano, alkoxy, and / or halo groups, such as F, Cl, Br, and I groups. As used herein, the term haloalkyl is an alkyl group having one or more halo groups. In some embodiments, the haloalkyl refers to a perhaloalkyl group.

[0040]

[0048] Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, cycloalkyl groups have 3 to 8 ring members, while in other embodiments the number of ring carbon atoms ranges from 3 to 5, 6, or 7. Cycloalkyl groups can be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl groups, as well as fused rings such as, but not limited to, decalinyl, and the like. Cycloalkyl groups also include rings substituted with straight or branched chain alkyl groups as defined above. Representative substituted cycloalkyl groups may be mono- or more than mono-substituted, such as, but not limited to, 2,2-; 2,3-; 2,4-; 2,5-; or 2,6-disubstituted cyclohexyl groups or mono-, di- or tri-substituted norbornyl or cycloheptyl groups, which may be substituted, for example, with alkyl, alkoxy, amino, thio, hydroxy, cyano, and / or halo groups.

[0041]

[0049] Alkenyl groups are straight, branched, or cyclic alkyl groups having from 2 to about 20 carbon atoms and further containing at least one double bond. In some embodiments, alkenyl groups have from 1 to 12 carbons, or typically from 1 to 8 carbon atoms. Alkenyl groups can be substituted or unsubstituted. Alkenyl groups include, for example, vinyl, propenyl, 2-butenyl, 3-butenyl, isobutenyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienyl groups, among others. Alkenyl groups can be substituted in the same manner as alkyl groups. Divalent alkenyl groups, i.e., alkenyl groups with two points of attachment, include, but are not limited to, CH-CH=CH2, C=CH2, or C=CHCH3.

[0042]

[0050] As used herein, an "aryl", or "aromatic" group is a cyclic, aromatic hydrocarbon that does not contain heteroatoms. Aryl groups include monocyclic, bicyclic, and polycyclic ring systems. Thus, aryl groups include, but are not limited to, phenyl, azulenyl, heptalenyl, biphenylenyl, indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl, naphthacenyl, chrysenyl, biphenyl, anthracenyl, indenyl, indanyl, pentalenyl, and naphthyl groups. An aryl group with one or more alkyl groups can also be referred to as an alkaryl group. In some embodiments, aryl groups contain 6-14 carbons, and in others 6-12 or even 6-10 carbon atoms in the ring portion of the group. The phrase "aryl group" includes groups that contain fused rings, such as fused aromatic-aliphatic ring systems (e.g., indanyl, tetrahydronaphthyl, etc.). Aryl groups can be substituted or unsubstituted.

[0043]

[0051] Heterocyclyl or heterocycle refers to both aromatic and non-aromatic ring compounds, including monocyclic, bicyclic, and polycyclic ring compounds, containing three or more ring members, one or more of which are heteroatoms, such as, but not limited to, N, O, and S. Examples of heterocyclyl groups include, but are not limited to, unsaturated 3-8 membered rings containing 1-4 nitrogen atoms, such as, but not limited to, pyrrolyl, pyrrolinyl, imidazolyl, pyrazolyl, pyridinyl, dihydropyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazolyl (e.g., 4H-1,2,4-triazolyl, 1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, etc.), tetrazolyl (e.g., 1H-tetrazolyl, 2H-tetrazolyl, etc.), aryl, ... tetrazolyl, etc.); saturated 3-8 membered rings containing 1-4 nitrogen atoms, such as, but not limited to, pyrrolidinyl, imidazolidinyl, piperidinyl, piperazinyl; fused unsaturated heterocyclic groups containing 1-4 nitrogen atoms, such as, but not limited to, indolyl, isoindolyl, indolinyl, indolizinyl, benzimidazolyl, quinolyl, isoquinolyl, indazolyl, benzotriazolyl; unsaturated 3-8 membered rings containing 1-2 oxygen atoms and 1-3 nitrogen atoms, such as, but not limited to, oxazolyl, isoxazolyl, oxadiazolyl (e.g., 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, etc.); ... unsaturated fused heterocyclic groups containing 1-2 oxygen atoms and 1-3 nitrogen atoms, such as benzoxazolyl, benzoxadiazolyl, benzoxazinyl (e.g., 2H-1,4-benzoxazinyl, etc.); unsaturated 3-8 membered rings containing 1-3 sulfur atoms and 1-3 nitrogen atoms, such as, but not limited to, thiazolyl, isothiazolyl, thiadiazolyl (e.g., 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,5-thiadiazolyl, etc.); saturated 3-8 membered rings containing 1-2 sulfur atoms and 1-3 nitrogen atoms, such as, but not limited to, thiazolodinyl;Saturated and unsaturated 3-8 membered rings containing 1-2 sulfur atoms, such as, but not limited to, thienyl, dihydrodithiinyl, dihydrodithionyl, tetrahydrothiophene, tetrahydrothiopyran; unsaturated fused heterocyclic rings containing 1-2 sulfur atoms and 1-3 nitrogen atoms, such as, but not limited to, benzothiazolyl, benzothiadiazolyl, benzothiazinyl (e.g., 2H-1,4-benzothiazinyl, etc.), dihydrobenzothiazinyl (e.g., 2H-3,4-dihydrobenzothiazinyl, etc.), unsaturated 3-8 membered rings containing oxygen atoms, such as, but not limited to, For example, but not limited to, furyl; unsaturated fused heterocyclic rings containing 1-2 oxygen atoms, such as benzodioxolyl (e.g., 1,3-benzodioxoyl, etc.); unsaturated 3-8 membered rings containing an oxygen atom and 1-2 sulfur atoms, such as, but not limited to, dihydrooxathiinyl; saturated 3-8 membered rings containing 1-2 oxygen atoms and 1-2 sulfur atoms, such as 1,4-oxathiane; unsaturated fused rings containing 1-2 sulfur atoms, such as benzothienyl, benzodithiinyl;and unsaturated fused heterocyclic rings containing oxygen and one to two oxygen atoms, such as benzoxathiinyl. Heterocyclyl groups also include those described above in which one or more S atoms in the ring are double-bonded to one or two oxygen atoms (sulfoxides and sulfones). For example, heterocyclyl groups include tetrahydrothiophene oxide and tetrahydrothiophene 1,1-dioxide. Typical heterocyclyl groups contain 5 or 6 ring members. Thus, for example, heterocyclyl groups include morpholinyl, piperazinyl, piperidinyl, pyrrolidinyl, imidazolyl, pyrazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, tetrazolyl, thiophenyl, thiomorpholinyl, thiomorpholinyl where the S atom of thiomorpholinyl is bonded to one or more O atoms, pyrrolyl, pyridinyl homopiperazinyl, oxazolidin-2-onyl, pyrrolidin-2-onyl, oxazolyl, quinuclidinyl, thiazolyl, isoxazolyl, furanyl, dibenzylfuranyl, and tetrahydrofuranyl. The heterocyclyl or heterocycle may be substituted.;

[0044]

[0052] Heteroaryl groups are aromatic ring compounds containing five or more ring members, one or more of which are heteroatoms such as, but not limited to, N, O, and S. Heteroaryl groups include, but are not limited to, groups such as pyrrolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, thiophenyl, benzothiophenyl, furanyl, benzofuranyl, dibenzofuranyl, indolyl, azaindolyl (pyrrolopyridinyl), indazolyl, benzimidazolyl, imidazopyridinyl (azabenzimidazolyl), pyrazolopyridinyl, triazolopyridinyl, benzotriazolyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, imidazopyridinyl, isoxazolopyridinyl, thianaphthyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl, quinoxalinyl, and quinazolinyl groups. Heteroaryl groups include fused ring compounds in which all rings are aromatic, such as indolyl groups, and also fused ring compounds in which only one ring is aromatic, such as 2,3-dihydroindolyl groups. Although the phrase "heteroaryl group" includes fused ring compounds, the phrase does not include heteroaryl groups in which another group, such as an alkyl group, is attached to one of the ring members. Rather, heteroaryl groups that contain such substitutions are referred to as "substituted heteroaryl groups." Representative substituted heteroaryl groups may be mono- or multiply substituted with a variety of substituents, such as those listed above.

[0045]

[0053] As used herein, the prefix "halo" refers to a halogen (i.e., F, Cl, Br, or I) bonded to the group that is modified by the "halo" prefix. For example, a haloaryl is a halogenated aryl group.

[0046]

[0054] Groups described herein that have more than one point of attachment in the compounds of the present technology (i.e., divalent, trivalent, or polyvalent) are designated using the suffix "ene." For example, a divalent alkyl group is an alkylene group, a divalent aryl group is an arylene group, a divalent heteroaryl group is a divalent heteroarylene group, etc. Test procedure

[0055] Melt flow rate (MFR), as used herein, is measured for propylene-based polymers according to ASTM D1238 test method at 230°C using a 2.16 kg load. Melt flow rate can be measured in pellet form or on reactor powder. When measuring reactor powder, a stabilization package can be added that includes 2000 ppm of CYANOX 2246 antioxidant (methylene bis (4-methyl-6-tert-butylphenol), 2000 ppm of IRGAFOS 168 antioxidant (tris (2,4-di-tert.-butylphenyl) phosphite), and 1000 ppm of acid scavenger ZnO.

[0047]

[0056] For high melt flow rate polymers, the test die orifice may be smaller as shown below:

[0048] [Table 1]

[0049] Calculations for polypropylene polymer:

[0050] [Table 2]

[0051]

[0057] Particle size can be measured using a sieve test. The sieve test is performed on a GRADEX Particle Size Analyzer available from Rotex Global. The average particle size based on weight fraction is determined from the particle size distribution obtained from the GRADEX Particle Size Analyzer.

[0052]

[0058] Fines is defined as the weight fraction of polymer particles that pass through a GRADEX 120 mesh (125 microns).

[0059] Xylene solubles (XS) is defined as the weight percent of the resin that remains in solution after a sample of polypropylene random copolymer resin is dissolved in hot xylene and the solution is cooled to 25° C. This is also referred to as the gravimetric XS method using a 60 minute settling time according to ASTM D5492-06, and is also referred to herein as the "wet method."

[0053]

[0060] The ASTM D5492-06 method mentioned above can be adapted to determine the xylene soluble fraction as described below. In general, the procedure consists of weighing 2 g of sample and dissolving the sample in 200 ml of o-xylene in a 400 ml flask with a 24 / 40 joint. The flask is connected to a water-cooled condenser and the contents are stirred and heated to reflux under nitrogen (N2) and then maintained at reflux for an additional 30 minutes. The solution is then cooled in a temperature-controlled water bath at 25°C for 60 minutes to crystallize the xylene insoluble fraction. Once the solution has cooled and the insoluble fraction has precipitated from the solution, separation of the xylene soluble fraction (XS) from the xylene insoluble fraction (XI) is accomplished by filtration through 25 micron filter paper. 100 ml of the filtrate is collected in a pre-weighed aluminum pan and the o-xylene is evaporated from this 100 ml filtrate under a stream of nitrogen. Once the solvent has evaporated, the pan and contents are placed in a vacuum oven at 100°C for 30 minutes or until dry. The pan is then allowed to cool to room temperature and weighed. The xylene soluble portion is calculated as XS(wt%)=[(m3-m2)*2 / m1]*100, where m1 is the original weight of the sample used, m2 is the weight of the empty aluminum pan, and m3 is the weight of the pan and residue (in this disclosure, an asterisk * indicates that the specified item or value is multiplied).

[0054]

[0061] XS can also be measured according to the Viscotek method as follows: 0.4 g of polymer is dissolved in 20 ml of xylene with stirring at 130° C. for 60 min. The solution is then cooled to 25° C. and after 60 min, the insoluble polymer fraction is filtered using a 0.2 μm syringe filter. The resulting filtrate is analyzed by Flow Injection Polymer Analysis using a Viscotek ViscoGEL H-100-3078 column with a THF mobile phase running at 1.0 ml / min. The column is connected to a Viscotek Model 302 Triple Detector Array with light scattering, viscometer and refractometer detectors operating at 45° C. Instrument calibration is maintained with Viscotek PolyCAL™ Restyrene Standards. Polypropylene (PP) homopolymers, such as biaxially oriented polypropylene (BOPP) grade Dow 5D98, are used as reference materials to ensure that the Viscotek instrument and sample preparation procedures provide consistent results. Values ​​for a reference polypropylene homopolymer, such as 5D98, are initially derived from testing using the ASTM methods identified above.

[0055]

[0062] Weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn) (also referred to as "MWD") and higher average molecular weight (Mz and Mz+1) are measured by gel permeation chromatography (GPC) according to the GPC analytical method for polypropylene. The polymers are analyzed on a Polymer Char High Temperature GPC with an IR5 MCT (Mercury Cadmium Telluride - high sensitivity, thermoelectrically cooled IR detector), a Polymer Char 4 capillary viscometer, a Wyatt 8-corner MALLS and 3 Agilent Plgel Olexis (13um). The oven temperature is set at 150°C. The solvent is nitrogen purged 1,2,4-trichlorobenzene (TCB) containing ~200 ppm 2,6-di-t-butyl-4-methylphenol (BHT). The flow rate was 1.0 mL / min and the injection volume was 200 μl. A sample concentration of 2 mg / mL is prepared by dissolving the sample in N2 purged, preheated TCB (containing 200 ppm BHT) for 2 hours at 160° C. with gentle stirring.

[0056]

[0063] The GPC column set is calibrated by running 20 narrow molecular weight distribution polystyrene standards. The molecular weights (MW) of the standards range from 266 to 12,000,000 g / mol, and the standards were contained in six "cocktail" mixtures. Each standard mixture has at least 10 years of separation between the individual molecular weights. The polystyrene standards are prepared at 0.005 g in 20 mL of solvent for molecular weights equal to or greater than 1,000,000 g / mol, and 0.001 g in 20 mL of solvent for molecular weights less than 1,000,000 g / mol. The polystyrene standards are dissolved at 160°C for 60 min with stirring. The narrow standard mixtures are run first and in order of decreasing highest molecular weight components to minimize degradation effects. Logarithmic molecular weight calibrations are generated using a fourth order polynomial fit as a function of elution volume. The equivalent polypropylene molecular weight can be calculated using the following formula along with the Mark-Houwink coefficients reported for polypropylene (Th. G. Scholte, NLJ Meijerink, HM Schoffeleers, and AMG Brands, J. Appl. Polym. Sci., 29, 3763-3782 (1984)) and polystyrene (EP Otocka, RJ Roe, NY Hellman, PM Muglia, Macromolecules, 4, 507 (1971)):

[0057]

number

[0058] where Mpp is the equivalent MW of PP, MPS is the equivalent MW of PS, and the logK and Mark-Houwink coefficient a values ​​for PP and PS are shown below (GPC data were processed using a procedure adapted from ISO 16014-1 with a lower integration limit placed at 3500 Daltons to exclude interference from additives). It is calculated by using

[0059] [Table 3]

[0060]

[0064] Melting points or melting temperatures and crystallization temperatures are determined using differential scanning calorimetry (DSC). The term "crystallinity" refers to the order of arrangement of atoms or molecules that form a crystalline structure. Polymer crystallinity can be examined using DSC. me means the temperature at which melting ends, and T max means the peak melting temperature, both of which are determined by one skilled in the art from DSC analysis using data from the final heating step. One suitable method for DSC analysis uses a model Q1000™ DSC from TA Instruments, Inc. Calibration of the DSC is performed in the following manner. First, a baseline is obtained by heating the cell from -90°C to 290°C without a sample in the aluminum DSC pan. A 7 milligram fresh indium sample is then analyzed by heating the sample to 180°C, cooling the sample to 140°C at a cooling rate of 10°C / min, followed by holding the sample isothermally at 140°C for 1 minute, followed by heating the sample from 140°C to 180°C at a heating rate of 10°C / min. The heat of fusion and onset of melting of the indium sample are determined and checked to be within 0.5°C from 156.6°C for the onset of melting and within 0.5 J / g from 28.71 J / g for the heat of melting. Deionized water is then analyzed by cooling a small drop of fresh sample in a DSC pan from 25°C to -30°C at a cooling rate of 10°C / min. The sample is kept isothermal at -30°C for 2 minutes and then heated to 30°C at a heating rate of 10°C / min. The onset of melting is determined and checked to be within 0.5°C of 0°C.

[0061]

[0065] One method of determining the crystallinity of highly crystalline polypropylene polymers is by Differential Scanning Calorimetry (DSC). A small sample (milligram size) of the propylene polymer is sealed in an aluminum DSC pan. The sample is placed in the DSC cell with a nitrogen purge of 25 centimeters per minute and cooled to approximately -80°C. A standard thermal history for the sample is established by heating to 225°C at 10°C per minute. The sample is then cooled to approximately -80°C and reheated to 225°C at 10°C per minute. The heat of fusion (ΔH) observed for the second scan is 観察 ) is recorded. The observed heat of fusion is calculated according to the following formula:

[0062]

number

[0063] [wherein, the heat of fusion (ΔH ) for isotactic polypropylene reported in B. Wunderlich, Macromolecular Physics, Volume 3, Crystal Melting, Academic Press, New Your, 1980, p 48. アイソタクチックPP ) is 164.92 Joules per gram of polymer (J / g)] is related to the degree of crystallinity in weight percent based on the weight of a polypropylene sample.

[0064]

[0066] Alternatively, crystallinity may be determined using the heat of crystallization upon heating (HCH) method. In the HCH method, the sample is equilibrated at 200°C and held at that temperature for 3 minutes. After the isothermal step, data storage is initiated and the temperature of the sample is decreased to -80°C at 10°C per minute. Once -80°C is reached, data sampling is stopped and the sample is held at that temperature for 3 minutes. After a second isothermal step, data storage is initiated and the temperature of the sample is increased to 200°C at 10°C per minute.

[0065]

[0067] The average fiber diameter can be determined by taking the average of 50 measurements from five SEM images of different locations of the fabric. SEM images are collected on a Tabletop Microscope TM3030Plus (HITACHI). The imaging conditions are listed below: the observation conditions are standard observation mode with 5 kV voltage, and the image signal is collected from secondary electrons. All images are collected at magnification ×2500.

[0066]

[0068] The tensile strength of the SMS nonwoven fabrics described herein may be determined by the following test method. The SMS fabric is cut into the tensile test template shown in Figure 5 (units are 1 inch), with the length direction being the machine direction (MD) of the fabric. The tensile test is performed on a Check-Line Test Stand (Model: FGS-50PVL) at room temperature (23°C). During the test, the speed of extension is set at 100 mm / min, and the maximum breaking strength (peak tension, grams) is recorded as "MD tensile strength" and the breaking elongation is recorded as "MD elongation".

[0067]

[0069] The air permeability of the SMS nonwoven fabrics described herein is determined by NWSP 70.1 method, where the differential pressure is set at 200 Pa and the fabric is cut into a circle with an area of ​​20 cm^2. The test is performed at 23°C and 50% RH. Polypropylene Polymer

[0070] Described herein are polyolefin polymers, such as polypropylene polymers (e.g., homopolymers), having very high melt flow rates (MFR). These extremely high MFR polypropylene polymers are prepared under peroxide-free conditions using Ziegler-Natta catalysts. Such high melt flow rate polypropylene polymers are particularly well suited for producing meltblown webs and for nonwoven applications.

[0068]

[0071] The polypropylene polymers described herein may have one or more of the following advantages over polypropylene polymers produced by peroxide cracking processes: less odor; no harmful volatiles (e.g., butanol) resulting from the decomposition of peroxide by-products (e.g., Trigonox 101); and less MFR variability due to the lack of residual peroxide. The polypropylene polymers described herein are also suitable for the preparation of multi-layer spunbond-meltblown-spunbond (SMS) fabrics in which the meltblown layer is prepared from meltblown fibers comprising the ultra-high MFR polypropylene polymers described herein.

[0069]

[0072] In one aspect, the following characteristics: exhibiting a melt flow rate of greater than about 900 g / 10 min; Molecular weight distribution (M) of about 4.5 or greater than 6 w / M n ) Approximately less than 8 M z+1 / M w having a ratio, and having a xylene solubles content of less than about 4.0% by weight; A polymer composition is provided comprising a polypropylene polymer having

[0070]

[0073] Generally, the present disclosure relates to a method for producing high melt flow rate polyolefin polymers, particularly polypropylene polymers, including polypropylene homopolymers, polypropylene random copolymers and polypropylene block copolymers. By the method of the present disclosure, polypropylene polymers having melt flow rates of greater than about 900 g / 10 min, such as greater than about 1200 g / 10 min, such as greater than about 1500 g / 10 min, such as greater than about 1800 g / 10 min, such as greater than about 2200 g / 10 min, such as greater than about 4000 g / 10 min, can be produced without the need to use a single-site catalyst and / or without the need to use any peroxide. The polypropylene polymer may be greater than about 1300 g / 10 min, e.g., greater than about 1400 g / 10 min, greater than about 1500 g / 10 min, greater than about 1600 g / 10 min, greater than about 1700 g / 10 min, greater than about 1800 g / 10 min, greater than about 1900 g / 10 min, greater than about 2000 g / 10 min, greater than about 2100 g / 10 min, greater than about 2200 g / 10 min, greater than about 2300 g / 10 min, greater than about 2400 g / 10 min, greater than about 2500 g / 10 min, greater than about 2600 g / 10 min, greater than about The composition may exhibit a melt flow rate of greater than 2700 g / 10 min, greater than about 2800 g / 10 min, greater than about 2900 g / 10 min, greater than about 3000 g / 10 min, greater than about 3100 g / 10 min, greater than about 3200 g / 10 min, greater than about 3300 g / 10 min, greater than about 3400 g / 10 min, greater than about 3500 g / 10 min, greater than about 3600 g / 10 min, greater than about 3700 g / 10 min, greater than about 3800 g / 10 min, greater than about 3900 g / 10 min, and greater than about 4000 g / 10 min.In some embodiments, the polypropylene polymer may be in the range of about 1300 g / 10 min to about 2200 g / 10 min, e.g., about 1300 g / 10 min, about 1400 g / 10 min, about 1500 g / 10 min, about 1600 g / 10 min, about 1700 g / 10 min, about 1800 g / 10 min, about 1900 g / 10 min, about 2000 g / 10 min, about 2100 g / 10 min, about 2200 g / 10 min, about 2300 g / 10 min, about 2400 g / 10 min, about 2500 g / 10 min, etc. The melt flow rates of the polypropylene polymers are about 1000g / 10min, about 2600g / 10min, about 2700g / 10min, about 2800g / 10min, about 2900g / 10min, about 3000g / 10min, about 3100g / 10min, about 3200g / 10min, about 3300g / 10min, about 3400g / 10min, about 3500g / 10min, about 3600g / 10min, about 3700g / 10min, about 3800g / 10min, about 3900g / 10min, and about 4000g / 10min. The melt flow rates can be about 7000g / 10min or less. Thus, the method of the present disclosure allows for the production of very high melt flow rate polypropylene polymers in a very efficient manner. The present disclosure also relates to polyolefin polymers produced from the method.

[0071]

[0074] The polypropylene polymer of the present disclosure, which can be a polypropylene homopolymer, is produced using a Ziegler-Natta catalyst. The catalyst generally comprises a solid catalyst component in combination with a selective control agent. Optionally, the catalyst may also comprise an activity limiting agent. The catalyst is activated during polymerization using a cocatalyst. The solid catalyst component may vary depending on the particular application. In some embodiments, the polypropylene polymer is catalyzed in the presence of a Ziegler-Natta catalyst, which comprises a solid catalyst component, a selective control agent, and optionally an activity limiting agent, and the solid catalyst component comprises a magnesium moiety, a titanium moiety, and an internal electron donor. Generally, the solid catalyst component contains a magnesium moiety, a titanium moiety, and an internal electron donor. In one aspect, the solid catalyst component may optionally comprise an organophosphorus compound, an organosilicon compound, and an epoxy compound. In some embodiments, the solid catalyst component further comprises an organosilicon compound and an epoxy compound. In some embodiments, the internal electron donor comprises an aryl diester, a diether, a succinate, an organic acid ester, a polycarboxylic acid ester, a polyhydroxy ester, a heterocyclic polycarboxylic acid ester, a compound having at least one ether group and at least one ketone group, or a mixture of any two or more thereof. In some embodiments, the at least one additional internal electron donor comprises an aryl diester, an acylated catechol, a catechol containing carbonic acid, or an alkoxyalkyl ether. In some embodiments, the at least one additional internal electron donor comprises an aryl diester. The internal electron donor can comprise a phthalate compound or a substituted phenylenediester.

[0072]

[0075] The selectivity control agent used according to the present disclosure is an organosilicon compound. Examples of suitable organosilicon compounds include, but are not limited to, propyltriethoxysilane, diisobutyldimethoxysilane, n-propyltrimethoxysilane, or mixtures thereof. It is believed that the use of a selectivity control agent facilitates the production of very high melt flow rate polymers while also producing polymer products with high bulk density, low fines, and good handling. In one aspect, the organosilicon compound can be used with an activity limiting agent such as pentyl valerate. In some embodiments, the selectivity control agent includes propyltriethoxysilane, diisobutyldimethoxysilane, n-propyltrimethoxysilane, or mixtures thereof, and is used in combination with an activity limiting agent. The selectivity control agent and the activity limiting agent are both external electron donors and can be considered to form a mixed external electron donor. The molar ratio of the activity limiting agent to the selectivity control agent can be about 40:60 to about 80:20, for example, about 50:50 to about 70:30. The mixed external electron donors can be used to control the xylene solubles content, especially at higher hydrogen ratios in the reactor by adding larger amounts of the mixed external electron donors.

[0073]

[0076] In one embodiment, the method for producing the polymer can be carried out in a gas phase reactor. The catalyst used according to this method has been found to operate at relatively low hydrogen partial pressures compared to past methods while producing high melt flow rate polymers. For example, in one embodiment, the hydrogen partial pressure in the reactor can be maintained below 413700 Pa (60 psi), such as below about 399900 Pa (about 58 psi). Similarly, reducing the propylene partial pressure during the process can increase the melt flow rate of the polymer produced.

[0074]

[0077] The reactor temperature can also be controlled and manipulated to optimize the production of the polymer. For example, in one embodiment, the reactor temperature can be about 68°C to about 75°C. Alternatively, higher temperatures can be used. For example, in alternative embodiments, the reactor temperature can be greater than about 75°C, such as greater than about 80°C, such as greater than about 85°C, such as greater than about 90°C, and generally less than about 95°C. In some embodiments, the reactor temperature can be about 65°C to about 95°C, such as about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, and about 95°C. The reactor temperature can be about 72°C or higher, such as about 80°C to about 90°C. Higher reactor temperatures can increase hydrogen reaction and thus allow the production of polymers with higher melt flow rates at lower hydrogen concentrations, as compared to operating the reactor at lower temperatures. Higher reactor temperatures can also reduce the weight average molecular weight and reduce the molecular weight distribution, which facilitates the fiber blowing process during the production of the meltblown web.

[0075]

[0078] In one embodiment, the hydrogen ratio to other components in the reactor may be relatively high. In some embodiments, the H2 / C3 molar ratio during polymerization is about 0.1 to about 0.3, such as about 0.1, about 0.2, and about 0.3. As described above, the xylene solubles are controlled by varying the amount of external electron donor present, which is both the amount of selectivity control agent and activity limiter. For lower xylene solubles and higher melt flow, more external electron donor can be fed to the reactor. In one embodiment, the external electron donor mix can include a mixture of pentyl valerate and propyltriethoxysilane in a molar ratio of about 50:50 to about 70:30. Combining high hydrogen concentration in the presence of an external electron donor and using certain catalyst systems described below has been found to produce polymers with extremely high melt flow rates.

[0076]

[0079] The method of the present disclosure can produce polypropylene polymers having melt flow rates generally greater than about 900 g / 10 min. For example, the melt flow rate of the polymer can be from about 900 g / 10 min to about 9000 g / 10 min, such as from about 900 g / 10 min to about 7000 g / 10 min, including all increments of 5 g / 10 min therebetween. In certain embodiments, the melt flow rate of the polypropylene polymer can be from about 1000 g / 10 min to about 7000 g / 10 min. In certain embodiments, the melt flow rate of the polypropylene polymer can be greater than about 1000 g / 10 min, such as greater than about 1200 g / 10 min, such as greater than about 1400 g / 10 min, such as greater than about 1800 g / 10 min, such as greater than about 2200 g / 10 min, such as greater than about 4000 g / 10 min. In certain embodiments, the melt flow rate of the polypropylene polymer may be greater than about 1400 g / 10 min, such as greater than about 1800 g / 10 min, such as greater than about 2200 g / 10 min. In some embodiments, the melt flow rate of the polypropylene polymer may be less than about 9000 g / 10 min, such as less than about 7000 g / 10 min, such as less than about 4000 g / 10 min.In some embodiments, the melt flow rate of the polypropylene polymer is greater than about 1300 g / 10 min, e.g., greater than about 1400 g / 10 min, greater than about 1500 g / 10 min, greater than about 1600 g / 10 min, greater than about 1700 g / 10 min, greater than about 1800 g / 10 min, greater than about 1900 g / 10 min, greater than about 2000 g / 10 min, greater than about 2100 g / 10 min, greater than about 2200 g / 10 min, greater than about 2300 g / 10 min, greater than about 2400 g / 10 min, greater than about 2500 g / 10 min, greater than about greater than about 2600g / 10min, greater than about 2700g / 10min, greater than about 2800g / 10min, greater than about 2900g / 10min, greater than about 3000g / 10min, greater than about 3100g / 10min, greater than about 3200g / 10min, greater than about 3300g / 10min, greater than about 3400g / 10min, greater than about 3500g / 10min, greater than about 3600g / 10min, greater than about 3700g / 10min, greater than about 3800g / 10min, greater than about 3900g / 10min, and greater than about 4000g / 10min. In some embodiments, the melt flow rate of the polypropylene polymer is about 1300 g / 10 min to about 2200 g / 10 min, e.g., about 1300 g / 10 min, about 1400 g / 10 min, about 1500 g / 10 min, about 1600 g / 10 min, about 1700 g / 10 min, about 1800 g / 10 min, about 1900 g / 10 min, about 2000 g / 10 min, about 2100 g / 10 min, about 2200 g / 10 min, about 2300 g / 10 min, about 2400 g / 10 min in, about 2500g / 10min, about 2600g / 10min, about 2700g / 10min, about 2800g / 10min, about 2900g / 10min, about 3000g / 10min, about 3100g / 10min, about 3200g / 10min, about 3300g / 10min, about 3400g / 10min, about 3500g / 10min, about 3600g / 10min, about 3700g / 10min, about 3800g / 10min, about 3900g / 10min, and about 4000g / 10min.

[0077]

[0080] The polypropylene polymer can be a polypropylene homopolymer. Polypropylene copolymers, including polypropylene random copolymers and polypropylene block copolymers, can also be formed by the present method. The comonomer can include ethylene or butylene.

[0078]

[0081] The use of Ziegler-Natta catalyst systems generally results in molecular weight distributions (M) of greater than about 4.5 or greater than about 6. w / M n ) can be formed. In some embodiments, the polypropylene polymer has a molecular weight distribution of greater than about 4.5. In some embodiments, the polypropylene polymer has a molecular weight distribution of greater than about 6. In some embodiments, the polypropylene polymer has a molecular weight distribution of greater than about 7. In some embodiments, the polypropylene polymer has a molecular weight distribution of about 6.0 to about 10.0, such as about 6.0, about 6.5, about 7.0, about 7.5, about 8.0, about 8.5, about 9.0, about 9.5, and about 10.0. Maintaining the molecular weight distribution of about 6 to about 10 can provide various advantages when producing nonwoven webs. For example, maintaining the molecular weight distribution within the above ranges can produce webs that are dimensionally stable and do not neck when produced and manipulated.

[0079]

[0082] Polypropylene polymers produced according to the present disclosure have an M of less than about 8, e.g., less than about 7 and less than about 6. z+1 / M w In some embodiments, the polypropylene polymer may have an M ratio of less than about 7. z+1 / M w In some embodiments, the polypropylene polymer has an M of about 6.0 to about 8.0, such as about 6.0, about 7.0, and about 8.0. z+1 / M w The ratio is:

[0080]

[0083] Polypropylene polymers produced according to the present disclosure generally have a controlled xylene solubles content. In some embodiments, the xylene solubles content is less than about 4.0% by weight. In some embodiments, the xylene solubles content is about 1.5% to about 4% by weight, such as about 1.5%, about 2.0%, about 2.5%, about 3.0%, about 3.5%, and about 4.0% by weight. The xylene solubles content can be less than about 2% by weight. A lower xylene solubles content can provide processing advantages, while a higher amount can produce a softer feeling nonwoven fabric.

[0081]

[0084] The polypropylene polymers described herein may have a melting temperature of greater than about 155° C., e.g., greater than about 160° C., greater than about 165° C., greater than about 170° C., greater than about 175° C., and greater than about 180° C. In some embodiments, the polypropylene polymer exhibits a melting temperature of about 155° C. to about 180° C., e.g., about 155° C., about 160° C., about 165° C., about 170° C., about 175° C., and about 180° C. In some embodiments, the polypropylene polymer exhibits a melting temperature of about 155° C. to about 165° C.

[0082]

[0085] In some embodiments, the polypropylene polymer has a weight average molecular weight (Mw) of less than about 80,000 g / mol, e.g., less than about 75,000 g / mol, less than about 70,000 g / mol, less than about 65,000 g / mol, less than about 60,000 g / mol, less than about 55,000 g / mol, less than about 50,000 g / mol. In some embodiments, the polypropylene polymer has a weight average molecular weight of about 55,000 g / mol to about 70,000 g / mol, e.g., about 55,000 g / mol, about 60,000 g / mol, about 65,000 g / mol, and about 70,000 g / mol.

[0083]

[0086] The polypropylene polymer of the present disclosure can have a number average molecular weight (Mn) of less than about 8,500 g / mol, such as less than about 8,000 g / mol, less than about 7,700 g / mol, and less than about 7,000 g / mol. In some embodiments, the polypropylene polymer has a number average molecular weight of less than about 8,500 g / mol. In some embodiments, the polypropylene polymer has a number average molecular weight of about 7,000 g / mol to about 8,000 g / mol, such as about 7,000 g / mol, about 7,500 g / mol, and about 8,000 g / mol.

[0084]

[0087] As described above, the polypropylene polymer is catalyzed with a Ziegler-Natta catalyst. As described herein, the Ziegler-Natta catalyst can include an internal electron donor, which includes a substituted phenylene diester or phthalate compound. The catalyst can include a solid catalyst component that can vary depending on the particular application.

[0085]

[0088] The solid catalyst component can include (i) magnesium, (ii) a transition metal compound of an element of Groups IV-VIII of the Periodic Table, (iii) halides, oxyhalides, and / or alkoxides of (i) and / or (ii), and (iv) combinations of (i), (ii), and (iii). Non-limiting examples of suitable catalyst components include halides, oxyhalides, and alkoxides of magnesium, manganese, titanium, vanadium, chromium, molybdenum, zirconium, hafnium, and combinations thereof.

[0086]

[0089] In one embodiment, the preparation of the catalyst component involves halogenation of mixed magnesium and titanium alkoxides.

[0090] In various embodiments, the catalyst component is a magnesium moiety compound (MagMo), a mixed magnesium titanium compound (MagTi), or a magnesium chloride compound containing benzoate (BenMag). In one embodiment, the catalyst precursor is a magnesium moiety ("MagMo") precursor. The MagMo precursor comprises a magnesium moiety. Non-limiting examples of suitable magnesium moieties include anhydrous magnesium chloride and / or its alcohol adducts, magnesium alkoxides or aryloxides, mixed magnesium alkoxyhalides, and / or carboxylated magnesium dialkoxides or aryloxides. In one embodiment, the MagMo precursor is a magnesium di(C 1-4 ) alkoxide. In a further embodiment, the MagMo precursor is diethoxymagnesium.

[0087]

[0091] In another embodiment, the catalyst component is a mixed magnesium / titanium compound ("MagTi"). A "MagTi precursor" has the formula Mg d Ti(OR e )fX g [In the formula, R e is an aliphatic or aromatic hydrocarbon group having 1 to 14 carbon atoms, or COR', where R' is an aliphatic or aromatic hydrocarbon group having 1 to 14 carbon atoms; each OR egroups are the same or different); X is independently chlorine, bromine or iodine, preferably chlorine; d is 0.5-56, or 2-4; f is 2-116, or 5-15; g is 0.5-116, or 1-3. The precursor is prepared by controlled precipitation by removal of alcohol from the reaction mixture used in its preparation. In one embodiment, the reaction medium comprises an aromatic liquid, especially a chlorinated aromatic compound, most often a mixture of chlorobenzene and an alkanol, especially ethanol. Suitable halogenating agents include titanium tetrabromide, titanium tetrachloride or titanium trichloride, especially titanium tetrachloride. Removal of the alkanol from the solution used for halogenation results in the precipitation of a solid precursor having a particularly desired morphology and surface area. Moreover, the precursor obtained has a particularly uniform particle size.

[0088]

[0092] In another embodiment, the catalyst precursor is a magnesium chloride material containing benzoate ("BenMag"). As used herein, "magnesium chloride containing benzoate" ("BenMag") can be a catalyst containing a benzoate internal electron donor (i.e., a halogenated catalyst component). The BenMag material can also contain titanium moieties, such as titanium halides. The benzoate internal donor is unstable and can be replaced by other electron donors during catalyst and / or catalyst synthesis. Non-limiting examples of suitable benzoate groups include ethyl benzoate, methyl benzoate, ethyl p-methoxybenzoate, methyl p-ethoxybenzoate, ethyl p-ethoxybenzoate, ethyl p-chlorobenzoate. In one embodiment, the benzoate group is ethyl benzoate. In one embodiment, the BenMag catalyst component can be the product of halogenation of any catalyst component (i.e., MagMo precursor or MagTi precursor) in the presence of a benzoate compound.

[0089]

[0093] In another embodiment, the solid catalyst component can be formed from a magnesium moiety, a titanium moiety, an epoxy compound, an organosilicon compound, and an internal electron donor. In one embodiment, an organophosphorus compound can also be incorporated into the solid catalyst component. For example, in one embodiment, a magnesium compound containing a halide can be dissolved in a mixture including an epoxy compound, an organophosphorus compound, and a hydrocarbon solvent. The resulting solution can be treated with a titanium compound in the presence of an organosilicon compound, and optionally an internal electron donor, to form a solid precipitate. The solid precipitate can then be treated with an additional amount of titanium compound. The titanium compound used to form the catalyst has the following chemical formula: Ti(OR) g X 4-g wherein each R is independently C1-C4 alkyl; X is Br, Cl, or I; and g is 0, 1, 2, 3, or 4. may have the following structure:

[0090]

[0094] In some embodiments, the organosilicon is a monomeric or polymeric compound. The organosilicon compound may contain -Si-O-Si- groups within one molecule or between other molecules. Other illustrative examples of organosilicon compounds include polydialkylsiloxanes and / or tetraalkoxysilanes. Such compounds may be used individually or in combination. The organosilicon compound may be used in combination with aluminum alkoxides and internal electron donors.

[0091]

[0095] The aluminum alkoxides mentioned above can be of the formula Al(OR')3, where each R' is individually a hydrocarbon of up to 20 carbon atoms, including where each R' is individually methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, and the like.

[0092]

[0096] Examples of halide-containing magnesium compounds include magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride, hi one embodiment, the halide-containing magnesium compound is magnesium chloride.

[0093]

[0097] Illustrative epoxy compounds include, but are not limited to, those having the formula:

[0094] [ka]

[0095] [wherein "a" is 1, 2, 3, 4, or 5; X is F, Cl, Br, I, or methyl; and R a is H, alkyl, aryl, or cyclyl. In one embodiment, the alkyl epoxide is epichlorohydrin. In some embodiments, the epoxy compound is a haloalkyl epoxide or a non-haloalkyl epoxide.

[0096]

[0098] According to some embodiments, the epoxy compound is ethylene oxide; propylene oxide; 1,2-epoxybutane; 2,3-epoxybutane; 1,2-epoxyhexane; 1,2-epoxyoctane; 1,2-epoxydecane; 1,2-epoxydodecane; 1,2-epoxytetradecane; 1,2-epoxyhexadecane; 1,2-epoxyoctadecane; 7,8-epoxy-2-methyloctadecane; 2-vinyloxirane; 2-methyl-2-vinyloxirane; 1,2-epoxy-2-methyl ... Epoxy-5-hexene;1,2-epoxy-7-octene;1-phenyl-2,3-epoxypropane;1-(1-naphthyl)-2,3-epoxypropane;1-cyclohexyl-3,4-epoxybutane;1,3-butadiene dioxide;1,2,7,8-diepoxyoctane;Cyclopentene oxide;Cyclooctene oxide;α-Pinene oxide;2,3-epoxynorbornane;Limonene oxide;Cyclodecane epoxide;2,3,5,6-diepoxynorbornane 1,4-Bis(1,2-epoxypropyl)benzene;1,3-Bis(1,2-epoxy-1-methylethyl)benzene;1,4-Bis(1,2-epoxy-1-methylethyl)benzene;Epifluorostyrene oxide;1,2-epoxybutylbenzene;1,2-epoxyoctylbenzene;Stilbene oxide;3-Vinylstyrene oxide;1-(1-methyl-1,2-epoxyethyl)-3-(1-methylvinylbenzene);1,4-Bis(1,2-epoxypropyl)benzene;1,3-Bis(1,2-epoxy-1-methylethyl)benzene;1,4-Bis(1,2-epoxy-1-methylethyl)benzene;Epifluorostyrene oxide drin;Epichlorohydrin;Epibromohydrin;Hexafluoropropylene oxide;1,2-epoxy-4-fluorobutane;1-(2,3-epoxypropyl)-4-fluorobenzene;1-(3,4-epoxybutyl)-2-fluorobenzene;1-(2,3-epoxypropyl)-4-chlorobenzene;1-(3,4-epoxybutyl)-3-chlorobenzene;4-Fluoro-1,2-cyclohexene oxide;6-chloro-2,3-epoxybicyclo[2.2.1]heptane;4-Fluorostyrene oxide;1-(1,2-epoxypropyl)-3-trifluorobenzene;3-Acetyl-1,2-epoxypropane;4-Benzoyl-1,2-epoxybutane;4-(4-benzoyl)phenyl-1,2-epoxybutane;4,4'-Bis(3,4-epoxybutyl)benzophenone;3,4-Epoxy-1-cyclohexanone;2,3-Epoxy-5-oxobicyclo[2.2.1]heptane;3-Acetylstyrene oxide;4-(1,2-epoxypropyl)benzophenone;Glycidyl methion ether;Butyl glycidyl ether;2-ethylhexyl glycidyl ether;Allyl glycidyl ether;Ethyl 3,4-epoxybutyl ether;Glycidyl phenyl ether;Glycidyl 4-tert-butylphenyl ether;Glycidyl 4-chlorophenyl ether;Glycidyl 4-methoxyphenyl ether;Glycidyl 2-phenylphenyl ether;Glycidyl 1-naphthyl ether;Glycidyl 2-phenylphenyl ether;Glycidyl 1-naphthyl ether;Glycidyl 4-indolyl ether;Glycidyl N-methyl ether ETHYL-α-QUINOLONE-4-YL ETHER;ETHYLENE GLYCOL DIGLYCIDYL ETHER;1,4-BUTANEDIOL DIGLYCIDYL ETHER;1,2-DIGLYCIDYLOXYBENZENE;2,2-BIS(4-GLYCIDYLOXYPHENYL)PROPANE;TRIS(4-GLYCIDYLOXYPHENYL)METHANE;POLY(OXYPROPYLENE)TRIOL TRIGLYCIDYL ETHER;GLYCIDYL ETHER OF PHENOL NOVOLAC;1,2-EPOXY-4-METHOXYCYCLOHEXANE;2,3-EPOXY-5,6-DIMETHOXYBICYCLO[2.2.1]HEPTA 4-Methoxystyrene oxide;1-(1,2-epoxybutyl)-2-phenoxybenzene;Glycidyl formate;Glycidyl acetate;2,3-epoxybutyl acetate;Glycidyl butyrate;Glycidyl benzoate;Diglycidyl terephthalate;Poly(glycidyl acrylate);Poly(glycidyl methacrylate);Copolymers of glycidyl acrylate and other monomers;Copolymers of glycidyl methacrylate and other monomers;1,2-epoxy-4-methoxycarbonylcyclohexane;2,3-epoxy-5-butoxycarbonylbicyclo[2.2.1]Heptane;Ethyl 4-(1,2-epoxyethyl)benzoate;Methyl 3-(1,2-epoxybutyl)benzoate;Methyl 3-(1,2-epoxybutyl)-5-phenyl(pheyl)benzoate;N,N-Glycidyl-methylacetamide;N,N-Ethylglycidylpropionamide;N,N-Glycidylmethylbenzamide;N-(4,5-epoxypentyl)-N-methyl-benzamide;N,N-Diglycylaniline;Bis(4-diglycidylaminophenyl)methane;Poly(N,N-glycidylmethylacrylamide); The epoxy group is selected from the group consisting of 1,2-epoxy-3-(diphenylcarbamoyl)cyclohexane; 2,3-epoxy-6-(dimethylcarbamoyl)bicyclo[2.2.1]heptane; 2-(dimethylcarbamoyl)styrene oxide; 4-(1,2-epoxybutyl)-4'-(dimethylcarbamoyl)biphenyl; 4-cyano-1,2-epoxybutane; 1-(3-cyanophenyl)-2,3-epoxybutane; 2-cyanostyrene oxide; and 6-cyano-1-(1,2-epoxy-2-phenylethyl)naphthalene.

[0097]

[0099] As an example of an organophosphorus compound, a phosphate ester such as a trialkyl phosphate ester may be used. Such compounds have the formula:

[0098] [ka]

[0099] [wherein R1, R2, and R3 are each independently methyl, ethyl, and linear or branched (C3-C 10 ) alkyl groups. In one embodiment, the trialkyl phosphate ester is tributyl phosphate ester.

[0100]

[0100] In yet another embodiment, substantially spherical MgCl2-nEtOH adducts can be formed by a spray crystallization process. In this process, MgCl2-nROH melt (n is 1-6) is sprayed inside a vessel while an inert gas is introduced to the top of the vessel at a temperature of 20-80°C. The molten droplets are transferred to a crystallization zone where an inert gas is introduced at a temperature of -50 to 20°C and the molten droplets crystallize into spherical non-agglomerated solid particles. The spherical MgCl2 particles are then classified into desired sizes. Particles of undesired sizes can be recycled. In a preferred embodiment of the catalyst synthesis, the spherical MgCl2 precursor has an average particle size (Malvern d) of about 15-150 microns, preferably 20-100 microns, most preferably 35-85 microns. 50 ).

[0101]

[0101] The catalyst components can be converted to solid catalysts by halogenation. Halogenation involves contacting the catalyst components with a halogenating agent in the presence of an internal electron donor. Halogenation converts the magnesium moieties present in the catalyst components to a magnesium halide support on which titanium moieties (e.g., titanium halide) are deposited. Without wishing to be bound by any particular theory, it is believed that the internal electron donor during halogenation (1) controls the location of titanium on the magnesium-based support, (2) facilitates the conversion of the magnesium and titanium moieties to their respective halides, and (3) controls the crystallite size of the magnesium halide support during conversion. Thus, the provision of an internal electron donor results in a catalyst composition with enhanced stereoselectivity.

[0102] In one embodiment, the halogenating agent has the formula Ti(OR e ) f X h [In the formula, R eand X is as defined above, f is an integer from 0 to 3, h is an integer from 1 to 4, and f+h is 4. In one embodiment, the halogenating agent is TiCl4. In a further embodiment, the halogenation is carried out in the presence of a chlorinated or non-chlorinated aromatic liquid, such as dichlorobenzene, o-chlorotoluene, chlorobenzene, benzene, toluene, or xylene. In yet another embodiment, the halogenation is carried out using a mixture of a halogenating agent and a chlorinated aromatic liquid comprising 40 to 60 volume percent of the halogenating agent, such as TiCl4.

[0103] The reaction mixture can be heated during halogenation. The catalyst components and the halogenating agent are initially contacted at a temperature below about 10° C., such as below about 0° C., such as below about −10° C., such as below about −20° C., such as below about −30° C. The initial temperature is generally above about −50° C., such as above about −40° C. The mixture is then heated at a rate of 0.1 to 10.0° C. / min, or at a rate of 1.0 to 5.0° C. / min. The internal electron donor can be added later, after the initial contact period of the halogenating agent and the catalyst components. The temperature of the halogenation is 20° C. to 150° C. (or any value or subrange therein), or 0° C. to 120° C. The halogenation can be continued for a period of 5 to 60 minutes, or 10 to 50 minutes, in the substantial absence of the internal electron donor.

[0104]

[0104] The manner in which the catalyst components, halogenation agent, and internal electron donor are contacted can vary. In one embodiment, the catalyst components are first contacted with a mixture containing the halogenation agent and the chlorinated aromatic compound. The resulting mixture is stirred and can be heated if desired. The internal electron donor is then added to the same reaction mixture without isolation or recovery of the precursors. The above process can be carried out in a single reactor with the addition of the various components controlled by automated process control.

[0105] In one embodiment, the catalyst component is contacted with an internal electron donor prior to reacting with the halogenating agent.

[0106] The contact time between the catalyst component and the internal electron donor is at least -30°C, or at least -20°C, or at least 10°C, and at a temperature of not more than 150°C, or not more than 120°C, or not more than 115°C, or not more than 110°C, for at least 10 minutes, or at least 15 minutes, or at least 20 minutes, or at least 1 hour.

[0106]

[0107] In one embodiment, the catalyst components, the internal electron donor, and the halogenating agent are added simultaneously or substantially simultaneously.

[0108] The halogenation procedure may be repeated one, two, three or more times as desired. In one embodiment, the resulting solid material is recovered from the reaction mixture and contacted one or more times with the mixture of halogenating agents in chlorinated aromatic compounds in the absence (or presence) of the same (or different) internal electron donor component for at least about 10 minutes, or at least about 15 minutes, or at least about 20 minutes, up to about 10 hours, or up to about 45 minutes, or up to about 30 minutes, at a temperature of at least about -20°C, or at least about 0°C, or at least about 10°C, up to about 150°C, or up to about 120°C, or up to about 115°C.

[0107]

[0109] After the above halogenation procedure, the resulting solid catalyst composition is separated from the reaction medium used in the final process, for example by filtration, to produce a wet filter cake. The wet filter cake can then be rinsed or washed with a liquid diluent to remove unreacted TiCl4, and can be dried to remove residual liquid if desired. Typically, the resulting solid catalyst composition is washed one or more times with a "washing liquid", which is a liquid hydrocarbon, for example an aliphatic hydrocarbon, such as isopentane, isooctane, isohexane, hexane, pentane, or octane. The solid catalyst composition can then be separated and dried or slurried in a hydrocarbon, especially a relatively heavy hydrocarbon, for example mineral oil, for further storage or use.

[0108]

[0110] In one embodiment, the resulting solid catalyst composition has a titanium content of about 1.0 weight percent to about 6.0 weight percent, or about 1.5 weight percent to about 4.5 weight percent, or about 2.0 weight percent to about 3.5 weight percent based on the total solids weight. The weight ratio of titanium to magnesium in the solid catalyst composition is suitably about 1:3 to about 1:160, or about 1:4 to about 1:50, or about 1:6 to 1:30. In one embodiment, the internal electron donor may be present in the catalyst composition in a molar ratio of internal electron donor to magnesium of about 0.005:1 to about 1:1, or about 0.01:1 to about 0.4:1. The weight percentages are based on the total weight of the catalyst composition.

[0109]

[0111] The catalyst composition may be further treated by one or more of the following procedures, either before or after isolation of the solid catalyst composition: the solid catalyst composition may be contacted (halogenated) with additional amounts of a titanium halide compound, if desired; exchanged under metathesis conditions with an acid chloride such as phthaloyl dichloride or benzoyl chloride; and rinsed or washed, heat treated; or aged. These additional procedures may be combined in any order or used separately, or not at all.

[0110]

[0112] As described above, the catalyst composition can include a combination of a magnesium moiety, a titanium moiety, and an internal electron donor. The catalyst composition is produced by the halogenation procedure described above, which converts the catalyst component and the internal electron donor into a combination of magnesium and titanium moieties into which the internal electron donor is incorporated. The catalyst component from which the catalyst composition is formed can be any of the catalyst precursors described above, including magnesium moiety precursors, mixed magnesium / titanium precursors, magnesium chloride precursors containing benzoate, magnesium, titanium, epoxy, and phosphorus precursors, or spherical precursors.

[0111]

[0113] A variety of different types of internal electron donors can be incorporated into the solid catalyst component. In one embodiment, the internal electron donor is an aryl diester, such as a phenylene substituted diester. In one embodiment, the internal electron donor has the following chemical structure:

[0112] [ka]

[0113] wherein R1, R2, R3 and R4 are each a hydrocarbyl group having 1 to 20 carbon atoms, the hydrocarbyl group having a branched or linear structure or comprising a cycloalkyl group having 7 to 15 carbon atoms; E1 and E2 are the same or different and are selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, a substituted alkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, a substituted aryl group having 1 to 20 carbon atoms, or an inert functional group having 1 to 20 carbon atoms and optionally containing heteroatoms; X1 and X2 are each O, S, an alkyl group, or NR5, and R5 is a hydrocarbyl group having 1 to 20 carbon atoms or hydrogen. may have:

[0114]

[0114] As used herein, the terms "hydrocarbyl" and "hydrocarbon" refer to substituents containing only hydrogen and carbon atoms, such as branched or unbranched, saturated or unsaturated, cyclic, polycyclic, fused, or acyclic species, and combinations thereof. Non-limiting examples of hydrocarbyl groups include alkyl-, cycloalkyl-, alkenyl-, alkadienyl-, cycloalkenyl-, cycloalkadienyl-, aryl-, aralkyl, alkylaryl, and alkynyl- groups.

[0115]

[0115] As used herein, the terms "substituted hydrocarbyl" and "substituted hydrocarbon" refer to hydrocarbyl groups substituted with one or more non-hydrocarbyl substituents. A non-limiting example of a non-hydrocarbyl substituent is a heteroatom. As used herein, "heteroatom" refers to an atom other than carbon or hydrogen. A heteroatom can be a non-carbon atom in Groups IV, V, VI, and VII of the periodic table. Non-limiting examples of heteroatoms include halogens (F, Cl, Br, I), N, O, P, B, S, and Si. Substituted hydrocarbyl groups also include halohydrocarbyl groups and silicon-containing hydrocarbyl groups. As used herein, the term "halohydrocarbyl" group refers to a hydrocarbyl group substituted with one or more halogen atoms. As used herein, the term "silicon-containing hydrocarbyl group" is a hydrocarbyl group substituted with one or more silicon atoms. The silicon atom may or may not be in a carbon chain.

[0116] In one embodiment, the substituted phenylenediester has the following structure (I):

[0117] [ka]

[0118] has. In one embodiment, structure (I) includes R1 and R3 that are isopropyl groups. R2, R4, and R5-R 14 are hydrogen.

[0119] In one embodiment, structure (I) comprises R, R, and R 10 R2, R4, R6 to R9, and R 11 ~R 14 are hydrogen.

[0120] In one embodiment, structure (I) comprises R, R, and R 12R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0121] In one embodiment, structure (I) includes R1 as a methyl group and R3 is a t-butyl group. R7 and R 12 are ethyl groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0122] In one embodiment, structure (I) is R, R, R, R 10 , R 12 , and R 14 R2, R4, R6, R8, R 11 , and R 13 are hydrogen.

[0123] In one embodiment, structure (I) contains R1 as a methyl group and R3 is a t-butyl group. R5, R7, R9, R 10 , R 12 , and R 14 are i-propyl groups. R2, R4, R6, R8, R 11 , and R 13 are hydrogen.

[0124] In one embodiment, the substituted phenylene aromatic diester has R1-R2 as described in detail in U.S. Pat. No. 8,536,372, which is incorporated herein by reference. 14 The compound has a structure selected from the group consisting of structures (II)-(V), including options for each of the following:

[0125] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are ethoxy groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0126] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are fluorine atoms. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0127] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are chlorine atoms. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0128] In one embodiment, structure (I) includes R1 which is a methyl group and R3 is a t-butyl group. 12 are bromine atoms. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0129] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are iodine atoms. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14are hydrogen.

[0130] In one embodiment, structure (I) includes R1 which is a methyl group and R3 is a t-butyl group. 11 , and R 12 are chlorine atoms. R2, R4, R5, R8, R9, R 10 , R 13 , and R 14 are hydrogen.

[0131] In one embodiment, structure (I) includes R1 which is a methyl group and R3 is a t-butyl group. 11 , and R 13 are chlorine atoms. R2, R4, R5, R7, R9, R 10 , R 12 , and R 14 are hydrogen.

[0132] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. R2, R4, and R5-R 14 are each fluorine atoms. In one embodiment, structure (I) includes R1 which is a methyl group and R3 is a t-butyl group. 12 are trifluoromethyl groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0133] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are ethoxycarbonyl groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0134] In one embodiment, R1 is a methyl group and R3 is a t-butyl group. 12 are ethoxy groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0135] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a t-butyl group. 12 are diethylamino groups. R2, R4, R5, R6, R8, R9, R 10 , R 11 , R 13 , and R 14 are hydrogen.

[0136] In one embodiment, structure (I) includes R1 which is a methyl group, and R3 is a 2,4,4-trimethylpentan-2-yl group. R2, R4, and R5-R 14 are hydrogen.

[0137] In one embodiment, structure (I) includes R1 and R3, each of which is a sec-butyl group. R2, R4, and R5 to R 14 are hydrogen.

[0138] In one embodiment, structure (I) includes R1 and R4 that are each a methyl group. R2, R3, R5-R9, and R 10 ~R 14 are hydrogen.

[0138]

[0139] In one embodiment, structure (I) includes R1 which is a methyl group. R4 is an i-propyl group. R2, R3, R5-R9, and R 10 ~R 14 are hydrogen.

[0140] In one embodiment, structure (I) includes R1, R3, and R4, each of which is an i-propyl group. R2, R5-R9, and R 10 ~R 14 are hydrogen.

[0139]

[0141] In another embodiment, the internal electron donor can be a phthalate compound, for example, the phthalate compound can be dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diisopropyl phthalate, dibutyl phthalate, diisobutyl phthalate, diamyl phthalate, diisoamyl phthalate, methyl butyl phthalate, ethyl butyl phthalate, or ethyl propyl phthalate.

[0140]

[0142] In addition to the solid catalyst component described above, the catalyst system of the present disclosure can also include a cocatalyst. The cocatalyst can include hydrides, alkylates, or arylates of aluminum, lithium, zinc, tin, cadmium, beryllium, magnesium, and combinations thereof. In one embodiment, the cocatalyst is a hydrocarbyl aluminum cocatalyst represented by the formula R3Al, where each R is an alkyl, cycloalkyl, aryl, or hydride group; at least one R is a hydrocarbyl group; two or three R groups can be combined with a cyclic group to form a heterocyclic structure; each R can be the same or different; and each R, which is a hydrocarbyl group, has 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. In a further embodiment, each alkyl group can be linear or branched, and such hydrocarbyl group can be a mixed group, i.e., the group can contain alkyl, aryl, and / or cycloalkyl groups. Non-limiting examples of suitable groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, 2-methylpentyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, 5,5-dimethylhexyl, n-nonyl, n-decyl, isodecyl, n-undecyl, n-dodecyl.

[0141]

[0143] Non-limiting examples of suitable hydrocarbyl aluminum compounds are: triisobutylaluminum, tri-n-hexylaluminum, diisobutylaluminum hydride, di-n-hexylaluminum hydride, isobutylaluminum dihydride, n-hexylaluminum dihydride, diisobutylhexylaluminum, isobutyldihexylaluminum, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, tri-n-octylaluminum, tri-n-decylaluminum, tri-n-dodecylaluminum. In one embodiment, the cocatalyst is selected from triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, diisobutylaluminum hydride, and di-n-hexylaluminum hydride.

[0142]

[0144] In one embodiment, the cocatalyst is triethylaluminum. The molar ratio of aluminum to titanium is from about 5:1 to about 500:1, or from about 10:1 to about 200:1, or from about 15:1 to about 150:1, or from about 20:1 to about 100:1. In another embodiment, the molar ratio of aluminum to titanium is about 45:1.

[0143]

[0145] A suitable catalyst composition may include a solid catalyst component, a cocatalyst, and an external electron donor, which may be a mixed external electron donor (M-EED) of two or more different components. Suitable external electron donors or "external donors" include one or more activity limiting agents (ALA) and / or one or more selectivity control agents (SCA). As used herein, an "external donor" is a composition that includes a component or mixture of components that is added independently of the precatalyst formulation that alters the catalyst performance. As used herein, an "activity limiting agent" is a composition that reduces the catalyst activity when the polymerization temperature in the presence of the catalyst is increased above a threshold temperature (e.g., above about 95°C). A "selectivity control agent" is a composition that improves the stereoregularity of the polymer, where improved stereoregularity is generally understood to mean increased stereoregularity or reduced xylene solubles or both. It should be understood that the above definitions are not mutually exclusive and a single compound may be classified, for example, as both an activity limiting agent and a selectivity control agent.

[0144]

[0146] The selectivity control agent according to the present disclosure is generally an organosilicon compound. For example, in one embodiment, the selectivity control agent can be an alkoxysilane.

[0147] In one embodiment, the alkoxysilane has the general formula: SiR m (OR') 4-m (I) wherein R is independently a hydrocarbyl or amino group, each optionally substituted with one or more substituents containing one or more Group 14, 15, 16, or 17 heteroatoms, said R containing up to 20 atoms, not counting hydrogen and halogens; R′ is C 1-4 m is 0, 1, 2, or 3. In one embodiment, R can have the formula: 6-12 Aryl, alkyl or aralkyl, C 3-12 Cycloalkyl, C 3-12 Branched alkyl, or C 3-12 A cyclic or acyclic amino group, R' is C 1-4alkyl, and m is 1 or 2. In one embodiment, for example, the second selectivity control agent can include n-propyltriethoxysilane. Other selectivity control agents that can be used include propyltriethoxysilane or diisobutyldimethoxysilane. In some embodiments, the selectivity control agent includes propyltriethoxysilane, diisobutyldimethoxysilane, n-propyltrimethoxysilane, or mixtures thereof, and can be used in combination with an activity limiting agent, as described below.

[0145]

[0148] In one embodiment, the catalyst system may include an activity limiting agent (ALA). The ALA inhibits or otherwise prevents upset of the polymerization reactor, ensuring continuity of the polymerization process. Typically, the activity of Ziegler-Natta catalysts increases with increasing reactor temperature. Ziegler-Natta catalysts also typically maintain high activity near the melting point temperature of the polymer being produced. Heat generated by exothermic polymerization reactions can cause polymer particle agglomeration, which can ultimately lead to disruption of the continuity of the polymer production process. The ALA prevents reactor upset by reducing catalyst activity at elevated temperatures, reducing (or preventing) particle agglomeration, and ensuring continuity of the polymerization process.

[0146]

[0149] The activity limiting agent can be a carboxylic acid ester. The aliphatic carboxylic acid ester is C4-C 30 It can be an aliphatic acid ester, it can be a monoester or a polyester (diester or higher), it can be linear or branched, it can be saturated or unsaturated, and any combination thereof. 30 The aliphatic acid esters may also be substituted with one or more group 14, 15, or 16 heteroatom-containing substituents. 4- C 30 Non-limiting examples of aliphatic acid esters include aliphatic C 4-30 Monocarboxylic acid C 1-20 Alkyl ester, aliphatic C 8-20 Monocarboxylic acid C 1-20 Alkyl ester, aliphatic C 4-20 C for mono- and dicarboxylic acids 1-4Allyl mono- and diesters, aliphatic C 8-20 C for mono- and dicarboxylic acids 1-4 Alkyl esters, as well as C 2-100 (Poly)glycol or C 2-100 (Poly)glycol ether C 4-20 In a further embodiment, the C4-C 30 Aliphatic acid esters are laurate, myristate, palmitate, stearate, oleate, sebacate, (poly)(alkylene glycol) mono- or diacetate, (poly)(alkylene glycol) mono- or di-myristate, (poly)(alkylene glycol) mono- or di-laurate, (poly)(alkylene glycol) mono- or di-oleate, glyceryl tri(acetate), C2- 40 glyceryl tri-esters of aliphatic carboxylic acids, and mixtures thereof. In a further embodiment, C4-C 30 The aliphatic ester is isopropyl myristate, di-n-butyl sebacate, and / or pentyl valerate. 30 The aliphatic esters are isopropyl myristate and / or pentyl valerate.

[0147]

[0150] In one embodiment, the selectivity control agent and / or activity limiting agent can be added to the reactor separately. In another embodiment, the selectivity control agent and the activity limiting agent can be premixed together and then added to the reactor as a mixture. Additionally, the selectivity control agent and / or activity limiting agent can be added to the reactor in different ways. For example, in one embodiment, the selectivity control agent and / or activity limiting agent can be added directly to the reactor, such as a fluidized bed reactor. Alternatively, the selectivity control agent and / or activity limiting agent can be added indirectly to the reactor volume, for example, by being fed through a cycle loop. The selectivity control agent and / or activity limiting agent can be mixed with the catalyst particles in the cycle loop before being fed to the reactor.

[0148]

[0151] The catalyst system of the present disclosure described above can be used to produce olefin-based polymers. The process comprises contacting an olefin with the catalyst system under polymerization conditions.

[0149]

[0152] One or more olefin monomers can be introduced into the polymerization reactor to react with the catalyst system and form a polymer, such as a fluidized bed of polymer particles. The olefin monomer can be, for example, propylene. Any suitable reactor can be used, including a fluidized bed reactor, a stirred gas reactor, a moving packed bed reactor, a multi-zone reactor, a bulk phase reactor, a slurry reactor, or a combination thereof. Suitable commercially available reactors include UNIPOL reactors, SPHERIPOL, SPHERIZONE reactors, and the like.

[0150]

[0153] As used herein, "polymerization conditions" are the temperature and pressure parameters in a polymerization reactor suitable for promoting polymerization between the catalyst composition and an olefin to form a desired polymer. The polymerization process can be a gas phase, slurry, or bulk polymerization process operating in one or more reactors.

[0151]

[0154] In one embodiment, polymerization occurs via gas phase polymerization. As used herein, "gas phase polymerization" is the passage of an ascending fluidizing medium containing one or more monomers in the presence of a catalyst through a fluidized bed of polymer particles maintained in a fluidized state by the fluidizing medium. "Fluidization", "fluidized", or "fluidizing" is a gas-solid contact process in which a bed of finely divided polymer particles is lifted and agitated by an ascending gas flow. Fluidization occurs in a bed of fine particles when the upward flow of a fluid through the interstices of the bed of particles acquires a pressure differential and frictional resistance increment that exceeds the weight of the particles. Thus, a "fluidized bed" is a plurality of polymer particles suspended in a fluidized state by the flow of the fluidizing medium. The "fluidizing medium" is one or more olefin gases, optionally a carrier gas (e.g., H2 or N2) and optionally a liquid (e.g., a hydrocarbon) that rises through the gas phase reactor.

[0152]

[0155] A typical gas phase polymerization reactor (or gas phase reactor) includes a vessel (i.e., reactor), a fluidized bed, a distribution plate, inlet and outlet piping, a compressor, a cycle gas cooler or heat exchanger, and a product discharge system. The vessel includes a reaction zone and a velocity reduction zone, each disposed above the distribution plate. A bed is disposed in the reaction zone. In one embodiment, the fluidizing medium includes propylene gas and at least one other gas, such as an olefin, and / or a carrier gas, such as hydrogen or nitrogen.

[0153]

[0156] In one embodiment, the contacting step occurs by feeding the catalyst composition to a polymerization reactor and introducing the olefin into the polymerization reactor. In one embodiment, the cocatalyst can be mixed with the catalyst composition (premix) prior to the introduction of the catalyst composition into the polymerization reactor. In another embodiment, the cocatalyst is added to the polymerization reactor independently of the catalyst composition. The independent introduction of the cocatalyst into the polymerization reactor can occur simultaneously or substantially simultaneously with the catalyst composition feed. In some embodiments, the cocatalyst and the external electron donor are fed to the polymerization reactor in a molar ratio of about 1.5 to about 15, e.g., about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, about 6.5, about 7.0, about 7.5, about 8.0, about 8.5, about 9.0, about 9.5, about 10, about 10.5, about 11, about 11.5, about 12, about 12.5, and about 13.

[0154]

[0157] In one embodiment, the polymerization process may include a preactivation step. Preactivation involves contacting the catalyst composition with a cocatalyst and a selectivity control agent and / or activity limiting agent. The resulting preactivated catalyst stream is then introduced into the polymerization reaction zone and contacted with the olefin monomer to be polymerized. Optionally, an additional amount of selectivity control agent and / or activity limiting agent may be added.

[0155]

[0158] The process may include mixing a selectivity control agent (and optionally an activity limiting agent) with the catalyst composition. The selectivity control agent may be complexed with a cocatalyst and mixed with the catalyst composition (premix) prior to contacting the catalyst composition with the olefin. In another embodiment, the selectivity control agent and / or the activity limiting agent may be added independently to the polymerization reactor. In one embodiment, the selectivity control agent and / or the activity limiting agent may be fed to the reactor through a cycle loop.

[0156]

[0159] The above process can be used to produce polypropylene polymers with very high melt flow rates. In addition, polymers with relatively low amounts of fines and relatively high bulk densities can be produced. However, the polymers produced according to the present disclosure can contain fines in an amount less than about 8% by weight, such as less than about 7% by weight, such as less than about 6% by weight. The bulk density can be, for example, greater than about 0.30 g / cc, such as greater than about 0.4 g / cc, such as greater than about 0.42 g / cc, such as greater than about 0.45 g / cc. The bulk density is generally less than about 0.6 g / cc, such as less than about 0.5 g / cc, such as less than about 0.4 g / cc.

[0157]

[0160] The polypropylene polymer produced according to the present disclosure can then be incorporated into various polymer compositions to produce molded articles. The polymer compositions can contain the high melt flow rate polypropylene polymer in an amount generally greater than about 70% by weight, such as greater than about 80% by weight, such as greater than about 90% by weight, such as greater than about 95% by weight. The polymer compositions can contain a variety of different additives and ingredients. For example, the polymer compositions can contain one or more antioxidants. For example, in one embodiment, the polymer compositions can contain a hindered phenol antioxidant and / or a phosphite antioxidant. The polymer compositions can also contain an acid scavenger, such as calcium stearate. In addition, the polymer compositions can contain colorants, UV stabilizers, and the like. Each of the above additives can be present in the polymer composition generally in an amount of about 0.015 to about 2% by weight.

[0158]

[0161] Alternatively, the high melt flow rate polypropylene polymer can be used as a processing aid. The processing aid can be a flow agent, lubricant, mold release agent, wax, etc., to improve the melt flow properties of other polymers. In some embodiments, the high melt flow rate polypropylene polymer comprises a wax, lubricant, mold release agent, or flow aid. In this embodiment, the high melt flow rate polypropylene polymer of the present disclosure can be present in the polymer composition in an amount of about 2% to about 50% by weight, including all 1% increments therebetween. For example, the high melt flow rate polypropylene polymer can be present in the polymer composition in an amount of less than about 50% by weight, such as less than 40% by weight, such as less than about 30% by weight, such as less than about 25% by weight, such as less than about 20% by weight, such as less than about 10% by weight, and generally more than about 5% by weight. In some embodiments, the polypropylene polymer comprises a processing aid in combination with at least one other polymer exhibiting a lower melt flow rate, and the polypropylene polymer is contained in the composition in an amount of less than about 50% by weight. Polymers that can be combined with the high melt flow rate polypropylene polymer include other lower melt flow rate polypropylene polymers, polyethylene polymers, polyester polymers, and the like.

[0159]

[0162] Polyolefin polymers such as polypropylene polymers with very high melt flow rates are well suited to be used in a variety of different applications to produce a variety of different articles and products. In some embodiments, the polyolefin polymers such as polypropylene polymers do not contain any peroxides. High melt flow rate polymers generally have excellent flow properties, which makes the polymers easy to process in extrusion or molding processes at very small dimensions. For example, high melt flow rate polyolefin polymers are well suited to form small fibers and thin films. The polymers produced in the process can produce fibers with very low denier and / or higher processing speeds. For example, polyolefin polymers produced according to the present disclosure are particularly well suited to form meltblown fibers and meltblown nonwoven webs. Such fibers can be continuous or discontinuous and can have fiber diameters of less than about 5 microns, such as less than about 3 microns, such as less than about 2 microns, such as less than about 1 micron, and such as less than about 0.5 microns. Nonwoven webs produced from the polymers are dimensionally stable and do not exhibit necking during production and handling. Meltblown nonwoven webs made from the fibers have excellent filtration properties, making them well suited for use as barrier layers. For example, meltblown webs made in accordance with the present disclosure can provide excellent barriers against fluids, airborne contaminants, and microorganisms, such as viruses. As a result, meltblown webs made in accordance with the present disclosure are particularly well suited for incorporation into protective apparel and clothing.

[0160]

[0163] For example, referring to FIG. 1, one embodiment of a face mask 10 that can be manufactured using a meltblown web of the present disclosure is shown. The face mask 10 includes a body portion 12 attached to straps 14 and 16. The straps 14 and 16 are designed to extend around the user's ears to keep the body portion 12 over the wearer's nose and mouth. The body portion 12 can be manufactured from a meltblown web of the present disclosure. For example, the body portion 12 can be manufactured from a single layer of meltblown material. Alternatively, the meltblown web of the present disclosure can be one of several layers used to form the body portion 12. For example, in one aspect, the body portion 12 can include a meltblown layer of the present disclosure disposed between two outer layers.

[0161]

[0164] The very high melt flow rate polyolefin polymers described herein, such as polypropylene polymers, are well suited for meltblown nonwoven applications. In one embodiment, a meltblown web is provided that is composed of nonwoven meltblown fibers, the meltblown fibers being made from any one of the polymer compositions described herein.

[0162]

[0165] In one embodiment, meltblown fibers made from any one of the polymer compositions described herein are provided having a diameter of less than about 5 microns, e.g., less than about 4.5 microns, less than about 4.0 microns, less than about 3.5 microns, less than about 3.0 microns, less than about 2.5 microns, less than about 2.0 microns. In some embodiments, the meltblown fibers have a diameter of less than about 3 microns. In some embodiments, the meltblown fibers have a diameter of about 5 microns, about 4.5 microns, about 4.0 microns, about 3.5 microns, about 3.0 microns, about 2.5 microns, about 2.0 microns, or about 1.5 microns. In some embodiments, the meltblown fibers have a diameter of about 1.5 to about 3.0 microns. The size and distribution of the meltblown fibers can be determined by the resin MFR and / or MFR. z+1 / Mw The ratio can be determined by (higher MW polymer chains).

[0163]

[0166] In one embodiment, a nonwoven web is provided that comprises a multi-layer structure that includes one or more meltblown layers that include any one of the meltblown fibers described herein.

[0167] In some embodiments, the nonwoven web comprises one meltblown layer. In some embodiments, the nonwoven web comprises two or more meltblown layers. In some embodiments, the two or more meltblown layers comprise the same meltblown layer. In some embodiments, the two or more meltblown layers comprise different meltblown layers.

[0164]

[0168] In some embodiments, the nonwoven web further comprises two or more spunbond layers comprising spunbond fibers. In some embodiments, the spunbond fibers exhibit the following characteristics: a melt flow rate of about 20 g / 10 min to about 70 g / 10 min; a molecular weight distribution (M w / M n and a xylene solubles content of about 1.5% to about 4% by weight.

[0169] In some embodiments, the polypropylene polymer has an M of about 3.0 to about 4.0, such as about 3.0, about 3.5, and about 4.0. w / M nIn some embodiments, the polypropylene polymer has a weight average molecular weight of less than about 300,000 g / mol, e.g., less than about 250,000, less than about 200,000, and less than about 150,000. In some embodiments, the polypropylene polymer has a weight average molecular weight of about 150,000 to about 250,000, e.g., about 150,000, about 200,000, and about 250,000. In some embodiments, the polypropylene polymer has a number average molecular weight of less than about 60,000 g / mol, e.g., less than about 55,000 g / mol, less than about 50,0000 g / mol, less than about 45,000 g / mol, and less than about 40,000 g / mol. In some embodiments, the polypropylene polymer has a number average molecular weight of about 40,000 to about 55,000 g / mol, e.g., about 40,000 g / mol, about 45,000 g / mol, about 50,000 g / mol, and about 55,000 g / mol. In some embodiments, the polypropylene polymer exhibits a melting temperature greater than 155° C.

[0165]

[0170] In some embodiments, the nonwoven web comprises two or more spunblown layers. In some embodiments, the two or more spunblown layers comprise the same spunblown layer. In some embodiments, the two or more spunblown layers comprise different spunblown layers.

[0166]

[0171] In some embodiments, the nonwoven web has a multi-layer structure including a first spunbond layer, a meltblown layer, and a second spunbond layer. In some embodiments, the first spunbond layer and the second spunbond layer are the same. In some embodiments, the first spunbond layer and the second spunbond layer are different.

[0167]

[0172] In some embodiments, the nonwoven web has a thickness of about 100 l / m 2 / sec, e.g., about 95 l / m 2 / sec, approximately 90 l / m 2 / sec, approximately 85 l / m 2 / sec, approximately 80 l / m 2 / sec, approximately 75 l / m 2 / sec, approximately 70 l / m 2 / sec, approximately 65 l / m 2 / sec, approximately 60 l / m 2 / sec, approximately 65 l / m 2 / sec, approximately 50 l / m 2 / sec, approximately 55 l / m 2 / sec and approximately 50 l / m 2 In some embodiments, the nonwoven web has a breathability of from about 40 to about 80 l / m 2 / sec, e.g., about 40 l / m 2 / sec, approx. 45l / m 2 / sec, approx. 50l / m 2 / sec, approx. 55l / m 2 / sec, approx. 60l / m 2 / sec, approx. 65l / m 2 / sec, approx. 70l / m 2 / sec, approx. 75l / m 2 / sec, and 80 l / m 2 The breathability can be determined by the meltblown fiber size (average fiber diameter) and / or the meltblown fiber size distribution (fiber size standard deviation).

[0168]

[0173] In some embodiments, the nonwoven web has a machine direction (MD) tensile strength of about 2500 g / 1 inch to about 3500 g / 1 inch, for example, about 2500 g / 1 inch, about 3000 g / 1 inch, and about 3500 g / 1 inch.

[0169]

[0174] In another aspect, there is provided a method of producing any one of the nonwoven webs disclosed herein, comprising contacting one or more meltblown layers with two or more spunbond layers at a bonding temperature of about 130°C to about 140°C.

[0170]

[0175] The bonding temperature can be about 130° C., about 135° C., or about 140° C. In some embodiments, the bonding temperature is about 135° C.

[0176] Having thus generally described the invention, it will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the invention. EXAMPLES

[0171] Example 1

[0177] A variety of different high melt flow rate polypropylene homopolymers were produced in accordance with the present disclosure using two different catalysts, Catalyst A and Catalyst B. The preparation of these polypropylenes is also described in International Application No. PCT / US2021 / 049547, filed September 9, 2021, which is incorporated by reference for its disclosure of such polymers. Samples Nos. 13-18 below were made using Catalyst B, a LYNX 1010 catalyst commercially available from WR Grace and Company. The LYNX 1010 catalyst includes a solid catalyst component that includes a magnesium moiety, a titanium moiety, an epoxy compound, and an organosilicon compound. The LYNX 1010 catalyst includes a phthalate compound as an internal electron donor.

[0172]

[0178] The following Samples Nos. 1-12 and 19-21 were prepared using Catalyst A which uses a similar solid catalyst component but a non-phthalate substituted phenylenediester internal electron donor.

[0179] Both catalyst systems were used with a selectivity control agent. The selectivity control agent used was propyltriethoxylsilane. The selectivity control agent was used with pentyl valerate as the activity limiter. The molar ratio of selectivity control agent to activity limiter was 40:60.

[0173]

[0180] The reactor was used for carrying out polymerization in a gas-phase fluidized bed by using a compressor and a cooler connected to a cycle gas line.

[0181] The above catalyst was used in combination with triethylaluminum (TEAl) as a cocatalyst to produce polypropylene resin powder in a fluidized bed reactor.

[0174]

[0182] The fluidized bed reactor was operated under the following conditions: Reactor temperature: 72°C for Examples 1 to 17, 80°C for Example 18 Floor weight: 30.840kg(68lbs)~32.660kg(72lbs) Superficial gas velocity: 0.3048m~0.4877m(1.0~1.6ft) / sec

[0183] All polymers were produced at hydrogen to monomer ratios ranging from about 0.11 to about 0.23. All polymers produced had xylene solubles contents ranging from 1.5% to 6% by weight and molecular weight distributions greater than 2.5. Catalyst productivity ranged from 10 to 40 tons per kg of catalyst, averaging approximately 20 tons / kg. Extremely high melt flow rate polymers were produced without the need for the use of peroxides. Polymer particle size was determined using the GRADEX sieve test.

[0175]

[0184] The following samples were produced with the following results:

[0176] [Table 4]

[0177] [Table 5]

[0178]

[0185] As shown above, all of the samples had melt flow rates greater than 900 g / 10 min, with the highest melt flow being 8,152 g / 10 min. The results are also shown in Figures 2-4. As shown in Figure 4, the amount of fines generated during the process was relatively small.

[0179]

[0186] As shown above, higher reactor temperatures are beneficial. Sample 18 was produced at 80° C., whereas Samples 1-17 were produced at 72° C. Comparing Examples 14 and 18, the molecular weight distribution (MWD) and Mw are both lower at the higher reactor temperature, but the melt flow rate is higher even though the hydrogen ratio is kept about the same.

[0180]

[0187] Additional samples were made with Catalyst A at higher reactor temperatures as shown in the table below.

[0181] [Table 6]

[0182]

[0188] Materials made with both catalysts A and B were evaluated on a meltblown line to produce fibers with the average fiber diameters shown in Table 6:

[0183] [Table 7]

[0184] Example 2

[0189] Resin properties:

[0190] All reactor grade powders were pelletized on a Brabender single screw extruder at 60 RPM and a processing temperature of 200° C. The additive package was the same for all powders according to this disclosure during pelletization: 400 ppm Irganox® 1010, 800 ppm Irgafos® 168, and 180 ppm ZnO.

[0185]

[0191] Comparative #4 is a commercial polypropylene grade intended for meltblown applications that is produced using a Ziegler-Natta catalyst and peroxide cracked to achieve a high MFR. Comparative #3 is a metallocene catalyzed polypropylene resin that is not peroxide cracked.

[0186]

[0192] Invention #1 and #2 were produced using Catalyst B, LYNX 1010 catalyst available from WR Grace and Company. LYNX 1010 catalyst contains a solid catalyst component containing a magnesium moiety, a titanium moiety, an epoxy compound, and an organosilicon compound. LYNX 1010 catalyst contains a phthalate compound as an internal electron donor.

[0187]

[0193] Comparatives #1 and #2 were made using Catalyst A which uses a similar solid catalyst component but a non-phthalate substituted phenylenediester internal electron donor.

[0188] [Table 8]

[0189]

[0194] MB Fabric Properties: MB fabrics were produced on a lab-scale LBRD extrusion line (5 / 8" extruder, L / D=24:1) with a MB head (23-hole die). All samples were produced under the same manufacturing conditions. The processing temperature was kept at 230°C and the throughput was kept at 0.6 ghm (belt speed=3.5 m / min). Air pressure of 5 psi and 259°C were provided for quenching. Fabric basis weight was kept at 20 grams. No calendering or bonding was applied to the MB fabrics and the fabrics were collected after rolling at room temperature at low pressure.

[0190]

[0195] The average fiber thickness (or fiber diameter) and size distribution of the MB fabric are the most important factors for the MB fabric. In general, finer fiber thickness results in a softer fabric, better liquid barrier resistance, and lower breathability. As described in the Test Procedures section, the average fiber diameter was obtained by taking the average of 50 measurements from five SEM images at different locations of the fabric.

[0191] [Table 9]

[0192]

[0196] As shown in the table above, under the same MB manufacturing conditions, the two MB fabrics produced with catalyst A (Comparative #1 and #2) have a larger average fiber thickness and a wider distribution than the two samples of the present invention. This is due to the larger Mz and Mz+1 of Comparative #1 and #2, which causes more entanglement of long chain molecules during attenuation and more fiber breakage. Fiber breakage prevents further attenuation of MB fibers, resulting in larger diameter fibers.

[0193]

[0197] SMS Fabric Properties: SMS multi-layer fabrics (SBNW-MB-SBNW) were calendered off-line from non-calendered MB fabrics and SBNW fabrics produced on the NRX-12 SBNW facility. Six different MB fabrics were produced, four inventive samples and two comparative samples were used for the SMS fabrics. In the SBNW layer, two commercial grade SBNW pellets (X and Y) were used for the different SMS fabrics. Pellet X was a crack grade hPP resin for SBNW applications produced with CONSISTA® C602 catalyst available from WR Grace with UNIPOL® PP technology, while pellet Y was a 35 MFR crack grade PP resin for SBNW applications produced with unknown catalyst and process technology.

[0194] [Table 10]

[0195]

[0198] All SBNW fabrics were initially produced on a lab-scale BRD extrusion line (1.25" extruder, L / D=30:1) using an NRX-12 SBNW equipment containing a SBNW spinpack with 72 holes and 0.35 mm diameter per hole. All samples were prepared at the same manufacturing conditions to match the MB manufacturing process. The processing temperature was kept at 230°C and the throughput was kept at 0.6 ghm (belt speed=3.5 m / min). The fabric basis weight was kept at 20 gsm. The aspirator air pressure for attenuation was kept at 28 psi. Immediately after producing the two layers of non-calendered SBNW fabric, they were calendered offline in a sandwich construction with non-calendered MB fabric (MB as the core layer) at a bonding temperature of 135°C. The tensile strength and air permeability of the SMS nonwoven fabrics were determined according to the methods described in the Test Procedures section.

[0196]

[0199] Machine direction (MD) tensile strength is one of the most important properties of SMS fabrics, since it affects the mechanical performance of SMS fabric end products such as diapers and face masks. The MD tensile strength of SMS fabrics mainly depends on the two SBNW layers and the bonding conditions of the SBNW and MB layers. Thus, at the same bonding temperature of 135°C and the same SBNW layers (HT2511 or PP 3155E5), the SMS fabrics produced with the inventive MB layers showed similar tensile strengths as their comparative counterparts (within 10% difference from the average value). The reason for the small difference in tensile strength between the inventive and comparative grades is that the mechanical properties were determined by the SBNW layers rather than the MB core layer of the SMS fabric.

[0197] [Table 11]

[0198]

[0200] Breathability is another important property of SMS fabrics as it affects the filtration efficiency of SMS fabric end products such as industrial filters. Generally, finer fibers in the MB layer result in smaller pore size, which contributes to lower breathability and higher filtration efficiency. Low breathability is usually correlated with high hydrohead or high liquid barrier resistance, which is important for SMS fabric end products for medical and hygiene applications such as diapers. The two inventive grades showed similar breathability to Comparative #3 and #4, while Comparative #1 and #2 had much higher breathability. This is due to the larger average fiber diameter and larger standard deviation of Comparative #1 and #2, which leads to higher M z+1 / M w Ratio (or high M z and M. z+1 ) was caused by this.

[0199]

[0201] These results also highlight the better balance of breathability versus mechanical performance of the SMS fabrics of Inventive #1 and #2 over Comparative 1 and 2 (compared to the current commercial products with metallocene catalyst or crack grades, Comparative 3 and 4).

[0200]

[0202] While certain particular embodiments have been shown and described, it is to be understood that changes and modifications can be made in accordance with ordinary skill in the art without departing from the science and technology in its broader aspects as defined in the following claims.

[0201]

[0203] The embodiments described herein by way of example may suitably be practiced without any element or elements, limitations, not specifically disclosed herein. Thus, for example, the terms "comprising," "including," "containing," and the like, should be read broadly and without limitation. Moreover, the terms and expressions used herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of any of the features shown and described or portions thereof, recognizing that various modifications are possible within the scope of the claimed technology; further, the phrase "consisting essentially of" is understood to include the elements specifically recited and additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase "consisting of" excludes any elements not specified.

[0202]

[0204] The present disclosure is not limited to the specific embodiments described in this application. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope thereof. In addition to those recited herein, functionally equivalent methods and compositions within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the scope of the appended claims, including the full scope of equivalents to which such claims are entitled. It is to be understood that the disclosure is not limited to specific methods, reagents, compounds, compositions, or biological systems, which may of course vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0203]

[0205] Additionally, when features or aspects of the disclosure are described in terms of a Markush group, one skilled in the art will recognize that the disclosure is also described with respect to every individual member or subgroup of members of that Markush group.

[0204]

[0206] As will be understood by those of skill in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein encompass any and all possible subranges and combinations of subranges. Any described range can be readily recognized as fully describing and enabling the range such that the same range is divided into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily divided into a lower third, a middle third, and an upper third, etc. Also, as will be understood by those of skill in the art, all terms such as "less than," "at least," "greater than," "less than," etc., are inclusive of the numbers recited and extend to ranges that can then be divided into subranges as discussed above. Finally, as will be understood by those of skill in the art, a range includes each individual member.

[0205]

[0207] All publications, patent applications, issued patents, and other documents mentioned in this specification are incorporated herein by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions contained in the text incorporated by reference are excluded to the extent that they conflict with definitions in this disclosure.

[0206]

[0208] Other embodiments are within the scope of the following claims.

Claims

1. The following characteristics: exhibiting a melt flow rate greater than about 900 g / 10 min; Molecular weight distribution (M ｗ / M ｎ ), M less than about 8 ｚ＋１ / M ｗ ratio, and Xylene solubles content less than about 4.0% by weight 1. A polymer composition comprising a polypropylene polymer having:

2. The polymer composition of claim 1, wherein (a) the polypropylene polymer exhibits a melt flow rate of from about 1300 g / 10 min to about 4000 g / 10 min, and / or (b) the polypropylene polymer has a xylene solubles content of from about 1.5 wt% to about 4 wt%.

3. The polypropylene polymer has an M of greater than about 6 ｗ / M ｎ 10. The polymer composition of claim 1, having

4. The polypropylene polymer has an M of less than about 7 ｚ＋１ / M ｗ The polymer composition of claim 1 having a ratio:

5. 4. The polymer composition of claim 3, wherein the polypropylene polymer exhibits a melting temperature greater than about 155°C or a melting temperature of from about 155°C to about 165°C.

6. 10. The polymer composition of claim 1, wherein the polypropylene polymer has a weight average molecular weight of less than about 80,000 g / mol.

7. 10. The polymer composition of claim 1, wherein the polypropylene polymer has a number average molecular weight of less than about 8,500 g / mol.

8. 7. The polymer composition of claim 6, wherein the polypropylene polymer is catalyzed in the presence of a Ziegler-Natta catalyst comprising an internal electron donor, and the internal electron donor comprises a substituted phenylenediester or phthalate compound.

9. A polypropylene polymer catalyzed in the presence of a Ziegler-Natta catalyst, the Ziegler-Natta catalyst comprising a solid catalyst component, a selective control agent, and optionally an activity limiting agent, the solid catalyst component comprising a magnesium moiety, a titanium moiety, and an internal electron donor; (a) the solid catalyst component further comprises an organosilicon compound and an epoxy compound; and / or 10. The polymer composition of claim 1, wherein (b) the selective control agent comprises an organosilicon compound.

10. 10. The polymer composition of claim 1, wherein the polypropylene polymer does not contain any peroxides.

11. A meltblown web comprised of nonwoven meltblown fibers, the meltblown fibers being made from the polymer composition of claim 1.

12. 10. A meltblown fiber made from the polymer composition of claim 1, wherein the meltblown fiber has a diameter of less than about 5 microns.

13. A nonwoven web comprising a multi-layer structure comprising one or more meltblown layers comprising the meltblown fibers of claim 12.

14. 14. The nonwoven web of claim 13, further comprising two or more spunbond layers comprising spunbond fibers.

15. Spunbond fibers have the following properties: exhibiting a melt flow rate of about 20 g / 10 min to about 70 g / 10 min; A molecular weight distribution (M ｗ / M ｎ ), and having a xylene solubles content of about 1.5% to about 4% by weight; 15. The nonwoven web of claim 14 prepared from a polymer composition comprising a polypropylene polymer having one or more of:

16. 16. The nonwoven web of claim 15, wherein the polypropylene polymer has a weight average molecular weight of less than about 300,000 g / mol.

17. 16. The nonwoven web of claim 15, wherein the polypropylene polymer has a number average molecular weight of less than about 60,000 g / mol.

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