WO2022079601A1

WO2022079601A1 - Melt processible high density polyethylene compositions comprising a polyorganosiloxane polymer

Info

Publication number: WO2022079601A1
Application number: PCT/IB2021/059356
Authority: WO
Inventors: Roman I. VASILIEV; Timofey MAKAROV; Claude LAVALLÉE
Original assignee: 3M Innovative Properties Company
Priority date: 2020-10-16
Filing date: 2021-10-12
Publication date: 2022-04-21
Also published as: RU2020134081A

Abstract

Described herein is the use of a polyorganosiloxane polymer in the melt processing of a high density polyethylene composition. The polyorganosiloxane polymer has been shown to reduce and/or eliminate gross melt fracture.

Description

MELT PROCESSIBLE HIGH DENSITY POLYETHYLENE COMPOSITIONS COMPRISING A POLYORGANOSILOXANE POLYMER

TECHNICAL FIELD

[0001] The present disclosure relates to the use of a polyorganosiloxane polymer in the melt processing of high density polyethylene polymer to reduce and/or eliminate gross melt fractures.

SUMMARY

[0002] Extrusion of polymer materials to obtain and form products is a large segment of the plastic and polymer product industry. Any composition of a melt-processed thermoplastic polymer has a critical shear rate, above which the extrudate surface becomes uneven or deformed and below which the extrudate is smooth. The quality of the extruded product (or extrudate) and the overall success of the extrusion process usually depend on the processing conditions and the interaction of the fluent material with the extrusion die.

[0003] There is a desire to identify methods to reduce gross melt fracture in high density polyethylene compositions to enable throughput and/or high shear rates. It has been discovered that compositions comprising at least one polyorganosiloxane polymer are exceptionally efficient for reducing gross melt fracture in high density polyethylene melt processible compositions.

[0004] In one aspect, a melt processible polymer composition is described, the composition comprising: (a) a melt-processible polymer comprising a high density polyethylene; and (b) a polyorganosiloxane.

[0005] In another aspect, a method of extrusion is disclosed, wherein when presence of a polyorganosiloxane reduced and/or eliminates the gross melt fracture in a melt-processible polymer composition comprising a high density polyethylene.

[0006] In yet another aspect, polyorganosiloxane is used to reduced and/or eliminate gross melt fracture in a melt-processible polymer composition comprising a high density polyethylene.

[0007] The above summary is not intended to describe each embodiment. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages will be apparent from the description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic representation of pressure versus throughput for a hypothetical resin. DETAILED DESCRIPTION

[0009] As used herein, the term

“a”, “an”, and “the” are used interchangeably and mean one or more.

“and/or” is used to indicate one or both stated cases may occur, for example A and/or B includes, (A and B) and (A or B);

“alkyl” means a linear or branched, cyclic or acyclic, saturated monovalent hydrocarbon having from one to about twelve carbon atoms, e.g., methyl, ethyl, 1 -propyl, 2-propyl, pentyl, and the like;

“aryl” means a monovalent aromatic, such as benzyl, phenyl, and the like;

“backbone” refers to the main continuous chain of the polymer;

“monomer” is a molecule which can undergo polymerization which then form part of the essential structure of a polymer; and

“polymer” refers to a macrostructure comprising interpolymerized units of monomers.

[0010] As used herein, the term “perfluoroalkyl group” includes linear, branched, and/or cyclic alkyl groups in which all C-H bonds have been replaced by C-F bonds.

[0011] The singular forms “a”, “an”, and “the” do not refer only to a single object, but include the general class, a specific example of which may be used for illustrative purposes.

[0012] As used herein, the term “comprising at least” followed by a list refers to that comprising any one of the listed items and any combination of two or more of the listed items. As used herein, the term “at least one of’ followed by a list refers to any of the listed items or to any combination of two or more of the listed items.

[0013] As used herein, recitation of ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0014] As used herein, recitation of “at least” followed by a number includes the named number and all those greater. For example, “at least 1” includes all numbers of one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0015] Extrusion is the process wherein a material, such as a resin, is pushed through a die of a given cross-section. It is generally believed that when the extrusion rate exceeds a certain value, the internal stresses on the resin reach a critical value, where the release of those stress result in deformities or imperfections in the extrudate, polymer buildup at the die aperture (also known as material accumulation at the extrusion die, or sags at the extrusion die), and/or increased back pressure during extrusion. These problems slow down the extrusion process, as the process either has to be interrupted to clean the equipment or has to be performed at a lower rate. Shown in Fig.

1 is a schematic showing pressure (or shear stress) versus throughput (or shear rate) for a capillary or pellet extrusion of a hypothetical resin. Because the die geometry can influence the occurrence of extrusion defects, shear rate is the throughput normalized for the die geometry, while shear stress is the pressure normalized for the die geometry. Two lines are shown in Fig. 1. Line A represents where the resin shows adhesion (or sticks) at the die wall. Line B represents where the resin slips along the dye wall. Along region 1 of Line A, the extrudate shows no defects. As the pressure increases, the resin sticks to the die walls and surface defects, such as sharkskin, appear around region 2. As the pressure is further increased, the shear stress exceeds the adhesive strength of the resin to the die wall and the resin jumps (shown by line 3) to Line B, which is accompanied by increased throughput. The pressure decreases (shown by line 4) due to the loss of adhesion to the wall. However, if the pressure becomes low enough, the resin jumps back (shown by line 5) to Line A. As the pressure fluctuates (increasing followed by decreasing), the resin jumps repeatedly between Lines A and B in so-called “cyclic melt” fracture. Once a pressure is reached wherein the resin is no longer able to return to the stick conditions, the material then enters gross melt fracture, shown by region 6.

[0016] The defects described above, “sharkskin” and “cyclic melt fracture” are surface defects, which can usually be resolved through the use of a polymer processing additive, or “PPA”. A common PPA is a fluoropolymer, which coats the die walls, promoting slip. As described above, gross melt fracture occurs at higher shear rates than cyclic or sharkskin melt fracture. Gross melt fracture impacts the bulk polymer during processing, not just the surface, and is unaffected by traditional fluoropolymer PPA’s. The onset of gross melt fracture appears to scale with the high rate tensile stress growth behavior of the polymer melts. Thus, the faster one processes the melt processible polymer, the more likely gross melt fracture will occur. In other words, gross melt fracture inhibits high throughput processing of high density polyethylene.

[0017] In the present disclosure, it has been discovered that polyorganosilanes can be used to reduce and/or eliminate gross melt fractures in a melt-processible polymer comprising a high density polyethylene.

[0018] The polyorganosiloxane comprises repeat units of formula (-Si(R⁷)2O-), wherein R⁷ is defined below. The polyorganosiloxane are preferably linear. More preferably, the polyorganosiloxanes are organosiloxane-polyamide block copolymers or organosiloxane-urethane block copolymers.

[0019] The poly(organosiloxane) may comprise a number of organic substituents at carbons that have bonds with silicon atoms in the siloxane. For example, each organic substituent may independently be alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxy, or halogen. In one embodiment, the polyorganosiloxane polymer includes a poly(organosiloxanes). The poly(organosiloxane) may comprise the units of general formula (- Si(R⁷)2O-), where R⁷ is as defined below for embodiments of R⁷ in Formula I. Examples of these include dimethylsilicones, diethylsilicones, and diphenylsilicones. In some embodiments, at least 40 percent, and in some embodiments, at least 50 percent, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of R⁷ groups may be phenyl, methyl, or a combination thereof. In some embodiments, at least 50 percent, at least 50 percent, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of R⁷ groups are methyl. A high molecular weight polydimethylsiloxane (PDMS) is commercially available, e.g., from Dow Coming Corporation, Midland, MI.

[0020] Preferably, a polydimethylsiloxane polymer suitable for the compositions of the present disclosure comprises (-Si(R⁷)2O-) repeat units and repeated amino groups, i.e., -(C=O)-N(R⁸)-G- N(R⁸)-(C=O)-. R⁷ and R⁸ are as described further below.

[0021] In one embodiment, a linear polyorganosiloxane-polyamide block copolymer suitable for practicing the present disclosure comprises at least two repeat units of Formula I:

[0022] In this formula, each R⁷ is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen. Each Y is independently alkylene, arylalkylene, alkylarylene, or a combination thereof. Subscript n is independently 0 to 1,500 and subscript p is 1 to 10. Each B is independently a covalent bond, alkylene, arylalkylene, alkylarylene, or a combination thereof. When each B is a covalent bond, the polyorganosiloxane- polyamide block copolymer of Formula I is referred to as polyorganosiloxane-polyoxamide block copolymer. G is a divalent group, which is a residue corresponding to a diamine of formula R⁸HN- G-NHR⁸ with two -NHR⁸ groups removed. R⁸ is hydrogen or alkyl (e.g., an alkyl comprising 1 to 10, 1 to 6, or 1 to 4 carbon atoms), or R⁸ and G taken together with the nitrogen to which they are both connected to form a heterocyclic group. Each asterisk (*) indicates the connection site of the repeat unit to another group in the copolymer, such as, e.g., another repeat unit of Formula I.

[0023] Suitable alkyl groups for R⁷ in Formula I usually comprise 1 to 10, 1 to 6, or 1 to 4 carbon atoms. Examples of suitable alkyl groups include methyl, ethyl, isopropyl, n-propyl, n-butyl, and isobutyl. In suitable haloalkyl groups for R⁷, often only part of the hydrogens of the corresponding alkyl groups has been substituted for halogens. Examples of haloalkyl groups include chloroalkyl and fluoroalkyl groups comprising 1 to 3 halogen atoms and 3 to 10 hydrogen atoms. Suitable alkenyl groups for R⁷ often comprise 2 to 10 carbon atoms. Examples of the alkenyl groups often comprise 2 to 8, 2 to 6, or 2 to 4 carbon atoms, such as ethenyl, n-propenyl, and n-butenyl. Suitable aryl groups for R⁷ often comprise 6 to 12 carbon atoms. An example of the aryl group is phenyl. The aryl group may be unsubstituted or substituted with alkyl (i.e., it may be an alkylarenyl group) (e.g., the alkyl group may be an alkyl comprising 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), alkoxyl (e.g., with an alkoxyl comprising 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), or halogen (e.g., with chloro, bromo, or fluoro). Suitable arylalkylenyl and alkylarylenyl groups for R⁷ usually comprise an alkylene group comprising 1 to 10 carbon atoms and an aryl group comprising 6 to 12 carbon atoms. In certain arylalkylenyl and alkylarylenyl groups, the aryl group is phenyl and the alkylene group comprises 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. For example, R⁷ may be an arylalkylenyl group in which any of said alkylene groups is bonded to phenyl.

[0024] In some embodiments, in some of the repeat units of Formula I at least 40 percent, and in some embodiments at least 50 percent, of R⁷ groups are phenyl, methyl, or a combination thereof. For example, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of R⁷ groups may be phenyl, methyl, or combinations thereof. In some embodiments, in some of the repeat units of Formula I at least 40 percent, and in some embodiments at least 50 percent, of R⁷ groups are methyl. For example, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of R⁷ groups may be methyl. The remaining R⁷ groups may be selected from an alkyl comprising at least two carbon atoms, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen.

[0025] Each Y in Formula I is independently alkylene, arylalkylene, alkylarylene, or a combination thereof. Suitable alkylene groups usually comprise up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. Examples of alkylene groups include methylene, ethylene, propylene, butylene, and similar groups. Suitable arylalkylene and alkylarylene groups usually comprise an arylene group comprising 6 to 12 carbon atoms bonded to an alkylene group comprising 1 to 10 carbon atoms. In certain arylalkylene and alkylarylene groups, the arylene moiety is phenylene. In other words, a divalent arylalkylene or alkylarylene group comprises phenylene bonded to alkylene comprising 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. With reference to group Y, the term “combination thereof’ refers to a combination of two or more groups selected from the alkylene, arylalkylene, or alkylarylene groups. Such a combination may be, e.g., one alkylarylene bonded to one alkylene (such as alkylene-arylene-alkylene). In one example of the combination alkyl ene-arylene-alkylene, the arylene is phenylene and each of the alkylenes comprises 1 to 10, 1 to 6, or 1 to 4 carbon atoms. [0026] Each subscript n in Formula I is independently 0 to 1,500. For example, subscript n may be up to 1,000, up to 500, up to 400, up to 300, up to 200, up to 100, up to 80, up to 60, up to 40, up to 20, or up to 10. The value of n is often at least 1, at least 2, at least 3, at least 5, at least 10, at least 20, or at least 40. For example, subscript n may be 40 to 1,500, 0 to 1,000, 40 to 1,000, 0 to 500, 1 to 500, 40 to 500, 1 to 400, 1 to 300, 1 to 200, 1 to 100, 1 to 80, 1 to 40, or 1 to 20. [0027] Subscript p is 1 to 10. For example, the value of p is often an integer up to 9, up to 8, up to 7, up to 6, up to 5, up to 4, up to, or up to 2. The value of p may be 1 to 8, 1 to 6, or 1 to 4. [0028] G in Formula I is a divalent group, which is a residue corresponding to a diamine of formula R⁸HN-G-NHR⁸ with two amino groups (i.e., -NHR⁸ groups) removed. The diamine may comprise primary or secondary amino groups. R⁸ is hydrogen or alkyl (e.g., an alkyl comprising 1 to 10, 1 to 6, or 1 to 4 carbon atoms), or R⁸ and G taken together with the nitrogen to which they are both connected to form a heterocyclic group (such as a 5-7-member ring). In some embodiments, R⁸HN-G-NHR⁸ is piperazine. In some embodiments, R⁸ is hydrogen or alkyl. In some embodiments, both amino groups in the diamine are primary amino groups (i.e., both R⁸ groups are hydrogen), and the diamine has the formula H2N-G-NH2.

[0029] In some embodiments, G is alkylene, heteroalkylene, polyorganosiloxane, arylene, arylalkylene, alkylarylene, or a combination thereof. Suitable alkylenes often comprise 2 to 10, 2 to 6, or 2 to 4 carbon atoms. Examples of alkylene groups include ethylene, propylene, and butylene. Suitable heteroalkylenes are often polyoxyalkylenes, such as polyoxyethylene comprising at least 2 ethylene units, polyoxypropylene comprising at least 2 propylene units, or their copolymers. Examples of polyorganosiloxanes include alkylene-capped polydimethylsiloxanes. Suitable arylalkylene groups usually comprise an arylene group comprising 6 to 12 carbon atoms bonded to an alkylene group comprising 1 to 10 carbon atoms. Some examples of arylalkylene groups are phenylene-alkylenes, in which phenylene is bonded to an alkylene comprising 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Some examples of alkylarylene groups are alkylene-phenylenes, in which an alkylene comprising 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms is bonded to phenylene. With reference to group G, the term “combination thereof’ refers to a combination of two or more groups selected from alkylene, heteroalkylene, polyorganosiloxane, arylene, arylalkylene, and alkylarylene. Such a combination may be, e.g., one alkylarylene bonded to one alkylene (such as alkylene -arylene -alkylene). In one example of the combination alkylene-arylene-alkylene, the arylene is phenylene and each of the alkylenes comprises 1 to 10, 1 to 6, or 1 to 4 carbon atoms. [0030] In one embodiment, the polyorganosiloxanes may have a molecular weight higher than 25,000, 50,000, or even 100,000 g/mol. In one embodiment, the polyorganosiloxanes may have a molecular weight of at most 200,000, 500,000, 750,000, 1,000,000, or even 2,000,000 g/mol.

[0031] In some embodiments, the polyorganosiloxane-polyamide is a polyorganosiloxane- poly oxamide. The polyorganosiloxane-poly oxamide usually does not comprise groups of formula - B-(CO)-NH-, where B is alkylene. All carbonylamino groups in the backbone of a copolymer material are usually a part of oxalylamino group (i.e., -(CO)-(CO)-NH-), and B is a covalent bond. In other words, any carbonyl group in the backbone of a copolymer material is bonded to another carbonyl group and forms part of an oxalyl group. In particular, the polyorganosiloxane- poly oxamide comprises a multitude of aminooxalylamino groups.

[0032] The polyorganosiloxane-polyoxamide is a block copolymer and may be an elastomeric material. In contrast to many known polyorganosiloxane-polyoxamides, which are usually obtained as brittle solids or hard plastics, the polyorganosiloxane-polyoxamides of the present disclosure may comprise more than 50 weight percent of polyorganosiloxane fragments relative to the weight of the copolymer. The weight fraction of polyorganosiloxane in the polyorganosiloxane-polyoxamide can be increased by using polyorganosiloxane segments with a higher molecular weight to provide more than 60 weight percent, more than 70 weight percent, more than 80 weight percent, more than 90 weight percent, more than 95 weight percent, or more than 98 weight percent of polyorganosiloxane segments in the polyorganosiloxane-polyoxamides. Higher amounts of polyorganosiloxane may be used to obtain elastomeric materials with a lower modulus while retaining a reasonable strength.

[0033] Silicone-polyurethane copolymers (SPU) suitable as the polymer processing additives in the compositions and methods of the present disclosure include block copolymers comprising an organosilicon block and second blocks derived from a multifunctional isocyanate. As used herein, the term “silicone-polyurea” may be used interchangeably with the term “silicone-polyurethane”. The blocks derived from an isocyanate may comprise two functional groups (such as -NHCONH- or - NHC(O)O-) bonded to a divalent organic radical (such as alkyl, cycloalkyl and aryl groups comprising 1 to 30 carbon atoms). Examples of suitable diisocyanate compounds from which the second blocks can be derived include ethylenediisocyanate, 1,6-hexylenediisocyanate, 1,12-dodecylenediisocyanate, 4,4 ’ -diphenylmethanediisocyanate, 3,3’ -dimethoxy-4,4 ’ -diphenylmethanediisocyanate, 3,3’ -dimethyl- 4,4’-diphenylmethanediisocyanate, 4,4’-diphenyldiisocyanate, toluene-2,6-diisocyanate, mixtures of toluene-2,6-diisocyanate and toluene-2,4-diisocyanate, 1,4-cyclohexylenediisocyanate, 4,4’- dicyclohexylmethanediisocyanate, 3,3’ -diphenyl-4,4 ’ -biphenylenediisocyanate, 4,4 ’ - biphenylenediisocyanate, 2,4-diisocyanate diphenyl ether, 2, 4-dimethyl- 1,3 -phenylenediisocyanate, 4,4 ’-(diphenyl ether)diisocyanate, isophoronediisocyanate, and mixtures thereof. [0034] The organosilicon blocks include the blocks of general formula (Si(R⁷)2O-), where R⁷ is as defined above for R⁷ in Formula I. Non-limiting examples include dimethylsilicones, diethylsilicones, and diphenylsilicones.

[0035] Copolymers comprising polydioranosiloxane-urethane (a subclass of the SPU class of materials) suitable for the compositions of the present disclosure comprise flexible polydioranosiloxane units, rigid units of polyisocyanate residues, terminal groups, and optionally flexible and/or rigid units of organic polyamine residues. Certain copolymers comprising polydioranosiloxane-urea are commercially available under the trademark “GENIOMER 140” from Wacker Chemie AG, Germany. The polyisocyanate residues are a polyisocyanate with removed -NCO groups, the organic polyamine residues are an organic polyamine with removed -NH groups, and the polyisocyanate residue is connected to the polydioranosiloxane units or organic polyamine residues via urethane bonds. The terminal groups may be non-functional groups or functional groups, depending on the intended application of the copolymer comprising the polydioranosiloxane-urea.

[0036] In some embodiments, the copolymers comprising polyoranosiloxane-urethane comprise at least two repeat units of Formula II

[0037] In Formula II, each R⁹ is a fragment which is independently alkyl, cycloalkyl, aryl, perfluoroalkyl, or perfluoroether. In some embodiments of R⁹, the alkyl comprises 1 to 12 carbon atoms and may be further substituted, e.g., with trifluoroalkyl, vinyl, vinyl radical, or a higher alkenyl of formula -R¹⁰(CH2)_aCH=CH2, where R¹⁰ is -(CFE - or -(CH2)_cCH=CH- and a is 1, 2, or 3; b is 0, 3, or 6; and c is 3, 4, or 5. In some embodiments of R⁹, the cycloalkyl comprises about 6 to 12 carbon atoms and may be further substituted with one or more alkyl, fluoroalkyl, or vinyl. In some embodiments of R⁹, the aryl comprises about 6 to 20 carbon atoms and may be further substituted, e.g., with alkyl, cycloalkyl, fluoroalkyl, and vinyl. In some embodiments of R⁹, the perfluoroalkyl is as disclosed in U.S. Pat. No. 5028679, the disclosure of which is incorporated herein by reference, and the group comprising a perfluoroether is as disclosed in U.S. Pat. Nos. 4900474 and 5118775, the disclosures of which are incorporated herein by reference. In some embodiments, R⁹ is a group comprising fluorine as disclosed in U.S. Pat. No. 5236997, the disclosure of which is incorporated herein by reference. In some embodiments, at least 50% of R⁹ fragments are methyl radicals, while the remaining fragments are monovalent alkyl or substituted alkyl radicals comprising 1 to 12 carbon atoms, alkenylene radicals, phenyl radicals, or substituted phenyl radicals. In Formula II, each Z’ is arylene, arylalkylene, alkylene, or cycloalkylene. In some embodiments of Z’, the arylene or arylalkylene comprises about 6 to 20 carbon atoms. In some embodiments of Z’, the alkylene or cycloalkylene radical comprises about 6 to 20 carbon atoms. In some embodiments, Z’ is 2,6- toluylene, 4,4'-methylenediphenylene, 3,3'-dimethoxy-4,4'-biphenylene, tetramethyl-meta- xylylene, 4,4'-methylenedicyclohexylene, 3,5,5-trimethyl-3-methylenedicyclohexylene, 1,6- hexamethylene, 1,4-cyclohexylene, 2,2,4-trimethylhexylene, or mixtures thereof. In Formula II, each Y’ is independently alkylene, arylalkylene, alkylarylene, or arylene. In some embodiments of Y’, the alkylene comprises 1 to 10 carbon atoms. In some embodiments of Y’, the arylalkylene, alkylarylene, or arylene comprises 6 to 20 carbon atoms. In Formula II, each D is independently a hydrogen atom, an alkyl radical comprising 1 to 10 carbon atoms, phenyl, or a radical complementing the ring structure comprising B’ or Y’ to form a heterocycle. In Formula II, B’ is a polyvalent radical selected from the group consisting of alkylene, arylalkylene, alkylarylene, cycloalkylene, phenylene, and polyalkyleneoxide (such as polyethyleneoxide, polypropyleneoxide, polytetramethyleneoxide, and copolymers and mixtures thereof). In Formula II, s is a number between 0 and about 1,000; r is a number equal to or larger than 1; and q is a number of about 5 or larger, in some embodiments about 15 to 2,000, and in some embodiments about 30 to 1,500.

[0038] When using polyisocyanates (Z’ is a radical with functionality higher than 2) and polyamines (B ’ is a radical with functionality higher than 2), the structure of Formula II will be modified to reflect the branching of the polymer backbone. When using terminal group blocking agents, the structure of Formula II will be modified to reflect the terminal groups of the polyorganosiloxane-urea chain.

[0039] Block copolymers comprising the units of Formula I and polymers comprising the polyorganosiloxane-urea of Formula II may be obtained, e.g., as disclosed in U.S. Pat. No. 8552136 (Papp et al.).

[0040] In one embodiment, the polyorganosiloxane polymers have an average particle size (weight average) of greater than about 100, 200, 500, 1000, 1200, or even 1500 nm; and at most 2, 2.5, 3, 3.5, 4, 5, 7, 10, 15, or even 20 micrometers. In a typical embodiment, the polyorganosiloxane polymer may have an average particle size (weight average) of from about 1 to about 30 pm.

[0041] In one embodiment, the composition may comprise blends of polyorganosiloxane polymers which comprise different molecular weights, Mooney viscosity, Intrinsic Viscosity, and/or long chain branching indices.

[0042] In the present disclosure, an effective amount of polyorganosiloxane polymer is used to eliminate and/or reduce the formation of gross melt fracture during high throughput processing of a melt processable composition comprising a high density polyethylene polymer. [0043] The melt-processible polymer compositions disclosed herein include a melt-processible high density polyethylene. As used herein, “melt-processible” is meant that the respective polymer or composition can be processed in commonly used melt-processing equipment such as, for example, an extruder. The melt-processible polymer composition disclosed herein can refer to the extruded final form of the composition (such as a pellet, a film, a fiber, a coated wire or cable sheath, etc.) or can refer to a masterbatch (or concentrate), which is diluted with additional polymer (such as high density polyethylene) before being extruded.

[0044] In one embodiment, the melt processible polymer may typically have a melt flow index (measured according to ASTM D 1238-13 with a 2.16 kg weight at 190 °C; or ISO 1133-1:2011 using a 5 kg at 190 °C) of at most 0.5g/10 minutes. In one embodiment, the melt processible polymer has a melt flow index of at least 0.05, 0.1, 0.15, or even 0.2 g/10 minutes. In one embodiment, the melt processible polymer has a melt flow index of at most 0.3, 0.4, or even 0.5 g/10 minutes.

[0045] In one embodiment, the melt processible polymer may typically have a melt flow index (measured according to ASTM D1238-13 using a 21.60 kg weight at 190°C) of at most 10 g/10 minutes. In one embodiment, the melt processible polymer has a melt flow index of at least 0.5, 1, 2, or even 4 g/10 minutes. In one embodiment, the melt processible polymer has a melt flow index of at most 6, 7, 8, or even 10 g/10 minutes.

[0046] The high density polyethylene useful in the present disclosure may be a homopolymer or a copolymer comprising primarily interpolymerized ethylene monomeric units. High density polyethylene is differentiated from low density polyethylene homopolymer (LDPE) in terms of density, with high density polyethylene having a slightly higher density for example greater than 0.93, 0.94, 0.95, or even 0.96; and at most 0.96, 0.97, 0.98, or even 1.0 g/cm³) as measured by ASTM D 1505-18, than its low density counterpart; and a higher melting point, with high density polyethylene having a higher melting point (120-140°C) and deflection temperature (0.46 MPa (megaPascals) of between 75-85°C).

[0047] The high density polyethylene homopolymer comprises solely -(CH2-CH2)- repeat units along the polymer backbone, excluding the polymer ends, where the polymerization is initiated or terminated.

[0048] In the instance of a copolymer, the high density polyethylene comprises primarily the divalent repeat unit -(CH2-CH2)- along the polymer backbone along with other monomeric units in an amount of at least 0.01 wt (weight)% and less than 5, 3, 1, 0.5, 0.1, or even 0.05 weight percent. Exemplary monomers copolymerizable with ethylene include olefins; vinyl ester monomers; acrylic and alpha-alkyl acrylic acid monomers; and vinyl monomers. The olefins may be characterized by the general structure CH2=CHR, wherein R is an alkyl radical, and generally, the alkyl radical contains not more than 10 carbon atoms, preferably from one to six carbon atoms. Representative olefins are propylene, 1-butene, 1-hexene, 4-methyl-l -pentene, and 1-octene. Representative vinyl ester monomers are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl chloroacetate, and vinyl chloropropionate. Representative acrylic and alpha-alkyl acrylic acid monomers include acrylic acid, methacrylic acid, ethacrylic acid, methyl acrylate, ethyl acrylate, N,N-dimethyl acrylamide, methacrylamide, and acrylonitrile. Representative vinyl monomers include vinyl aryl monomers such as styrene, o-methoxystyrene, p-methoxystyrene, and vinyl naphthalene; vinyl and vinylidene halide monomers such as vinyl chloride, vinylidene chloride, and vinylidene bromide; alkyl ester monomers of maleic and fumaric acid and anhydrides thereof such as dimethyl maleate, diethyl maleate, and maleic anhydride; vinyl alkyl ether monomers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, and 2-chloroethyl vinyl ether; vinyl pyridine monomers; N-vinyl carbazole monomers; and N-vinyl pyrolidine monomers.

[0049] A particularly useful class of high density polyethylene copolymers include those with monomeric units derived from propylene, 1-butene, 1-hexene, 1-octene, 1 -decene, 4-methyl-l - pentene, and 1 -octadecene.

[0050] In one embodiment, the melt-processible composition comprises at least 40, 50, 60, 70, 80, 90, or even 95 % by weight of high density polyethylene.

[0051] In one embodiment, the melt-processible composition comprises the high density polyethylene polymer and the polyorganosiloxane and no other organic polymers. As used herein, an organic polymer refers to a compound comprising a repeated monomeric unit (in other words, a unit derived from an unsaturated carbon-carbon double bond) that has a molecular weight of at least 15,000; 20,000; 25,000; 30,000; or even 35,000 grams/mole.

[0052] In one embodiment, the melt-processible composition comprises the high density polyethylene polymer and the polyorganosiloxane polymer as described above, as well as an additional organic polymer (or third polymer). The additional organic polymer may be added to achieve specific properties in the final product and/or may be used in the manufacture of a masterbatch, which is subsequently added to the high density polyethylene polymer. Additional polymers blended with the high density polyethylene polymer include polypropylene; linear or branched low-density polyethylenes (e.g. those having a density of from 0.89 to 0.925g/cm³), and olefin copolymers such as ethylene and acrylic acid copolymers; ethylene and methyl acrylate copolymers; ethylene and ethyl acrylate copolymers; ethylene and vinyl acetate copolymers; ethylene, acrylic acid, and ethyl acrylate copolymers; and ethylene, acrylic acid, and vinyl acetate copolymers. Typically, these blends, of the high density polyethylene and the additional organic polymer, comprise less than 50, 40, 30, 20, 15, 10, 5, or even 2 wt % of the additional organic polymer based on the total weight of the melt processible composition. In some embodiments, the additional organic polymer comprises greater than 0.001 wt % and less than 5, 2, 1, 0.5, or even 0.1 wt % based on the total weight of the melt processible composition.

[0053] In one embodiment, the additional organic polymer is a fluorinated polymer, wherein the fluorinated polymer has an atomic fluorine to carbon ratio of at least 1:2. Such fluorinated polymers are known in the art and may be derived from a fluorinated olefin (e.g., tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, etc.), a fluorinated bisolefin, a fluorinated vinyl ether, and/or a fluorinated allyl ether. In one embodiment, the weight ratio of the fluorinated polymer to the polyorganosiloxane polymer is 1:50 to 50: 1; 1: 10 to 10: 1; or even 1 : 5 to 3 : 1. If a fluorinated polymer was added to aid processing, typically, a fluorinated polymer would be present in the melt processible composition from at least 50, 100, 150, 200, 250, 300, 400, or even 500 ppm and at most 750, 1000, 1200, 1500, 1800, or even 2000 ppm.

[0054] In one embodiment, the melt-processible composition is substantially free of a fluorinated polymer, meaning that the melt-processible composition comprises less than 100, 50, 30, 20, 10, 5, 1, or even 0.5 ppm (parts per million) of a fluorinated polymer; or even no fluorinated polymer is detected using techniques known in the art, such as pyrolysis of the melt-processible composition and fluorine content measurement using ion chromatography or an ion specific electrode.

[0055] The melt-processible compositions of the present disclosure may optionally comprise traditional excipients such as antioxidants, hindered amine light stabilizers (HALS), UV-stabilizers, metal oxides (such as magnesium oxide and zinc oxide), antiblocking agents (such as coating or noncoating), and pigments and fillers (such as titania, carbon black and silica), and synergists.

[0056] Synergists are compounds that allows the use of a lower amount of the polyorganosiloxane- containing polymer while achieving essentially the same improvement in extrusion and processing properties of the high density polyethylene polymer as if a higher amount of the polyorganosiloxane -containing polymer was used. Exemplary synergists include: polyethylene glycol, polycaprolactone, aliphatic polyesters, aromatic polyesters, amine oxides, carboxylic acids, fatty acid esters, and combinations thereof.

[0057] The best-known synergists include poly(oxyalkylenes). Polyoxyalkylenes may be introduced and selected based on their properties as synergists in the mixtures of the melt-processible polymer composition. A polyoxyalkylene may be selected so that it ( 1) is in a liquid (or molten) state at the chosen extrusion temperature; and (2) has a lower melt viscosity than the melt-processible polymer and the polyorganosiloxane polymer. Suitable polyoxyalkylene include, but are not limited to, polyethyleneglycols (PEG). PEG may be represented by formula H(OC2H4)_XOH, where x’ is about 15 to 3,000. Many of the polyethyleneglycols indicated, as well as their ethers and esters, are commercially available from multiple sources. Ethers and esters of the PEG indicated may also be suitable. [0058] Aliphatic polyesters, such as poly(butyleneadipinate), polylactic acid and polycaprolactone polyesters (in particular, with a number average molecular weight in the range of 1,000 to 32,000, preferably 2,000 to 10,000, and most preferably 2,000 to 4,000), and aromatic polyesters, such as poly(diisobutylphthalate), may also be suitable synergists.

[0059] Other excipients include, e.g., amine oxides such as octyldimethylamine oxide, carboxylic acids such as hydroxybutanebioic acid, fatty acid esters such as sorbitan monolaurate, and triglycerides.

[0060] Mixtures of two or more different polyoxyalkylenes, or polyoxyalkylene mixtures with other types of synergist, such as the abovementioned esters, may also be used.

[0061] Polyoxyalkylene thermal stability may be improved with a metal salt of a carboxylic acid, sulfonic acid, or alkylsulfate, as disclosed, e.g., in international patent application WO 2015 / 042 415.

[0062] In one embodiment, the melt-processible polymer composition comprises at least 25, 40, or even 50 weight percent of a synergist relative to the polyorganosiloxane polymer. In one embodiment, the melt-processible polymer composition comprises at most 60, 80, 100, 120, 150, or even 200 weight percent of a synergist relative to the polyorganosiloxane polymer.

[0063] The polyorganosiloxane polymer can be melt-processed (e.g., melt extruded) at the temperatures applied during processing. In one embodiment, the polyorganosiloxane polymers can be mixed with the high density polyethylene polymer and optionally additional components, to obtain a composition read for extruding into pellets or polymer articles. In another embodiment, the polyorganosiloxane polymers are provided in masterbatch, which may or may not comprise high density polyethylene and optionally additional components, that can be added to high density polyethylene polymer for processing into polymer articles. Unexpectedly, it has been discovered that the presence of the polyorganosiloxane reduces and/or eliminates gross melt fracture of the melt-processible polymer. Gross melt fracture occurs during high throughput processing of some polymers as a result of instability of the polymer flow at the entrance of the die. Gross melt fracture is exemplified by one or more of the following: (a) distortion of extrudate (e.g., corkscrew appearance), (b) scratches, (c) onion peel appearance (wherein there is a different core and skin morphology), and (d) flaws or particulate within the extrudate strand. Typically, the shear rate, the temperature, and the pressure all influence whether or not the melt processible composition (e.g., the high density polyethylene) will undergo gross melt fracture.

[0064] The effective amount of polyorganosiloxane present in the melt-processible composition of the present disclosure is the amount of polyoragnosiloxane needed to reduce and/or eliminate gross melt fracture. The exact amount used may be varied depending the final form of the melt- processible composition (masterbatch versus pellet or final product) and the stress applied to the melt processible composition. For example, if the polyorganosiloxane polymer is blended with the high density polyethylene polymer in a masterbatch, the amount of polyorganosiloxane may be, for example, from at least 0.1, 0.2, 0.5 or even 1 wt %; and at most 2, 5, 10 ,15, 20, 25, or even 30 wt % of the polyorganosiloxane polymer in the melt-processible composition. Typically, if the amount of polyorganosiloxane gets too high, the melt-processible composition may become sticky. If the polyorganosiloxane polymer composition is to be extruded into final form and is not further diluted by the addition of polymer, the composition typically contains a lower concentration of the polyorganosiloxane polymer, e.g., at least 0.001, 0.002, 0.005, 0.01, 0.05, or even 0.1 wt%; and at most 0.2, 0.5, 1, 1.5, or even 2 wt % of the polyorganosiloxane polymer in the melt-processible composition.

[0065] The melt-processible composition of the present disclosure can be prepared by any of a variety of ways. For example, the melt processible polymer and the polyorganosiloxane-containing polymer can be combined together by any of the blending means usually employed in the plastics industry, such as with a compounding mill, a Banbury mixer, or a mixing extruder in which the polyorganosilane is uniformly distributed throughout the melt processible polymer. The mixing operation is most conveniently carried out at a temperature above the melting point or softening point of the high density polyethylene, though it is also feasible to dry-blend the components in the solid state as particulates and then cause uniform distribution of the components by feeding the dry blend to a twin-screw melt extruder.

[0066] The melt-processible composition of the present disclosure may be extruded using techniques known in the art, such as pellet mill extrusion; ram extrusion; film extrusion; pipe, wire, and cable extrusion; fiber and strand production; etc. Different types of extruders that may be used to extrude the compositions of this present disclosure are described, for example, by Rauwendaal, C., "Polymer Extrusion”, Hansen Publishers, p. 23-48, 1986. The die design of an extruder can vary, depending on the desired extrudate to be fabricated.

[0067] As mentioned, gross melt fracture is a result of high throughput processing, wherein the process conditions of shear rate, temperature, and the pressure (or shear stress) combine to cause distortions. For example, gross melt fracture can occur when the shear rate is at least 10, 20, 50, 100, 200, 300, 400, or even 500 s’¹ and at most 1000, 2000, 3000, or even 5000 s’¹; at temperatures of at least 120, 150, or even 180°C and at most 200, 250, or even 300°C; and/or at a shear stress greater than 0.1, 0.2, 0.3, or even 0.4 MPa and up until extrusion becomes impossible (e.g., extrudate is grossly distorted and no longer forms a strand, reach capacity of equipment, etc.). All three parameters (shear rate, temperature, and shear stress) can be interconnected and will contribute to whether or not gross melt fracture occurs. For example, a decrease in temperature can cause gross melt fracture to occur at lower shear rates. [0068] As will be exemplified below, the addition of a polyorganosiloxane polymer to high density polyethylene has been shown to reduce and/or eliminate gross melt fracture even though they were processed under high shear (e.g., shear stress and/or shear rate) conditions, which can result in clear articles at high throughput.

EXAMPLES

[0069] Unless otherwise noted, all parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, and all reagents used in the examples were obtained, or are available, from general chemical suppliers such as, for example, Sigma- Aldrich Company, Milwaukee, WI, USA, or known to those skilled in the art, unless otherwise stated or apparent. [0070] The following abbreviations are used in this section: wt=weight, g=grams, kg=kilograms, cc=cubic centimeter, min=minutes, mm=millimeters, ppm=parts per million, s=seconds, rpm=revolutions per minute, °C=degrees Celsius, MPa= megaPascals, kPa=kiloPascals, MFI=melt flow index, and MFR = melt flow rate. Abbreviations for materials used in this section, as well as descriptions of the materials, are provided in Table 1.

Table 1

[0071] Extrusion and Rheology Measurements

[0072] Melt-processible polymer compositions were extruded after resins were combined with additives, if used, as indicated in Table 3 using a single screw rheology extruder (Lab Station, Brabender GmbH & Co KG, Duisburg, Germany), with round capillary die (1x30 mm). Additives were added to a concentration of 300 ppm via 3% by weight masterbatches, which were prepared on batch mixer (Plasti-Corder, Brabender GmbH & Co KG) in the same resin base. The temperature profile applied in the zones of the extruder was as indicated for “Tl,” “T2,” or “T3” in Table 2, as indicated in Table 3. Rheology tests were performed after approximately 60 min stabilization time from starting extrusion. Shear rate during stabilization time was kept constant (-1600 s’¹). The extruder was cleaned between melt-processible polymer compositions by extruding antiblock masterbatch (50 wt % of natural silica in linear low density polyethylene) to achieve a pressure level that is the same as pure material without additive. All tested additives gave high quality dispersion in the resin as observed by optical microscopy. Several shear rates were selected to observe strand surface quality: 1) 4 rpm -300-400 s’¹, 2) 12 rpm -1100-1200 s’¹, 3) 20 rpm -1800-1900 s’¹. Shown in Table 4 below is select data taken from an apparent shear rate of around 2000 s’¹. Reported is the apparent shear stress at the given rpm and the surface of the extruded strand was visually observed for gross melt fracture. Strand surface was rated according to the following criteria: 1) gross melt fracture, 2) no observed gross melt fracture.

Table 2 Extruder temperature profiles

Table 3. Extrusion conditions and results

Table 4, Apparent shear rates, apparent shear stress, and surface observations

[0073] For CE-1, CE-2, and CE-3, cyclic melt fracture was observed starting at an apparent shear rate of approximately 300 s’¹ and gross melt fracture was observed starting at approximately 900 s’ \ Above approximately 900 s’¹, defects were observed after the stabilization time for CE-1, CE-

2, and CE-3. During the stabilization time for EX-1, these defects were completely eliminated and the strand surface appeared smooth.

[0074] Foreseeable modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. This invention should not be restricted to the embodiments that are set forth in this application for illustrative purposes. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document mentioned or incorporated by reference herein, this specification as written will prevail.

Claims

What is claimed is:

1. A melt processible polymer composition comprising: high density polyethylene; and an effective amount of polyorganosiloxane to reduce and/or eliminate gross melt fracture of the melt processible polymer composition.

2. The melt processible polymer composition of claim 1, wherein the high density polyethylene has a melt flow index less than 0.5 g/ 10 minutes when measured with a load of 2.16 kg at 190°C.

3. The melt-processible polymer composition of any one of the previous claims, wherein the melt-processible polymer composition comprises at least 40 wt% of high density polyethylene.

4. The melt-processible polymer composition of any one of the previous claims, wherein the melt-processible polymer composition is substantially free of a third polymer.

5. The melt-processible polymer composition of any one of the previous claims, wherein the melt processible polymer composition is substantially free of a fluorinated polymer.

6. The melt-processible polymer composition of any one claims 1-3, wherein the melt- processible polymer composition comprises less than 50% by weight of a third polymer.

7. The melt-processible polymer composition of any one claims 1-3 and 6, wherein the melt processible polymer composition further comprises a fluorinated polymer.

8. The melt-processible polymer composition of any one of the previous claims, wherein the polyorganosiloxane comprises repeated -Si(R⁷)2-O- groups, where each R⁷ is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen.

9. The melt-processible polymer composition of any one of the previous claims, wherein the polyorganosiloxane polymer comprises repeat blocks comprising at least one - Si(R⁷)2-O- group and at least one amide and/or polyurethane group, wherein R⁷ is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen.

10. The melt-processible polymer composition of any one of the previous claims, wherein the polyorganosiloxane polymer comprises at least two repeat units of Formula I:

wherein each R is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen; each Y is independently alkylene, arylalkylene, alkylarylene, or a combination thereof; n is independently 0 to 1,500; p is 1 to 10; each B is independently a covalent bond, alkylene, arylalkylene, alkylarylene, or a combination thereof; G is a divalent group, which is a residue corresponding to a diamine of formula R HN-G- NHR with two -NHR groups removed, where R is hydrogen or alkyl; or R and G taken together with the nitrogen to which they are both connected to form a heterocyclic group; and each asterisk (*) indicates the connection site of the repeat unit to another group in the copolymer, such as, e.g., another repeat unit of Formula I.

11. The melt-processible polymer composition of any one of the previous claims, the melt- processible polymer composition comprising 0. 1 to 30% by weight of the polyorganosiloxane versus the high density polyethylene.

12. The melt-processible polymer composition of any one of the previous claims, the melt- processible polymer composition comprising 0.001 to 1% by weight of the polyorganosiloxane versus the melt-processible polymer.

13. The melt-processible polymer composition of any one of the previous claims, further comprising one or more lower molecular weight processing adjuvants, selected from group consisting of polyoxyalkylene polymers, aliphatic polyesters, polylactic acid and polycaprolactone polyesters, and aromatic polyesters.

14. A method of forming an extrudate, the method comprising: extruding a melt-processible composition comprising a high density polyethylene, wherein at a specific shear rate, temperature, and shear stress the extrudate exhibits gross melt fracture and wherein the addition of polyorganosiloxane to the melt-processible composition reduces and/or eliminates the gross melt fracture in the extrudate. The method of claim 14, wherein the shear rate is at least 10 s ¹ to at most 5000 s-¹. The method of any one of claims 14-15, wherein the temperature is at least 120 and at most 300°C. The method of any one of claims 14-16, wherein the shear stress is at least 0. 1 MPa. The method of any one of claims 14-17, wherein the high density polyethylene has a melt flow index in the range of 0.1 to 0.3 g/ 10 minutes when measured with a load of 2.16 kg at 190°C. The method of claim any one of claims 14-18, wherein the polyorganosiloxane comprises repeated -Si(R⁷)2-O- groups, where each R⁷ is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen. The method of claim any one of claims 14-19, wherein the polyorganosiloxane polymer comprises repeat blocks comprising at least one - Si(R⁷)2-O- group and at least one amide and/or polyurethane group, wherein R⁷ is independently alkyl, haloalkyl, arylalkylenyl, alkylarylenyl, alkenyl, aryl, or aryl substituted with alkyl, alkoxyl, or halogen. The method of claim any one of claims 14-20, wherein the polyorganosiloxane polymer comprises at least two repeat units of Formula I:

22. The method of claim any one of claims 14-21, the melt-processible polymer composition comprising 0.001 to 10% by weight of the polyorganosiloxane versus the melt-processible polymer.

23. The method of claim any one of claims 14-22, wherein the melt processible polymer composition is substantially free of a fluorinated polymer.

24. The method of claim any one of claims 14-23, wherein the melt processible polymer composition further comprises a fluorinated polymer.

25. The method of claim any one of claims 14-24, further comprising one or more polymer processing additives, selected from the group consisting of polyoxyalkylene polymers, aliphatic polyesters, polylactic acid and polycaprolactone polyesters, and aromatic polyesters.

26. Use of polyorganosiloxane to eliminate gross melt fracture in high density polyethylene.

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