Polyolefin composition using ionomer cavity filler

Abstract

Disclosed is a polymer composition useful for producing articles containing cavities. The composition comprises a continuous polymer phase and a cavity-forming agent dispersed in the continuous polymer phase. The continuous polymer phase comprises a polyolefin, and the cavity-forming agent comprises ionomers other than ethylene-based and propylene-based ionomers. By cavity-forming polyolefins with an ionomery, various advantages can be provided, such as lower density of the cavity-forming film at lower extrusion temperatures and lower density of the cavity-forming film at higher orientation temperatures.

Description

[Technical Field]

[0001] This invention relates to the field of polymer compositions. More specifically, the invention relates to compositions, articles, products containing articles, and methods for producing articles that are useful for forming articles containing cavities. [Background technology]

[0002] Cavity-forming articles can be produced from polymer compositions containing small particles or inclusions (referred to as "cavitating" or "porosizing" agents) using various conversion techniques for producing films, sheets, and fibers. Conventional conversion processes involve forming articles using plastic extrusion and dies. With respect to films, films can be formed by casting or blown film extrusion processes. With respect to cast films or sheets, the molten polymer exits the die and is cooled on chill rolls. In the blown film mechanism, the film exits the die and is formed into a tube, where air fills the inside of the tube, forming a bubble structure. The top of the bubble is crushed in a frame and pulled by a set of nip rolls. In both mechanisms, the film may be trimmed. In both film conversion processes, the molten polymer is molten oriented as it exits the die. The majority of the cavity volume is formed not in the molten orientation as it exits the die. The articles are typically cooled after formation.

[0003] Once the article is formed from the conversion process and cooled, it can then be stretched (oriented), typically in-line with the extrusion process, by three different orientation processes: (a) mechanical orientation (MDO); (b) transverse orientation (TDO); or (c) biaxial orientation (Biax), which includes both mechanical and transverse orientation in either a sequential or simultaneous manner. Orientation processes involving voiding agents create cavities within the continuous polymer phase. When cavities are formed in a polymer film, the voided film tends to have a lower density and higher opacity than its non-voided counterparts. The use of polymeric voiding agents to create cavities in polymers is well documented in the literature and patents. However, polymeric voiding agents have only achieved limited success and are mostly used in combination with inorganic voiding agents, which themselves have limited properties (see, for example, US4,770,931).

[0004] Commercially available polymers present various problems when used as cavity fillers in polyolefin matrices. These problems include: 1. They tend to split into droplets with a smaller diameter than desired, resulting in a higher film density and lower opacity after stretching. 2. During the extrusion process, these tend to deform into an elongated shape (e.g., platelet or ellipsoid), and in this case, spherical cavitating agents are most desirable for cavitation efficiency. 3. These tend to reduce the density of the hollowed-out film only slightly. The extrusion and orientation process window is very narrow to achieve commercially acceptable film properties. For example, higher extrusion temperatures can cause bubble instability and lower extrusion rates, which can reduce equipment utilization and lead to film breakage or holes due to low-temperature orientation conditions. However, lowering the extrusion temperature and raising the orientation temperature can result in a higher density of the hollowed-out film. 4. They tend to be incompatible with melt processing with continuous polymer phases. While certain polymers may be exceptionally good at voiding, they are not commercially viable due to (a) melt temperatures exceeding the processing temperature of the continuous polymer phase, or (b) reactivity or decomposition at the required processing temperature. Voiding agents with poor melt process compatibility may also be difficult to purge from the extrusion process and can lead to contamination that may cause breakage during orientation or other quality defects. Includes.

[0005] To control splitting and deformation, the polymer molecular weight (MW) and branching can be modified to increase the viscosity ratio of the continuous polymer phase relative to the inclusions. However, this means that specialized polymers must be fabricated, which increases costs. Moreover, high-MW polymers may not melt-process with the continuous polymer phase. Therefore, in the art, there is a need for polymeric voiding agents for more effective polyolefin continuous phases, in particular agents that can withstand deformation and fission, provide improved density reduction after orientation, and have good melt process compatibility with the polyolefin continuous phase. The present invention addresses this and other needs, which will become apparent from the following description and the appended claims. [Overview of the project]

[0006] The present invention is described in the appended claims. In short, in one embodiment, the present invention is (A) A continuous polymer phase containing a polyolefin, (B) Cavity-forming agent dispersed in a continuous polymer phase and Includes, The cavity-forming agent comprises one or more ionomers, One or more ionomers do not contain ethylene-based ionomers and propylene-based ionomers. A composition is provided. In a second embodiment, the present invention provides a hollowed-out article comprising the composition of the present invention. Hollowed articles can be used to produce a variety of products, including bags (including woven bags), labels (including shrink labels), shrink films, laminates, stand-up pouches, wraps, straps, ribbons, strips, tapes, lids, trays, bowls, cups, bottles, yarn, fabrics (including raffia fabrics), and clothing.

[0007] In a third embodiment, the present invention provides a method for manufacturing a hollowed-out article. The method is: (a) The step of forming a melt containing the composition of the present invention, (b) A step of forming an article from a molten material, (c) The steps of cooling the article to the orientation temperature and optionally heating the article, (d) The step of orienting the article from step (c) in at least one direction to form a hollowed-out article, (e) optionally, (i) annealing the hollowed article at a temperature higher than the orientation temperature, (ii) shrinking the hollowed article in the direction of orientation, or both of (i) and (ii), (f) optionally, (i) annealing the hollowed article at or below the orientation temperature to maintain a desired shrinkage in the article, (ii) shrinking the hollowed article in the orientation direction, or both of (i) and (ii) Includes. In various embodiments, the article prepared by the method may be a film, a sheet, a fiber, or a tube. [Modes for carrying out the invention]

[0008] Explanation of terms To facilitate understanding of the present invention, several terms are defined below. Terms left undefined shall have the meanings commonly understood by those skilled in the art in the relevant field. As used herein, the indefinite articles "a" and "an" mean one or plural unless otherwise indicated by context. Similarly, unless otherwise indicated by context, the singular form of a noun includes the plural form, and vice versa. The term "acrylic-containing polymer" refers to a polymer in which acrylic acid or methacrylic acid, their esters, or their salts constitute at least 20 mole percent of the polymer. Furthermore, the term "acrylic-containing polymer" also includes polymers in which monomers having one or more carboxylic acids, carboxylic acid esters, or carboxylic acid salts constitute at least 10 mole percent of the polymer. Examples of monomers having one or more carboxylic acids, carboxylic acid esters, or carboxylic acid salts include itaconic acid, citric acid, maleic acid, fumaric acid, aconitic acid, and malic acid.

[0009] The terms "amide polymer" and "polyamide" are used interchangeably. They refer to polymers having repeating units linked by more than 50 percent amide bonds. Polymers may also contain at least one other type of bond. Amide polymers include homopolymers and copolymers (meaning that more than one monomer is used to form an amide polymer). Examples of amide polymers (polyamides) include aliphatic, semi-aromatic, and aromatic polymers. Examples of aliphatic polyamides include polycaprolactam, poly(hexamethylene adipamide), poly(hexamethylene succinimide), polylaurolactam, poly(11-aminoundecanoic acid), and poly(hexamethylene sebacimid). Examples of semi-aromatic polyamides include poly(hexamethylene terephthalamide), poly(hexamethylene isophthalamide), and polymers that utilize both terephthalic acid and isophthalic acid together with aliphatic diamines. The term "article" refers to a molded object. Examples of articles include films, sheets, fibers, or tubes. Articles may consist of a single layer or multiple layers.

[0010] The term "carrier resin" refers to a polymer resin that can be blended with a cavitating agent to form a composition in a separate step before being extruded into an article. This composition can be a masterbatch that can be combined with a let-down resin to form a fully formulated (or target) composition, or it can be the target composition itself. The carrier resin may be the same as or different from the let-down resin. The carrier resin will generally be part or all of the continuous polymer phase. The term "cationic component" is used to refer to a material that is a cation (cationic) or contains one and can be used to neutralize one or more anions of a polymer to produce an ionomer. The cationic component can be an alkali metal ion (e.g., Li+, Na+, K+, and Rb+), an alkaline earth metal ion (e.g., Mg++ and Ca++), a transition metal ion (e.g., Fe++, Fe+++, Co++, Ni++, Cu++, Zn++, and Ag++), an aluminum ion (Al+++), a polyatomic cation (e.g., guanidinium, ammonium, phosphonium, and pyrylium), or a combination thereof.

[0011] The term "cavitated article" refers to an article that has been subjected to uniaxial orientation (i.e., stretching or drawing in the machine or transverse direction) or biaxial orientation (i.e., stretching or drawing in the machine and transverse directions) and has cavities or voids. In a tubular orientation process such as a double bubble or triple bubble orientation process, the transverse direction is the circumferential direction of the bubble and the machine direction is the axial direction of the tube's progression. Orientation occurs in a process where air inflates the tube (expanding the diameter of the tube to impart transverse orientation) and a nip roll at the top of the tube increases the machine direction speed. The terms "cavity" and "void" are used interchangeably. They refer to regions within a cavitated article that are not occupied by the continuous polymer phase or the cavitating agent. In other words, they are the empty spaces within the cavitated article. The empty space may be occupied by a gas such as air.

[0012] The terms "voiding agent" and "cellularizing agent" are used interchangeably. They refer to one or more materials that can form voids or cells within a polymer (continuous polymer phase) during an orientation / drawing process. The voiding agent can be organic or inorganic. Inorganic voiding agents are typically in particulate form. Typically, organic or polymeric voiding agents have some degree of non - affinity such that when mixed with the continuous polymer phase in a melt, they form a different phase, where the voiding agent (inclusion) forms a droplet phase within the continuous polymer phase (matrix). The inclusion and the matrix ideally have poor or no adhesion to each other such that their binding force is low or non - existent. The term "composition" refers to a mixture of materials including the composition, as well as reaction products and decomposition products formed from the materials of the composition. The terms "continuous polymer phase" and "polymer matrix" or simply "matrix" are used interchangeably. They refer to a continuous domain formed by one or more polymers. The discontinuous domains formed from the voiding agent do not form part of this phase but can be dispersed throughout the phase.

[0013] The terms "ester polymer" and "polyester" are used interchangeably. They refer to polymers having repeating units linked by more than 50 percent ester bonds. Polymers may contain at least one other type of bond. Ester polymers include homopolymers and copolymers (meaning that more than one monomer is used to form an ester polymer). Examples of ester polymers (polyesters) include aliphatic, semi-aromatic, and aromatic polymers. Examples of aliphatic polyesters include polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxybutyrate, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Examples of semi-aromatic polyesters include poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate), poly(trimethylene terephthalate), polymers in which some or all of the terephthalic acid is replaced by another aromatic dicarboxylic acid, and polymers in which some or all of the diol is replaced by another non-aromatic glycol (e.g., polyethylene terephthalate glycol). The term "ethylene-based ionomer" refers to ethylene-based polymers that have a Tg lower than 100°C, such as ethylene-(meth)acrylic acid copolymers in which some or all of the anionic moieties are neutralized with sodium or zinc. A commercially available example of an ethylene-based ionomer is SURLYN® ionomer manufactured by The Dow Chemical Company.

[0014] The terms “ethylene polymer” and “polyethylene” are used interchangeably. They refer to polymers containing more than 50 mole percent (mol%) of polymerized ethylene monomer (based on the total amount of polymerizable monomers) and which may contain at least one comonomer. Ethylene polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). Examples of ethylene polymers (polyethylenes) include low-density polyethylene (LDPE) and linear polyethylene. Examples of linear polyethylene include linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (ULDPE), very low-density polyethylene (VLDPE), single-site catalyst linear low-density polyethylene (m-LLDPE), substantially linear or linear plastomers / elastomers, and high-density polyethylene (HDPE). These polymers can be polymerized in a variety of methods known in the industry. Specific polymerization methods, including the selection of catalysts where applicable, are typically selected based on compatibility with the monomers, the desired polymer structure and properties, and economic factors.

[0015] The term "inclusions" is used to refer to discontinuous domains formed by cavitating agents within a continuous polymer phase. The term "ionomer" refers to a polymer having a combination of electrically neutral and neutralizable repeating units, where the neutralizable component is a pendant group covalently bonded to the polymer backbone and at least partially neutralized ("ionized") with a cationic component. Typically, less than 15 mole percent (e.g., 1–15 mole%) of the repeating units are ionized or can be ionized. Ionomers can be polymer products of neutralization of precursor polymer components with cationic components. Ionomers can be formed in various ways, including (a) grafting neutralizable monomers or already neutralized monomers onto a polymer, (b) neutralizing neutralizable repeating units copolymerized onto the polymer backbone, and (c) copolymerizing already neutralized repeating units with comonomers. Typically, ionomers are prepared by copolymerizing a monomer (e.g., ethylene or styrene) with a carboxylic acid-containing comonomer (acrylic acid and methacrylic acid are the most common, but others such as unsaturated acid anhydrides can also be used), and then partially neutralizing the copolymer with a cationic component. Other methods include copolymerization or grafting of sulfonic acid-containing monomers or simply sulfur trioxide, or similar methods involving the incorporation of phosphonic acid groups followed by neutralization with a cationic component.

[0016] The term "ionomer precursor" refers to (i) a polymer having one or more anions (or charged repeating units) that can be neutralized by a cationic component to produce an ionomer, or (ii) a polymer formed by the reaction of a non-neutralizable polymer with an acid-functionalized monomer, oligomer, or polymer. The term "letdown resin" refers to a polymer resin that, during extrusion, is blended with a cavity filler or a cavity filler masterbatch to form an article. The letdown resin will generally be part or all of the continuous polymer phase. The term "masterbatch" refers to a composition having a higher concentration of a cavity-causing agent than the fully formulated or fully blended (or target) composition. A masterbatch may contain a carrier resin. Typically, a masterbatch is diluted with a letdown resin to form the target composition. The letdown resin may be the same polymer as the carrier resin or a different polymer. A masterbatch can be formed by dry mixing and / or melt blending of the components.

[0017] The terms "olefin polymer" and "polyolefin" are used interchangeably. They refer to polymers containing more than 50 mole percent (based on the total amount of polymerizable monomers) of polymerized olefin monomers and may contain at least one comonomer. Examples of olefin polymers include ethylene polymers, propylene polymers, butylene polymers, and polymers based on blends of ethylene, propylene, butylene, hexene, and octen comonomers. Non-olefin monomers commonly found in copolymers with ethylene, which would still be classified as olefin polymers, include acrylic acid, methacrylic acid, methyl acrylate, vinyl acetate, and methyl methacrylate. Olefin polymers can be prepared using cyclic olefin monomers such as norbornene. The term "polymer" refers to a material prepared by reacting ("polymerizing") monomers, whether of the same or different types, where the monomers, in their polymerized form, provide multiple and / or repeating "units" or "mer units" that constitute the polymer. Thus, the term "polymer" encompasses both homopolymers (polymers prepared from only one type of monomer) and copolymers (polymers prepared from at least two types of monomers). The term also encompasses all forms of copolymers, e.g., random, block, etc. Polymers are often referred to as "composed of" one or more specific monomers, "based on" specific monomers or monomer types, or "containing" specific monomer content, and in this context, the term "monomer" refers to the polymerized residue or residue of a particular monomer, not to the unpolymerized species.

[0018] The term "propylene-based ionomer" refers to a propylene-based polymer that is an ionomer. The terms "propylene polymer" and "polypropylene" refer to polymers containing more than 50 mole percent (based on the total amount of polymerizable monomers) of polymerized propylene monomer and which may contain at least one comonomer. Propylene polymers include propylene homopolymers and propylene copolymers (meaning units derived from propylene and one or more comonomers).

[0019] The term "styrene-containing polymer" refers to a polymer that contains more than 20 mole percent (based on the total amount of polymerizable monomers) of polymerized styrene monomer and may contain at least one comonomer. Styrene-containing polymers include styrene homopolymers and styrene copolymers (meaning units derived from styrene and one or more comonomers). Examples of styrene-containing polymers include polystyrene, high-impact polystyrene, styrene-butadiene copolymer, styrene-isoprene copolymer, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile polymer, styrene-acrylonitrile-maleic anhydride copolymer, styrene-maleic anhydride copolymer, styrene-maleimide copolymer, styrene-methyl methacrylate copolymer, acrylonitrile-styrene-acrylate copolymer, methacrylate-acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-butadiene-styrene copolymer. Styrene-containing polymers may also have olefins incorporated into their backbone. Examples include variants of the listed polymer constituent monomers, such as alpha-methylstyrene instead of styrene, acrylic or methacrylic acid monomers or salts thereof grafted in or onto the polymer, sulfonic acid or phosphonic acid or salts thereof grafted onto the polymer, or dicarboxylic acid or salts thereof, and carboxylic acid anhydrides incorporated into the backbone or grafted onto the polymer.

[0020] Embodiments and Exemplary Embodiments Surprisingly, it was discovered that certain ionomers can effectively void the polyolefin continuous phase. Ionomers tend to withstand deformation and fission during processing, can reduce the density of polyolefin articles after orientation, and tend to be compatible with the melt process of the polyolefin continuous phase. In particular, ionomers are used as cavity fillers. 1. Lower extrusion temperatures can reduce the density of the hollowed-out film, improving the stability of the blown film bubbles. 2. At higher orientation temperatures, the density of the hollowed-out film can be reduced, minimizing the possibility of film breakage and holes, thereby improving the orientation stability of the film. 3. This allows for the adjustment of elastic and interfacial tension properties, and therefore, porosity (i.e., density and opacity) can be improved using a post-polymerization process rather than polymerizing new molecules.

[0021] composition Therefore, in one embodiment, the present invention is (A) A continuous polymer phase containing a polyolefin, (B) Cavity-forming agent dispersed in a continuous polymer phase and Includes, The cavity-forming agent comprises one or more ionomers, One or more ionomers do not contain ethylene-based ionomers and propylene-based ionomers. A composition is provided. The cavity-forming agent is introduced into the continuous polyolefin phase. (A) a. Neutralization of the ionomer precursor, or b. Formation and neutralization of ionomer precursors, or c. Direct formation of ionomers by reaction with neutralized presets. From there, by in-situ ionomer formation inside the continuous polyolefin phase, (B) By melt-blending an ionomer-containing cavity filler in an undiluted form into a continuous polyolefin phase (direct addition), (C) By melt-blending an ionomer-containing form of the cavity-forming agent, diluted with a non-cavity-forming agent polymer, into a continuous polyolefin phase (masterbatch addition), or (D) Processing a blend containing a cavity-forming agent (including the ionomer and non-ionomer components of the cavity-forming agent) at its final concentration level (i.e., completely diluted) The composition may be formed in various ways, such as those mentioned above.

[0022] The composition may contain one or more conventional additives in conventional amounts. Examples of additives include heat stabilizers, light stabilizers, antioxidants, slip agents, antiblocking agents, antistatic agents, flame retardants, pigments, dyes, processing aids, plasticizers, lubricants, and combinations thereof. As described above, the composition may be prepared by any known method, such as melt blending. The components of the composition may be added to the melt blending apparatus simultaneously or sequentially. Alternatively, the components may be dry-mixed together to form a uniformly dispersed dry mixture, which may then be introduced into the melt blending apparatus. The melt blending apparatus disperses the cavity-removing agent throughout the continuous polymer phase. Blending may be performed in batch or continuous order. Examples of melt blending apparatuses include mixers / kneaders, Banbury mixers, Farrell continuous mixers, single-screw extruders, twin-screw extruders, roll mills, and combinations thereof. The melt blending procedure produces a composition having cavity-removing agent particles uniformly dispersed throughout the continuous polymer phase.

[0023] In various embodiments, the composition may be a masterbatch. In the case of a masterbatch, the concentration of the cavity filler may be in the range of 20 to 80% by mass on a basis of the total mass of the composition. Any range between 20 and 80% by mass, for example, 30 to 70% and 40 to 60% by mass, is intended and disclosed herein. In various other embodiments, the composition may be the target composition or a fully formulated or fully blended composition. Such compositions may be formed into articles without dilution with additional resins, such as letdown resins. Fully blended compositions may have a cavity-filling agent concentration in the range of 0.1 to 40% by mass on a basis of the total mass of the composition. Any range between 0.1 to 40% by mass, for example, 1 to 35% by mass, 1 to 30% by mass, 1 to 20% by mass, and 1 to 15% by mass are intended and disclosed herein.

[0024] Continuous polymer phase The continuous polymer phase contains polyolefins. In various embodiments, the polyolefin includes ethylene-based polymers, propylene-based polymers, or both. Examples of ethylene-based polymers include ethylene homopolymers and ethylene / C3-C3 polymers. 10 Examples include α-olefin copolymers (linear or branched), ethylene / C4-C8α-olefin copolymers (linear or branched), high-density polyethylene ("HDPE"), low-density polyethylene ("LDPE"), linear low-density polyethylene ("LLDPE"), medium-density polyethylene ("MDPE"), ethylene-vinyl acetate copolymer ("EVA"), ethylene-methyl methacrylate copolymer ("EMA"), ethylene-acrylic acid copolymer ("EAA"), ethylene methacrylate copolymer ("EMAC"), neutralized copolymers of ethylene-acrylic acid copolymer or ethylene-methacrylate copolymer ("olefinic ionomers"), ethylene-norbornene copolymer ("COC"), ethylene-graft-maleic anhydride copolymer ("PE-g-MAH"), and combinations thereof. C3-C 10 Examples of α-olefin comonomers include propylene, 1-butene, 1-hexene, 1-octene, and combinations thereof. Examples of C4-C8 α-olefin comonomers include 1-butene, 1-hexene, 1-octene, and combinations thereof.

[0025] Examples of propylene-based polymers include propylene homopolymer, propylene / ethylene copolymer, and propylene / C4-C 10 Examples include α-olefin copolymers, propylene impact copolymers, and combinations thereof. C4-C 10 Examples of α-olefin comonomers include 1-butene, 1-hexene, 1-octene, and combinations thereof. In various embodiments, the polyolefin is a carrier resin, a letdown resin, or both. The carrier resin may be the same polymer as the letdown resin, or a different polymer. The amount of continuous polymer phase in the composition can vary over a wide range. For example, the composition may contain 60 to 99% by mass of continuous polymer phase. Any range between 60 and 99% by mass, such as 65 to 99% by mass, 70 to 99% by mass, and 80 to 99% by mass, is intended and disclosed herein.

[0026] Cavity-forming agent The cavity-forming agent is dispersed in the continuous polymer phase. The cavity-forming agent includes ionomers other than ethylene-based ionomers and propylene-based ionomers. Examples of ionomers for cavity formation include ester-based polymer ionomers, amide-based polymer ionomers, styrene-containing polymer ionomers, acrylic-containing polymer ionomers, cellulose-based polymer ionomers, biodegradable polymer ionomers, and combinations thereof. Ionomers of styrene-containing polymers can be synthesized from homopolymers or copolymers of polystyrene by various methods known in the industry. Similarly, with respect to polyesters, polyamides, acrylic polymers, cellulose, and biodegradable polymers, these classes of polymers can be made into better cavitation agents by modifying their interfacial and rheological properties through ionomerization. Surprisingly, in this regard, it has been discovered that the cavitation ability of polymers in polyolefin matrices can be greatly improved by modifying the interfacial tension between the polymer and the matrix, the melt elasticity or extensional viscosity of the polymer, and / or the melt viscosity of the polymer, all of which may be achieved by converting the polymer into the corresponding ionomer.

[0027] As described above, ionomers contain an ionomer precursor and a cationic component. Ionomers may be prepared in a variety of processing operations. One method is to combine an acid or anhydride copolymer with a cationic component (usually as a metal hydroxide or metal salt) in an extruder. The extruder can be almost any type commonly known in the industry, including co-rotating twin-screw extruders, counter-rotating twin-screw extruders, single-screw extruders, and kneader extruders. The neutralization reaction can be carried out as an intermediate step or during the final extrusion operation. This method is sometimes called plastic compounding, where the individual components are melt-processed in a compounder / extruder, and the individual components are an ionomer precursor, a cationic component, and optionally a carrier resin. Residence time, temperature, and mixing intensity to ensure a complete reaction, and the possibility of needing devolatilization, may influence the selection and design of the extrusion operation. Ionomers may also be prepared in a solid state or in solution.

[0028] Another method involves grafting a monomer, already neutralized with a cationic component, onto a polymer to form an ionomer. Such monomers may include, for example, metal or ammonium salts of acrylic or methacrylic acid, among many other monomer types that exist or can be produced for this purpose. This grafting may be carried out in any of the extruder types listed above and may involve using additional components to enhance and / or halt the grafting reaction, which may be done during an intermediate production step or a final extrusion step. Ionomers can also be formed in copolymerization in which the cationic component is one of the comonomer species. Ionomers can also be formed in solution with a suitable solvent by neutralization of an acid species with the cationic component, grafting an acid species onto a polymer and subsequent neutralization with the cationic component, grafting an already neutralized monomer species onto a polymer, or by any kind of coupling or chain transfer reaction to incorporate ionomer repeating units, oligomers, or polymers into a separate polymer, up to and including block copolymers. Examples of the last type may be transesterification of polyester ionomers with non-ionomer polyesters, amide transfer of polyamide ionomers with non-ionomer polyamides, or grafting of carboxylic acid ionomers or polyelectrolytes onto non-electroactive polymers. In various embodiments, non-olefinic ionomers may be formed in situ by incorporating an ionomer precursor with one or more olefinic ionomers or polyelectrolytes. The formation of non-olefinic ionomers may occur by the transfer of cations from the olefinic ionomer or polyelectrolyte to a neutralizable non-olefinic ionomer precursor, or by covalent bonding between the olefinic ionomer or polyelectrolyte and the non-olefinic ionomer precursor.

[0029] In various embodiments, the ionomer precursor may include styrene-containing polymers, ester-based polymers, amide-based polymers, acrylic-containing polymers, cyclic olefin copolymers (COCs), non-olefinic biopolymers, cellulosic polymers, or combinations thereof. In various embodiments, the ionomer precursor comprises a styrene-containing polymer. In various embodiments, the ionomer precursor includes styrene-maleic anhydride copolymer (SMA), styrene-maleimide copolymer (SMI), styrene-methyl methacrylate copolymer (SMMA), styrene-acrylonitrile copolymer (SAN), styrene-acrylonitrile-maleic anhydride copolymer (SAN-MAH), acrylonitrile-styrene-acrylate copolymer (ASA), acrylonitrile-butadiene-styrene copolymer (ABS), or a combination thereof. In various embodiments, the ionomer precursor comprises SMA. In various embodiments, the cationic component may include zinc, sodium, calcium, lithium, magnesium, aluminum, ammonium, or a combination thereof.

[0030] In various embodiments, the cationic component includes sodium, such as sodium stearate. In various embodiments, the cationic component includes aluminum, such as aluminum stearate. In various embodiments, the cationic component includes zinc. Zinc may be supplied from any suitable compound, such as zinc carboxylate salts, zinc sulfate, or salts formed in situ from zinc oxide. In various embodiments, the zinc source includes zinc carboxylate salts. Examples of such salts include zinc acetate, zinc propanoate, zinc butanoate, zinc valerate, zinc caproate, zinc caprylate, zinc decanoate, zinc laurate, and zinc stearate. In various embodiments, the ionomer comprises SMA, SMI, SMMA, SAN, SAN-MAH, ASA, ABS, or a combination thereof, and zinc ions. In various embodiments, the ionomer contains SMA and zinc ions. In various embodiments, the ionomer comprises SMA, SMI, SMMA, SAN, SAN-MAH, ASA, ABS, or a combination thereof, and zinc stearate. In various embodiments, the ionomer comprises SMA and zinc stearate.

[0031] In various embodiments, the ionomer comprises the reaction product of SMA and zinc stearate. In various embodiments, the ionomer comprises a zinc-neutralized styrene-maleic anhydride copolymer. In various embodiments, the ionomer comprises a sodium-neutralized styrene-maleic anhydride copolymer. In various embodiments, the ionomer comprises maleic anhydride-grafted general-purpose polystyrene (GPPS) neutralized with zinc. In various embodiments, the ionomer comprises maleic anhydride graft GPPS neutralized with sodium. In various embodiments, the ionomer comprises a maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer (ABS) neutralized with zinc. In various embodiments, the ionomer comprises a maleic anhydride grafted ABS copolymer neutralized with sodium. In various embodiments, the ionomer comprises a methacrylate graft ABS neutralized with sodium.

[0032] In various embodiments, the ionomer comprises a methacrylate graft ABS neutralized with zinc. In various embodiments, the ionomer comprises the reaction product of styrene-methyl methacrylate copolymer (SMMA), fumaric acid, and aluminum stearate. In various embodiments, the ionomer comprises a fumarate-grafted styrene-acrylonitrile copolymer (SAN) neutralized with sodium. In various embodiments, the ionomer comprises a fumarate graft SAN copolymer neutralized with zinc. In various embodiments, the ionomer comprises the reaction product of fumarate graft SAN and zinc stearate. In various embodiments, the ionomer comprises a SAN-MAH copolymer neutralized with zinc. In various embodiments, the ionomer comprises a styrene-maleic anhydride copolymer neutralized with a blend of sodium and zinc. In various embodiments, the ionomer comprises a reaction product of a styrene-maleic anhydride copolymer with a blend of sodium stearate and zinc stearate.

[0033] In various embodiments, the ionomer comprises a reaction product of styrene-maleic anhydride copolymer and zinc oleate. In various embodiments, the ionomer comprises a reaction product of styrene-maleic anhydride copolymer and zinc erucate. In various embodiments, the ionomer comprises zinc-neutralized fumarate graft GPPS. In various embodiments, the ionomer comprises the reaction product of fumarate graft GPPS and zinc stearate. In various embodiments, the ionomer has a molar ratio of 0.1% to 100% acid equivalent to monomer units, and a neutralization of 0.5% to 100% acid equivalent. In various embodiments, the cavity-forming agent comprises only an ionomer. In various other embodiments, the cavity filler further comprises a non-ionomer polymer. The non-ionomer polymer may include styrene-containing polymers, polyesters, polyamides, thermoplastic polyurethanes, or combinations thereof.

[0034] Examples of non-ionomer polymers include styrene-containing polymers, ester-based polymers, amide-based polymers, acrylic-containing polymers, cyclic olefin copolymers (COCs), non-olefinic biopolymers, cellulosic polymers, or combinations thereof. If a non-ionomer polymer is included, the cavity filler may have a mass ratio of ionomer to non-ionomer polymer of 1:99 to 99:1. Any range between 1:99 and 99:1, for example, 5:95 to 95:5 and 10:90 to 90:10, is intended and disclosed herein. The amount of cavity-forming agent in the composition can vary over a wide range. For example, the composition may contain 0.1 to 40% by mass of the cavity-forming agent. Any range between 0.1 and 40% by mass, such as 0.1 to 40%, 0.1 to 30%, 1 to 30%, 1 to 20%, and 1 to 15%, is intended and disclosed herein. Polymers are bound together by attractive forces acting on their constituent molecules. At the interface between two immiscible polymers, interfacial tension arises due to differences in the attractive forces within each polymer, reflecting differences in polarity and other factors that affect affinity and adhesion. This leads to the formation of droplets or inclusions of the cavity filler within the matrix polymer when they are blended. Therefore, interfacial tension is a measure of the inaffinity between polymers. The more similar the polymeric materials, the lower the interfacial tension, the weaker the driving force binding the droplets (cavity filler), and the smaller the droplet size. Taking this to the extreme, if the two materials are miscible (and therefore have zero interfacial tension), no inclusions will form.

[0035] The interfacial tension can be calculated using the method outlined in the Examples section. The measurement used for the calculation is based on a 20% by mass amount of ionomer cavity filler added to the composition, using a parallel plate rheometer. In various embodiments, the interfacial tension between the continuous polymer phase and the ionomer component of the cavity-forming agent may be 0.1 to 20 mN / m at 190°C. Any range between 0.1 and 20 mN / m, for example, 1.5 to 20 mN / m, 3 to 20 mN / m, 6 to 20 mN / m, and 9 to 20 mN / m are intended and disclosed herein. In various other embodiments, the interfacial tension between the continuous polymer phase and the ionomer component of the cavity filler is at least 0.5 mN / m at 190°C. In various other embodiments, the ratio of the interfacial tension of the ionomer to the interfacial tension of the non-ionomer equivalent polymer is greater than 1.1.

[0036] Cavity-forming agents may also be characterized by their aspect ratio. The aspect ratio is the ratio of the major axis diameter of an inclusion to the minor axis diameter of the inclusion. For spheres, the aspect ratio is 1, and for ellipsoids, the aspect ratio is greater than 1. With respect to a film of cavity-forming agent oriented in the direction of the major axis, a cavity-forming agent having an aspect ratio close to 1 prior to orientation will result in more efficient cavity formation, i.e., a lower density of the cavity-forming article. Methods for measuring the aspect ratio can be found in the section on analytical methods. In various embodiments, the cavity-forming agent comprises at least one ionomer having an inclusion mean aspect ratio of 1-5, 1-4, 1-3, or 1-2, measured according to the methods described in the section on analytical methods, before orientation, after orientation, or both. In various embodiments, the cavity filler is used for 100 to 500 seconds. -1 The material comprises at least one ionomer having an extensional viscosity in the range of 10 to 100,000 Pa·s at any of the extensional rates, where the extensional viscosity is measured using the cogswell method at 190°C or higher. Any range between 10 and 100,000 Pa·s, e.g., 100 to 50,000 Pa·s, 500 to 50,000 Pa·s, 200 to 25,000 Pa·s, 500 to 25,000 Pa·s, 500 to 20,000 Pa·s, 1,000 to 20,000 Pa·s, 500 to 15,000 Pa·s, and 2,000 to 15,000 Pa·s is intended and disclosed herein. The higher the extensional viscosity, the less the cavity filler is presumed to extend, and the aspect ratio of the cavity filler inclusion is closer to 1.

[0037] In various embodiments, the ionomer component of the cavity-forming agent may be more elastic than the continuous polymer phase, such that the elastic ratio of the ionomer component of the cavity-forming agent to the continuous polymer phase can be in the range of 0.1 to 50, 0.5 to 40, or 1.0 to 25 at 230°C, or 1.0 to 700, 25 to 650, or 50 to 650 at 200°C, when measured at 0.1 radians / second. In various other embodiments, the elastic ratio of the ionomer component of the cavity-forming agent to the continuous polymer phase is in the range of 10 to 1,000, 10 to 700, or 20 to 700 at 200°C when measured at 0.1 rad / second. In various embodiments, the ionomer component of the cavity-forming agent may have lower viscosity than the continuous polymer phase under typical extrusion conditions, such that the viscosity ratio of the ionomer component of the cavity-forming agent to the continuous polymer phase can be in the range of 0.01 to 1.3, 0.1 to 0.50, or 0.1 to 0.20 at 230°C, or 0.10 to 1.3, 0.2 to 0.8, or 0.3 to 0.5 at 200°C, when measured at 100 radians / second. In various other embodiments, the viscosity ratio of the ionomer component of the cavity-forming agent to the continuous polymer phase is in the range of 0.10–100, 0.1–50, 0.1–25, or 0.25–20 at 200°C when measured at 100 rad / sec.

[0038] In various embodiments, when the tensile modulus of the cavity filler is measured at the Vicat softening temperature of the continuous polymer phase, the tensile modulus of the cavity filler is at least 10% higher than the tensile modulus of the continuous polymer phase. Preferably, the tensile modulus of the cavity filler is 10% to 10,000% higher than the tensile modulus of the continuous polymer phase. More preferably, the tensile modulus of the cavity filler is 20% to 5,000% higher than the tensile modulus of the continuous polymer phase. In various embodiments, the surface energy of the ionomer differs from that of the continuous polymer phase by 0 dynes / cm or more, 2 dynes / cm or more, or 5 dynes / cm or more. In various embodiments, ionomer cavity voiders exhibit different shear rheological behavior from the ionomer precursors of the ionomers. When measured using the same sample preparation and testing methods, the elastic modulus (G'), dynamic modulus (G"), and / or viscosity of ionomer cavity voiders will be higher compared to the properties of the ionomer precursors. Ionomer cavity voiders generally withstand deformation caused by the continuous polymer phase during extrusion and orientation processes due to their rheological differences.

[0039] In various embodiments, ionomer cavitators have a lower melt flow rate (MFR) compared to ionomer precursors. Cavitators with a lower MFR generally withstand deformation caused by the continuous polymer phase. In various embodiments, when measured using a load of 2.1 kg at 230°C according to ASTM D1238, the ionomer cavitation agent has an MFR of 0.1 to 35 g / 10 min, 0.1 to 20 g / 10 min, 0.1 to 15 g / 10 min, or 0.1 to 10 g / 10 min. Hollowed-out items The composition of the present invention is particularly suitable for producing hollowed-out articles. Accordingly, in a second embodiment, the present invention provides a hollowed-out article comprising the composition of the present invention. Examples of hollowed-out articles include films, sheets, fibers, and tubes. The hollowed-out article may be single-layered or multi-layered.

[0040] Hollowed articles can be used to produce a variety of products, including bags (including woven bags), labels (including shrink labels), shrink films, laminates, stand-up pouches, wraps, straps, ribbons, strips, tapes, lids, trays, bowls, cups, bottles, yarn, fabrics (including raffia fabrics), and clothing. In various embodiments, the hollowed article is a film. A hollowed film can be used to manufacture a laminated structure. For example, a hollowed film can be laminated on one or both sides to another material, such as a polymer or a metal, to form a laminate. Hollowed film can be used to produce packaging materials such as stand-up pouches, bags, woven bags, raffia fabrics, labels (e.g., shrink labels), shrink films, laminates, wraps, straps, ribbons, film strips, tapes, lids, trays, bowls, cups, and bottles. In various embodiments, the hollowed-out article is a sheet. The hollowed-out sheet can be thermoformed to produce products such as lids, bowls, and cups. In various embodiments, the hollowed-out article is a fiber. Products such as yarn, cloth, and clothing can be made using the hollowed-out fiber.

[0041] Method for creating hollowed-out articles In a third embodiment, the present invention provides a method for manufacturing a hollowed-out article. In various embodiments, the method is (a) The step of forming a melt containing the composition of the present invention, (b) A step of forming an article from a molten material, (c) A step of cooling the article, (d) The step of orienting the cooled article in at least one direction to form a hollowed-out article; Includes. In various other embodiments, the method is (a) The step of forming a melt containing the composition of the present invention, (b) A step of forming an article from a molten material, (c) The steps of cooling the article to the orientation temperature and optionally heating the article, (d) The step of orienting the article from step (c) in at least one direction to form a hollowed-out article, (e) optionally, (i) annealing the hollowed article at a temperature higher than the orientation temperature, (ii) shrinking the hollowed article in the direction of orientation, or both of (i) and (ii), (f) optionally, (i) annealing the hollowed article at or below the orientation temperature to maintain a desired shrinkage in the article, (ii) shrinking the hollowed article in the orientation direction, or both of (i) and (ii) Includes.

[0042] In the above method, the article may be a film, a sheet, a fiber, or a tube. The molten material containing the composition of the present invention may be formed from any known substance. For example, the cavity filler may be heated in an extruder and melt-blended with the letdown resin and additives there. The molten material may then be formed into an article by any known technique, such as an extrusion process, where the molten mixture is pressed into a die (typically a metal structure having cutouts or holes), the mixture is formed into an article, and the article hardens during cooling. Cooling may be performed by any known method, for example, by bringing the article into contact with a cooled surface or a cooling fluid such as air, and / or in a liquid bath. The cooled articles are then subjected to orientation procedures (otherwise known as stretching or drawing procedures) to form hollowed or oriented articles. Examples of drawing procedures include suction methods (e.g., fiber stretching units), tensile frame stretching, machine direction orientation (MDO), transverse stretching tenter frames, biaxial stretching, multiaxial stretching, profile stretching, vacuum stretching, double bubble / triple bubble orientation, and combinations thereof.

[0043] Cooled articles are typically stretched at temperatures below the melting point of the continuous polymer phase to form cavities. For ethylene-based polymer matrices, the stretching temperatures are typically 50°C or higher, 60°C or higher, or 70°C or higher, and in each case, up to 10°C lower than the melting point of the continuous polymer phase. For propylene-based polymer matrices, the stretching temperatures are typically 70°C or higher, 90°C or higher, or 110°C or higher, and in each case, up to 10°C lower than the melting point of the continuous polymer phase. The cooled article may be stretched, for example, to 2 to 10 times its original dimensions, in the mechanical direction, transverse direction, or both. Any stretch ratio between 2 and 10, e.g., 3X, 4X, 5X, and 6X, is intended and disclosed herein. The stretching procedure creates voids or cavities around the particles of the cavity-forming agent in the continuous polymer phase of the resulting article. With respect to uniaxially stretched or oriented articles, the cavities may have a long axis with an average length of 0.8 μm to 24 μm and a short axis with an average length of 0.2 μm to 10.0 μm.

[0044] Annealing is a process that relieves internal stress in an article (typically a film) by keeping it at a high temperature, and the stress relief may be enhanced by shrinking the article at the annealing temperature. In MDO, the film article accumulates internal stress as it is progressively stretched by rollers. After stretching, the film article moves across one or more annealing rollers. Typically, the film article is annealed by heating it to a temperature higher than the stretching temperature, causing it to shrink. In TDO and biaxial stretching, similar techniques can be used to anneal the film article. General provisions To eliminate any uncertainty, the present invention includes, expressly intends to disclose, any combination of the embodiments, features, characteristics, parameters, and / or ranges referenced herein. In other words, the subject matter of the present invention may be defined by any combination of the embodiments, features, characteristics, parameters, and / or ranges referenced herein.

[0045] Any elements, components, or steps not specifically named or identified as part of the present invention are intended to be expressly omitted. Any process / method, apparatus, compound, composition, embodiment, or component of the present invention may be modified by transitional terms such as “contains,” “essentially consists of,” or “consists of,” or variations thereof. While efforts have been made to ensure accuracy, the numerical values ​​and ranges described herein may be considered approximations. These values ​​and ranges may vary from the numbers described, depending on the desired characteristics to be obtained by this disclosure and the variability resulting from the standard deviation observed in the measurement techniques. Furthermore, the ranges described herein are intended and specifically intended to include all subranges and values ​​within the described range. For example, the range 50–100 is intended to include all values ​​within the range, including subranges such as 60–90, 70–80, etc. Any two numbers of the same characteristic or parameter reported in the examples may define a range. These numbers may be rounded to the nearest thousandth, hundredth, tenth, integer, 10, 100, or 1000 to define a range.

[0046] All documents cited herein, including patents and non-patent literature, are cited herein by reference in their entirety. To the extent that any cited subject matter conflicts with any disclosure herein, the disclosure herein shall prevail over the cited content. Unless otherwise stated in the context or by convention in the art, all parts and percentages are based on mass, and all test methods are current as of the filing date of this specification. The present invention can be further illustrated by the following embodiments, which are included solely for illustrative purposes and are not intended to limit the scope of the invention. [Examples]

[0047] Analysis method The aspect ratio is the ratio of the major axis divided by the minor axis. The major axis diameter refers to the major axis of the inclusion when viewed in the plane of the machine direction (if the inclusion is not spherical). The minor axis diameter refers to the minor axis of the inclusion when viewed in the plane of the machine direction (if the inclusion is not spherical). The number-mean cross-sectional diameter of the voiding agent in an article can be quantified using scanning electron microscope (SEM) images. SEM images of cross-sections of articles formed by (i) extrusion alone or (ii) extrusion and machine direction orientation (MDO) can be used for analysis at magnifications of 3000× (COxem EM30N) to 4000× (JEOLJSM-6500F field emission scanning electron microscope (FEG-SEM)). The major axis diameter can be determined by measuring each inclusion at the widest point of the cross-section. The measurement direction of the minor axis is perpendicular to the measurement direction of the major axis and is measured at the midpoint of the major axis. The software tool μScope Essentials from PixeLINK can be used for particle analysis. Reference markers on the image can be used for distance calibration.

[0048] The average aspect ratio of inclusions is determined by measuring the aspect ratio of all inclusions (a minimum of 25) within one or more randomly selected square or rectangular windows extending across the thickness of the cavity layer, and then dividing the sum of these ratios by the number of inclusions being measured. In the case of multiple windows, their combined width should be large enough to contain the minimum number of inclusions. The selection of windows should ensure that the inclusions represent a sample that is representative of all inclusions within the specimen. The viscosity ratio is the complex viscosity of the cavity-forming polymer divided by the viscosity of the continuous polymer phase, where the viscosities for both polymers are under the same experimental setup and test conditions. The ratio must be calculated with respect to the viscosities at the same test temperature and frequency. Individual viscosity data are obtained from DMA dynamic parallel-plate rheology measurements under ASTM D4440. 100 seconds is used to represent the shear rate typically observed in the extrusion process. -1Choose the frequency.

[0049] The elastic ratio is the elastic storage modulus (G') of the cavity-forming polymer divided by the elastic storage modulus of the continuous polymer phase, where the elastic storage modulus for both polymers is under the same experimental setup and test conditions. The ratio must be calculated using data collected at the same test temperature and frequency, where the elastic storage modulus is typically measured at very low frequency rates. Generally, low frequencies are around 0.1 radians / second, more preferably around 0.01 radians / second, depending on the experimental setup. Individual storage modulus (G') data are obtained from DMA dynamic parallel-plate rheology measurements under ASTM D4440.

[0050] A procedure was constructed to measure the interfacial tension between a single cavity-forming agent type, not supported in another polymer, and a continuous polymer phase resin (for reference, see: Graebling, D., Muller, R., and Palierne, JF, 1993, "Linear viscoelastic behavior of some incompatible polymer blends in the met. This procedure is intended for measuring pure cavity-forming agents (unsupported) and is not intended for measuring the interfacial tension of blends of different cavity-forming agents. Interpretation of data with a model of emulsion of viscoelastic liquids," Macromolecules, 26, 320-329). 1. Measure the complex viscosity of the continuous polymer phase resin as a function of frequency at the temperature of the interfacial tension measurement (ASTM D4440). The continuous polymer phase resin should be of the same polyolefin family as the continuous polymer phase used in the hollowed-out article. For polyethylene, the temperature range should be 180°C to 200°C. For polypropylene, the temperature range should be 210°C to 230°C. Estimate the zero-shear viscosity of the continuous polymer phase from the complex viscosity versus frequency plot (frequency in rad / sec is calculated using the Cox-Mertz law). -1 (This is equivalent to the shear rate at [location].) 2. As a function of frequency, the complex viscosity of the cavity filler (inclusion polymer) is measured at the temperature used for the interfacial tension measurement, and the zero shear viscosity is estimated. The measurement of the cavity filler should be performed under the same conditions as in step 1 for the continuous polymer phase. 3. Calculate the viscosity ratio K (zero shear viscosity of the cavity filler / zero shear viscosity of the continuous polymer phase). 4. Prepare a blend of the cavitating agent and the continuous polymer phase. The amount of cavitating agent added should be sufficient to determine the deviation from linearity in the storage modulus (G'), which is generally 20-30% by mass, but not so high that the cavitating agent is no longer a discontinuous phase. Measure the storage modulus (G') versus frequency (rad / sec) of the blend and plot it on a log-log scale. Only at small frequencies, the G' versus frequency plot for the pure polymer is linear. For immiscible polymer blends, deviation from linearity occurs due to the relaxation of the dispersed domains. This relaxation has a specific relaxation time (λ), which is the reciprocal of the frequency (rad / sec) at which the shoulder of the deviation ends. D ) has. 5. Measure the particle size (diameter) of the cavity filler during blending. If various particle sizes are present, calculate the average diameter. 6. Equations (1) and (2):

[0051]

number

[0052] The Cogswell extensional viscosity is a capillary rheology measurement method using an orifice die (zero L / D) in accordance with ASTM D3835. The entrance loss is directly available from these measurements. The measurements are also carried out using a long die (20L / D). A barrel diameter of 12 mm and a die diameter of 1 mm with a die entrance angle of 180° are used. The die lengths are 0.3 mm and 20 mm. The samples are typically not dried, however, hydrophilic resins should be dried prior to testing. The samples are loaded into the preheated test barrel of the capillary rheometer. Various flow rates are tested, and the shear rate range resulted in 10 - 10,000 / sec at 230 °C. For each flow rate, the pressure loss across the die is measured and the viscosity-shear rate data is calculated. The Rabinowitsch and Bagley corrections are performed. The Cogswell equation is used to calculate the extensional viscosity vs. extensional rate. Shear rate

[0053] [Number] Shear stress (Bagley corrected) [Number] Shear viscosity [Number] Rabinowitsch correction [Number] Cogswell extensional viscosity [Number] Cogswell tensile stress

number

number

[0054] During the ceremony,

number

number

number

[0055] An analytical balance is used to measure the mass of the film to the nearest ten-thousandth of a gram (g), and ten-thousandth of a gram is used to measure the mass of the film to the nearest ten-thousandth of a gram (cm³). 3 The density of the film was determined using a pycnometer (Accupyc1340, Micromeritics, Norcross, Georgia) to measure the volume of the sample up to 1 / 3 cm³. The pycnometer used sulfur hexafluoride gas as the medium to determine the volume. The density was determined by dividing the film mass by the film volume using pycnometer software, and the result was expressed in g / cm³.3 I reported it. The density of the polymer was measured according to ASTM D792. (g / cm³) 3 The results were recorded using ). The glass transition temperature (Tg) was measured according to ASTM D3418, and the results were reported in degrees Celsius (°C). The optical density was measured using an X-rite 331C transmission densitometer and calculated using the following formula: Opacity=100-10 (2-光学密度) The film opacity was calculated using [a specific method / tool], and the results were reported as a percentage (%).

[0056] The melt flow index (MFI) for ethylene polymers was measured at 190°C / 2.16 kg in accordance with ASTM D1238, and the results were reported as gram-by-gram values ​​per 10 minutes (g / 10 min). We followed ASTM D1238, but also measured the melt flow rate (MFR) for non-ethylene polymers under different conditions. The results are reported as grams per 10 minutes (g / 10 min). The tensile modulus and tensile yield stress were measured according to ASTM D882, and the results were reported in megapascals (MPa).

[0057] Experimental Procedure Unless otherwise stated, ionomerous cavity fillers were prepared by supplying individual components to the feed port of a Coperion twin-screw extruder line to form ionomers. When a masterbatch was formed, the polyethylene carrier and ionomer components (cavity filler polymer and metal salt) were blended in the Coperion twin-screw extruder. Unless otherwise stated, the individual components included styrene-maleic anhydride copolymer (SMA), zinc stearate, and linear low-density polyethylene (LLDPE) as the carrier resin. Hollowed films were prepared using a 3-layer LabTech blown film line with a 120mm die. The die was fed by two 30mm screws with an L / D ratio of 30:1 for the skin layer and one 45mm screw with an L / D ratio of 33:1 for the core layer. The films were stretched on an in-line MDO manufactured by LabTech.

[0058] material The materials used in the examples are listed in Table 1 below. [Table 1]

[0059] Several properties of the cavity-forming agent materials were measured and reported in Tables 2 and 3 below. For ionomers with a polymer-to-zinc stearate mass ratio of 34:1, the melt viscosity and elasticity ratios for SMA1 and SMA2 ionomers were measured. For SMA1 and SMA2 ionomers, a polymer-to-zinc stearate ratio of 34:1 corresponds to neutralization of 5.7 mol% and 3.3 mol%, respectively. For ionomers with a polymer-to-zinc stearate mass ratio of 24:1, the remaining properties for SMA1 and SMA2 ionomers were measured. For SMA1 and SMA2 ionomers, a polymer-to-zinc stearate ratio of 24:1 corresponds to neutralization of 8.1 mol% and 4.6 mol%, respectively. For the PP ionomers in Table 3, the neutralization level was 100%, and the molar ratio of acid equivalents was approximately 1%. All ionomers in this example do not contain a carrier resin. Ionomers were generated using a melt blending experimental method that does not involve a carrier resin.

[0060] [Table 2]

[0061] [Table 3]

[0062] (Example 1) A three-layer film was produced on a LabTech blown film line using a 120 mm die diameter, with a throughput of 35 kg / hour, an extrusion temperature of 190°C, and a volume-based layer ratio of 15 / 70 / 15. The skin layer contained MDPE1, and the core layer was filled with a 15 mass% cavified masterbatch letdown with mLLDPE3. Each masterbatch contained 60% by mass of a cavity-forming agent and 40% by mass of mLLDPE1 as the carrier resin. The cavity-forming agent was SMA1 and zinc stearate blended in a mass ratio of 60:1 (3.2 mol% neutralized). Additional cavity-forming masterbatches were prepared with a mass ratio of 40:1 (4.8 mol% neutralized) and 24:1 (8.1 mol% neutralized). A control of SMA1 without zinc stearate was blended with the mLLDPE1 carrier resin to form a non-ionomer masterbatch.

[0063] The film was stretched five times using mechanical direction orientation (MDO) at 65°C and 75°C, then annealed at 110°C to relax the film by 27.8%. The density and opacity of the obtained films were measured and reported in Table 4. [Table 4] As can be seen from Table 4, film density decreased with increasing amounts of zinc stearate, and opacity generally decreased.

[0064] (Example 2) The three-layer films were prepared as described in Example 1, except for those described later. Each masterbatch contained 60% by mass of a cavity filler and 40% by mass of mLLDPE1 as a carrier resin. The cavity fillers were (1) neat SMA1, (2) neat SMA2, (3) an SMA1 ionomer with a mass ratio of 24:1 SMA1 to zinc stearate (8.1 mol% neutralized), and (4) an SMA2 ionomer with a mass ratio of 24:1 SMA2 to zinc stearate (4.6 mol% neutralized).

[0065] Using barrel and die temperatures set to 200°C, 215°C, and 230°C, films were extruded at three different extrusion temperatures to demonstrate the effect of ionomers on the final film density over increasing extrusion temperature associated with blown film extrusion. The films were stretched 4.5 times using machine direction orientation (MDO) at 70°C and annealed at 110°C, resulting in a 27.8% relaxation of the films.

[0066] The film density was measured and is reported in Table 5. [Table 5]

[0067] (Example 3) To compare melt flow rates (MFRs), various cavity fillers were prepared in a Coperion ZSK-26 compounder without a carrier resin, at a throughput of 18 kg / hour and an extrusion temperature of 220°C. The following cavity fillers were used: (1) SMA1, (2) SMA1 and zinc stearate (1.6 mol% neutralized) in a mass ratio of 120:1 SMA1 to zinc stearate, (3) SMA1 and zinc stearate (3.2 mol% neutralized) in a mass ratio of 60:1 SMA1 to zinc stearate, (4) SMA1 and zinc stearate (4.8 mol% neutralized) in a mass ratio of SMA1 to zinc stearate of 40:1 (5) SMA1 and zinc stearate (8.1 mol% neutralized) in a mass ratio of SMA1 to zinc stearate of 24:1 (6) General-purpose polystyrene (GPPS), and (7) GPPS and zinc stearate in a mass ratio of 24:1 It generated.

[0068] The molecular weight (MFR) of each cavity filler was measured using ASTM D1238 at 5 kg and 230°C. The results are shown in Table 6. [Table 6] The data in Table 6 demonstrate that an ionomer was formed between SMA1 and zinc stearate. If no ionomer was formed, zinc stearate or an acid byproduct would act as a lubricant, and the MFR would increase as the amount of zinc stearate increased, as seen in the case of GPPS.

[0069] (Example 4) - Comparison The three-layer films were prepared as described in Example 1, except for those described later. Each masterbatch contained 60% by mass of a cavity filler and 40% by mass of mLLDPE1 as the carrier resin. The cavity filler was general-purpose polystyrene (GPPS) alone, or GPPS blended with zinc stearate in a mass ratio of 40:1. The films were stretched five times using mechanical direction orientation (MDO) at 65°C and annealed at 110°C to relax the films by 27.8%.

[0070] The density and opacity of the obtained films were measured and reported in Table 7. [Table 7] As shown in Table 7, the density and opacity of the two films were almost identical. As expected, zinc stearate did not react with GPPS, and no ionomer was formed without other steps to initiate the reaction.

[0071] (Example 5) The three-layer films were prepared as described in Example 1, except for those described later. Each masterbatch contained 60% by mass of a cavity filler and 40% by mass of mLLDPE1 as the carrier resin. The cavity filler was neat GPPS and a 2:1 by mass blend of GPPS and SMA1-zinc stearate ionomer in a 12:1 mass ratio of SMA1 to zinc stearate (16.2 mol% neutralized). The films were stretched 5-fold using mechanical direction orientation (MDO) at 75°C and annealed at 110°C to relax the films by 27.8%.

[0072] The density and opacity of the obtained films were measured and reported in Table 8. [Table 8] As shown in Table 8, blending GPPS with the SMA1 ionomer improved the density at an orientation temperature of 75°C.

[0073] (Example 6) The three-layer films were prepared as described in Example 1, except for those described later. The skin layer contained mLLDPE2, and the core layer contained a 15% by mass cavity-forming masterbatch let down with mLLDPE2. Each masterbatch contained 60% by mass of a cavity-forming agent and 40% by mass of mLLDPE4 as a carrier resin. The cavity-forming agent was SMA1 ionomer and / or glycol-modified poly(ethylene terephthalate) (PETG). The cavity-forming agents were blended as follows: (1) 100% by mass of PETG, (2) 75% by mass of PETG and 25% by mass of SMA1 ionomer, (3) 50% by mass of PETG and 50% by mass of SMA1 ionomer, (4) 25% by mass of PETG and 75% by mass of SMA1 ionomer, (5) 100% by mass of SMA1 ionomer.

[0074] In this example, the SMA1 ionomer had an input ratio of 34:1 by mass, consisting of SMA1 to zinc stearate (5.7 mol% neutralized). The film was stretched five times using mechanical direction orientation (MDO) at 50°C, then annealed at 70°C to relax the film by 3%.

[0075] The density and opacity of the obtained films were measured and reported in Table 9. [Table 9] As can be seen from Table 9, the balance between reducing film density and increasing film opacity can be achieved by blending PETG and ionomer as secondary cavity-forming components.

[0076] (Example 7) - Comparison The three-layer films were prepared as described in Example 1, except for those described later. The skin layer contained mLLDPE2, and the core layer contained a 15% by mass cavity-forming masterbatch let down with mLLDPE2. Each masterbatch contained 60% by mass of a cavity-forming agent and 40% by mass of mLLDPE5 as a carrier resin. The cavity-forming agents were (1) neat PP and (2) PP-zinc acrylate in a polypropylene to zinc acrylate mass ratio of 80:1 (100 mol% neutralized). The film was extruded using a barrel and die temperature set to 190°C. The film was stretched in-line on an MDO unit at 65°C with a stretch ratio of 4.5 times. These films did not develop cavities.

[0077] The density and opacity of the obtained films were measured and reported in Table 10. [Table 10]

[0078] (Example 8) The three-layer films were prepared as described in Example 1, except for those described later. The skin layer contained Ziegler-Natta catalyst (Zn) LLDPE1, and the core layer was filled with a 15% by mass cavitation masterbatch let down with Zn LLDPE1. The cavitation masterbatch contained 60% by mass of SMA1 and 40% by mass of Zn LLDPE1 as the carrier resin. A neutralization masterbatch containing 2.5% by mass of zinc stearate in Zn LLDPE1 was added at 10% by mass to one of the core layers of the film. The combination of the neutralization masterbatch and the cavitation masterbatch yielded an ionomer of SMA1 with a neutralization level of 5.4 mol% (equivalent to a mass ratio of SMA1 to zinc stearate of 36:1). The extrusion temperature was 210°C. Using machine direction orientation (MDO) at 50°C, the film was stretched to 4.5x, 5.0x, 5.5x, 6.0x, and 6.5x stretch ratios at 50°C, and then annealed at 70°C to relax the film by 3%.

[0079] The density and opacity of the obtained films were measured and reported in Table 11. [Table 11]

[0080] (Example 9) The three-layer films for tensile testing were prepared as described in Example 1, except as described below. The skin layer contained mLLDPE2, and the core layer contained a 15% by mass cavity-forming masterbatch let down with mLLDPE2. Each masterbatch contained 60% by mass of a cavity-forming agent and 40% by mass of mLLDPE1 as a carrier resin. The cavity-forming agent was blended as follows: (1) SMA1, (2) SMA1 ionomer in a 24:1 ratio (8.1 mol% neutralized), (3) Stearic acid and SMA1, (4) SMA2, (5) SMA2 ionomers in a 24:1 ratio (4.6 mol% neutralized), and (6) Stearic acid and SMA2.

[0081] Additionally, a control film of neat mLLDPE2 was prepared. The film was not stretched prior to the tensile test. The tensile properties of the film were measured according to ASTM D882. The results are reported in Table 12. The yield stress ratio is the yield stress of the cavity filler divided by the yield stress of the continuous polymer phase. In Table 12, mLLDPE2 is the continuous polymer phase.

[0082] [Table 12] As shown in Table 12, the films containing ionomers (films B and E) had lower yield stresses than the films without ionomers (films A, C, D, F, and G). SMA1 and SMA2 with stearic acid are not ionomers.

[0083] (Example 10) The three-layer films were prepared as described in Example 1, except for those described later. The skin layer contained mLLDPE2, and the core layer contained a 15% by mass cavity-forming masterbatch let down with mLLDPE2. Each masterbatch contained 60% by mass of a cavity-forming agent and 40% by mass of mLLDPE4 as a carrier resin. The cavity-forming agent was (1) NEET SMA1, (2) SMA1 having (4.7 mol% neutralized) zinc acetate dihydrate in a mass ratio of SMA1 to zinc stearate dihydrate of 120:1, and (3) SMA1 having zinc acetate dihydrate (8.0 mol% neutralized) in a mass ratio of SMA1 to zinc stearate dihydrate of 70:1 That was the case.

[0084] The film was stretched five times using mechanical direction orientation (MDO) at 75°C, then annealed at 110°C to relax the film by 27.8%. The density of the obtained films was measured and reported in Table 13. [Table 13] As shown in Table 13, the film density decreased with increasing amounts of zinc acetate dihydrate added.

[0085] Example 11 - Prediction When measured at 230°C with a 5kg load, it has a melt flow rate between 30 and 36g / 10min, and exhibits tensile properties (e.g., within 50%) and thermal properties (approximately 100°C) similar to those of GPPS given in Table 3. gA styrene-containing polymer having no neutralizable units can be grafted with neutralizable units or neutralized units by techniques known to those skilled in the art. The grafted polymer may have a molar ratio of 1.35% acid equivalent and may already be completely neutralized with zinc or be neutralized with zinc in a subsequent step, resulting in an ionomer. This polymer can then be processed in a continuous phase of 1 MI, 0.918 g / cc mL LDPE as an additive in the ratio of SMA1 and 70:1 styrene-maleic anhydride copolymer to zinc acetate dihydrate, as in Example 10. The ionomer of this styrene-containing polymer will yield similar results to that of SMA1 and 70:1 zinc acetate dihydrate, and it can be expected that the results will differ significantly from those of the unmodified, non-ionomer form of the styrene-containing polymer.

[0086] (Example 12) Ionomers were prepared using a 24:1 mass ratio of cavity-forming polymer to zinc stearate. Each polymer was melt-blended in a Coperion ZSK-26 compounder at a barrel temperature of 210°C–220°C and a throughput of 18 kg / hour. Zinc stearate was added to the feed port along with the polymer at a rate of 1.5 lbs / hour. These ionomers, along with various other cavity-forming agents, were measured for their extensional viscosity using the Cogswell method, as defined in the section on analytical methods. For each cavity-forming agent, peak extensional viscosity values ​​were selected within the extensional rate range of 100–500 1 / second. The results are shown in Table 14. [Table 14]

[0087] The data in Table 14 show that ionomers have significantly higher extensional viscosity than their corresponding non-ionomers. The non-ionomer extensional viscosity represents the lower end of the extensional viscosity range for each specific polymer, where each polymer has a different initial extensional viscosity. Ionomer formation allows for the modification of extensional viscosity. Higher extensional viscosity is thought to reduce particle deformation during the extrusion process. This results in less particle splitting, which allows for larger particles than non-ionomers under the same extrusion conditions. Ionomer particles are presumed to be rounder than non-ionomer equivalent polymers, depending on the extrusion conditions. Higher extensional viscosity is desirable for creating the desired shape for cavity formation.

[0088] (Example 13) Six different films were produced using different polyethylene grades (mLLDPE3, MDPE1, HDPE1). Each film contained either SMA1 or SMA1 ionomer. SMA1 ionomers were prepared using a 24:1 mass ratio of SMA to zinc stearate. In a twin-screw extruder, 60% by mass of SMA ionomer was extruded at 40% by mass (4.5 MI, 0.918 g / cm³). 3 It was blended with polyethylene carrier resin. Films were produced on a 3-ply blown film line with an extruder and die temperature of 190°C, a throughput of 34 kg / hour, a die gap of 2.25 mm, and a primary nip speed of 5.4 m / min. The film gauge ranged from 25 to 35 micrometers. The films were then imaged by SEM, and the mean aspect ratio of the particles was measured according to the method outlined in the Analytical Methods section. The results are shown in Table 15.

[0089] [Table 15] The data in Table 15 show that the ionomers in each of the three types of polyethylene continuous phases have smaller aspect ratios.

[0090] Next, unless otherwise stated, the films were oriented in the machine direction, at 85°C and a stretch ratio of 4.5 times. The films were annealed at 110°C on two annealing rolls, with the annealing roll stretch set to 0.85 times. The density results from the oriented films are shown in Table 16. [Table 16] The data from Table 16 shows that the oriented film with the SMA1 ionomer had a much lower density than the oriented film using the SMA1 voiding agent. Compared to Table 15, the ionomer voiding agent had a much smaller aspect ratio.

[0091] (Example 14) Ionomers were prepared using a 24:1 mass ratio of cavity-forming polymer to zinc stearate, without the use of a carrier resin. Each ionomer was prepared by melt-blending the polymer and zinc stearate in a Coperion ZSK-26 compounder at a die temperature of 240°C, an extrusion temperature of 220°C, and a throughput of 18 kg / hour. Each polymer was added to the feed port along with the zinc stearate. Neither the ionomers nor the non-ionomers were supported. The melt flow rate (MFR) was measured for each cavity-forming agent at 230°C using a load of 2.1 kg. The melt flow rate results are shown in Table 17.

[0092] [Table 17] The data in Table 17 clearly shows that ionomer formation reduces the MFR compared to non-ionomer polymers. Each ionomer will have a different MFR depending on the starting polymer MFR.

[0093] (Example 15) In a Coperion ZSK-26 compounder, with a die temperature of 240°C, an extrusion temperature of 220°C, and a throughput of 18 kg / hour, the compound yielded 1.0 MI and 0.918 g / cm³. 3 SMA1 and SMA1 ionomer (SMA1 to zinc stearate in a 24:1 ratio by mass) were melt-blended into polyethylene at a concentration of 20% by mass. In a twin-screw compounder, the compound yielded 0.5 MI and 0.918 g / cm³.3 SMA2, SMA2 ionomer, SAN-MAH1, and SAN-MAH1 ionomer were individually melt-blended into polyethylene at a concentration of 20% by mass. Each blend was tested at 190°C using a parallel plate rheometer. The zero-shear viscosity of each component was measured at 190°C using a parallel plate rheometer. Inclusion size was measured and calculated using the interfacial tension procedure outlined in the Analytical Methods section. For non-spherical inclusions, particle volume was calculated based on the optimal geometry (e.g., ellipsoid, cone, rod), and spherical diameter was calculated for equivalent volumes. The average inclusion diameter was obtained for each inclusion material. Interfacial tension was then calculated for each ionomer and its equivalent non-ionomer polymer, and the ratio of interfacial tensions was calculated. In some cases, non-linear ridges were not visible in the blend shear-viscosity curve, meaning their values ​​were at a much lower test frequency than the test equipment capacity allowed. Since the rheometer's minimum capacity was limited to 0.01 radians / second, it was assumed that the shoulders were below 0.01 radians / second. In these examples, the frequency of the non-linear ridges was set to 0.01 radians / second for the calculation of interfacial tension.

[0094] Table 18 shows the ratio of ionomer to non-ionomer interfacial tensions. [Table 18]

[0095] The data in Table 18 shows that the interfacial tension increases upon ionomer formation, meaning the interfacial tension ratio is greater than 1.1. This improvement in interfacial tension is thought to improve particle size and shape. Although the present invention has been described in detail with particular reference to its preferred embodiments, it will be understood that changes and modifications can be made within the spirit and scope of the invention.

Claims

1. (A) A continuous polymer phase containing polyolefins, (B) Cavity-forming agent dispersed in a continuous polymer phase and A composition comprising, The cavity-forming agent comprises one or more ionomers, One or more ionomers do not contain ethylene-based ionomers and propylene-based ionomers. composition.

2. The composition according to claim 1, wherein the polyolefin comprises an ethylene-based polymer, a propylene-based polymer, or both.

3. The composition according to any one of claims 1 to 2, wherein at least one ionomer has an inclusion mean aspect ratio of 1 to 5, 1 to 4, 1 to 3, or 1 to 2 before orientation, after orientation, or both.

4. The composition according to any one of claims 1 to 3, wherein at least one ionomer has a melt flow rate of 0.1 to 35 g / 10 min, 0.1 to 20 g / 10 min, 0.1 to 15 g / 10 min, or 0.1 to 10 g / 10 min when measured using a load of 2.1 kg at 230°C according to ASTM D1238.

5. At least one type of ionomer, 100 seconds -1 ~500 seconds -1 The composition according to any one of claims 1 to 4, having a cogswell extension viscosity of 100 to 100,000 Pa·s, 500 to 50,000 Pa·s, 500 to 25,000 Pa·s, 500 to 20,000 Pa·s, or 500 to 15,000 Pa·s at any of the extension rates.

6. The composition according to any one of claims 1 to 5, wherein the elastic ratio of at least one ionomer to a continuous polymer phase is in the range of 10 to 1,000, 10 to 700, or 20 to 700 at 200°C when measured at 0.1 rad / second.

7. The composition according to any one of claims 1 to 6, wherein the viscosity ratio of at least one ionomer to a continuous polymer phase is in the range of 0.10 to 100, 0.1 to 50, 0.1 to 25, or 0.25 to 20 at 200°C when measured at 100 rad / second.

8. The composition according to any one of claims 1 to 7, wherein the surface energy of at least one ionomer differs from the surface energy of the continuous polymer phase by 0 dynes / cm or more, 2 dynes / cm or more, or 5 dynes / cm or more.

9. At least one ionomer comprises an ionomer precursor and a cationic component, The ionomer precursor includes styrene-containing polymers, ester-based polymers, amide-based polymers, acrylic-containing polymers, cyclic olefin copolymers (COCs), non-olefinic biopolymers, cellulosic polymers, or combinations thereof. The composition according to any one of claims 1 to 8.

10. The composition according to claim 9, wherein the ionomer precursor comprises styrene-maleic anhydride copolymer (SMA), styrene-maleimide copolymer (SMI), styrene-methyl methacrylate copolymer (SMMA), styrene-acrylonitrile copolymer (SAN), styrene-acrylonitrile-maleic anhydride copolymer (SAN-MAH), acrylonitrile-styrene-acrylate copolymer (ASA), acrylonitrile-butadiene-styrene copolymer (ABS), or a combination thereof.

11. The composition according to any one of claims 9 to 10, wherein the cationic component comprises zinc, sodium, calcium, lithium, magnesium, aluminum, ammonium, or a combination thereof.

12. The composition according to claim 11, wherein the cationic component contains zinc.

13. The composition according to claim 12, wherein the zinc is supplied from a zinc carboxylate salt, zinc sulfate, or a salt formed in situ from zinc oxide.

14. The composition according to claim 13, wherein the zinc carboxylate salt comprises zinc acetate, zinc stearate, or both.

15. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a styrene-maleic anhydride copolymer and a zinc ion.

16. The composition according to any one of claims 1 to 15, wherein at least one ionomer comprises a reaction product of styrene-maleic anhydride copolymer and zinc stearate.

17. The composition according to any one of claims 1 to 15, wherein at least one ionomer comprises a zinc-neutralized styrene-maleic anhydride copolymer.

18. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a sodium-neutralized styrene-maleic anhydride copolymer.

19. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises maleic anhydride-grafted general-purpose polystyrene (GPPS) neutralized with zinc.

20. The composition according to any one of claims 1 to 11, comprising at least one ionomer of maleic anhydride graft GPPS, which is neutralized with sodium.

21. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer (ABS) that has been neutralized with zinc.

22. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a maleic anhydride-grafted acrylonitrile-butadiene-styrene copolymer (ABS) that has been neutralized with sodium.

23. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a methacrylate grafted acrylonitrile-butadiene-styrene copolymer (ABS) neutralized with zinc.

24. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a methacrylate grafted acrylonitrile-butadiene-styrene copolymer (ABS) that has been neutralized with sodium.

25. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a reaction product of styrene-methyl methacrylate copolymer (SMMA), fumaric acid, and aluminum stearate.

26. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a fumarate-grafted styrene-acrylonitrile copolymer (SAN) that has been neutralized with sodium.

27. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a styrene-acrylonitrile-maleic anhydride copolymer (SAN-MAH) neutralized with zinc.

28. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a fumarate-grafted styrene-acrylonitrile copolymer (SAN) neutralized with zinc.

29. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a reaction product of grafted styrene fumarate-acrylonitrile copolymer (SAN) and zinc stearate.

30. The composition according to any one of claims 1 to 14, comprising a styrene-maleic anhydride copolymer in which at least one ionomer is neutralized with a blend of sodium and zinc.

31. The composition according to any one of claims 1 to 11, wherein at least one ionomer comprises a reaction product of styrene-maleic anhydride copolymer and a blend of sodium stearate and zinc stearate.

32. The composition according to any one of claims 1 to 13, wherein at least one ionomer comprises a reaction product of styrene-maleic anhydride copolymer and zinc oleate.

33. The composition according to any one of claims 1 to 13, wherein at least one ionomer comprises a reaction product of styrene-maleic anhydride copolymer and zinc erucate.

34. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a zinc-neutralized fumarate graft GPPS.

35. The composition according to any one of claims 1 to 14, wherein at least one ionomer comprises a reaction product of fumarate graft GPPS and zinc stearate.

36. The composition according to any one of claims 1 to 35, wherein at least one ionomer has a molar ratio of 0.1% to 100% acid equivalent to monomer units, and a neutralization of 0.5% to 100% acid equivalent.

37. The composition according to any one of claims 1 to 36, wherein the cavity-forming agent comprises only an ionomer.

38. The composition according to any one of claims 1 to 36, wherein the cavity-forming agent further comprises a non-ionomer polymer.

39. The composition according to claim 38, wherein the non-ionomer polymer comprises a styrene-containing polymer, an ester-based polymer, an amide-based polymer, an acrylic-containing polymer, a cyclic olefin copolymer (COC), a non-olefinic biopolymer, a cellulosic polymer, a thermoplastic polyurethane, or a combination thereof.

40. The composition according to any one of claims 38 to 39, wherein the mass ratio of the ionomer to the non-ionomer polymer is 1:99 to 99:

1.

41. The composition according to any one of claims 1 to 40, comprising 0.1 to 40 mass percent of a cavity-forming agent based on the total mass of the composition.

42. A hollowed-out article comprising the composition according to any one of claims 1 to 41.

43. The hollowed article according to claim 42, which is a film, sheet, fiber, or tube.

44. A product comprising a hollowed-out article as described in any one of claims 42 to 43, the product being a bag, woven bag, raffia fabric, label, shrink label, shrink film, laminate, stand-up pouch, wrap, strap, ribbon, film strip, tape, lid, tray, bowl, cup, bottle, yarn, cloth, or garment.

45. A method for manufacturing a hollowed-out article, (a) A step of forming a molten material comprising the composition according to any one of claims 1 to 41, (b) A step of forming an article from a molten material, (c) A step of cooling the article to an orientation temperature, which may include a step of heating the article, (d) The step of orienting the article from step (c) in at least one direction to form a hollowed-out article, Includes, (e) (i) a step of annealing the hollowed article at a temperature higher than the orientation temperature, (ii) a step of shrinking the hollowed article in the direction of orientation, or both of (i) and (ii), It may include, or (f) (i) Annealing the hollowed article at or below the orientation temperature to maintain a desired shrinkage in the article, (ii) Shrinking the hollowed article in the direction of orientation, or both of (i) and (ii), A method that may include this.

46. The method according to claim 45, wherein the article is a film, a sheet, a fiber, or a tube.

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