Article including thermoplastic elastomer composition and related process

Abstract

An article includes a thermoplastic elastomer composition. The thermoplastic elastomer composition includes a hydrogenated styrenic block copolymer, a plasticizer having a number average molecular weight of at least 2,000 grams per mole, and a wax having a polar functional group. The article can be a filament or a gasket, for example. A process for making the article including coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive directly onto a substrate is also described.

Description

[0001] ARTICLE INCLUDING THERMOPLASTIC ELASTOMER COMPOSITION AND RELATED PROCESS

[0002] Cross-Reference to Related Application

[0003] This application claims priority to U.S. Provisional Application No. 63 / 605,353, filed December 1, 2023, the disclosure of which is incorporated by reference in its entirety herein.

[0004] Background

[0005] Rubber seals around openings are useful, for example, in the automotive and building industries as described in WO 2018 / 161068 (Murree et al.), U.S. Pat. Appl. Pub. No. 2008 / 0182074 (Pasquale et al.), and FR2851193, published August 20, 2004. The seals can have multiple layers or otherwise include multiple materials bonded together.

[0006] In unrelated disclosures, adhesives coextruded with other materials are described in U.S. Pat. Nos. 4,497,926 (Toy), 7,491,434, (Khandpur et al.), and 9,486,982 (Emslander et al.), U.S. Pat. Pub. No. 2021 / 0324244 (Bieber et al.), and GB1553881, published October 10, 1979.

[0007] In further unrelated disclosures, adhesives provided as core-sheath filaments are described in U.S. Pat. Appl. Pub. Nos. 2023 / 0089703 (Kalish et al.), 2022 / 0290335 (Behling et al.), 2022 / 0290334 (Sahni et al.), 2022 / 0259465 (Kugel et al.), and 2022 / 0134652 (Napierala et al.) and Int. Pat. Appl. Pub. No. WO 2021 / 130620 (Sahni et al.).

[0008] Summary

[0009] The present disclosure provides a thermoplastic elastomer composition that can be readily extmded. Advantageously, the thermoplastic elastomer composition may be formed into a filament, which then may be extruded into another useful article, for example, a gasket. Further advantageously, the thermoplastic elastomer composition can be coextruded with a pressure sensitive adhesive composition.

[0010] In one aspect, the present disclosure provides a thermoplastic elastomer composition. The thermoplastic elastomer composition includes a hydrogenated styrenic block copolymer, a plasticizer having a number average molecular weight of at least 2,000 grams per mole, and a wax having a polar functional group.

[0011] In another aspect, the present disclosure provides an article that includes a thermoplastic elastomer composition. The thermoplastic elastomer composition includes a hydrogenated styrenic block copolymer, a plasticizer having a number average molecular weight of at least 2,000 grams per mole, and a wax having a polar functional group. In some embodiments, the article is an extruded article. In some embodiments, the article is a filament. In some embodiments, the article is a gasket. In some embodiments, the article is a composite article in which the thermoplastic elastomer composition is in direct contact with a pressure sensitive adhesive. In some embodiments, the article is a coextruded article in which the thermoplastic elastomer composition is coextruded with a pressure sensitive adhesive.

[0012] In another aspect, the present disclosure provides a process of making the aforementioned article. The process includes extruding the thermoplastic elastomer composition. The process can include coextruding the thermoplastic elastomer composition with a pressure sensitive adhesive composition.

[0013] In this application:

[0014] Terms such as "a", "an" and "the" are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one".

[0015] The phrase "comprises at least one of followed by a list refers to comprising any one of the items in the list and any combination of two or more items in the list. The phrase "at least one of followed by a list refers to any one of the items in the list or any combination of two or more items in the list.

[0016] The term “polystyrene” as used herein includes polymers and copolymers of substituted styrene monomers and / or unsubstituted styrene.

[0017] The term "elastomer" refers to a molecule having a structure which essentially includes the multiple repetition of units derived, actually or conceptually, from monomers of low relative molecular mass. The term "elastomer" refers to a type of polymer with elastic character.

[0018] All numerical ranges are inclusive of their endpoints and nonintegral values between the endpoints unless otherwise stated (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0019] Brief Description of the Drawings

[0020] FIG. 1 is a schematic perspective exploded view of a section of a core-sheath filament, according to an embodiment of the present disclosure.

[0021] FIG. 2 is a side cross-sectional view of an exemplary embodiment of a dispensing head for dispensing the filament of FIG. 1.

[0022] FIG. 3 is a side elevational view of a barrel component within the dispensing head of FIG. 2, revealing certain internal surfaces in dotted lines.

[0023] FIG. 4 is a side elevational view of a screw component within the dispensing head of FIG. 2.

[0024] FIG. 5 is a front cross-sectional view of the screw component of FIG. 4.

[0025] FIG. 6 is perspective view of a system that incorporates the filament of FIG. 1 and dispensing head of FIGS. 2-4, respectively. FIG. 7 is a side view of a system for coextruding the thermoplastic elastomer composition of the present disclosure and a pressure sensitive adhesive, which includes an embodiment of the coextrusion dispensing head and includes the adhesive dispensing system of FIG. 6.

[0026] FIG. 8A is a perspective view of one embodiment of a coextrusion dispensing head.

[0027] FIG. 8B is a front view of the coextrusion dispensing head.

[0028] FIG. 8C is a side view of the coextrusion dispensing head.

[0029] FIG. 8D is atop view of the coextrusion dispensing head.

[0030] FIG. 8E is a side cross-sectional view of the coextrusion dispensing head of FIG. 8C taken along line a-a in Figure 8B.

[0031] FIG. 8F is a perspective cross-sectional view of the coextrusion dispensing head along line a-a in FIG. 8B.

[0032] FIG. 9 is a perspective view of the D-shaped hollow coextruded thermoplastic and adhesive article that may be coextruded by the coextrusion dispensing head of Figures 8A-8F.

[0033] FIG. 10A is a perspective view of another embodiment of a coextrusion dispensing head.

[0034] FIG. 10B is a front view of a coextrusion dispensing head.

[0035] FIG. IOC is a side view of a coextrusion dispensing head.

[0036] FIG. 10D is atop view of a coextrusion dispensing head.

[0037] FIG. 10E is a side cross-sectional view of FIG. 10A taken along the line b-b in FIG. 10B.

[0038] FIG. 1 OF is a perspective cross-sectional view of FIG. 10A taken along the line b-b in FIG. 10B.

[0039] FIG. 11 is a perspective view of a composite article of the present disclosure.

[0040] FIG. 12 is a perspective view of a flat-stock ribbon coextrusion dispensing head.

[0041] FIG. 13 is a cross-sectional view of the flat-stock ribbon coextruded composite article made in the Examples.

[0042] FIG. 14 is a perspective view of examples of article shapes.

[0043] Detailed Description

[0044] The thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, includes a hydrogenated styrenic block copolymer. The thermoplastic elastomer composition can include a single block copolymer or a mixture of two or more block copolymers. In some embodiments, at least one block copolymer in the thermoplastic elastomer composition is a block copolymer comprising a hydrogenated midblock and two or more polystyrene end blocks. The midblock is generally a rubbery block (or low-Tg block), and the polystyrene end blocks are sometimes referred to as glassy blocks or high-Tg blocks. While the present disclosure is not to be bound by theory, it is believed that at the service temperature of the adhesive, the block copolymer microphase separates into ordered nanoscale domains that include rubbery block domains and glassy block domains. When microphase separated, these copolymers form elastic, dimensionally stable solids that display significant shear strength. Unlike chemically crosslinked rubbers, the block copolymers are capable of being reversibly melted and resolidified; thus, they are known as thermoplastic elastomers. Thus, the thermoplastic elastomer composition of the present disclosure is not chemically crosslinked and advantageously does not require energy intensive curing steps.

[0045] In some embodiments, the block copolymer is a linear block copolymer of general formula (S-R)m-S where each S is independently a polystyrene block, each R is independently a rubbery block, and m is a value of at least 1. Variable m can be from 1 to 10, 1 to 5, 1 to 3, or in some embodiments, less than, equal to, or greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In some embodiments, the linear block copolymer is a triblock copolymer wherein m is 1 and can also be represented by formula S-R-S.

[0046] In some embodiments, the block copolymer can be a star (also known as a radial or multi-arm) block copolymer of general formula (S-R)n-Y where each R and S are the same as defined above, n is an integer equal to at least 3, and Y is the residue of a multifunctional coupling agent used in the formation of the star block copolymer. The variable n represents the number of arms in the star block copolymer and can be from 3 to 10, from 3 to 8, from 3 to 6, or in some embodiments, less than, equal to, or greater than 3, 4, 5, 6, 7, 8, 9, or 10. For each of the arms, each S and each R may have different lengths.

[0047] In the block copolymer, including any of those described above, the polystyrene blocks can have the same or different molecular weights. In some embodiments, each polystyrene block independently has a weight average molecular weight of 4,000 to 50,000 grams per mole. Similarly, if there is more than one midblock (e.g., rubbery block), the midblocks can have the same or different molecular weights. In some embodiments, each midblock independently has a weight average molecular weight of 5,000 to 500,000 grams per mole.

[0048] Generally, each rubbery block has a glass transition temperature (Tg) that is less than ambient temperature. For example, the glass transition temperature can be less than 20°C, less than 0°C, less than - 10°C, or less than -20°C, less than -40°C, less than -60°C, or in some embodiments, less than, equal to, or greater than -60°C, -55°C, -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, or 20°C. The glass transition temperature can be determined using conventional methods known in the art, including Differential Scanning Calorimetry or Dynamic Mechanical Analysis.

[0049] In the hydrogenated styrenic block copolymer, each rubbery block is a hydrogenated derivative of a polymerized conjugated diene. The conjugated diene often contains 4 to 12 carbon atoms. Examples of useful conjugated dienes include butadiene, isoprene, 2 -ethylbutadiene, 1 -phenylbutadiene, 1,3 -pentadiene, 1,3 -hexadiene, 2, 3 -dimethyl- 1,3 -butadiene, 3 -ethyl- 1,3 -hexadiene and combinations thereof. Each rubbery block can be a homopolymer or copolymer. In some embodiments, the rubbery block comprises at least one of poly(ethylene / propylene), poly(ethylene / butylene), or polyisobutylene.

[0050] The glass transition temperature of each polystyrene block is generally at least 50°C, at least 60°C, at least 70°C, at least 80°C, at least 90°C, at least 100°C, or in some embodiments, less than, equal to, or greater than 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or 100°C.

[0051] Styrene monomers useful for making the polystyrene blocks may be unsubstituted or substituted. Useful styrene monomers at least 8 carbon atoms and in some embodiments contain at least 10 carbon atoms or at least 12 carbon atoms and up to 18 carbon atoms, up to 16 carbon atoms, or up to 14 carbon atoms. Examples of suitable styrene monomers include styrene, vinyltoluene (e.g., 2, 3, or 4-vinyltoluene), alpha-methyl styrene, 2,4-dimethyl styrene, ethyl styrene, 2,4-diethyl styrene, 3,5-diethyl styrene, alpha-2 - methyl styrene, 4-tert-butyl styrene, 4-isopropyl styrene, and combinations thereof. Each polystyrene block can be a homopolymer or a copolymer. In some embodiments, the polystyrene end blocks each comprise at least one of unsubstituted polystyrene, poly(vinyltoluene), poly(alpha-methylstyrene), poly(2,4- dimethylstyrene), poly (ethylstyrene), poly(2,4-diethylstyrene), poly (3, 5 -diethylstyrene), poly(4-tert- butylstyrene), or poly(4-isopropyl styrene). In some embodiments, the polystyrene blocks each comprise unsubstituted polystyrene. In some embodiments in which one or more polystyrene blocks comprises a copolymer, at least 50 weight percent (wt%) (in some embodiments, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, at least 98 wt% or at least 99 wt%) of the monomeric units are derived from styrene.

[0052] Polystyrene blocks including the polystyrene end blocks can represent from 5 to 50 percent by weight of the block copolymer. With such an amount of polystyrene in the block copolymer, a useful balance of cohesive strength and modulus may be achieved. The block copolymer can have a polystyrene block content of from 7 wt% to 40 wt%, 9 wt% to 40 wt%, 15 wt% to 35 wt%, or in some embodiments, less than, equal to, or greater than 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 27 wt%, 30 wt%, 32 wt%, 35 wt%, 37 wt%, or 40 wt%, based on the total weight of the block copolymer.

[0053] In addition to the polystyrene blocks and the rubbery blocks, star block copolymers include a residue of a multifunctional coupling agent Y. The coupling agent often has multiple carbon-carbon double bonds, carbon-carbon triple bonds, or other groups that can react with carbanions of a living polymer that may be used to form the star block copolymers. The multifunctional coupling agents can be aliphatic, aromatic, heterocyclic, or a combination thereof. Examples of suitable coupling agents include polyvinyl acetylene, diacetylene, di(meth)acrylates (e.g., ethylene dimethacrylate), divinyl benzene, divinyl pyridine, and divinyl thiophene. Other useful coupling agents include multi-functional silyl halide (e.g., tetrafunctional silyl halide), polyepoxides, polyisocyanates, polyketones, polyanhydrides, polyalkenyls, and dicarboxylic acid esters. The weight average molecular weight of the hydrogenated styrenic block copolymer is often not more than 1,200,000 grams per mole (g / mol). In some embodiments, the weight average molecular weight is not more than 1,000,000 g / mol, 900,000 g / mol, 800,000 g / mol, 600,000 g / mol, or 500,000 g / mol. In some embodiments, the weight average molecular weight of the hydrogenated styrenic block copolymer is at least 75,000 g / mol, at least 100,000 g / mol, at least 200,000 g / mol, at least 300,000 g / mol, or at least 400,000 g / mol. The weight average molecular weight of the hydrogenated styrenic block copolymer can be from 75,000 g / mol to 1,200,000 g / mol, from 100,000 to 1,000,000 g / mol, from 100,000 to 900,000 g / mol, or from 100,000 to 500,000 g / mol.

[0054] In some embodiments, the thermoplastic elastomer composition includes a hydrogenated styrenic diblock copolymer. The hydrogenated styrenic diblock copolymer generally has a single polystyrene block and a single rubbery block and can be represented here by the chemical structure S-R, wherein S and R are as defined above in any of their embodiments.

[0055] The polystyrene block content in the diblock copolymer can be from 10 wt% to 50 wt%, from 10 wt% to 40 wt%, from 15 wt% to 50 wt%, from 15 wt% to 40 wt%, from 20 wt% to 50 wt%, from 20 wt% to 40 wt%, or in some embodiments, less than, equal to, or greater than 10 wt%, 12 wt%, 15 wt%, 17 wt%, 20 wt%, 22 wt%, 25 wt%, 27 wt%, 30 wt%, 32 wt%, 35 wt%, 37 wt%, or 40 wt% relative to the overall weight of the diblock copolymer. The weight average molecular weight of the diblock copolymer can be from 75,000 g / mol to 250,000 g / mol, from 100,000 g / mol to 250,000 g / mol, from 125,000 g / mol to 250,000 g / mol, or from 125,000 g / mol to 200,000 g / mol.

[0056] In some embodiments, the hydrogenated styrenic block copolymer comprises at least one of a polystyrene-containing diblock copolymer, a polystyrene-containing triblock copolymer, or a polystyrene- containing star block copolymer, wherein the polystyrene-containing diblock copolymer, the polystyrene- containing triblock copolymer, and the polystyrene-containing star block copolymer each independently comprise a block of at least one of poly(ethylene / propylene), poly(ethylene / butylene), or polyisobutylene, in some embodiments, poly(ethylene / butylene). In some embodiments, the hydrogenated styrenic block copolymer comprises a styrene-ethylene / butylene-styrene block copolymer.

[0057] The hydrogenated styrenic block copolymer can be present in any suitable amount in the thermoplastic elastomer composition. In some embodiments, the hydrogenated styrenic block copolymer is present in amount of from 10 wt% to 40 wt%, from 20 wt% to 40 wt%, from 10 wt% to 30 wt%, or 20 wt% to 30 wt%, based on the total weight of the thermoplastic elastomer composition.

[0058] Suitable materials for use as the hydrogenated styrenic block copolymer alone or in combination are commercially available, for example, under the trade designation KRATON (e.g., KRATON G1633 and G1654) from Kraton Performance Polymers (Houston, TX, USA), under the trade designation SEPTON (e.g., SEPTON 8004), from Kuraray (Tokyo, Japan), under the trade designation TUFTEC (e.g., TUFTEC 1051) from Asahi Kasei (Tokyo, Japan) and under the trade designations VECTOR and TAIPOL from TSRC Corporation (New Orleans, LA, USA). The thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, includes a plasticizer having a number average molecular weight of at least 2,000 grams per mole. A combination of two or more plasticizers may also be useful. In some embodiments, the plasticizer comprises a hydrocarbon plasticizer. Any plasticizer (in some embodiments, hydrocarbon plasticizer) typically known by those skilled in the art may be used in the context of the present disclosure. In some embodiments, the plasticizer has a number average molecular weight Mnno greater than 10,000 g / mol, no greater than 8,000 g / mol, no greater than 6,000 g / mol, or no greater than 5,000 g / mol. The number average molecular weight of the plasticizer may be determined by any methods known to the skilled person, for example Gel Permeation Chromatography (GPC) or by light scattering techniques. Unless otherwise stated, the number average molecular weight of the plasticizer is measured using the method described in the Examples below. When the thermoplastic elastomer composition of the present disclosure is coextruded with a pressure sensitive adhesive (PSA), for example, molecular weights in these ranges will limit migration of the plasticizer into the PSA. Plasticizer migration into the PSA could lower the glass transition temperature (Tg), swell the elastics network, and can segregate to the bond line, each of which may negatively affect the adhesive performance of the PSA, particularly after heat aging.

[0059] In some embodiments, the plasticizer useful for practicing the present disclosure is a polymeric hydrocarbon plasticizer (e.g., polybutene or polyisobutylene), a liquid hydrocarbon plasticizer (e.g., REGALREZ 1018 hydrocarbon resin from Synthomer, London, England), or a hydrocarbon mineral oil. Examples of useful hydrocarbon mineral oils include naphthalenic oil, paraffinic oil, aromatic oil, and castor oil. Further examples of useful plasticizer include phthalate esters, adipate esters, and a liquid aliphatic resin available from Neville Chemical Company, Pittsburgh, PA, under the trade designation “NEVTAC LT”, useful with, for example, a hydrogenated styrenic block copolymer having a rubbery phase Tgof about -40 °C or higher.

[0060] In some embodiments, the plasticizer is present in the thermoplastic elastomer composition in an amount no greater than 45 wt%, no greater than 42.5 wt%, no greater than 40 wt%, or no greater than 35 wt%, based on the total weight of the thermoplastic elastomer composition. In some embodiments, the plasticizer is present in the thermoplastic elastomer composition in an amount from 10 to 45 wt%, from 15 to 42.5 wt%, from 20 to 40 wt%, from 15 to 40 wt%, or from 20 to 35 wt%, based on the total weight of the thermoplastic elastomer composition.

[0061] The thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, comprises a wax having a polar functional group. In some embodiments, the polar functional group comprises at least one of a hydroxyl group, a carboxylic acid group, a carboxylic acid ester group, an amino group, or a carboxamide group. In some embodiments, the wax has a melting point in a range from 35 °C to 65 °C. The wax is useful, for example, for decreasing the surface tack of the article. The polar functional group can be useful, for example, for allowing the wax to bloom to the surface. Waxes can be derived, for example, from fatty acids having at least 16, 18, or 20 carbon atoms. Examples of useful waxes include ethylene bis stearamide, emcamide, oleamide, and methyl 12-hydroxystearate. Examples of useful commercially available waxes having polar functional groups include those available from Akrochem Corporation, Akron, OH, under the trade designation “PRO AID” and “AKROWAX”. In some embodiments, the wax is present in an amount of at least 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt% and / or not more than 10 wt%, 9 wt%, 8 wt%, 7 wt%, or 6 wt%, based on the total weight of the thermoplastic elastomer composition. In some embodiments, the wax is present in an amount from 1 wt% to 10 wt%, 2 wt% to 8 wt%, 3 wt% to 7 wt%, or 4 wt% to 6 wt%, based on the total weight of the thermoplastic elastomer composition. A combination of two or more waxes may be useful.

[0062] In some embodiments, the thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, further comprises a polyolefin thermoplastic elastomer. The polyolefin thermoplastic elastomer can either be a mixture of an olefinic thermoplastic and an elastomer (e.g., a non-crosslinked elastomer or crosslinked elastomer) or an olefin copolymer (in some embodiments, block copolymer) with at least one hard segment and a soft segment. Compositions including a thermoplastic polyolefin matrix with an elastomer in the matrix are sometimes referred to as thermoplastic vulcanizates (TPVs). Examples include a polypropylene matrix, with an ethylene propylene diene monomer (EPDM) rubber in the matrix. Examples of the diene in the EPDM include dicyclopentiadiene, alkyldicyclopentadiene, 1,4-pentadiene, 1,4- hexadiene, 1,5-hexadiene, 1,4-heptadiene, 2-methyl-l,5- hexadiene, cyclooctadiene, 1,4- octadiene, 1,7-octadiene, 5-ethylidene-2-norbomene, 5-n-propylidene-2- norbomene, and 5- butylidene-2-norbomene. In some embodiments, the polyolefin thermoplastic elastomer is an olefin copolymer, in some embodiments, a block copolymer. Hard segments of such copolymers may include polyethylene and polypropylene segments. Soft segments of such copolymers can include C4-C18, C5-C12, or Cfi-CT poly (1 -alkene) segments. Examples of useful soft segments include those prepared from 1 -butene, 1 -hexene, 1 -octene, 1-dedene, 4-methyl-l -pentene, and 1 -octadecene. Polyolefin block copolymers are typically made by metallocene catalysis. Useful polyolefin block copolymers include those available from Dow Chemical (Midland, Michigan) under the trade designation “INFUSE” and “ENGAGE”. Useful thermoplastic vulcanizates include those available from Celenase Corporation (Irving, Texas) under the trade designation “SANTOPRENE”. A combination of two or more polyolefin thermoplastic elastomers may be useful in the thermoplastic elastomer composition.

[0063] In some embodiments, the thermoplastic elastomer composition comprises a polyolefin thermoplastic elastomer in an amount not more than 40 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, or not more than 10 wt% and / or at least 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%, based on the total weight of the thermoplastic elastomer composition. In some embodiments, the thermoplastic elastomer composition comprises from 0 to 40 wt%, from 1 to 40 wt%, from 2 to 30 wt%, from 5 to 30 wt%, from 0 to 15 wt%, or from 5 to 15 wt%, of a polyolefin thermoplastic elastomer, wherein the weight percentages are based on the total weight of the thermoplastic elastomer composition. In some embodiments, the thermoplastic elastomer composition further comprises a polyphenylene ether resin, which also may be referred to as a polyphenylene oxide resin. A combination of two or more polyphenylene ether resins may be useful in the thermoplastic elastomer composition. In some embodiments, the polyphenylene ether resin contains the repeating unit -[CeHs-O-]-. In some of these embodiments, one or more of the hydrogens may be replaced by halogen, alkyl, haloalkyl having at least two carbon atoms between the halogen atom and the phenyl nucleus, alkoxy, and haloalkoxy having at least two carbon atoms between the halogen atoms and phenyl nucleus. In some embodiments, the polyphenylene ether is poly(2,6-dimethyl-l,4-phenylene oxide). In some embodiments, the polyphenylene ether is poly(para-phenylene oxide). In some embodiments, the polyphenylene ether resin has a number average molecular weight (Mn) of from 300 g / mol to 25,000 g / mol, from 300 g / mol to 10,000 g / mol, from 1,000 to 8,000 g / mol, or in some embodiments, less than, equal to, or greater than 1,000 g / mol, 1,200 g / mol, 1,500 g / mol, 1,700 g / mol, 2,000 g / mol, 2,500 g / mol, 3,000 g / mol, 3,500 g / mol, 4,000 g / mol, 4,500 g / mol, 5,000 g / mol, 5,500 g / mol, 6,000 g / mol, 6,500 g / mol, 7,000 g / mol, 7,500 g / mol, or 8,000 g / mol, 10,000 g / mol, 25,000 g / mol, or 50,000 g / mol. Number average molecular weights are determined using gel permeation chromatography according to methods known to a person skilled in the art. In some embodiments, the polyphenylene ether resin is present in the thermoplastic elastomer composition in an amount from 0 wt% to 15 wt%, from 1 wt% to 10 wt%, from 2 wt% to 8 wt%, or from 3 wt% to 7 wt%, based on the total weight of the thermoplastic elastomer composition.

[0064] Polyphenylene ether resins can be made by any known method. Suitable methods of preparation are described in U.S. Pat. Nos. 3,306,874 (Hay); 3,306,875 (Hay); 3,257,357 (Stamatoff); and 3,257,358 (Stamatoff). Examples of suitable polyphenylene ether resins are commercially available under the trade designations “NORYL SA90” and “NORYL SA120” from Sabie, Houston, TX, and under the trade designation “STARAIR” from China Bluestar International Chemical Co., Ltd., Beijing, China.

[0065] A number of additives may also be useful in the thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure. Examples of such additives include antioxidants, such as hindered phenols, amines, sulfur and phosphorous hydroperoxide decomposers, and butylated hydroxytoluene (BHT)); fillers such as talc, zinc oxide, titanium dioxide, aluminum oxide, clays (e.g., kaolin), diatomaceous earth, wollastonite, glass, and silica (e.g., fumed silica), and calcium carbonate; pigments such as carbon black; activated charcoal; thermally conductive particles; fire retardants; and foaming agents or hollow spheres. Fillers can have various sizes and shapes (e.g., fibers and nanoparticles of various materials). Thermoplastic elastomer compositions can also include at least one of dyes, ultraviolet light absorbers, hindered amine light stabilizers, and heat stabilizers (e.g., sodium benzoate), if desired.

[0066] Magnetic fillers may be of particular importance for applications related to refrigerator and freezer gaskets. Various ferrite powders can be added to the thermoplastic elastomer composition, such as magnesium ferrite, barium ferrite, and strontium ferrite. These fillers may be included to impart a magnetic strength to the surface of the gasket, and thereby hold a seal shut. The particles may have an anisotropic shape to orient the magnetic field during dispensing. An external magnetic field may be required after dispensing to align particles, especially isotropic particles.

[0067] Foams are porous materials that are composed of gas filled networks or chambers segmented by a solid matrix. In some embodiments, the thermoplastic elastomer composition of the present disclosure and / or article of the present disclosure is a foam. In some embodiments, the thermoplastic elastomer composition of the present disclosure and / or article of the present disclosure is not a foam and / or does not include a foaming agent or hollow spheres. In some embodiments, the thermoplastic elastomer composition includes hollow ceramic microspheres (e.g., glass bubbles), expandable polymeric microspheres (e.g., pentane filled expandable microspheres), gaseous cavities, or mixtures thereof. The term “ceramic” refers to glasses, crystalline ceramics, glass-ceramics, and combinations thereof. Gaseous cavities can be introduced into the thermoplastic elastomer composition using physical blowing agents or chemical blowing agents, for example. Examples of suitable physical blowing agents include carbon dioxide, nitrogen, SF6, nitrous oxide, noble gases (e.g., argon, helium, or xenon), air (e.g., nitrogen and oxygen blend), and combinations thereof. Examples of suitable chemical blowing agents include diazo compounds, sulfonyl hydrazides, tetrazoles, nitroso compounds, acyl sulfonyl hydrazides, hydrazones, thiatriazoles, azides, sulfonyl azides, oxalates, thiatrizene dioxides, or any combination thereof. More specific examples of suitable chemical blowing agents include a blend of sodium bicarbonate and citric acid, dinitrosopentamethylenetetramine, p-toluenesulfonyl hydrazide, 4-4’-oxybis(benzenesulfonyl hydrazide, azodicarbonamide (1,1’- azobisformamide), p-toluenesulfonyl semicarbazide, 5-phenyltetrazole, 5-phenyltetrazole analogues, diisopropylhydrazodicarboxylate, 5-phenyl-3,6-dihydro-l,3,4-oxadiazin-2-one, and sodium borohydride.

[0068] Examples of suitable hollow ceramic microspheres include glass bubbles marketed by 3M Company, Saint Paul, Minnesota, as “3M GLASS BUBBLES” in grades KI, K15, K20, K25, K37, K46, S15, S22, S32, S35, S38, S38HS, S38XHS, S42HS, S42XHS, S60, S60HS, iM30K, iM16K, XLD3000, XLD6000, and G-65, and any of the HGS series of “3M GLASS BUBBLES”; glass bubbles marketed by Potters Industries, Carlstadt, N.J., under the trade designations “Q-CEL HOLLOW SPHERES” (e.g., grades 30, 6014, 6019, 6028, 6036, 6042, 6048, 5019, 5023, and 5028); and hollow glass particles marketed by Silbrico Corp., Hodgkins, IL underthe trade designation “SIL-CELL” (e.g., grades SIL 35 / 34, SIL-32, SIL- 42, and SIL-43). Examples of suitable expandable microspheres include those available from Matsumoto Yushi Seiyaku Co., Ltd. Osaka, Japan under the trade designation “MATSUMOTO MICROSPHERE F- 2800D”; those available from Chase Corporation, Westwood, MA under the trade designation “DU ALITE U010-185D”; those available from Pierce Stevens (Buffalo, N.Y.) under the designations “F30D”, “F80SD”, and “F100D”; and from Akzo-Nobel (Sundsvall, Sweden) under the designations “EXPANCEL 551”, “EXPANCEL 461”, “EXPANCEL 091”, and “EXPANCEL 930”. Each of these microspheres features a polymeric shell. In some embodiments, the thermoplastic elastomer composition includes thermally conductive particles. The thermally conductive particles can be a single type (i.e., composition) of thermally conductive particles or can include a plurality (i.e., more than one) of different types of thermally conductive particles. Further, the thermally conductive particles can contain a single distribution of thermally conductive particle sizes (i.e., the size distribution is a mono-modal size distribution). Alternatively, the thermally conductive particles can have a multi-modal size distribution. For example, the thermally conductive particles can have a bi-modal size distribution or a tri-modal size distribution. The multi-modal size distributions can result from a mixture of different types of thermally conductive particles that have different sizes, from a mixture of the same type of thermally conductive particles that have different sizes, or from both.

[0069] Examples of useful thermally conductive particles include those made from or that contain diamond, polycrystalline diamond, silicon carbide, silicon nitride, aluminum oxide, boron nitride (hexagonal or cubic), boron carbide, silica (silicon dioxide), graphite, amorphous carbon, aluminum nitride, aluminum hydroxide (e.g., aluminum trihydroxide (ATH)), aluminum, aluminum silicate, zinc oxide, zirconium oxide, tin oxide, copper oxide, chromium oxide, titanium oxide, magnesium hydroxide, magnesium oxide, calcium hydroxide, calcium carbonate, barium titanate, carbon nanotubes, carbon black, carbon fibers, clay, nickel, tungsten, copper, silver, gold, nickel, platinum, and combinations of any of these.

[0070] In some embodiments, the thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, further comprises a flame retardant. Examples of flameretardant particles include phosphorous-containing compounds, nitrogen-containing polymers, boron- containing compounds, antimony oxide, a humite / hydromagnesite blend, wollastonite, glass frit (e.g., as disclosed in U.S. Pat. No. 4,879,066 (Crompton)), and mixtures thereof. The term “phosphorous-containing flame retardant” as used herein means that the flame retardant includes at least one phosphorous atom. The term “nitrogen-containing polymer” as used herein means that the polymer includes at least one nitrogen atom. Further fire resistant compounds that may be useful in the thermoplastic elastomer composition include endothermic particles (aluminum hydroxide (i.e., aluminum trihydrate, A1(OH)3) and magnesium hydroxide (i.e., Mg(OH)2)) and intumescent compounds (e.g., intumescent graphite).

[0071] When present, any of the additives described above can be included in the thermoplastic elastomer composition in any suitable amount, for example, in an amount up to 30 wt%, up to 25 wt%, or up to 20 wt%, based on weight of the thermoplastic elastomer composition. In some embodiments, a filler, thermally conductive particles, or hollow spheres may be present in an amount of at least 1 wt% or at least 3 wt% or in an amount ranging from 2 wt% to 30 wt%, from 2 wt% to 20 wt%, or from 2 wt% to 15 wt%, based on the total weight of the thermoplastic elastomer composition. Antioxidants and pigments may be present in the thermoplastic elastomer composition in an amount of at least 0.1 wt% or at least 0.5 wt% or in an amount ranging from 0.1 wt% to 5 wt%, from 0.5 wt% to 4 wt%, or from 0.5 wt% to 3 wt%, based on the total weight of the thermoplastic elastomer composition. In some embodiments, the thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, has a Shore A hardness of not more than 60 as measured using a durometer according to the method described in the Examples below. In some embodiments, the thermoplastic elastomer composition has a Shore A hardness of not more than 55, 50, 45, 40, or 35 and / or at least 20, 25, or 30. Shore A hardnesses in these ranges typically allow the thermoplastic elastomer composition to perform well as a seal. Such hardnesses are achievable in the thermoplastic elastomer composition even in the absence of gaseous cavities, for example, when the composition is not a foam.

[0072] In some embodiments, the thermoplastic elastomer composition of the present disclosure, which is included in the article of the present disclosure, has a complex melt viscosity in a range from 4,000 pascal- seconds (Pa-s) to 30,000 Pa-s, in some embodiments, 4,000 Pa-s to 25,000 Pa-s or to 20,000 Pa-s, measured on a rheometer at a temperature of 175 °C at a shear rate of one radian per second as described in the Examples below. Melt viscosities in these ranges allow the thermoplastic elastomer composition to hold its shape once it exits an extrusion die but also to conform to and re-shape around comers and curves. Furthermore, melt viscosities in these ranges allow for good throughput and can be useful with a variety of dies.

[0073] In some embodiments, thermoplastic elastomer composition of the present disclosure and / or the article of the present disclosure is essentially free of volatile organic solvent. Volatile organic solvents are typically those have a boiling point of up to 150 °C at atmospheric pressure. Common organic solvents include aliphatic and alicyclic hydrocarbons (e.g., hexane, heptane, and cyclohexane), hydrocarbon solvents (e.g., benzene, toluene, xylenes, and d-limonene); acyclic and cyclic ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone, pentanone, hexanone, cyclopentanone, and cyclohexanone); ethers (e.g., diethyl ether, glyme, diglyme, diisopropyl ether, and tetrahydrofuran), esters (e.g., ethyl acetate and butyl acetate), sulfoxides (e.g., dimethyl sulfoxide), amides (e.g., N,N-dimethylformamide, N,N dimethylacetamide, and N-methyl-2-pyrrolidone), halogenated solvents (e.g., methylchloroform, 1,1,2- trichloro-l,2,2-trifluoroethane, trichloroethylene, and trifluorotoluene), and alcoholic solvents (e.g., methanol, ethanol, or propanol such as isopropanol). The thermoplastic elastomer composition and / or article can be essentially free of any of these solvents. “Essentially free of volatile organic solvent” can mean that volatile organic solvent may be present (e.g., from a previous synthetic step or in a commercially available component) in an amount of up to 2.5 (in some embodiments, up to 2, 1, 0.5, 0.1, 0.05, 0.01, or 0.00) wt%, based on the total weight of the adhesive.

[0074] In some embodiments, the article of the present disclosure further comprises a PSA. In some embodiments, the thermoplastic elastomer composition has a surface in direct contact with a PSA. The article of the present disclosure may have more than one layer of the thermoplastic elastomer and / or more than one layer of the PSA. However, the article can one just one layer of the thermoplastic elastomer composition in direct contact with one layer of a PSA. In some embodiments, the thermoplastic elastomer composition is coextruded with the PSA. PSAs are generally known to possess the following desirable properties: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and, typically, (4) sufficient cohesive strength to be cleanly removable from the adherend. Materials that have been found to function well as PSAs are polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power. The Dahlquist criterion is commonly used to describe such behavior of PSAs. The Dahlquist criterion for a PSA suggests that the shear Storage Modulus G’ should not exceed 0.3 megapascal (Mpa) at 25°C applying an oscillatory strain at lhertz (Hz) within the linear viscoelastic region of the PSA.

[0075] The PSA can be made using a number of different chemistries including styrenic block copolymers, (meth)acrylics, (meth)acrylic block copolymers, natural rubber, styrene butadiene rubber, butyl rubber, polyisobutylene, ethylene vinyl acetate, amorphous poly(alpha-olefins), silicones, polyvinyl ether, polyisoprene, polybutadiene, butadiene-acrylonitrile rubber, polychloroprene, polyurethane, polyvinylpyrrolidone, or combinations thereof.

[0076] In some embodiments, the PSA includes a styrenic block copolymer. The PSA composition can include a single block copolymer or a mixture of two or more block copolymers. The styrene block copolymer can have any of the features described above in connection with the thermoplastic elastomer composition in any of its embodiments. In addition, each rubbery block in the block copolymer can be the polymerized product of a conjugated diene, a hydrogenated derivative of a polymerized conjugated diene, or a combination thereof. The conjugated diene often contains 4 to 12 carbon atoms. Examples of useful conjugated dienes include butadiene, isoprene, 2-ethylbutadiene, 1 -phenylbutadiene, 1,3 -pentadiene, 1,3- hexadiene, 2, 3 -dimethyl- 1,3 -butadiene, 3 -ethyl- 1,3 -hexadiene and combinations thereof. Each rubbery block can be a homopolymer or copolymer. In some embodiments, the rubbery block comprises at least one of poly (butadiene), poly (isoprene), poly(2 -ethylbutadiene), poly(l -phenylbutadiene), poly (1,3- pentadiene), poly(l,3-hexadiene), poly(2,3-dimethyl-l,3-butadiene), poly (3 -ethyl- 1,3 -hexadiene), poly(ethylene / propylene), poly(ethylene / butylene), orpoly(isoprene / butadiene). In some embodiments, the rubbery block comprises at least one of polybutadiene, polyisoprene, poly(isoprene / butadiene), poly(ethylene / butylene), poly(ethylene / propylene), or poly isobutylene. In some embodiments, the rubbery block comprises poly(ethylene / butylene).

[0077] In some embodiments of the PSA, the block copolymer comprises at least one of a polystyrene- containing diblock copolymer, a polystyrene-containing triblock copolymer, or a polystyrene-containing star block copolymer, wherein the polystyrene-containing diblock copolymer, the polystyrene-containing triblock copolymer, and the polystyrene-containing star block copolymer each independently comprise a block of at least one of polyisoprene, polybutadiene, poly(ethylene / propylene), poly(ethylene / butylene), or polyisobutylene. In some embodiments, the block copolymer comprises at least one of a polystyrene- containing diblock copolymer, a polystyrene-containing triblock copolymer, or a polystyrene-containing star block copolymer, wherein the polystyrene-containing diblock copolymer, the polystyrene-containing triblock copolymer, and the polystyrene-containing star block copolymer each independently comprise a block of at least one of polyisoprene or polybutadiene. In some embodiments, the block copolymer comprises at least one of a styrene-isoprene-styrene triblock copolymer or a styrene-butadiene-styrene triblock copolymer.

[0078] Suitable materials for use as the block copolymer alone or in combination are commercially available, for example, under the trade designation KRATON (e.g., KRATON D1161P, D1118, D1119, and A1535) from Kraton Performance Polymers (Houston, TX, USA), under the trade designation SOLPRENE (e.g., SOLPRENE S-1205) from Dynasol (Houston, TX, USA), under the trade designation QUINTAC from Zeon Chemicals (Louisville, KY, USA), and under the trade designations VECTOR and TAIPOL from TSRC Corporation (New Orleans, LA, USA).

[0079] The PSA in some embodiments of the article of the present disclosure can include a tackifying resin. When the PSA is based on a styrenic block copolymer, the PSA typically includes a tackifying resin. A tackifier is not the same as a plasticizer, which is understood by those skilled in the art. In general, the difference between a tackifier and a plasticizer is that the addition of a tackifier increases the Tgof the adhesive’s rubber phase while the addition of the plasticizer decreases the Tgof the adhesive’s rubber phase.

[0080] In some embodiments, the tackifying resin comprises at least one of a polyterpene (e.g., those based on a-pinene, P-pinene, or limonene), a terpene phenolic tackifier, an aromatic modified terpene resin, a rosin acid, a rosin ester, an aliphatic hydrocarbon resin (e.g., those based on cis- or trans-piperylene, isoprene, 2-methyl-but-2-ene, cyclopentadiene, dicyclopentadiene, or combinations thereof), an aromatic resin (e.g. those based on styrene, a-methyl styrene, methyl indene, indene, coumarone, or combinations thereof), or a mixed aliphatic-aromatic hydrocarbon resin. The aromatic hydrocarbon resins may be C9- type petroleum resins obtained by copolymerizing a C9 fraction produced by thermal decomposition of petroleum naphtha, and aliphatic hydrocarbon resins may be C5-type petroleum resins obtained by copolymerizing a C5 fraction produced by thermal decomposition of petroleum naphtha. Mixed aliphatic / aromatic resins may be C5 / C9-type petroleum resins obtained by polymerizing a combination of a C5 fraction and C9 fraction produced by thermal decomposition of petroleum naphtha. Any of these tackifying resins may be hydrogenated (e.g., partially or completely). The term rosin, as employed herein, includes natural rosin, refined or unrefined (refined rosin will usually contain, by weight, about 90% of rosin acids and about 10% of inert material), such as natural wood rosin, natural gum rosin, and tall oil rosin; modified rosin, refined or unrefined, such as disproportionated rosin, hydrogenated rosin, and polymerized rosin; and the pure or substantially pure acids, of which rosin is comprised, alone or in admixture. In some embodiments, the rosin includes the rosin acid C19H29COOH, in some embodiments, at least one of abietic acid, neoabietic acid, palustric acid, levopimaric acid, pimaric acid, or an isopimaric acid. In some embodiments, the rosin comprises dehydro- or hydrogenated rosin acids, for example, dehydroabietic acid, dihydroabietic acid, and tetrahydroabietic acid. The tackifying resin can also include a metal rosinate (sometimes referred to in the art as a metal resinate). The metal rosinate can be metal salt (e.g., zinc, calcium, or magnesium) of any of the rosins described above.

[0081] In some embodiments, the tackying resin is selected to be compatible with the rubbery block of the thermoplastic elastomeric block copolymer. The compatibility of the tackifying resin with the rubbery block can be determined by measuring the effect of the tackifying resin on the glass transition temperature of the rubbery block. If a tackifying resin is compatible, it will generally increase the glass transition temperature of the rubbery block as measured by Differential Scanning calorimetry or Dynamic Mechanical Analysis. In some embodiments, the tackifying resin is a hydrocarbon tackifier, an aromatic modified aliphatic tackifying resin, or a terpene tackifier.

[0082] Some suitable tackifying resins are commercially available under the trade designations “ARKON” from Arakawa Chemical Industries Co., Ltd. (Osaka, Japan); “ESCOREZ” from ExxonMobil Chemical Company (Spring, Texas); “REGALITE”, “REGALREZ”, and “PICCOTAC” from Eastman Chemical (Kingsport, TN); “WINGTACK” from Cray Valley (Exton, PA); and others listed in the Examples, below.

[0083] In some embodiments, the PSA includes a tackifying resin with high compatibility with the styrene end blocks of the block copolymer. Such aromatic resins include coumarone-indene resins, poly alpha methyl styrene, polystyrene resins, vinyl toluene-a-methyl styrene copolymers, polyindene resins, and polyphenylene ether resins such as unsubstituted polyphenylene ether resins and substituted polyphenylene ether resins (e.g., poly(2,6-dimethyl-l,4-phenylene)ether).

[0084] In some embodiments, the PSA includes at least about 30 wt% and up to about 60 wt% of the tackifying resin, based on the total weight of the PSA. In some embodiments, the tackifying resin is present in a range from 32 wt% to 50 wt%, 34 wt% to 48 wt%, 30 wt% to 40 wt%, 35 wt% to 50 wt%, or 35 wt% to 55 wt%, based on the total weight of the PSA.

[0085] A number of additives may also be useful in the PSA of the article of the present disclosure. Examples include antioxidants, inorganic fillers, plasticizers, pigments, dyes, ultraviolet light absorbers, hindered amine light stabilizers, and heat stabilizers (e.g., sodium benzoate), as described above in any of their embodiments, if desired. When present, typically the antioxidant is present in the PSA in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the block copolymer; typically the ultraviolet light absorber is present in the PSA in an amount of 0.1 to 3 parts by weight per 100 parts by weight of the block copolymer; the inorganic filler can present in the PSA in an amount of up to 50 parts by weight per 100 parts by weight of the block copolymer; and the plasticizer can be present in the composition in an amount from one to 30, 20, 15, or 10 percent by weight of the total PSA weight.

[0086] In some embodiments, the article of the present disclosure comprising the thermoplastic elastomer composition described above in any of its embodiments is a filament. PSAs as described above can also be provided as filaments. In some embodiments, the filament has a relatively narrow diameter, in some embodiments, an average diameter of 1 millimeter (mm) or greater, 2 mm or greater, 3 mm or greater, 4 mm or greater, or 5 mm or greater, and 20 mm or less, 18 mm or less, 15 mm or less, 12 mm or less, or any combination of these diameters. In some embodiments, the filament may comprise an average diameter of 1 to 20 mm, 5 to 15 mm, 8 to 12 mm, or 10 mm.

[0087] In some embodiments, the filament has an aspect ratio of length to diameter of 50 : 1 or greater, 100 : 1 or greater, or 250 : 1 or greater. Filaments having a length of at least about 20 feet (6 meters) can be useful in a process according to the present disclosure. Depending on the application of use of the filament, a relatively consistent diameter over its length can be desirable. In some embodiments, the filament comprises a maximum variation of diameter of 20% over a length of 50 centimeters (cm), or a maximum variation in diameter of 15% over a length of 50 cm. In some embodiments, the filament has a cylindrical shape, i.e., the filament is in the shape or form of a cylinder.

[0088] In some embodiments of the article of the present disclosure, the article comprises a core-sheath filament. The core comprises the thermoplastic elastomer composition described above in any of its embodiments, and the sheath includes a composition different from the core, in some embodiments, a polyolefin. In some embodiments, the sheath exhibits a melt flow index (MFI) of less than 15 grams per 10 minutes (g / 10 min). Typically, the sheath is non-tacky. Referring to FIG. 1, a schematic perspective exploded view of a section of a core-sheath filament 100 is provided, comprising a core 102 and a sheath 104 encasing the outer surface 106 of the core 102. In some embodiments, the article of the present disclosure is a filament wrapped around a spool, for example, for storage.

[0089] PSAs useful for practicing the present disclosure can also be provided as a core-sheath filament in which the core comprises the PSA described above in any of its embodiments, and the sheath comprises a typically non-tacky composition. The core-sheath filament comprising the PSA core can also be wrapped around a spool.

[0090] Filaments according to the present disclosure and / or useful for practicing some embodiments of the process of the present disclosure, can generally be made using techniques known in the art for making filaments. Filaments can be made by extrusion through a die, such as a coaxial die to form the core-sheath structure. Optional additives described above can be added to a thermoplastic elastomer composition in an extruder (e.g., a twin-screw extruder) equipped with a side staffer that allows for the inclusion of additives. Similarly, optional additives can be added to a sheath composition in the extruder. The core can be extruded through the center layer of a coaxial die having an appropriate diameter while the sheath can be extruded through the outer layer of the coaxial die. Often, the shape of the center layer is circular or oval, and the shape of the outer layer is concentric around the center layer. One suitable die is a filament spinning die as described in U.S. Patent No. 7,773,834 (Ouderkirk et al.). Optionally, the strand can be cooled upon extrusion using a water bath. The filament can be lengthened using a belt puller. The speed of the belt puller can be adjusted to achieve a desired filament diameter.

[0091] The core typically makes up 50 wt% or more, 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, 75 wt% or more, 80 wt% or more, 85 wt% or more, 90 wt% or more, 97 wt% or less, 94 wt% or less, 90 wt% or less, 85 wt% or less, 80 wt% or less, 70 wt% or less, or 65 wt% or less of the total weight of the core-sheath filament, or any combination of these weight percentages. In some embodiments, the core makes up 50 wt% to 97 wt%, 60 to 90 wt%, 70 to 90 wt%, 50 to 70 wt%, or 80 to 97 wt% of the core-sheath filament.

[0092] Without wishing to be bound by theory, it is believed that the overall final material properties of a dispensed core-sheath filament with the thermoplastic elastomer composition as the core will demonstrate viscoelasticity; i.e., demonstrating stress relaxation over time.

[0093] The sheath can provide structural integrity to the core-sheath filament and limit the core from coming into contact with itself or other surfaces. The presence of the sheath typically does not adversely affect final material performance, either because it is sufficiently thin to contribute a relatively small amount of material to the core material or by being formed of material that is a component of the core thermoplastic elastomer composition. The sheath can advantageously be thick enough to support the filament form factor and to allow for delivery of the core-sheath filament to a deposition location. In some embodiments, a desirable property of the sheath material is its ability to hold energy under a static load, showing minimal stress dissipation over time. A low MFI and a high tensile strength help prevent the core-sheath filament from breaking when subjected to high inertial forces, such as when the core-sheath is starting to be unspooled.

[0094] In some embodiments of the filament of the thermoplastic elastomer composition or the PSA, the sheath includes a polyolefin (e.g., a polyethylene homopolymer, a polyethylene-based copolymer, a polypropylene homopolymer, or a polypropylene-based copolymer). In some embodiments, the sheath material exhibits an MFI of less than 15 g / 10 min. Such a low melt flow index is indicative of a sheath material that has sufficient strength to allow the core-sheath filament to withstand the physical manipulation required for handling. For instance, a core-sheath filament might need to be unwound from a spool, be introduced into an apparatus, and be advanced into a nozzle for melting, all without breakage of the coresheath filament. In certain embodiments, the sheath material exhibits a MFI of 14 g / 10 min or less, 13 g / 10 min or less, 11 g / 10 min or less, 10 g / 10 min or less, 8 g / 10 min or less, 7 g / 10 min or less, 6 g / 10 min or less, 5 g / 10 min or less, 4 g / 10 min or less, 3 g / 10 min or less, 2 g / 10 min or less, or 1 g / 10 min or less. In some embodiments, the sheath material is non-tacky. A material is non-tacky if it passes a “Self-Adhesion Test”, in which the force required to peel the material apart from itself is at or less than a predetermining maximum threshold amount, without fracturing the material. The Self-Adhesion Test is described in U.S. Pat. Appl. Pub. No. 2022-0259465 (Kugel et al.). Employing a non-tacky sheath facilitates handling of the filament.

[0095] In some embodiments, the sheath material exhibits a combination of at least two of low MFI (e.g., less than 15 g / 10 min), moderate elongation at break (e.g., 100% or more as determined by ASTM D638- 14 using test specimen Type IV), low tensile stress at break (e.g., 10 Mpa or more as determined by ASTM D638-14 using test specimen Type IV), or moderate Shore D hardness (e.g., 30-70 as determined by ASTM D2240-15). In some embodiments, the sheath comprises at least one of a styrenic block copolymer, a polyolefin, ethylene vinyl acetate, a polyurethane, or a styrene butadiene copolymer. In some embodiments, the sheath comprises any one of these materials as the main component (e.g., the sheath may also include one or more additives). Examples of suitable styrenic block copolymers and styrene butadiene copolymers are as described in detail above with respect to the core. Suitable polyolefins are not particularly limited. Examples of suitable polyolefin resins include polypropylene (e.g., a polypropylene homopolymer, a polypropylene copolymer, and / or blends comprising polypropylene), polyethylene (e.g., a polyethylene homopolymer, a polyethylene copolymer, high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE)), and combinations thereof. For instance, suitable commercially available LDPE resins include “PETROTHENE NA217000” available from LyondellBasell (Rotterdam, Netherlands) and “MARLEX 1122” available from Chevron Phillips (The Woodlands, TX).

[0096] The term “polyurethane” as used herein applies to polymers made from the reaction product of a compound containing at least two isocyanate groups (-N=C=O), referred to herein as “isocyanates”, and a compound containing at least two active hydrogen-containing groups. Examples of active hydrogencontaining groups include primary alcohols, secondary alcohols, phenols, and water. Other active hydrogen-containing groups include primary and secondary amines which react with the isocyanate to form a urea linkage, thereby making a polyurea. A wide variety of isocyanate-terminated materials and appropriate co-reactants are well known, and many are commercially available (see, for example, Gunter Oertel, “Polyurethane Handbook”, Hanser Publishers, Munich (1985)). Suitable commercially available thermoplastic polyurethanes for the sheath of the core-sheath filament include those available from the Lubrizol Corporation (Wickliffe, OH) under the trade designations “ESTANE 58213” and “ESTANE ALR 87A”.

[0097] Suitable ethylene vinyl acetate (EVA) polymers (i.e., copolymers of ethylene with vinyl acetate) for use in the sheath include resins from DuPont (Wilmington, DE) available under the trade designation “ELVAX”. Typical grades range in vinyl acetate content from 9 to 40 weight percent and a melt flow index of as low as 0.03 grams per minute (per ASTM D1238). Suitable EVAs also include high vinyl acetate ethylene copolymers from LyondellBasell (Houston, TX) available under the trade designation “ULTRATHENE”. Typical grades range in vinyl acetate content from 12 to 18 weight percent. Suitable EVAs also include EVA copolymers from Celanese Corporation (Dallas, TX) available under the trade designation “ATEVA”. Typical grades range in vinyl acetate content from 2 to 26 weight percent.

[0098] In some embodiments, the sheath comprises one or more polymers from the thermoplastic elastomer composition described above. For example, the sheath can comprise a styrenic block copolymer, a polyolefin thermoplastic elastomer, or a combination thereof. The sheath can also contain additives to the thermoplastic elastomer composition described above in any of their embodiments. If the polymer for the sheath is not a polymer in the thermoplastic elastomer composition, it may be included in a low weight percentage of the total core-sheath filament, to minimize interference with the properties of the thermoplastic elastomer composition. Similarly, when a PSA is provided as a core-sheath filament for the process of the present disclosure, the sheath can comprise one or more polymers from the PSA composition described above. If the polymer for the sheath is not a polymer in the PSA composition, it may be included in a low weight percentage of the total core-sheath filament, to minimize interference with the adhesive properties of the PSA.

[0099] In some embodiments, the sheath makes up 3 wt% or more, 4 wt% or more, 5 wt% or more, 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, 10 wt% or more, 12 wt% or more, 13 wt% 20 wt% or less, 18 wt% or less, 16 wt% or less, 14 wt% or less, 12 wt% or less, 10 wt% or less, or 8 wt% or less of the total weight of the core-sheath filament, or any combination of these amounts. In some embodiments, the sheath can be present in an amount of 3 wt% to 20 wt%, 4 wt% to 20 wt.%, 4 wt% to 14 wt.%, 4 wt% to 10 wt.%, or 3 wt% to 7 wt.% of the core-sheath filament.

[0100] Further examples of PSAs useful in the article of the present disclosure and adhesives provided as core-sheath filaments are described in U.S. Pat. Appl. Pub. Nos. 2023 / 0089703 (Kalish et al.), 2022 / 0290335 (Behling et al.), 2022 / 0290334 (Sahni et al.), 2022 / 0259465 (Kugel et al.), and 2022 / 0134652 (Napierala et al.) and Int. Pat. Appl. Pub. No. WO 2021 / 130620 (Sahni et al.).

[0101] Advantages typically provided by making or using at least one of the thermoplastic elastomer composition or the PSA as a core-sheath filament once it is melted and mixed include one or more of low volatile organic compound (VOC) characteristics, avoiding die cutting, design flexibility, achieving intricate non-planar bonding patterns, printing on thin and / or delicate substrates, and printing on an irregular and / or complex topography.

[0102] In some embodiments, the article of the present disclosure comprising the thermoplastic elastomer composition described above in any of its embodiments is a gasket. The gasket is useful in automotive, construction, and industrial applications, for example, in gap filling and sealing of irregularly shaped openings often found in appliances and / or automotive parts. The gasket may be useful in the automotive industry, for example, as a sunroof seal, drip rail seal, water box seal, trunk seal, pinch protection seal, clamping protection seal, rear window seal, or head light seal. The gasket may also be useful, for example, as a gasket for a refrigerator door, toaster oven, washing machine, dryer, dishwasher, or freezer.

[0103] The present disclosure provides a process for making the article of the present disclosure. The process includes extruding the thermoplastic elastomer composition. In some embodiments, the process includes coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive, in some embodiments, directly onto a substrate.

[0104] Coextrusion means, for the purposes of the present disclosure, the simultaneous melt processing of multiple molten streams and combination of such molten streams into a single unified structure, for example, from a single extrusion die. The thermoplastic elastomer composition and PSA can be coextruded using any suitable type of coextrusion die. In some embodiments, a multilayer melt stream can be formed by a multilayer feedblock, such as that shown in U.S. Pat. No. 4,839,131 (Cloeren) or other specialized feedblock or a specialized die such as those made by Cloeren Co., Orange, TX. The feed block and die used are typically heated to facilitate polymer flow and layer adhesion, with the temperature of the die depending on the polymers used. Techniques of coextrusion are found in many polymer processing references, including Progelhof, R. C., and Throne, J. L., “Polymer Engineering Principles”, Hanser / Gardner Publications, Inc., Cincinnati, Ohio, 1993.

[0105] Compatible chemistries in coextmded layers can lead to interfacial diffusion. Such interlayer diffusion is not observed in laminated layers. In embodiments in which thermoplastic elastomer composition and PSA are coextruded, the polymeric compositions for each can be chosen to have similar properties such as chemical structure and melt viscosity. Compatibility of the thermoplastic elastomer composition and PSA can improve interlayer adhesion upon coextmsion.

[0106] Advantages obtained by coextruding the thermoplastic elastomer composition and the PSA include excellent sealing and bond strength performance as well as process simplification and automation. Conventional gaskets include a high durometer rubber or mechanical attachment and a lower durometer material for the seal. This complexity is avoided by the co-extruded thermoplastic elastomer composition and PSA disclosed herein, which have a strong interlayer bond as shown in the Examples below. Thus, the high durometer portion of the seal can be omitted without problem, thereby simplifying the process and the seal construction.

[0107] In some embodiments of the process of the present disclosure, the process includes forming a coresheath filament as described above. The process further includes melting the core-sheath filament and blending the sheath with the core to form a molten composition. The molten composition can be formed before reaching a nozzle, for example, can be formed by mixing in the nozzle, or can be formed during dispensing through the nozzle, or a combination thereof. The sheath composition can be uniformly blended throughout the core composition.

[0108] One suitable process for utilizing a core-sheath filament as described above uses a continuous nonpumped filament fed dispensing unit. In such a dispensing unit, the dispensing throughput is regulated by a linear feed rate of the core-sheath filament allowed into the dispense head. In some embodiments, an unheated filament is mechanically pushed into a heated zone, which provides sufficient force to push the filament out of a nozzle. A variation of this approach is to incorporate a conveying screw in the heated zone, which acts to pull in a filament from a spool and also to create pressure to dispense the material through a nozzle. The conveying screw can allow for increased throughput, as well as the opportunity for a desired level of component mixing and / or blending.

[0109] There can be several benefits to filament fed dispensing processes compared to traditional hot-melt deposition methods. First, filament fed dispensing processes typically permit quicker changeover to different materials. Also, these processes do not use a semi-batch mode with melting tanks and this minimize the opportunity for thermal degradation of a material and associated defects in the deposited material. Filament fed dispensing methods can use materials with higher melt viscosity, which affords a thermoplastic bead that can be deposited with greater geometric precision and stability without requiring a separate curing or crosslinking step. In addition, higher molecular weight raw materials can be used within the thermoplastic because of the higher allowable melt viscosity.

[0110] Deposition systems having various extruder types of are commercially available, including single screw extruders, twin screw extruders, hot-end extruders (e.g., for filament feed systems), and direct drive hot-end extruders (e.g., for elastomeric filament feed systems). The deposition systems can also have different motion types for the deposition of a material, including using XYZ stages, gantry cranes, and robot arms.

[0111] Typically, gasket seals are made in one location in non-custom lengths and shapes, and then manually applied at a manufacturing assembly plant. The process of the present disclosure provides for gaskets and adhesives to be directly created and bonded to substrates in one step at one location on the manufacturing floor. Coextruding a pressure sensitive adhesive and a thermoplastic elastomer directly on a substrate may produce a more desirable adhesive bond between the thermoplastic elastomer and the adhesive. Another potential advantage of coextruding the pressure sensitive adhesive and a thermoplastic elastomer directly on a substrate is the thermoplastic article may be formed into an irregular shape (e.g., comer or sharp edge) naturally that would otherwise not be desirable to manufacture independently. In addition, customized lengths and shapes of such gasket seals may be created, in particular gasket seals that include desirable radiuses or curves in a continuous length of gasket that is directly adhered to the work piece or substrate. The process of coextruding a pressure sensitive adhesive and a thermoplastic elastomer on a substrate may include a variety of features designed to improve efficiency in manufacturing and effectiveness of a gasket in unique applications.

[0112] In some embodiments, the thermoplastic elastomer composition and pressure sensitive adhesive are coextruded using the apparatus shown in FIGS. 2-14. FIG. 2 shows a dispensing head 150 having a configuration for receiving, melting, mixing, and dispensing the core-sheath filament 100 of FIG. 1. The dispensing head 150 includes a barrel 152 and a rotatable screw 154 received therein. A gearbox 156 and motor 158 are operatively coupled to the screw 154, and an alignment wheel 160, which may be motorized, is affixed to a side of the barrel 152 through which filament is guided into the dispensing head 150. Further details concerning each of these components are below.

[0113] The barrel 152 has the configuration of a barrel used in a single screw extruder. The barrel 152 has an inner surface 170 that is cylindrical and engages the screw 154 in an encircling relation. The inner surface 170 terminates in an outlet 172 at a distal end of the barrel 152. The outlet 172 is generally circular but could also be rectangular or have any other suitable shape. The barrel 152 includes one or more embedded heating elements (not visible) for heating the inner surface 170 and melting the filament during a dispensing operation. Optionally, the inner surface 170 of the barrel 152 can be grooved or otherwise textured to increase friction between the barrel 152 and the extruded material. Referring again to FIG. 2, an inlet 174 extends through the top side of the barrel for receiving the filament. As further shown, the inlet 174 includes a front sidewall 176 defining a beveled nip point where the front sidewall 176 converges with the outer surface of the screw 154. Advantageously, the beveled nip point prevents breakage of the filament as it is drawn into the barrel 152. The beveled nip point is part of a robust feeding mechanism enabling the filament to be continuously fed into the barrel 152 without need for operator attendance.

[0114] The drive mechanism for the dispensing head 150 is provided by the gearbox 156 and motor 158. In some embodiments, the dispensing head 150 includes controls allowing for adjustment of the speed and / or torque of the rotatable screw 154. In some embodiments, the motor 158 is a servo motor. Servo motors are advantageous because they can provide a high degree of torque over a wide range of rotational speed.

[0115] As shown, the inlet 174 generally has the shape of a reverse funnel, in which the transverse cross- sectional area of the inlet 174 increases with increasing proximity to the screw 154. The inlet 174 has one or more sidewalls, such as front sidewall 176 as shown. The front sidewall 176 can be planar or curved. As viewed from a transverse direction, at least a portion of the front sidewall 176 extends at an acute angle relative to a longitudinal axis of the screw 154. The acute angle, which facilitates feeding of the filament adhesive, can be from 10 degrees to 70 degrees, from 18 degrees to 43 degrees, from 23 degrees to 33 degrees, or in some embodiments, less than, equal to, or greater than 10 degrees, 13, 15, 17, 20, 22, 25, 27, 30, 32, 35, 37, 40, 42, 45, 47, 50, 53, 55, 57, 60, 65, or 70 degrees.

[0116] FIG. 3 shows a top view of the barrel 152, revealing further detail concerning the shape of the inlet 174. The inlet 174 includes outer entrance 175 and hidden surfaces extending from the outer entrance 175 and shown in dotted lines. As can be seen from FIG. 3, the front sidewall 176 is not planar, but has a complex compound curvature. Curved surfaces of the inlet 174, which include the front sidewall 176, collectively define a recess in the inner surface 170 of the barrel 152 to accommodate the filament as it is being fed. Overall, the inlet 174 can extend along from 10 percent to 40 percent, from 15 percent to 35 percent, 20 percent to 30 percent, or in some embodiment, less than, equal to, or greater than 10 percent, 12, 15, 17, 20, 22, 25, 27, 30, 32, 35, 37, or 40 percent of the nominal screw length.

[0117] The recess circumscribed by the inlet 174 can extend, as here, along both axial and circumferential directions relative to the screw 154. By providing space for the filament to move within the barrel 152, the recess reduces the likelihood that the flights of the rotatable screw 154 would sever the filament during operation of the dispensing head 150. This is inconvenient because filament breakage interrupts the dispensing process and requires that an operator manually re-inserts the filament into the dispensing head 150 before re-starting the process.

[0118] FIGS. 4 and 5 show features of the screw 154 in more detail. The screw 154 includes a shank 180 at one end for coupling to a drive mechanism. The shank 180 is connected to a shaft 182 with a diameter that progressively increases along its length. Extending around the shaft 182 are helical flights 184 for conveying molten material in the forward direction as the screw 154 rotates within the barrel 152.

[0119] Proximate to where the filament 100 is fed into the dispensing head 150, notches 188 are provided in the helical flights 184 to provide gripping lugs 186, as also shown in the cross-sectional view of FIG. 5. The gripping lugs 186 provide additional edges that assist in catching and actively conveying a continuous filament through the inlet 174 and into the barrel 152. This is a significant benefit over feeding mechanisms that require filament to be pushed into the feed zone, which can induce buckling and kinking of the filament. The gripping lugs 186 can extend across from 1 percent to 30 percent, from 3 percent to 25 percent, from 5 percent to 20 percent, or in some embodiments, less than, equal to, or greater than 1 percent, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 25, 27, or 30 percent of the nominal screw length.

[0120] Located on the opposite end of the screw 154 is a mixing section 190. The mixing section 190 includes a plurality of mixing elements — here, cylindrical posts 192. The mixing section 190 may be represented in other configurations not shown in FIG. 4, however. Other screw features that may be employed as mixing elements include fluted cylinders (as found in Maddock mixers), densely flighted screw sections with crosscuts (as found in Saxton mixers), or any of a variety of known post patterns, including those used for pineapple mixers. Optionally, posts or pins may be disposed on the interior sidewalls of the barrel 152 and aid in the mixing process; if so, crosscuts may be present in the flights of the screw 154 to avoid interference. Apertures may also be present, that serve to disperse or distribute the composition within the barrel, and these can also act as mixing elements.

[0121] The length of the mixing section 190 is not particularly restricted and can depend on various factors including the composition being extruded and the feed rate of the filament. The mixing section 190 can be from 5 percent to 30 percent, from 7 percent to 25 percent, from 8 percent to 20 percent, or in some embodiments, less than, equal to, or greater than 5 percent, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 25, 27, 30, or 35 percent of the nominal screw length.

[0122] For effective melting, mixing, and dispensing of a filament within a relatively compact enclosure, the ratio of nominal screw length and screw diameter can be from 8:1 to 20:1, from 9:1 to 17: 1, from 10: 1 to 14:1, or in some embodiments, less than, equal to, or greater than 8: 1, 9:1, 10: 1, 11:1, 12: 1, 13:1, 14: 1, 15: 1, 16: 1, 17: 1, 18: 1, 19: 1, or 20: 1.

[0123] The provided dispensing head 150 can display significant throughputs. In some embodiments, the dispensing head is capable of dispensing the composition at a throughput of at least 3 kg / hour, at least 4 kg / hour, at least 5 kg / hour, at least 6 kg / hour, at least 7 kg / hour, or at least 8 kg / hour.

[0124] FIG. 6 presents a schematic illustration of a dispensing system 228 that includes a dispensing head 250 outfitted with a mount for attachment to the end of a movable arm 230. The dispensing head 250 can have features analogous to that of the dispensing head 150 as previously described. The movable arm 230 is affixed to a table 232 and can have any number of joints to allow the dispensing head 250 to be translated and rotated in up to six degrees of freedom. The movable arm 230 allows the dispensing head 250 to dispense an extruded composition with precision and reproducibility, and over a wide range of locations relative to the table 232.

[0125] The dispensing system 228 additionally includes a filament 100 for continuously feeding into the dispensing head 250 as shown in FIG. 6. The filament 100 can be continuously unwound from a spool 236 as shown. It is to be understood that the location of the spool 236 relative to other components of the dispensing system 228 is not critical and can mounted where convenient. The spool 236 can be fixtured to the table 232 or a structure thereon.

[0126] In various embodiments, the portion of the spool 236 that contacts the filament 100 can have structural features that assist in conveyance of the filament 100. For example, that portion of the spool 236 may include spiked region, a tacky surface, or any other feature that assists in unwinding the filament 100. Although not illustrated in FIG. 6, the filament 100 may also be guided along a channel or pipe extending between the spool 236 and the dispensing head 250. The channel or pipe can include low-friction (e.g., fluoropolymer) surfaces to facilitate travel and prevent kinking of the filament 100 therein.

[0127] The dispensing head 250 of FIG. 6 is being shown dispensing a composition 238 in hot melt form onto the bonding surface of a substrate 240. The substrate 240 need not be limited and can be, for example, an industrial part to be adhesively coupled to an assembly. As an option, the substrate 240 can be mounted onto the table 232, thereby providing a spatial point of reference for positioning of the dispensing head 250. This can be especially useful in an automatic process, where a controller is used to control the position and orientation of the dispensing head 250.

[0128] FIG. 7 depicts a front view of the coextrusion dispensing system 500 for applying a pressure sensitive adhesive (PSA) and a thermoplastic elastomer (TPE) of the present disclosure directly on substrates, which incorporates the filament adhesive 100 and thermoplastic elastomer 314 additions. The filament adhesive 100 is fed in the adhesive barrel 152 where it is converted to molten adhesive and ultimately applied by in the coextrusion dispensing head 150. The molten adhesive travels through an adhesive transfer tube 302 from the adhesive dispensing head 250 to the coextrusion dispensing head 150. The coextrusion dispensing head 150 is controlled by a moveable arm 230. The thermoplastic elastomer 314 is fed to the thermoplastic elastomer dispensing head 312 and into the coextrusion dispensing head 304. The coextrusion dispensing head 150 may contain various ports to assist in processing such as a heating cartridge 316, air inlet 308, or a thermocouple channel 310. The coextrusion dispensing head 150 may contain more additional ports or less, depending on the configuration of the head 150 and the shape of the gasket desired. The pressure sensitive adhesive and thermoplastic elastomer are coextruded out of the dispensing head 150 to a substrate 240. The coextrusion dispensing head 150 includes a shaped dispensing face 292 for producing the desired shape gasket made from the molten TPE and molten adhesive, as further described below. The air introduced to the system 500 is expelled out of outlet 319 in FIG. 8 A. The coextrusion dispensing head 150 may move relative to a substrate 240, (e.g., the head moves but the substrate is static) or a substrate 240 may move relative to the dispensing head 150. In some embodiments, the thermoplastic elastomer 314 may be fed to the coextmsion dispensing head 150 through a similar dispensing head 250 illustrated in FIG. 2.

[0129] It may be useful to include multiple inlet ports for the PSA and thermoplastic elastomer, depending on the desired article. The selected chosen configuration may depend on the orientation and design characteristics of the final product. Similarly, the coextrusion dispensing head 150 may include multiple heaters, air inlet, and temperature probes to increase the ability to process different types of PSA and thermoplastic elastomers that required different process conditions.

[0130] FIGS. 8A-8F illustrate one embodiment of a coextrusion dispensing head 150 for producing a shaped thermoplastic article 400, such as a gasket with a PSA, which is illustrated in Figure 9. Figures 8E and 8F are cross sectional views of the coextrusion dispensing head 150 taken along line a-a in Figure 8B. The coextrusion dispensing head 150 is configured to receive molten thermoplastic elastomer through the thermoplastic elastomer inlet 330 feds into the system 500 from the top of the head 150. The coextrusion dispensing head 150 is also configured to receive molten pressure sensitive adhesive through the adhesive inlet 352 fed into the system 500 from the side of the coextrusion head 150. The pressure sensitive adhesive and thermoplastic elastomer exit the dispensing face 292a through the shaped dispensing face 322a that gives the extruded thermoplastic article 400 its shape. In the illustrated embodiment, the shaped dispensing face 322 includes a lower extrusion lip 320 and an upper extrusion lip 324 to form a shape like the letter D and to extrude a hollow D-shaped article 400 illustrated in Figure 9 on a substrate 240. The air introduced to the system 500 is expelled out of the air outlet 319. The lower dispensing lip 320 shapes the pressure sensitive adhesive portion, whereas the upper dispensing lip 324 shapes the top of the thermoplastic elastomer portion. Together both portions form the composite article 400, which may be a gasket with a PSA, that is applied to the substrate 240 in FIG. 9. The coextrusion dispensing head 150 may contain an air inlet 308, thermocouple channel 310 or a heating cartridge 316. The coextrusion dispensing face 326 may be at an angle normal to the bottom edge 290a of the coextrusion dispensing head 150 at an angle a no more than 90 degrees.

[0131] FIG. 8C shows a side view of the coextrusion dispensing head 150 where the thermocouple channel 310 and air inlet 308 are shown in detail. In some other embodiments, the coextrusion dispensing head 150 may contain more or fewer ports.

[0132] FIG. 8D is a top view of the coextrusion dispensing head 150 wherein the thermoplastic elastomer is fed to the system 500. The thermoplastic elastomer inlet 330 contains a TPE channel 340 that keeps the TPE separate from the pressure sensitive adhesive which is being fed through the coextrusion dispensing head 150 through another inlet.

[0133] FIGS. 8E and 8F depict a cross sectional view of the coextrusion dispensing head 150, which is convenient for discussing the flow of materials through the coextrusion dispensing head 150. The thermoplastic elastomer inlet 330 is isolated from the incoming pressure sensitive adhesive inlet 352 by a dedicated TPE channel 340, which in one embodiment is at least 240 mm in length. The adhesive inlet 352 is similarly in fluid communication with an isolated adhesive channel 354. In another embodiment, the adhesive channel 354 is at least 240 mm in length. The pressure sensitive adhesive channel 354 and TPE channel 340 are separated by a fluid barrier 356. In some embodiments, the fluid barrier 356 is at least 240 mm in length. The length, width, and angle of the fluid barrier 356 may vary between designs based on the desired coextrusion dispensing head 150 configuration. The pressure sensitive adhesive and TPE merge in a third channel, the coextrusion channel 358, wherein the PSA and TPE may be in fluid communication for at least 4 mm in length. In some embodiments, the coextrusion channel 358 may keep the PSA and TPE in fluid communication for less than, equal to, or greater than 10 mm, 15 mm, and 17 mm. One advantage the coextmsion channel 358 provides is a strong bond between the PSA and TPE in the final gasket. The extruded article is formed when the coextmsion channel 358 feeds the PSA and TPE through the shaped dispensing face 322, the lower dispensing lip 320 and upper dispensing lip 324. The air introduced to the coextmsion dispensing head 150 is expelled out of the air outlet 319. In some embodiments, the shaped dispensing face 322 may include multiple shapes or configurations, in various sizes to form a desired article configuration.

[0134] In some embodiments of the coextmsion dispensing head 150, the coextmsion channel 358 is configured to provide a desired amount of time the PSA and TPE are in contact with the coextmsion dispensing head 150 prior to extmsion. The time PSA and TPE are in contact may be directly proportional to the extmsion dispensing rate which can be at least 20 mm / s and no greater than 60 mm / s. In some embodiments, at a dispensing rate of 20 mm / s and coextmsion channel lengths of 4 mm, 10 mm, 15 mm, and 17 mm, the PSA and TPE are in fluid communication for 0.2, 0.5, 0.8, and 0.9 seconds, respectively. In some embodiments, at a dispensing rate of 60 mm / s and coextmsion channel lengths of 4 mm, 10 mm, 15 mm, and 17 mm, the PSA and TPE are in fluid communication for 0.1, 0.2, 0.3, and 0.3 seconds, respectively.

[0135] FIG. 9 shows a perspective view of the pressure sensitive adhesive and thermoplastic elastomer that forms a TPE article 400, in this case a gasket with a PSA, after both materials are coextmded together onto a substrate 240. The outer surfaces 403 and inner surfaces 402 including the flat surfaces 410 formed by the configured shape of the shape faces 322a when the materials are coextmded onto the substrate 240. A layer of pressure sensitive adhesive 404 is bonded to the outer flat surface opposite the flat internal surface 410 of the TPE article 400 and adhered to the substrate 240. The TPE article 400 may take on various curves and lengths depending on the desired application or gasket.

[0136] FIGS. 10A-10F illustrate another embodiment of a coextmsion dispensing head 300 for producing another shaped thermoplastic article 400, such as a gasket, which is illustrated in Figure 11. Figures 10E and 10F are cross sectional views of the coextmsion dispensing head 300 taken along line b-b in Figure 10B.

[0137] The coextmsion dispensing head 300 is configured to receive molten thermoplastic elastomer through the thermoplastic elastomer inlet 330 feds into the system 500 from the top of the coextmsion dispensing head 300. The coextrusion dispensing head 300 is also configured to receive molten pressure sensitive adhesive through the adhesive inlet 352 fed into the system 500 from the side of the coextrusion head 300. The pressure sensitive adhesive and thermoplastic elastomer exit the dispensing face 326 through the shaped dispensing faces 322b that gives the extruded article its shape. The lower dispensing lip 320 shapes the form of the pressure sensitive adhesive layer, whereas the upper dispensing lip 324 shapes the top portion of the thermoplastic elastomer article. Additionally, the middle dispensing lip 325 forms the middle portion of the thermoplastic elastomer article. In the illustrated embodiment, the shaped dispensing face 322 includes a lower extrusion lip 320 and an upper extrusion lip 324 to form shapes of intersecting circles and to extrude a hollow article 400 illustrated in Figure 11 on a substrate 240. The lower dispensing lip 320 shapes the pressure sensitive adhesive portion, whereas the upper dispensing lip portions 325, 324 shapes the intersection circle portions of thermoplastic elastomer. Together, they form the TPE article 400, which may be a gasket with a PSA, that is applied to the substrate 240 in FIG. 11. The coextmsion dispensing head 300 may contain a thermocouple channel 310, air inlet 308, or a heating cartridge 316. The coextrusion dispensing face 326 may be at an angle P relative to the bottom edge 290b of the coextrusion dispensing head 300 at an angle of 90 degrees. The air introduced to the system is expelled out of the air out 319.

[0138] FIG. 10C shows a side view of the coextrusion dispensing head 300 where the thermocouple channel 310 and air inlet 308 are shown in detail. In some other embodiments, the coextrusion dispensing head 300 may contain more or fewer ports, for example, to accommodate additional material flow streams.

[0139] FIG. 10D is a top view of the coextrusion dispensing head 300 wherein the thermoplastic elastomer is fed to the system. The thermoplastic elastomer inlet 330 contains a TPE channel 340 that keeps the TPE separate from the pressure sensitive adhesive which is being fed through the coextrusion dispensing head 300 through another inlet. FIGS. 10E and 10F depict a cross sectional view of the coextrusion dispensing head 300. The flow of materials through the coextrusion dispensing head 150, the channel lengths, the shaped dispensing face, the dispensing lips, dispensing rates, and fluid communication times are as described above in connection with FIGS. 8E and 8F.

[0140] FIG. 11 shows a perspective view of the molten pressure sensitive adhesive and thermoplastic elastomer that forms an alternative article 400, in this case a gasket with a PSA, after both materials are coextruded together onto a substrate 240. The outer surfaces 403a, 403b, inner surfaces 402a, 402b and flat surface 410 formed by the configured shape of the shape faces 322a when the materials are coextruded onto the substrate 240. A layer of pressure sensitive adhesive 404 is bonded to the outer flat surface opposite the flat internal surface 410 of the TPE article 400 and adhered to the substrate 240. The thermoplastic article 400 may take on various curves and lengths depending on the desired application or gasket.

[0141] FIG. 12 shows a perspective view of yet another embodiment of the coextrusion dispensing head

[0142] 380 referred to generally as a “flat stock ribbon” coextrusion dispensing head. The coextrusion dispensing head 304 contains a dispensing face 322a and a first outlet 323 including face 292c having semicircle portions 426a wherein the flat-stock ribbon profile is coextruded to form the thermoplastic article 400 illustrated in Figure 13.

[0143] FIG. 13 shows a cross-sectional view of the flat-stock ribbon article 400. The TPE 430 is coextmded with the PSA 432 onto the substrate 240. In some embodiments, the TPE 430 has ribbons 426 to increase the ability to create a seal.

[0144] FIG. 14 shows the various gasket shapes envisioned to be formed by the coextrusion head outlet. The shallow-D hollow profile is depicted by 450. The Tall-D hollow profile is depicted by 452. The stacked intersecting circle shape is depicted by 454. The profile shape is depicted by 456. The hollow L shape is depicted by 458. The hollow with top ribbons shape is depicted by 460. The flat stock ribbon shape is depicted by 462.

[0145] Further details regarding a suitable process for using the thermoplastic elastomer composition of the present invention is disclosed in Patent Application No. PCT / IB2024 / 061804, entitled “Coextrusion Dispensing Head for Pressure Sensitive Adhesives and Thermoplastic Elastomers and Methods of Using the Same,” having the same priority date as the present application and co-owned by the same assignee as the present application, which is hereby incorporated by reference.

[0146] As described above, the process of the present disclosure can include coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive directly onto a substrate. The substrate may comprise any desired material. In some embodiments, the surface of the substrate comprises at least one of metal (e.g., stainless steel or aluminum), ceramic (e.g., glass), a polymer (e.g., a plastic, rubber, thermoplastic elastomer, or thermoset), or a composite. A composite material may be made from any two or more constituent materials with different physical or chemical properties. When the constituents are combined to make a composite, a material having characteristics different from the individual components is typically achieved. Some examples of useful composites include fiber-reinforced polymers (e.g., carbon fiber reinforced epoxies and glass-reinforced plastic); metal matrix compositions, and ceramic matrix composites. The surface of the substrate to which the adhesive article is applied may include polymers such as polyolefins (polypropylene, polyethylene, high density polyethylene, blends of polypropylene), polyamide 6 (PA6), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), PC / ABS blends, polyvinyl chloride (PVC), polyamide (PA), polyurethane (PUR), thermoplastic elastomers (TPE), polyoxymethylene (POM), polystyrene (PS), an acrylic (e.g., (poly(methyl) methacrylate (PMMA)), and combinations thereof. The surface of the substrate may also include a metal coating on such polymers.

[0147] Before depositing the coextruded thermoplastic elastomer composition and PSA to the surface of the substrate, the substrate can be treated with one or more primers. The primer may be applied as a solvent- borne liquid, by any suitable method, which may include, for example, brushing, spraying, dipping, and the like. In some embodiments, the substrate surface may be treated with one or more organic solvents (e.g., methyl ethyl ketone, aqueous isopropanol solution, acetone) prior to application of the primer. In some embodiments, the article of the present disclosure includes a release liner. In some embodiments, the thermoplastic elastomer composition has a surface in direct contact with a PSA, the article further comprises a release liner on a surface of the pressure-sensitive adhesive opposite the thermoplastic elastomer composition. Various release liners may be useful. In some embodiments, the release liner comprises at least one of a polyester film, polyethylene film, polypropylene film, polyolefin coated polymer film, polyolefin coated paper, acrylic coated polymer film, and polymer coated kraft paper. The polyolefin coated film or paper may be polyethylene coated film or paper. In some embodiments, the release is coated on at least one of the major surfaces with a release coating. In some embodiments both major surfaces of the release liner are coated with a release coating. In this case, the release coating may the same or different on each of the major surfaces of the release liner. Examples of materials useful as release coatings for the liners disclosed herein include acrylics, silicones, fluoropolymers, and urethanes. In some embodiments, the release coating is a silicone coating. The thermoplastic elastomer composition and PSA may be coextruded onto the release liner, in some embodiments. The article comprising the thermoplastic elastomer composition and PSA may be removed from the liner and applied to another substrate, including any of those described above.

[0148] In some embodiments, the article comprising the thermoplastic elastomer composition and PSA can be easily removed from a substrate by pulling the material off at a low angle. This removability is possible despite the high bond strength the article achieves with the substrate, because stretching transmits very large forces at the peel front. The stretch-releasability of the article from its substrate can allow for end-of-life disassembly and recycling, which is advantageous.

[0149] Some Embodiments of the Disclosure

[0150] In a first embodiment, the present disclosure provides a thermoplastic elastomer composition comprising a hydrogenated styrenic block copolymer, a plasticizer having a number average molecular weight of at least 2,000 grams per mole, and a wax having a polar functional group. In a second embodiment, the present disclosure provides the thermoplastic elastomer composition of the first embodiment, wherein the polar functional group comprises at least one of a hydroxyl group, a carboxylic acid group, a carboxylic acid ester group, an amino group, or a carboxamide group. In a third embodiment, the present disclosure provides the thermoplastic elastomer composition of the first or second embodiment, wherein the wax has a melting point in a range from 35 °C to 65 °C. In a fourth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to third embodiments, wherein the wax is present in an amount from one percent by weight to ten percent by weight based on the total weight of the thermoplastic elastomer composition. In a fifth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to fourth embodiments, wherein the thermoplastic elastomer composition comprises the hydrogenated styrenic block copolymer in an amount from 10 percent by weight to 40 percent by weight, based on the total weight of the thermoplastic elastomer composition. In a sixth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to fifth embodiments, wherein the hydrogenated styrenic block copolymer is a styrene-ethylene / butylene-styrene block copolymer. In a seventh embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to the sixth embodiments, wherein the plasticizer is present in an amount from 10 percent by weight to 45 percent by weight, based on the total weight of the thermoplastic elastomer composition. In an eighth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to seventh embodiments, wherein the plasticizer is a hydrocarbon plasticizer. In a ninth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to eighth embodiments, wherein the plasticizer is a polybutene polymer.

[0151] In a tenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to ninth embodiments, further comprising a polyolefin thermoplastic elastomer. In an eleventh embodiment, the present disclosure provides the thermoplastic elastomer composition of the tenth embodiment, wherein the polyolefin thermoplastic elastomer is a polyolefin block copolymer. In a twelfth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the tenth or eleventh embodiment, wherein the polyolefin thermoplastic elastomer is present in the composition in an amount of not more than 40 percent by weight, based on the total weight of the composition. In a thirteenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to twelfth embodiments, further comprises a polyphenylene oxide resin. In a fourteenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to thirteenth embodiments, further comprising at least one of a filler, activated charcoal, a flame retardant, or thermally conductive particles. In a fifteenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to fourteenth embodiments, further comprising at least one of hollow ceramic microspheres, expandable polymeric microspheres, entrained gas, or a chemical blowing agent. In a sixteenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to fifteenth embodiments, having a Shore A hardness of not more than 60. In a seventeenth embodiment, the present disclosure provides the thermoplastic elastomer composition of any one of the first to sixteenth embodiments, wherein the thermoplastic elastomer composition has a complex melt viscosity in a range from 4,000 pascal-seconds to 30,000 pascal-seconds measured on a rheometer at a temperature of 175 °C at a shear rate of one radian per second.

[0152] In an eighteenth embodiment, the present disclosure provides an article comprising the thermoplastic elastomer composition of any one of the first to seventeenth embodiments. In a nineteenth embodiment, the present disclosure provides the article of the eighteenth embodiment, wherein the article is an extruded article. In a twentieth embodiment, the present disclosure provides the article of the eighteenth or nineteenth embodiment, wherein the article is a filament. In a twenty -first embodiment, the present disclosure provides the article of the twentieth embodiment, wherein the filament has a diameter in a range from five millimeters to 20 millimeters. In a twenty-second embodiment, the present disclosure provides the article of the twentieth or twenty-first embodiment, wherein the filament has a core and a sheath, wherein the core comprises the thermoplastic elastomer composition, and wherein the sheath comprises a different composition from the core. In a twenty-third embodiment, the present disclosure article the adhesive of the twenty-second embodiment, wherein the sheath comprises a polyolefin. In a twenty-fourth embodiment, the present disclosure provides the article of any one of the nineteenth to twenty -third embodiments, wherein the filament is wrapped around a spool.

[0153] In a twenty-fifth embodiment, the present disclosure provides the article of the eighteenth or nineteenth embodiment, wherein the article is a gasket. In a twenty-sixth embodiment, the present disclosure provides the article of the eighteenth, nineteenth, or twenty-fifth embodiment, wherein the thermoplastic elastomer composition has a surface in direct contact with a pressure sensitive adhesive. In a twenty-seventh embodiment, the present disclosure provides the article of the twenty-sixth embodiment, wherein the thermoplastic elastomer composition is coextruded with the pressure sensitive adhesive. In a twenty -eighth embodiment, the present disclosure provides the article of the twenty-sixth or twenty-seventh embodiment, wherein the pressure sensitive adhesive comprises a styrenic block copolymer. In a twentyninth embodiment, the present disclosure provides the article of the twenty-eighth embodiment, wherein styrenic block copolymer comprises at least one of a polystyrene-containing triblock copolymer or a polystyrene-containing star block copolymer, wherein the polystyrene-containing triblock copolymer and polystyrene-containing star block copolymer independently comprise a block of at least one of polyisoprene, polybutadiene, ethylene / butylene, or ethylene / propylene, and wherein the pressure sensitive adhesive further comprises a tackifier. In a thirtieth embodiment, the present disclosure provides the article of the twenty-eighth or twenty-ninth embodiment, wherein the styrenic block copolymer of the pressure sensitive adhesive is hydrogenated, that is, it comprises a block of ethylene / butylene or ethylene / propylene. In a thirty-first embodiment, the present disclosure provides the article of any one of the twenty-fifth to thirtieth embodiments, wherein the article is a gasket, and wherein the pressure sensitive adhesive adheres the gasket to a frame around an opening and / or to an appliance. In a thirty-second embodiment, the present disclosure provides the article of any one of the twenty-sixth to thirtieth embodiments, wherein the article further comprises a release liner on a surface of the pressure-sensitive adhesive opposite the thermoplastic elastomer composition.

[0154] In a thirty-third embodiment, the present disclosure provides a process for making the article of any one of the twenty-fifth to thirty-second embodiments, the process comprising extruding the thermoplastic elastomer composition onto a substrate. In a thirty -fourth embodiment, the present disclosure provides a process for making the article of any one of the twenty-sixth to thirty-second embodiments, the process comprising coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive directly onto a substrate. In a thirty -fifth embodiment, the present disclosure provides the process of the thirty -fourth embodiment, wherein the substrate comprises an opening, and wherein the coextruding comprises coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive directly onto the substrate to surround the opening. In a thirty-sixth embodiment, the present disclosure provides the process of the thirty-fourth embodiment, wherein the substrate is a release liner. In a thirty-seventh embodiment, the present disclosure provides the process of any one of the thirty-fourth to thirty-sixth embodiment, further comprising providing the pressure sensitive adhesive as a filament and melting the filament. In a thirty -eighth embodiment, the present disclosure provides the process of any one of the thirty- third to thirty-seventh embodiment, further comprising providing the thermoplastic elastomer composition as a filament and melting the filament.

[0155] Embodiments of the compositions and methods disclosed herein are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention.

[0156] EXAMPLES

[0157] Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight. The following abbreviations are used in this section: rpm = rotations per minute, g = gram, mg = milligram, mol = mole, centimeter = cm, mm = millimeter, in. = inch, ft = feet, °C = degrees Celsius, °F = degrees Fahrenheit, phr = parts per hundred, wt% = weight percent, lb = pound, mL = milliliter, sec = second, oz = ounces, hr = hour, and min. = minutes.

[0158] Table 1: Materials

[0159] Examples 1 to 9 and Illustrative Examples 1 to 3 Thermoplastic Elastomer Compositions

[0160] Examples 1 to 9 (Ex. 1-9) and Illustrative Examples 1 to 3 (I.E. 1-3) were prepared using the compositions shown in Table 2 (below). All amounts shown are given in parts by weight (pbw). In addition, each of Ex. 1-9 and I.E. 1-3 included one pbw antioxidant, 2 pbw pigment, and 4 pbw LDPE. The total pbw for each of Ex. 1-9 and I.E. 1-3 was 100. Table 2. Examples 1 to 9 and Illustrative Examples 1 to 3 Thermoplastic Elastomer Compositions.

[0161] Samples of Examples 1 to 9 and Illustrative Examples 1 to 3 were prepared using a ZE30R co- rotating twin screw extruder (obtained from KraussMaffei Berstorff, Hanover, Germany), and subjected to 200 rpm, through a gear pump (Nordson Xaloy 042709 gear pump turned at 20 rpm), and out an aluminum slot die that had a 2 mm by 75 mm exit orifice. The extruder and pump temperatures were set to 180 °C. The samples were then subjected to the Friction Test, Shore A Hardness, Test Stress Relaxation Test, Compression Set Test, and Melt Viscosity Test described below.

[0162] Samples of Examples 1 to 9 and Illustrative Examples 1 to 3 were also compounded using the ZE30R co-rotating twin screw extruder obtained from KraussMaffei Berstorff and subjected to 250 rpm mixing for 3 minutes. A Nordson Xaloy 042709 gear pump turned at 30 rpm to pump the molten adhesive out a 9.5 mm inner diameter brass nipple. The filament dropped 150 mm into a stainless-steel trough filled with ambient temperature water. The filament was manually pulled through the water bath, dried, and set aside for further testing. The extruder and gear pump were set to 160 °C, except the inlet zone, which was set to 150 °C. Also, the Thermoplastic Elastomer Compositions in filament form were each then coextruded with the PSA according to the method described below, and the Dispensability Test and Removability Tests were carried out on the coextruded samples.

[0163] Test Methods:

[0164] Friction Test

[0165] The Friction Test was carried out according to ASTM D1894, with the exception that the samples were not run for a minimum distance of 130 millimeters due to the amount stick-slip or uneven sliding. However, all of the samples ran a minimum of 50 millimeters or more which clearly differentiate the Examples. The test was carried out on a MTS Criterion 45 electromechanical load frame equipped with a ION load cell. Anodized aluminum panels were used as the contact material. The specimen size was 64 millimeters by 64 millimeters, and 4 specimens were measured for each Example. Specimen thicknesses were in a range from 1.04 mm to 1.17 mm. The averaged values are reported in Table 3. A value < 3 for the kinetic coefficient of friction is considered passing.

[0166] Shore A Hardness Test

[0167] ASTM D2240-15 type A was carried out. Specimens were prepared by pressing them to a nominal thickness of 6 mm using metal shims positioned between pieces of Release liner 1, within a heated metal press set to 140°C. Actual sample thicknesses were between 5.5 mm and 7.6 mm.

[0168] Stress Relaxation Test

[0169] A 2-in. long specimen with a 6.2 mm width was cut directly from the extruded sample. The thickness of the specimen was measured and recorded in Table 3, below. An RSA-G2 Solids Analyzer (TA Instmments, New Castle, DE) outfitted with a tension fixture capable of testing samples with rectangular dimensions was used to test all samples and the TRIOS software (TA Instruments) was used to program the experiments and collect the data. The tension fixture clamps were set to 25 mm apart at the start of each test. The test specimen was then loaded into the tension fixture and screwed until hand tight. The width and thickness of the specimen was recorded under the “Geometry” tab in the TRIOS software. The act of fixturing the specimen created some slack in the gauge region, resulting in a small compressive force on the specimen, so a small tensile force of 0.03N was applied to remove the slack. To ensure proper stress calculation, the starting gauge length was recorded to account for the slack removal. The gauge lengths are recorded in Table 3, below. The test was started with a 1-minute equilibration at 25 °C, after which a 5% strain was applied and held for 10 minutes at 25 °C. The ending gauge length (length after applied strain) was 5% higher than the initial gauge. Five points per second were collected by the TRIOS software. Stress relaxation was calculated and recorded in Table 3 as the change in the force response from t= 1 s to t=600s via the following equation: SR = (F(ls) - F(600s)) / F(ls).

[0170] Compression Set Test

[0171] ASTM D389-18 Type B (compression set under constant deflection in air) using a Type 2 sample was carried out with the modification of compression spacers were only 4.0 mm thick rather than the proscribed 4.5 mm. Samples were made using multiple layers of the extruded films pressed together in a heated metal press at 140 °C to have an initial thickness of 5.5 mm to 8.2 mm. Additionally, specimens were prepared by pressing them to a nominal thickness of 6 mm using metal shims positioned between pieces of Release liner 1, within the heated metal press set to 140 °C and were punched out with a 15-mm diameter die-punch rather than the ASTM specified 13 -mm diameter.

[0172] Melt Viscosity Test

[0173] The viscosity was measured with a TA Instruments DHR-3 rheometer using 25-mm disposable parallel plates (TA Instruments, New Castle, DE). The melt viscosity was measured at temperatures from 125 °C to 200 °C with shear rates of 100 to 0.1 rad / sec with 3 points per decade and a 5% strain and data was taken at 25 °C temperature intervals. The complex viscosity at 1 rad / sec at 175°C was chosen to be representative of the dispensing conditions and is reported in Table 3 below.

[0174] Coextrusion of Thermoplastic Elastomer Composition and PSA

[0175] A three-piece coextrusion die was manually machined out using a Jet JMD18 vertical end mill. The main body of the die was milled from a 75 mm x 50 mm x 50 mm block of aluminum 6061. Four countersunk holes were drilled to accept 35 mm long M6 bolts, for attachment to the end of the dispenser barrel. The die was attached to be centered under the main axis of the thermoplastic elastomer (TPE) composition dispenser screw. A 10-mm through-hole was drilled at a location centered along the main screw axis. The bottom of the block was cut back at an angle such that the height of the backside of the die was reduced to 38 mm. Four M5 tapped holes were made on the bottom of the die for affixing the bottom plate. A lipped internal cavity was machined out such that the internal plate could be placed on the 1 mm x 25 mm x 25 mm recessed lip. With the internal plate in place, the cavity was cut out to further create a 23 mm x 23 mm x 10 mm deep recess for the flow of TPE. The internal cavity angled down to an exit lip with a 2 mm x 20 mm cross section that had 3 additional hemispherical protrusions, each with a 3.1 -mm diameter. A ! ”-NPT fitting centered on the left side of the die accepted a 9.5 mm outer diameter copper tube that had the PSA flow stream. Perpendicular 6-mm holes directed the PSA flow stream from the side of the main body out the bottom. Holes were made to accept and attach 2 heaters (McMaster # 4877K126 and a thermocouple (McMaster #3860K203). The 3-piece die (main body, internal plate, and bottom plate) directed the TPE and PSA flow streams such that they were in contact within the die for 22 mm prior to exiting the die.

[0176] The internal plate was used to redirect the flow streams, such that they flowed in parallel before coming in contact with each other. The internal plate was fabricated from a 1 mm x 25 mm x 25 mm piece of steel. The front of the internal plate was narrowed to 20 mm wide, to fit into the die lip slot.

[0177] The bottom plate was machined from a 6.3 mm x 75 mm x 53 mm block of aluminum 6061. A slot was cut out to allow the PSA flow from the bottom of the main body to the lower die lip. The slot was 43 mm x 10 mm x 3 mm deep. The lower die lip had 1 mm x 20 mm cross section.

[0178] A redirecting block was fabricated using a CNC vertical endmill from a 41 mm x 63.5 mm x 32 mm high block of steel. Four countersunk holes were drilled to accept 35 mm long M6 bolts, for attachment to the end of the dispenser barrel. A 10 mm diameter was drilled down the center of the top face, to align with the PSA screw axis. A perpendicular hole redirected the PSA flow out the right face of the block. A 9 / 16”- 18 threaded hole accepted a 37-degree JIS fitting for attaching to the 9.5 mm outer diameter copper tube. Compression fittings were used on both ends for the copper tube, and the copper tube was approximately 200 mm long, to accommodate the separation between the PSA and thermoplastic elastomer composition dispensers. Silicone coated fiberglass fabric (McMaster 7569K17) was cut and wrapped around the copper tube for insulation. Holes were made to accept and attach 2 heaters (McMaster # 4877K126 and a thermocouple (McMaster #3860K203).

[0179] A 300 mm x 300 mm x 6.3 mm aluminum plate was attached to the end of the UR- 10 robotic arm. Substrates were taped down to the plate for dispensing. The motion speed was 50 millimeters per minute. The PSA dispenser was operated at 50 RPM for the feed motor and 500 RPM for the screw motor. The thermoplastic elastomer composition dispenser was operated at 150 RPM for the feed motor and 1500 for the screw motor. The PSA filament was on a spool, mounted on a freely rotating shaft. The thermoplastic elastomer composition filaments were manually fed into the dispensers.

[0180] Two identical miniaturized single screw dispensers were used, one for the thermoplastic elastomer composition and the other for PSA. Each extruder screw was turned using a 1 kW 240V servo motor attached to a 10: 1 planetary gearbox. A graphite filled bronze thrust bearing washer was used to minimize the force transmitted to the motor and gearbox. Both dispensers were affixed to a stationary metal frame that was 1100 mm above the floor.

[0181] The barrel was fabricated using a CNC vertical endmill from a 382 mm x 95 mm x 50 mm block of 4140 steel. A 30-mm diameter hole was drilled down the main center axis of the barrel to accept the extrusion screw. The outer surface of the barrel was machined down to 55 mm x 41 mm cross section, leaving a 20 mm thick flange at the end of the barrel nearest the motor / gearbox. The flange was bolted onto a half-circle ring shaped bearing mounting plate that contained the graphite filled bronze thrust washer. The bearing mounting plate was bolted to the backplate, to secure the location of the barrel. Rounded channels with 6.3 mm diameter were cut in the length of the barrel to accept heaters (McMaster #4877K173). Heater mounting plates were fabricated using a CNC vertical endmill from two 310 mm x 55 mm x 7 mm plates of aluminum 6061. Channels were machined to match the shape of the heaters, and securely press the heater against the barrel, in a clamshell-type arrangement. The barrel inlet plate was fabricated from a 55 mm x 7 mm x 51 mm plate of aluminum 6061. A U-shaped inlet with downward angle was included to provide a beveled nip, to improve gripping action of the filament between screw and barrel. The U-shaped orifice was 17 mm wide and extended down 28 mm from the top surface of the barrel flange. An opening larger than the U-shaped orifice in the inlet plate was machined into the barrel.

[0182] The barrel was fabricated using a 4-axis CNC vertical endmill from a 416-mm long by 29.8-mm diameter rod of 4140 steel. The motor mount shaft was machined to 17 mm diameter by 36 mm long with a slot cut to accept a shaft key. The main screw flight had a 20-mm pitch and was 4 mm thick. The flight height at the inlet was 7.8 mm. The flight height reduced to 0 mm along the length of the screw. A hollow cylinder was cut into the end of the screw opposite the motor shaft, going in 215 mm. The hollow core started with a diameter of 15 mm and gradually reduced to 6.5 mm. Passageway holes, with 2 mm diameter, were cut from the flight tips to the hollow core. Small half-circle notches, with 1.5 mm diameter were cut into the flight tips exposed to the inlet, to act as gripping lugs. The screw shaft and gearbox shaft were connected with a steel split shaft coupler connected with ceramic pins. Each half of the split shaft connector connected to a shaft and had holes to accept ceramic pins to connect the two halves. The ceramic pins helped prevent heat flow into the gearbox.

[0183] A backplate was used to help connect the motor / gearbox to the barrel. It also provided a mounting surface for the feed mechanism, and a way to attach the dispenser to the bracket mounted on the metal frame stand. The back plate was fabricated using a CNC vertical endmill from a 19 mm x 177 mm x 105 mm piece of machinable ceramic (McMaster #8489K123). Holes were drilled to accommodate mounting of the gearbox, barrel, and mounting bracket. The mounting backet was a steel right angle bracket, with each side of the right angle measuring 125 mm x 105 mm, and the thickness of the steel was 9.5 mm thick. Holes were drilled in the mounting bracket so it could be used to affix the backplate to the mounting rail.

[0184] A feed mechanism was affixed to convey filament directly into the barrel inlet opening. The feed mechanism was oriented such that filament was perpendicular to the barrel. The main feature of the feed mechanism was the spiked wheel, consisting of a spiked cylindrical wheel on a shaft. The spiked wheel was 25.4 millimeters diameter to the tips of the spikes. Each spike was 5 millimeters tall and formed an equilateral triangle. The spiked wheel was 12.7 millimeters wide, consisting of 5 rows of spikes. The shaft was 46 millimeters long and 8 millimeters diameter. The shaft was connected to a NEMA 17 stepper motor through a 4: 1 gearset, such that the spike wheel RPM was 4 times slower than the stepper motor. A freely rotating bearing (12.7 millimeters wide, 22 millimeters diameter) was mounted on a hinged shaft that included a torsion spring, and the bearing pressed the filament against the spiked wheel, to get a strong grip. The entire assembly was mounted in a housing that directed the filament into the spiked wheel, and then into the barrel inlet.

[0185] When the TPE and the PSA were coextmded, it was not possible to separate the PSA from the TPE by hand to create a tab, which indicates good adhesion between the TPE and PSA.

[0186] Dispense Quality Test

[0187] An anodized aluminum substrate (102 mm by 152 mm by 1.6 mm) was obtained, and a strip of PTFE tape (3M 5490 PTFE Extruded Film Tape) was affixed along the longest edge, covering a 25-mm by 152-mm section. Two specimen strips were coextruded onto each panel, equally spaced and aligned parallel to the 102-mm-long edge. A 125 mm long section of Thermoplastic Elastomer Composition (TPE) / PSA was coextruded, such that 77 mm of it was directly bonded to the anodized aluminum substrate, 25 mm of the sample was coated onto the PTFE tape, and the remaining 25-mm section over hung the substrate. The PSA dispenser was set to 193 °C, and the TPE dispenser was set to 205 °C. Both specimen strips were visually inspected. The filament was considered to pass if no delamination was visible and there was no more than 10% variability from the die geometry of the coextruded product. A value of good / fair / fail was assigned based on the qualitative assessment of the extruded thermoplastic elastomer to match the die profile which had three large ridges as shown in FIG. 13.

[0188] Removability test

[0189] The specimen strips created for the Dispense Quality Test were used for the Removability Test. The section of the specimen strip bonded to the PTFE tape and the overhanging section were used as a tab for manually gripping the coextmded strip. The strip was manually gripped near the initial peel front and was not re-gripped during the test. The strip was pulled perpendicularly (i.e., 90 degrees) to the substrate at approximately 25 mm per second. The strip was pulled until the peel front moved at least 40 mm (i.e., 40 mm of the strip de-bonded from the substrate). A passing value was obtained if both specimen strips cleanly de-bonded from substrate, without leaving residue on the substrate, and exhibited no signs of delamination (i.e. wrinkling, bubbles, or deformation associated with delamination) between PSA and the Thermoplastic elastomer Composition.

[0190] The Friction Test, Shore A Hardness Test, Stress Relaxation Test, Compression Set Test, and Melt Viscosity Test were carried out on each of Examples 1 to 9 and Illustrative Examples 1 to 3, which were prepared as described in the test methods. Also, the Thermoplastic Elastomer Compositions were created in filament form and then each was coextruded with the PSA according to the method described above, and the Dispensability Test and Removability Tests were carried out on the coextruded samples. The results are shown in Table 3, below.

[0191] Table 3. Results

[0192] Gel Permeation Chromatography

[0193] The molecular weights of polymers referred to in this disclosure can be measured with gel permeation chromatography (“GPC”) using polystyrene calibration standards. GPC is an established methodology in which polymers are separated according to molecular size where the largest molecule elutes first. The elugraph is calibrated using commercially available polystyrene molecular weight standards (EASICAL, Agilent Technologies, Santa Clara, CA). The molecular weight of polymers measured using GPC so calibrated are styrene equivalent molecular weights. The molecular weights reported here will be polystyrene equivalent molecular weights from a GPC system utilizing tetrahydrofuran (1.0 mL / min) as the mobile phase and an Agilent 1260 HPLC system comprising two columns in a series, Plgel MIXED-B and MIXED-C, and a refractive index detector (Agilent Technologies, Santa Clara, CA).

[0194] The “dw / dlogMw” is the weight fraction of the sample having the corresponding styrene equivalent molecular weight (logM). The dw / dlogMW value at a particular molecular weight (MW) can be tracked for a given sample formulation to be used as a quantifiable but indirect approach to the relative amount of material at that molecular weight.

[0195] The molecular weight at the peak dw / dlogMW, representing the molecular weight present at the highest weight fraction in the material (Peak MW,p) was 6134 g / mol for Plasticizer 1 and 385 g / mol for Plasticizer 2. The number-average molecular weight (n) of Plasticizer 1 was 3272 g / mol, and the Mnof Plasticizer 2 was 319 g / mol. Various modifications and alterations of this disclosure may be made by those skilled the art without departing from the scope and spirit of the disclosure, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.

Claims

What is claimed is:

1. An article comprising a thermoplastic elastomer composition comprising: a hydrogenated styrenic block copolymer; a plasticizer having a number average molecular weight of at least 2,000 grams per mole; and a wax having a polar functional group.

2. The article of claim 1, wherein the polar functional group comprises at least one of a hydroxyl group, a carboxylic acid group, a carboxylic acid ester group, an amino group, or a carboxamide group.

3. The article of claim 1 or 2, wherein the wax has a melting point in a range from 35 °C to 65 °C.

4. The article of any one of claims 1 to 3, wherein based on the total weight of the thermoplastic elastomer composition, the thermoplastic elastomer composition comprises the hydrogenated styrenic block copolymer in an amount from 10 percent by weight to 40 percent by weight, the plasticizer in an amount from 10 percent by weight to 45 percent by weight, and the wax in an amount from one percent by weight to ten percent by weight.

5. The article of any one of claims 1 to 4, wherein the thermoplastic elastomer composition further comprises a polyolefin thermoplastic elastomer in an amount of not more than 40 percent by weight, based on the total weight of the composition.

6. The article of claim 5, wherein the polyolefin thermoplastic elastomer is polyolefin block copolymer.

7. The article of any one of claims 1 to 6, wherein the hydrogenated styrenic block copolymer is a styrene-ethylene / butylene-styrene block copolymer.

8. The article of any one of claims 1 to 7, wherein the plasticizer is a hydrocarbon plasticizer.

9. The article of any one of claims 1 to 8, wherein the thermoplastic elastomer composition further comprises at least one of a polyphenylene oxide resin, a filler, activated charcoal, a flame retardant, thermally conductive particles, a magnetic filler, hollow ceramic microspheres, expandable polymeric microspheres, entrained gas, or a chemical blowing agent.

10. The article of any one of claims 1 to 9 having a Shore A hardness of not more than 60.

11. The article of any one of claims 1 to 10, wherein in the article is a filament having a diameter in a range from five millimeters to 20 millimeters.

12. The article of claim 11, wherein the filament has a core and a sheath, wherein the core comprises the thermoplastic elastomer composition, and wherein the sheath comprises a polyolefin.

13. The article of any one of claims 1 to 10, wherein the article is a gasket.

14. The article of any one of claims 1 to 10, or 13, wherein the thermoplastic elastomer composition has a surface in direct contact with a pressure sensitive adhesive.

15. A process for making the article of claim 14, the process comprising coextruding the thermoplastic elastomer composition and the pressure sensitive adhesive directly onto a substrate.

Images