Adapted additive particle size to provide surface improvements for lubricious thermoplastic articles

Abstract

Thermoplastic articles formed from a thermoplastic composition including a thermoplastic elastomer and an additive compounded in the thermoplastic elastomer are provided. The particle size of the additive is adapted to provide reduced surface roughness, and thus enhanced lubricity, to the thermoplastic articles.

Description

ADAPTED ADDITIVE PARTICLE SIZE TO PROVIDE SURFACE IMPROVEMENTS FOR LUBRICIOUS THERMOPLASTIC ARTICLESCLAIM OF PRIORITY

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 567,393 bearing Attorney Docket Number 1202404 and filed on March 19, 2024, which is hereby incorporated by reference in its entirety.FIELD

[0002] The present disclosure relates to thermoplastic articles having improved lubricity, as well as methods of preparing the thermoplastic articles. More particularly, the present disclosure relates to a thermoplastic article formed from a thermoplastic composition including a thermoplastic elastomer and an additive compounded in the thermoplastic elastomer. The particle size of the additive is adapted to provide reduced surface roughness, reduced wall thickness, and enhanced lubricity to the thermoplastic articles. The improved lubricity makes the thermoplastic articles especially useful for biomedical tubing applications, such as catheters.BACKGROUND

[0003] A lubricious catheter is a medical device that is inserted into the body to aid in the diagnosis, treatment, and management of various urological and cardiovascular diseases. The tubing of the catheter is designed to reduce the friction and resistance during insertion, which minimizes the discomfort and pain associated with catheterization. Accordingly, catheter lubricity is essential to improve patient comfort and ensure ease during medical procedures.

[0004] Conventionally, in order to achieve the desired catheter lubricity, a thermoplastic elastomer is either coated or compounded with an additive. It has been found that the performance of an additive-coated article is often superior to that of an additive-compounded article. However, there are a number of deficiencies associated with additive-coated catheters. First, coatingmethods are not cost effective, because they involve a secondary process beyond the forming of the catheter itself. Second, a coating applied to the surface of a catheter can exhibit poor durability, and be susceptible to wearing off during processing, handling, or use of the catheter.

[0005] That said, a number of deficiencies have also been observed in seeking to manufacture additive-compounded catheters as opposed to additive-coated catheters. The deficiencies of additive-compounded articles arise because additives are often cross-linked hydrogels or derivatives thereof, which rely upon migration to the surface for performance. However, this migration effect is often associated with surface roughness, which is undesirable for medical tubing. Similarly, an excess of surface migration can result in leaching, thus requiring higher loading levels of the additives. The surface roughness and leaching caused by the additives can create defects when used in thin-walled medical tubing applications, such as catheters.

[0006] As such, a need exists for effective methods of preparing thermoplastic articles including an additive compounded in a thermoplastic elastomer, wherein the surface roughness of the thermoplastic article is minimized and thus the lubricity is improved.SUMMARY

[0007] Disclosed herein are thermoplastic articles formed from a thermoplastic composition including a thermoplastic elastomer and an additive compounded in the thermoplastic elastomer. The particle size of the additive is adapted to provide reduced surface roughness, reduced wall thickness, and enhanced lubricity to the thermoplastic articles.

[0008] In accordance with a first aspect of the present disclosure, a thermoplastic article formed from a thermoplastic composition is disclosed. The thermoplastic composition comprises: (a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and (b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein theadditive has a D90 particle size of less than 50 microns in a dry state, and wherein the thermoplastic composition comprises from 0.1 to 20 wt.% of the additive.

[0009] In a second aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the thermoplastic elastomer has a Shore D hardness of 1 to 80.

[0010] In a third aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the additive has a D90 particle size of less than 30 microns in a dry state.

[0011] In a fourth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the additive has a D90 particle size of less than 20 microns in a dry state.

[0012] In a fifth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the additive has a D90 particle size of from 3 to 30 microns in a dry state.

[0013] In a sixth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the thermoplastic elastomer comprises thermoplastic polyurethane.

[0014] In a seventh aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the additive comprises polyvinylpyrrolidone.

[0015] In accordance with an eighth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, a film comprising the thermoplastic article is disclosed.

[0016] In a ninth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the film has a thickness of 24 microns to 4 millimeters.

[0017] In a tenth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the D90 particle size of the additive is less than the thickness of the film.

[0018] In an eleventh aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the D90 particle size of the additive is less than 50% of the thickness of the film.

[0019] In a twelfth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the D90 particle size of the additive is less than 10% of the thickness of the film.

[0020] In accordance with a thirteenth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, a tube comprising the thermoplastic article is disclosed.

[0021] In accordance with a fourteenth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, a tube comprising the film is disclosed.

[0022] In a fifteenth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the tube has a diameter of 3 to 20 french.

[0023] In a sixteenth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the tube comprises a single-layer wall.

[0024] In a seventeenth aspect of the disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the tube comprises a multi-layer wall.

[0025] In accordance with an eighteenth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, a method of preparing a thermoplastic article is disclosed. The method comprises (a) providing ingredients comprising a thermoplastic elastomer and an additive, wherein the thermoplastic elastomer has a Shore A hardness of 35 to 99, wherein the additive comprises a crosslinked hydrogel, and wherein the additive has a D90 particle size of less than 50 microns in a dry state; (b) compounding the ingredients to provide a thermoplastic composition, wherein the thermoplastic composition comprises from 0.1 to 20 wt.% of the additive; and (c) processing the thermoplastic composition to provide the thermoplastic article.

[0026] In accordance with a nineteenth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, a pellet comprising a thermoplastic composition is disclosed. The thermoplastic composition comprises: (a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and (b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein the additive has a D90 particle size of less than 30 microns in a dry state.

[0027] In accordance with a twentieth aspect of the present disclosure, which may be combined with any other aspect listed herein unless specified otherwise, the use of pellets in the manufacture of a single wall catheter is disclosed. The pellets comprise (a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and (b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein the additive has a D90 particle size of less than 30 microns in a dry state.DESCRIPTION OF THE FIGURES

[0028] The advantages of the inventive concepts will be apparent upon consideration of the following detailed disclosure, especially when taken in conjunction with the accompanying drawings wherein:

[0029] FIG. 1 is a line plot showing the relationship between additive particle size and the surface roughness of a thermoplastic article;

[0030] FIG. 2 is a bar graph showing the relationship between additive particle size, surface roughness, and film thickness of a thermoplastic article; and

[0031] FIG. 3 is a bar graph showing relationship between additive particle size, Static Coefficient of Friction, and film thickness of a thermoplastic article.DETAILED DESCRIPTION

[0032] Disclosed herein are thermoplastic articles formed from a thermoplastic composition including a thermoplastic elastomer and an additive compounded in the thermoplastic elastomer, as well as methods of preparing the thermoplastic articles. The particle size of the additive is adapted to provide reduced surface roughness, and thus enhanced lubricity, to the thermoplastic articles. While the present disclosure describes certain embodiments of the articles and methods of manufacture in detail, the present disclosure is to be considered exemplary and is not intended to be limited to the disclosed embodiments.

[0033] As used herein, the term “compounding” (including related terms, such as “compounded”) refers to the formation of a composition or mixture via melt mixing a neat polymer resin and at least one other ingredient including, but not limited to, one or more additives, or one or more other polymer resins, or both.

[0034] As used herein, the term “thermoplastic” refers to a polymer that softens when exposed to heat and returns to its original condition when at room temperature.

[0035] The terminology as set forth herein is for description of the embodiments only and should not be construed as limiting the disclosure as a whole. All references to singular characteristics or limitations of the present disclosure shall include the corresponding plural characteristic or limitation, and vice versa, unless otherwise specified or clearly implied to the contrary by the context in which the reference is made. Unless otherwise specified, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the description and the appended claims, the singular forms “a,” “an,” and “the” are inclusive of their plural forms, unless the context clearly indicates otherwise.

[0036] To the extent that the term “includes” or “including” is used in the description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use.

[0037] All combinations of method or process steps as used herein can be performed in any order, unless otherwise specified or clearly implied to the contrary by the context in which the referenced combination is made.

[0038] All ranges and parameters, including but not limited to percentages, parts, and ratios, disclosed herein are understood to encompass any and all sub-ranges assumed and subsumed therein, and every number between the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 1 to 6.1, or 2.3 to 9.4), and to each integer (1, 2, 3, 4, 5, 6, 7, 8, 9, and 10) contained within the range.

[0039] The articles and methods of manufacture of the present disclosure can comprise, consist of, or consist essentially of the essential elements of the disclosure as described herein, as well as any additional or optional element described herein, or which is otherwise useful in thermoplastic compounding applications.

[0040] Thermoplastic compositions are further described in co-pending U.S. Pat. Appln. Pub. No. 2022 / 0119724, which is incorporated by reference herein in its entirety.Thermoplastic Elastomer(s)

[0041] A thermoplastic article formed from a thermoplastic composition is disclosed. The thermoplastic composition comprises a thermoplastic elastomer and an additive compounded in the thermoplastic elastomer.

[0042] In general, the thermoplastic elastomer (“TPE”) may comprise any thermoplastic elastomer known for use in biomedical tubing devices, such as catheters. The thermoplastic elastomer may have a Shore A hardness of 35 to 99, including a Shore A hardness of 40 to 95, including a Shore A hardness of 45 to 95, including a Shore A hardness of 50 to 95, including a Shore A hardness of 60 to 90, including a Shore A hardness of 60 to 85, including a Shore A hardness of 65 to 85, including a Shore A hardness of 65 to 80, including a Shore A hardness of 65 to 75, including a Shore A hardness of 70 to 80. The thermoplastic elastomer may instead, or additionally, have a Shore D hardness of 1 to 80, including a Shore D hardness of 5 to 75, including a Shore D hardness of 20 to 75, including a Shore D hardness of 10 to 70, including a Shore D hardness of 15 to 60, including a Shore D hardness of 20 to 50, including a Shore D hardness of 25 to 50, including a Shore D hardness of 20 to 40, including a Shore D hardness of 25 to 40, including a Shore D hardness of 20 to 35.

[0043] The thermoplastic elastomer may comprise, or consist of, thermoplastic polyurethane (“TPU”), polyether block amide (“PEBA”), or a combination thereof.

[0044] With reference to exemplary thermoplastic elastomers, the terms “TPU” and “thermoplastic polyurethane” are used interchangeably herein, and refer to polymers containing urethane (also known as carbamate) linkages, urea linkages, amide, or combinations thereof (e.g., in the case of poly(urethane-urea)s). Thus, the subject thermoplastic polyurethanes contain at least urethane linkages and, optionally, urea or amide linkages.

[0045] In general, the TPU may be based on aliphatic chemistries or aromatic chemistries. The term “aromatic,” as used herein, refers to TPUs derived from mononuclear aromatic hydrocarbon groups or polynuclear aromatic hydrocarbon groups. The term encompasses those TPUs derived from arylene groups, i.e., a divalent aromatic group. The term “aliphatic,” as used herein, refers to TPUs derived from saturated or unsaturated, linear, branched, or cyclic hydrocarbon groups. This term encompasses those TPUs derived from alkylene (e.g., oxyalkylene), aralkylene, and cycloalkylene (e.g., oxycycloalkylene) groups, as a non-limiting example. The term “alkylene group,” as used herein, refers to a saturated, linear or branched, divalent hydrocarbon group. In some aspects of the present disclosure, the preferred alkylene groups are oxyalkylene groups. The term “oxyalkylene group,” as used herein, refers to a saturated, linear or branched, divalent hydrocarbon group with a terminal oxygen atom. The term “aralkylene group,” as used herein, refers to a saturated, linear or branched, divalent hydrocarbon group containing at least one aromatic group. The term “cycloalkylene group,” as used herein, refers to a saturated, linear or branched, divalent hydrocarbon group containing at least one cyclic group. The term “oxycycloalkylene group,” as used herein, refers to a saturated, linear or branched, divalent hydrocarbon group containing at least one cyclic group and a terminal oxygen atom.

[0046] Non-limiting examples of commercially available TPU include grades of the PELLETHANE® brand, such as grade 2363 -80 AE, sold by The Lubrizol Corporation (Wickliffe, Ohio).; and grades of the ELASTOLLAN® brand, such as grade 1180A 10, sold by BASF Corporation (Florham Park, New Jersey). Other commercially available medical grades of TPU may additionally, or instead, be used.

[0047] With reference to exemplary thermoplastic elastomers, the terms “PEBA” and “polyether block amide” are used interchangeably herein, and refer to a block copolymer containing a hard segment of polyamide and a soft segment of polyether. Non-limiting examples of commercially available PEBAinclude grades of the PEBAX® brand, such as grades 3533 SA01 and 7233, sold by Arkema Group (Colombes, France); and grades of the VESTAMID® brand, sold by Evonik Industries AG (Essen, Germany). Other commercially available medical grades of PEBA may additionally, or instead, be used.

[0048] In addition to TPU and PEBA, other exemplary thermoplastic elastomers include, without limitation, fluoropolymers, nylon, other polyethers including polyether ether ketone (PEEK), polyurethane polyether, polyesters, polyester polyurethane, poly(styrene-butadiene- styrene) (SBS), styrene-ethylene-butylene-styrene (SEBS), poly(styrene-block-isobutylene-block- styrene) (SIBS), polyvinyl chloride (PVC), or combinations of any of the foregoing.Additive(s)

[0049] In general, the additive may comprise any additive known for use in biomedical tubing devices, such as catheters. The term “additive,” as used herein, is inclusive of one additive, or multiple additives in combination, unless otherwise specified.

[0050] The additive may comprise, or consist of, a hydrophilic water-insoluble polymer. The additive may comprise, or consist of, a crosslinked hydrogel. As used herein, the term “hydrogel”refers to a water-insoluble polymer network that is capable of swelling up to l,000x in water, depending upon the level of crosslinking. Exemplary crosslinked hydrogels include, without limitation, polyvinylpyrrolidone, polyolefin-polyoxyalkylene block copolymer, polyvinyl alcohol (PVOH), polysaccharides, polyethylene glycol (PEO), carboxymethyl cellulose (CMC), sodium salt CMC, amylose, amylopectin, polyacrylic acid, sodium salt of polyacrylic acid, salts of any of the foregoing, or copolymers containing two or more of the foregoing.

[0051] In some aspects of the disclosure, the additive may comprise a polyolefin- polyoxyalkylene block copolymer, crosslinked polyvinylpyrrolidone, or a combination thereof. In some aspects, the additive may comprise, or consist of, a crosslinked polyvinylpyrrolidone hydrogel.

[0052] The crosslinked polyvinylpyrrolidone (“PVP”) hydrogel may include conventional and commercially available crosslinked polyvinylpyrrolidone. With reference to exemplary crosslinked polyvinylpyrrolidone, the terms “PVP,” “crospovidone,” “insoluble polyvinylpyrrolidone,” and “crosslinked PVP” may be used interchangeably, unless otherwise specified herein. Non-limiting examples of commercially available crosslinked polyvinylpyrrolidone include grades of the KOLLIDON® brand, such as grades CL, CL-F, CL- SF, and CL-M sold by BASF Pharma (a division of BASF Corporation, Florham Park, New Jersey). These different grades of KOLLIDON® differ from each other at least in their particles size distributions, bulk densities, and swelling behaviors. In some aspects of the present disclosure, the crosslinked PVP is KOLLIDON® CL. Other commercially available grades of crosslinked polyvinylpyrrolidone may additionally, or instead, be used.

[0053] The polyolefin-polyoxyalkylene block copolymer may include conventional and commercially available polyolefin-polyoxyalkylene block copolymers. The polyolefin-polyoxyalkylene block copolymer may comprise a polypropylene-polyoxyethylene block copolymer. Non-limiting examples of commercially available polyolefin-polyoxyalkylene block copolymers include grades of the PELESTAT brand, such as grade 300, sold by Sanyo Chemical (Kyoto, Japan). Other commercially available grades of polyolefin-polyoxyalkylene block copolymer may additionally, or instead, be used.

[0054] In general, crosslinking may be undertaken by any known means to reduce the soluble fraction in water or aqueous fluid. Exemplary crosslinking methods include, but are not limited to, UV radiation, hydrogen bonding, chemical crosslinking, exposure to heat, crosslinking through melt processing or extrusion, interpenetrating networks, covalent coupling, radical crosslinking sites, metal ionomeric crosslinking with Lewis acids, ring opening, the use of crosslinking agents such as neopentyl glycol diacrylate (NPGDA), the use of free radical photo-initiators, the use of metal chelating crosslinkers, the use of ester and amide crosslinking, imide or anhydride formation, and ketone oxime imine formation.

[0055] Optionally, the additive may further comprise one or more auxiliary additives in addition to the hydrogel. In general, the auxiliary additive may comprise any additive known for use in biomedical tubing devices, such as catheters. Suitable auxiliary additives include commercially available plastics additives, including additives available in the reference E. W. Flick, “Plastics Additives Database,” Plastics Design Library (Elsevier 2004). The auxiliary additives may include antimicrobial agents, antioxidants, stabilizers, colorants, radiopaque agents, or combinations thereof. The one or more auxiliary additives may be included in the thermoplastic composition in any amount sufficient to obtain a desired processing or performance property for the thermoplastic composition and / or the thermoplastic article.

[0056] In some aspects of the disclosure, the auxiliary additive comprises one or more synergists. The synergist may include molecules that inhibit migration and / or additives that improve lubricity performance or aid in facile processing. The synergist may comprise a lubricant. Exemplary synergists include, but are not limited to, pyrrolidones in addition to the requisite hydrogel, including alkyl pyrrolidones, such as lauryl pyrrolidone, polyvinylpyrrolidones, such as low molecular weight polyvinylpyrrolidone, linear polyvinylpyrrolidone, and the like, aloe, polysorbates, such as polysorbate 80 (including Tween 80), polyethylene glycol (PEG), polyvinyl alcohol (PVOH), butylene glycol, urea, surfactants, polyelectrolytes, osmotic pressure additives, fatty amides, polyacrylic acid, metal acid salts, carboxylic acid salts, polyester polyurethane, poly(styrene-butadiene-styrene) (SBS), styrene-ethylene-butylene-styrene (SEBS), poly(styrene- block-isobutylene-block-styrene) (SIBS), hydrocarbon polymers, other thermoplastic elastomers, potassium chloride (KC1), sodium chloride (NaCl), potassium iodide (KI), and the like, iodine, silver, barium, other heavy metals, and combinations of any of the foregoing.Additive Particle Size

[0057] In accordance with the present disclosure, the additive has a particle size distribution, when in the dry state, such that at least 90% of particles have a particle size (D90) of less than 200 microns, including less than 150 microns, including less than 100 microns, including less than 75 microns, including less than 50 microns, including less than 30 microns, including less than 25 microns, including less than 20 microns, including less than 10 microns, including less than 5 microns. In some aspects, the additives have a D90 particle size of from 0.1 to 200 microns, including from 0.5 to 150 microns, including from 1 to 100 microns, including from 1 to 75 microns, including from 1 to 50 microns, including from 3 to 30 microns, including from 3 to 25 microns, including from 3 to 20 microns, including from 5 to 20 microns, including from 5 to 10microns. Unless otherwise specified, the particle sizes disclosed herein are measured by means of a laser light scattering technique, using a particle size analyzer from Malvern Instruments.

[0058] The inventors have surprisingly found that adapting the particle size of the additive provides reduced surface roughness, and thus enhanced lubricity, to the thermoplastic articles.

[0059] Specifically, the particle size of the additive may be altered via grinding the additive. The term “grinding” as used herein encompasses any known methods of milling or other processing to produce a smaller particle size. More specifically, the particle size of the additive may be altered via cryogenic grinding (“cryogrinding”), which is an operation performed in a cryogenic mixing and grinding vessel. In some aspects of the disclosure, the additive is subjected to up to four consecutive cryogrinding steps, including three consecutive cryogrinding steps, including two consecutive cryogrinding steps, including one cryogrinding step.

[0060] Conventionally, in order to achieve the requisite catheter lubricity required by the end consumer, it has been found that additive-coated thermoplastic articles provide superior performance to additive-compounded thermoplastic articles. This is because it has previously proven difficult to produce a smooth film surface in thin-walled medical tubing applications via thermoplastic compounding. Known thermoplastic compounding methods have been unable to avoid the excessive migration of additives to the surface of the film, which produces an uneven film thickness (z.c., defects) and surface roughness undesirable for medical tubing. This excessive migration can likewise result in the small particle size additives leaching from the thermoplastic article altogether.

[0061] Here, though, the inventive use of small particle size additives improves the surface roughness and the lubricity of thin-walled thermoplastic articles, while avoiding the leaching issues previously observed in thermoplastic compounding of thin-walled medical tubing.

[0062] The inventive ability to produce thin walled (i.e., thin film) thermoplastic articles without experiencing surface quality issues is of particular importance to the disclosure. The inventors have found that the film thickness directly effects the lubricity of the thermoplastic article, in that thinner parts of the film display the best lubricious performance. Specifically, it has been found that the wall thickness of the thermoplastic article and the particle size of the additive can be correlated in preferred ratios.

[0063] In some aspects of the disclosure, the thermoplastic article is a film having a thickness of 24 microns to 4 millimeters, including a thickness of 50 microns to 3 millimeters, including a thickness of 0.1 millimeters to 2 millimeters, including a thickness of 0.1 millimeters to 1 millimeter, including a thickness of 0.1 millimeters to 0.75 millimeters including a thickness of 0.1 millimeters to 0.5 millimeters, including a thickness of 0.15 millimeters to 0.5 millimeters, including a thickness of 0.17 millimeters to 0.45 millimeters, including a thickness of 0.35 millimeters to 0.45 millimeters, including a thickness of 0.17 millimeters to 0.22 millimeters.

[0064] In some aspects of the disclosure, the D90 particle size of the additive is less than the thickness of the film, including a D90 particle size of the additive that is less than 75% of the thickness of the film, including a D90 particle size of the additive that is less than 60% of the thickness of the film, including a D90 particle size of the additive that is less than 50% of the thickness of the film, including a D90 particle size of the additive that is less than 40% of the thickness of the film, including a D90 particle size of the additive that is less than 30% of the thickness of the film, including a D90 particle size of the additive that is less than 25% of the thickness of the film, including a D90 particle size of the additive that is less than 20% of the thickness of the film, including a D90 particle size of the additive that is less than 10% of thethickness of the film, including a D90 particle size of the additive that is less than 5% of the thickness of the film.

[0065] In some aspects of the disclosure, the thermoplastic article is a tube having a wall thickness of 24 microns to 4 millimeters, including a thickness of 50 microns to 3 millimeters, including a thickness of 0.1 millimeters to 2 millimeters, including a thickness of 0. 1 millimeters to 1 millimeter, including a thickness of 0.1 millimeters to 0.75 millimeters including a thickness of 0.1 millimeters to 0.5 millimeters, including a thickness of 0.15 millimeters to 0.5 millimeters, including a thickness of 0.17 millimeters to 0.45 millimeters, including a thickness of 0.35 millimeters to 0.45 millimeters, including a thickness of 0.17 millimeters to 0.22 millimeters.Ranges of Ingredients

[0066] Table 1 shows exemplary ranges of ingredients for the thermoplastic composition, in terms of weight percent (wt. %) based upon the total weight of the thermoplastic composition. In any of the embodiments disclosed herein, the thermoplastic composition may comprise, consist essentially of, or consist of the ingredients of Table 1. It is to be appreciated that any individual range from Ranges 1, 2 and 3 may be combined with any other compositional range(s) of Ranges 1, 2, and 3 in Table 1 below. For example, any of the individual ranges from Range 1 may be combined with the ranges in Ranges 2 and / or 3, etc.

[0067] All percentages, parts, and ratios as used herein are by weight of the total blend on an “dry” basis, z.e., without solvents, unless otherwise specified.Table 1Methods of Preparing Thermoplastic Articles

[0068] In some aspects of the disclosure, the thermoplastic composition may be formed into a plurality of particles via extrusion or other means. Accordingly, the thermoplastic composition of the present invention may be in the form of pellets.

[0069] The thermoplastic composition may be made in batch or continuous operations. Mixing in a continuous process typically occurs in an extruder that is elevated to a temperature that is sufficient to melt the polymer matrix with addition of all additives at the feed-throat, or by injection or side-feeders downstream. Extruder speeds may range from 200 to 700 revolutions per minute (rpm), including from 300 rpm to 600 rpm. Typically, the output from the extruder is pelletized, e.g., ground or milled, to form minipellets, micropellets, pellets, or the like. The pelletized extruder output can then be used to form the thermoplastic article.

[0070] Generally, the subsequent thermoplastic articles of the present invention may be made by extrusion, injection molding, blow molding, rotational molding, thermoforming, calendering, and the like. General processing techniques are described in available references, for example, Dominick V. Rosato et al., Plastics Design Handbook (Springer 2013). Methods for forming thermoplastic articles from the thermoplastic composition via extrusion include adjusting various processing parameters including, but not limited to, ovality parameters, the gas flow rate, the free surface region, diameter, wall thickness, the screw speed, puller speed, the pull force, the tip and die design, process temperatures including zone temperatures, the cooling process, the manner of feeding, the use of a vacuum water tank, the use of coextrusion. Other downstream methodsinclude, without limitation, melt processing the thermoplastic composition with drugs for use in medical tubing, sterilization of the thermoplastic compounds via gamma, UV, X-ray, or other standard practices, processing the thermoplastic composition with further additives to impart radiopacity, antimicrobial, or further lubricity to the thermoplastic article, treatments with isopropanol or other traditional solvents, or any combination of the foregoing.

[0071] In some aspects of the present disclosure, a method of preparing a thermoplastic article includes the steps of: (a) providing ingredients comprising a thermoplastic elastomer and an additive; (b) compounding the ingredients to provide a thermoplastic composition; and (c) processing the thermoplastic composition to provide the article for the intended use, wherein the article comprises a film or a tube. The step of compounding the ingredients may include extruding the thermoplastic elastomer and additive.Use of the Thermoplastic Articles

[0072] In accordance with the present disclosure, the intended use of the thermoplastic composition is to make any thermoplastic article that requires enhanced lubricity.

[0073] In one aspect, the disclosure is directed to the use of pellets in the manufacture of a single wall catheter, the pellets comprising, or consisting of, the thermoplastic composition.

[0074] In one aspect, a tube comprises, or consists of, the thermoplastic article. The tube may have a diameter of from 3 to 20 french, including from 5 to 20 french, including from 4 to 18 french, including from 8 to 20 french, including from 10 to 20 french, including from 6 to 16 french, including from 10 to 16 french, including from 6 to 10 french, including from 10 to 12 french, including from 14 to 16 french. The thermoplastic articles may be used as single layer medical tubing, or as an outer layer in a multilayer tube.

[0075] Thermoplastic compositions of the present disclosure are particularly useful for making thermoplastic articles for biomedical applications, including, but not limited to, catheters, single wall tubing, multilayer tubing, connectors, valves, trocars, and the like. Exemplary biomedical articles include, but are not limited to, external catheters, neural catheters, urinary catheters, IVs, endotracheal tubing, respiratory tubing, feeding tubes, ports, vascular catheters, nasal cannula tubing, stents, colonoscopy tubing, scope imaging tubing, guide wires, surgical delivery tubing, indwelling, intermittent, or ex vivo applications, or any portions of a medical device where altered surface energy is required.

[0076] In one aspect, the intended use includes inserting the lubricious thermoplastic article into a human body.

[0077] In accordance with the present disclosure, it is possible to utilize the various inventive concepts in combination with one another. Additionally, any particular feature recited as relating to a particularly disclosed aspect of the methods and systems of the present disclosure should be interpreted as available for use with all disclosed aspects of the methods and systems of the present disclosure, unless incorporation of the particular feature would be contradictory to the express terms of the disclosed aspect. Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore, the disclosure, in its broader aspects, is not limited to the specific details presented therein, the representative apparatus, or the illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concepts.EXAMPLES

[0078] The following examples are included for the purposes of illustration, and do not limit the scope of the general inventive concepts described herein.Example 1

[0079] A study was conducted to evaluate the difference in surface roughness of thermoplastic articles based upon the particle size of the additives.

[0080] Three separate exemplary thermoplastic compositions were prepared, in which a commercially available polyvinylpyrrolidone hydrogel (KOLLIDON® CL), i.e., a PVP additive, was compounded into a commercially available thermoplastic polyurethane (PELLETHANE® 2363-80AE), i.e., a TPU elastomer, in order to form a thermoplastic article. In all samples of the exemplary thermoplastic compositions, the PVP additive was compounded at 7 wt. %, based upon the total weight of the thermoplastic composition. Accordingly, the only distinction between each of the three samples was the particle size of the PVP additive.

[0081] For the control sample, the PVP additive was compounded into the TPU as received, i.e., with no changes to the PVP additive particle size. This sample constituted the “large particle size” of the study, with a D90 value of 160 microns.

[0082] For the first exemplary sample, the PVP additive was subjected to cryogrinding twice prior to compounding with the TPU. This exemplary sample constituted the “medium particle size” of the study, with a D90 value of 47 microns.

[0083] For the second exemplary sample, the PVP additive was subjected to cryogrinding four times prior to compounding with the TPU. This exemplary sample constituted the “small particle size” of the study, with a D90 value of 28 microns.

[0084] Each of the three thermoplastic compositions were then processed under identical conditions to form thermoplastic articles, i.e., films. Specifically, each of the thermoplastic compositions were melt compounded into films of identical thicknesses and cooled under subambient temperatures.

[0085] As shown in FIG. 1, a reduction in the particle size of the PVP additive provides a reduction in the surface roughness of the resultant thermoplastic fdm, with the small particle size sample having the lowest surface roughness.Example 2

[0086] The same three thermoplastic films produced in Example 1 were further studied to evaluate the relationship between the thickness of the thermoplastic film and the surface roughness.

[0087] Specifically, the surface roughness of each of the thermoplastic films were evaluated for their root mean squared surface roughness using a microscope. Various sections of the films were analyzed to establish the impact that particle size has on a thermoplastic film. As shown in FIG. 2, the improvements in surface roughness of each sample are dependent upon the film thickness. Smaller particle sizes contributed to lower root mean squared surface roughness values in both thin and thick films, with a greater effect being demonstrated in thinner films.Example 3

[0088] The same three thermoplastic films produced in Example 1 were further studied to evaluate the difference in the static coefficient of friction (“Static COF”) of thermoplastic articles based upon both the presence of an additive and upon the particle size of the additive. For this example, an additional control was prepared (“Pellethane Control”). The Pellethane Control sample constituted a thermoplastic article produced from the same commercially available thermoplastic polyurethane (PELLETHANE® 2363-80AE) as the prior examples, but the Pellethane Control sample included no PVP additive, i.e., no additive was compounded into theTPU.

[0089] For each sample, the Static COF was measured using a da Vinci setup of a sliding friction test. Specifically, each film was fixed to a submerged 200 gram sled and evaluated against a silicone substrate. The sled and film fixture were attached to a pulley weight system. Thereafter, weight was added to the pully system until the fixed film moved along the substrate. This weight, and associated force, allowed for the calculation of the static coefficient of friction value.

[0090] As shown in FIG. 3, the presence of a PVP additive reduces the Static COF by 35-68%. Further, controlling the film thickness in favor of thinner films provides a reduced Static COF.

[0091] Although the present invention has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the present invention and various changes and modifications can be made to adapt the various uses and characteristics without departing from the spirit and scope of the present invention as described above and set forth in the attached claims.

[0092] From the foregoing, it will be seen that this invention is one well-adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

[0093] It will be understood that certain features and sub-combinations are of utility and can be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.

[0094] While specific elements and steps are discussed in connection to one another, it is understood that any element and / or steps provided herein is contemplated as being combinable with any other elements and / or steps regardless of explicit provision of the same while still being within the scope provided herein. Since many possible embodiments can be made of the disclosurewithout departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

[0095] All documents cited herein are incorporated herein by reference in their entirety unless otherwise specified. The citation of any document is not to be construed as an admission that it is prior art with respect to the disclosed invention.

[0096] It will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. Although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

Claims

CLAIMSWhat is claimed is:

1. A thermoplastic article formed from a thermoplastic composition, the thermoplastic composition comprising:(a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and(b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein the additive has a D90 particle size of less than 50 microns in a dry state, and wherein the thermoplastic composition comprises from 0.1 to 20 wt.% of the additive.

2. The thermoplastic article of claim 1, wherein the thermoplastic elastomer has a Shore D hardness of 1 to 80.

3. The thermoplastic article of claim 1 or claim 2, wherein the additive has a D90 particle size of less than 30 microns in a dry state.

4. The thermoplastic article of any one of claims 1-3, wherein the additive has a D90 particle size of less than 20 microns in a dry state.

5. The thermoplastic article of any one of claims 1-4, wherein the additive has a D90 particle size of from 3 to 30 microns in a dry state.

6. The thermoplastic article of any one of claims 1 -5, wherein the thermoplastic elastomer comprises thermoplastic polyurethane.

7. The thermoplastic article of any one of claims 1-6, wherein the additive comprises polyvinylpyrrolidone.

8. A film comprising the thermoplastic article of any one of claims 1-7.

9. The film of claim 8, wherein the film has a thickness of 24 microns to 4 millimeters.

10. The film of claim 8 or claim 9, wherein the D90 particle size of the additive is less than the thickness of the film.

11. The film of any one of claims 8-10, wherein the D90 particle size of the additive is less than 50% of the thickness of the film.

12. The film of any one of claims 8-11, wherein the D90 particle size of the additive is less than 10% of the thickness of the film.

13. A tube comprising the thermoplastic article of any one of claims 1-7.

14. A tube comprising the film of any one of claims 8-12.

15. The tube of claim 13 or claim 14, wherein the tube has a diameter of 3 to 20 french.

16. The tube of any one of claims 13-15, wherein the tube comprises a single-layer wall.

17. The tube of any one of claims 13-15, wherein the tube comprises a multi-layer wall.

18. A method of preparing a thermoplastic article, the method comprising:(a) providing ingredients comprising a thermoplastic elastomer and an additive, wherein the thermoplastic elastomer has a Shore A hardness of 35 to 99, wherein the additive comprises a crosslinked hydrogel, and wherein the additive has a D90 particle size of less than 50 microns in a dry state;(b) compounding the ingredients to provide a thermoplastic composition, wherein the thermoplastic composition comprises from 0.1 to 20 wt.% of the additive; and(c) processing the thermoplastic composition to provide the thermoplastic article.

19. A pellet comprising a thermoplastic composition, the thermoplastic composition comprising:(a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and(b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein the additive has a D90 particle size of less than 30 microns in a dry state.

20. The use of pellets in the manufacture of a single wall catheter, the pellets comprising:(a) a thermoplastic elastomer having a Shore A hardness of 35 to 99; and(b) an additive dispersed in the thermoplastic elastomer, the additive comprising a crosslinked hydrogel, wherein the additive has a D90 particle size of less than 30 microns in a dry state.

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