Low fluid retention articles and methods of forming the same

Abstract

Disclosed herein are articles including, a substrate having a first surface and a polyalphaolefin composition disposed on at least a portion of the first surface of the substrate. The polyalphaolefin composition has a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

Description

Low FLUID RETENTION ARTICLES AND METHODS OF FORMING THE SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 702,451 filed on October 2, 2024, U.S. Provisional Application Serial No. 63 / 566,611 filed on March 18, 2024, U.S. Provisional Application Serial No. 63 / 710,186 filed on October 22, 2024, U.S. Provisional Application Serial No. 63 / 650,679 filed on May 22, 2024, U.S. Provisional Application Serial No. 63 / 769,721 filed on March 10, 2025, and U.S. Provisional Application Serial No. 63 / 769,712 filed on March 10, 2025, the contents of each of which are relied upon and are incorporated herein by reference in their entireties.BACKGROUNDField

[0002] The present specification generally relates to low fluid retention articles and, in particular, to articles comprising polyalphaolefin compositions that have low fluid retention.Technical Background

[0003] Polymeric parts having low fluid retention surfaces may have various applications, such as pipette tips, bags, tubes, and spheroid plates, among other examples. Conventionally, a fluorinated compound may be added to a polymer composition to reduce fluid retention. However, the use of fluorinated compounds may lead to increased manufacturing times, due to slow surface development of the fluorinated compound. Moreover, in certain industries, it may be desirable to avoid fluorinated compounds due to their potential environmental impact. Silicone oils have also conventionally been used as a coating to produce low fluid retention surfaces. However, silicone oils may be soluble in common reagents, such as isopropyl alcohol, leading to contamination of fluid that contacts the article comprising the silicone oil coating.

[0004] Therefore, a continuing need exists for articles that have reduced fluid retention while being non-fluorinated and methods for making such articles.SUMMARY

[0005] According to a first aspect Al, an article comprises: a substrate comprising a first surface; and a polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, the polyalphaolefin composition comprising a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0006] A second aspect A2 includes the article of the first aspect Al, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

[0007] A third aspect A3 includes the article of the first aspect Al or the second aspect A2, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

[0008] A fourth aspect A4 includes the article of any one of the first to third aspects Al- A3, wherein the polyalphalolefin composition comprises a polyalphaolefin having a structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

[0009] A fifth aspect A5 includes the article of the fourth aspect A4, wherein the polyalphaolefin composition comprises greater than or equal to 90 wt.% of the polyalphaolefin, based on a total weight of the polyalphaolefin composition.

[0010] A sixth aspect A6 includes the article of any one of the first to fifth aspects A1-A5, wherein the substrate comprises a thermoplastic polymer composition.

[0011] A seventh aspect A7 includes the article of the sixth aspect A6, wherein the thermoplastic polymer composition comprises polypropylene, polystyrene, polymethylmethacrylate, polyvinyl chloride, polycarbonate, polysulfone, polyester, polyamide, polystyrene butadiene copolymers, fully hydrogenated styrenic polymers, polyurethanes, polyethylene, polymethyl pentene, polylactic acid, polybutylene succinate, polyhydroxyalkamoate, or a combination thereof.

[0012] An eighth aspect A8 includes the article of the sixth aspect A6 or the seventh aspect A7, wherein the thermoplastic polymer composition further comprises one or more additivesselected from the group consisting of an antioxidant, a clarifying agent, a nucleating agent, an antistatic agent, a colorant, a radiation stability agent, and a conductive agent.

[0013] A ninth aspect A9 includes the article of the eighth aspect A8, wherein the thermoplastic polymer composition comprises greater than 0 wt.% and less than or equal to 10 wt.% of the one or more additives.

[0014] A tenth aspect A10 includes the article of any one of the first to ninth aspects Al- A9, wherein the article comprises a fluid retention of less than or equal to 10% as measured by a fluid retention test.

[0015] An eleventh aspect Al 1 includes the article of any one of the first to tenth aspects A1-A10, wherein the article comprises a fluid retention of less than or equal to 5% as measured by a fluid retention test.

[0016] A twelfth aspect Al 2 includes the article of any one of the first to tenth aspects Al- A10, wherein the article comprises a fluid retention of less than or equal to 1% as measured by a fluid retention test.

[0017] A thirteenth aspect Al 3 includes the article of any one of the first to twelfth aspectsAl -Al 2, wherein the polyalphaolefin composition is free or substantially free of fluorine.

[0018] A fourteenth aspect Al 4 includes the article of any one of the first to twelfth aspectsAl -Al 2, wherein the article is selected from the group consisting of a pipette tip, a bag, a tube, and a spheroid plate.

[0019] A fifteenth aspect Al 5 includes the article of the fourtheenth aspect Al 4, wherein the article is the pipette tip.

[0020] A sixteenth aspect Al 6 includes the article of the fifteenth aspect Al 5, wherein the pipette tip comprises a liquid containment portion and an attachment portion, and wherein the first surface of the substrate is an interior surface of the pipette tip.

[0021] A seventeenth aspect Al 7 includes the article of the sixteenth aspect Al 6, wherein the polyalphaolefin composition is disposed on at least a portion of the first surface of the substrate in the liquid containment portion of the pipette tip.

[0022] An eighteenth aspect Al 8 includes the article of the sixteenth aspect Al 6 or the seventeenth aspect Al 7, wherein at least 90% of the first surface of the substrate in the liquid containment portion of the pipette tip is in direct contact with the polyalphaolefin composition.

[0023] A nineteenth aspect Al 9 includes the article of any one of the sixteenth to eighteenth aspects Al 6- Al 8, wherein the first surface of the substrate in the attachment portion of the pipette tip is substantially free from the polyalphaolefin composition.

[0024] According to a twentieth aspect A10, a method of forming an article comprises: coating at least a portion of a mold with a polyalphaolefin composition; disposing a thermoplastic polymer composition into the mold; solidifying the thermoplastic polymer composition within the mold to form an article; and removing the article from the mold; wherein the article comprises: a substrate comprising a first surface; and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, wherein the polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0025] A twenty-first aspect A21 includes the method of the twentieth aspect A20, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

[0026] A twenty-second aspect A22 includes the method of the twentieth aspect A20 or the twenty-first aspect A21, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

[0027] A twenty-third aspect A23 includes the method of any one of the twentieth to twenty-second aspects A20-A22, wherein the polyalphalolefin composition comprises a polyalphaolefin having the structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

[0028] A twenty-fourth aspect A24 includes the method of any one of the twentieth to twenty-third aspects A20-A24, wherein the polyalphaolefin composition is free or substantially free of fluorine.

[0029] A twenty-fifth aspect A25 includes the method of any one of the twentieth to twenty -fourth aspects A20-A24, wherein the formed article comprises a fluid retention of less than or equal to 10% as measured by a fluid retention test.

[0030] A twenty-sixth aspect A26 includes the method of any one of the twentieth to twenty-fifth aspects A20-A25, wherein the article comprises a pipette tip.

[0031] According to a twenty-seventh aspect A27, a method of forming an article comprises: solidifying a thermoplastic polymer composition within a mold to form a substrate, wherein the substrate comprises a first surface; and coating at least a portion of the first surface of the substrate with a polyalphaolefin composition to form an article, wherein the article comprises: the substrate; and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, wherein the polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0032] A twenty-eighth aspect A28 includes the method of the twenty- seventh aspect A27, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

[0033] A twenty-ninth aspect A29 includes the method of the twenty-seventh aspect A27 or the twenty-eighth aspect A28, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

[0034] A thirtieth aspect A30 includes the method of any one of the twenty-seventh to twenty-ninth aspects A27-A29, wherein the polyalphalolefin composition comprises a polyalphaolefin having the structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

[0035] A thirty-first aspect A30 includes the method of any one of the twenty-seventh to thirtieth aspects A27-A30, wherein the polyalphaolefin composition is free or substantially free of fluorine.

[0036] A thirty-second aspect A32 includes the method of any one of the twenty-seventh to thirty-first aspects A27-A31, wherein the formed article comprises a fluid retention of less than or equal to 10% as measured by a fluid retention test.

[0037] A thirty -third aspect A33 includes the method of any one of the twenty-seventh to thirty-third aspects A27-A32, wherein the article is a pipette tip.

[0038] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 schematically depicts an article, according to one or more embodiments of the present disclosure;

[0040] FIG. 2 depicts a cross-sectional view of a pipette tip, according to one or more embodiments of the present disclosure;

[0041] FIG. 3 is a photograph of a pipette tip holding fluid, according to Example 1 of the present disclosure;

[0042] FIG. 4 is a photograph of a comparative pipette tip with visible retained fluid, according to Example 1 of the present disclosure.

[0043] FIG. 5 is a photograph of an exemplary pipette tip with no visible retained fluid, according to Example 1 of the present disclosure;

[0044] FIG. 6 is a photograph of an emulsion of a polyalphaolefin composition in isopropyl alcohol, according to Example 2 of the present disclosure; and

[0045] FIG. 7 is a photograph of a separated emulsion of the polyalphaolefin composition in isopropyl alcohol, according to Example 2 of the present disclosure.DETAILED DESCRIPTION

[0046] Reference will now be made in detail to various embodiments of articles having low fluid retention and methods for making articles having low fluid retention.

[0047] According to embodiments, the article comprises a substrate comprising a first surface and a polyalphaolefin composition disposed on at least a portion of the first surface of the substrate. The polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0048] According to embodiments, a method of forming an article comprises coating at least a portion of a mold with a polyalphaolefin composition, disposing a thermoplastic polymer composition into the mold; solidifying the thermoplastic polymer composition within the mold to from an article and removing the article from the mold. The article comprises a substrate comprising a first surface and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate. The polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0049] According to embodiments, a method of forming an article comprises solidifying a thermoplastic polymer composition within a mold to form a substrate, wherein the substrate comprises a first surface, and coating at least a portion of the first surface of the substrate with a polyalphaolefin composition to form an article. The article comprises the substrate and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate. The polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

[0050] Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0051] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0052] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0053] As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0054] The term “substantially free,” when used to describe the amount and / or absence of a particular component in a composition and the resultant article, means that the component is not intentionally added to the composition and the resultant article. However, the composition and theresultant article may contain traces of the component as a contaminant or tramp in amounts of less than 0.05 weight percent (wt%).

[0055] The term “free,” when used to describe the amount and / or absence of a particular component in a composition and the resultant articles, means that the component is not present in the article.

[0056] As described herein, polymeric parts having low fluid retention surfaces may have various applications, such as pipette tips, bags, tubes, and spheroid plates, among other examples. Conventionally, a fluorinated compound may be added to a polymer composition to reduce fluid retention. However, the use of fluorinated compounds may lead to increased manufacturing times, due to slow surface development of the fluorinated compound. Moreover, in certain industries, it may be desirable to avoid fluorinated compounds due to their potential environmental impact. Silicone oils have also conventionally been used as a coating to produce low fluid retention surfaces. However, silicone oils may be soluble in common reagents, such as isopropyl alcohol, leading to contamination of fluid that contacts the article comprising the silicone oil coating.

[0057] Disclosed herein are articles that mitigate the aforementioned problems. Specifically, articles described herein comprise a substrate having a first surface, and a polyalphaolefin composition disposed on at least a portion of the first surface. The polyalphaolefin composition has a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C. The specified viscosity of the polyalphaolefin composition described herein ensures that the polyalphaolefin is not mechanically shed from the surface of the substrate or dissolved in conventional solvents, such as isopropyl alcohol. The articles comprising the polyalphaolefin compositions described herein are nonfluorinated articles having low fluid retention. As used herein, a “non-fluorinated article” is an article that is free or substantially free of fluorine.

[0058] Referring now to FIG. 1, the article 100 may comprise a substrate 110 and a polyalphaolefin composition 120. The substrate 110 may comprise a first surface 112. In one or more embodiments, the substrate 110 may comprise a second surface 114 opposite the first surface 112. In one or more embodiments, the first surface 112 and the second surface 114 may be major surfaces of the substrate 110.

[0059] In one or more embodiments, the first surface 112 of the substrate 110 may have an average roughness (Ra) of less than 25 nm. For example, without limitation, the first surface 112 of the substrate 110 may have an average roughness (Ra) of less than 25 nm, 24 nm, 23 nm, 22 nm, 21 nm, or 20 nm. As described herein the “average roughness (Ra)” refers to the arithmetic average of height deviations from the mean height of a surface. Without intending to be bound by theory, when the first surface 112 of the substrate 110 has an average roughness (Ra) of less than 25 nm, the article 100 may have a visually clear and clean look. Additionally, the roughness of the first surface 112 of the substrate 110 may contribute to preventing the mechanical shedding of the polyalphaolefin composition 120 from the first surface 112 of the substrate by providing increased surface area over which the polyalphaolefin composition 120 may contact the first surface 112 of the substrate 110. For example, the roughness of the first surface 112 of the substrate 110 may be at least partially the result of features on the first surface 112 that may be filled with the polyalphaolefin composition 120, improving the stability of the layer of the polyalphaolefin composition 120 on the first surface 112.

[0060] In one or more embodiments, the substrate 110 may comprise a thermoplastic polymer composition. The thermoplastic polymer composition used in the substrate 110 is not necessarily limited. For example, the thermoplastic polymer composition may be selected based on the intended use of the article 100. In one or more embodiments, the thermoplastic polymer composition may comprise polypropylene, polystyrene, polymethylmethacrylate, polyvinyl chloride, polycarbonate, polysulfone, polyester, polyamide, polystyrene butadiene copolymers, fully hydrogenated styrenic polymers, polyurethanes, polyethylene, polymethyl pentene, polylactic acid, polybutylene succinate, polyhydroxyalkamoate, or a combination thereof. In some embodiments, the thermoplastic polymer composition may comprise polypropylene. In one or more embodiments, the thermoplastic polymer may comprise a melt index (L) greater than or equal to 10 g / mol and less than or equal to 75 g / mol, as measured according to ASTM method DI 238 at 190 °C and 2.16 kg, to ensure moldability.

[0061] In some embodiments, the thermoplastic polymer composition may comprise one or more additives. The additives that may be included in the thermoplastic polymer composition are not necessarily limited. In embodiments, the additives may comprise antioxidants, clarifying agents, nucleating agents, antistatic agents, colorants, radiation stability agents, and conductiveagents. Antioxidants may be included in the thermoplastic polymer composition to prevent degradation of the polymers. Some embodiments of the thermoplastic polymer composition include multiple antioxidants. Clarifying agents and nucleating agents may improve the clarity of articles formed from the thermoplastic polymer composition. Without intending to be bound by theory, clarifying agents and nucleating agents may initiate the growth of crystalline phases of crystalline polymers, such as polypropylene. Increasing the number of relatively small crystalline structures in the article may reduce the light scattered by the crystalline phases improving the clarity of articles formed from the polymer composition. Antistatic agents may reduce the resistivity of the thermoplastic polymer composition to provide static protection. Colorants may be included in the thermoplastic polymer composition to impart color to articles formed form the thermoplastic polymer composition. Suitable colorants may be selected for use in transparent, translucent, or opaque articles. Radiation stability agents may be included in the thermoplastic polymer composition to reduce the effects of irradiation on the thermoplastic polymer composition. For example, radiation stability agents may reduce discoloration, such as yellowing, that may occur in some thermoplastic polymer composition. Radiation stability agents may also reduce the effect of radiation on the mechanical properties of articles formed from the thermoplastic polymer composition. Conductive agents may be included in the thermoplastic polymer composition to improve the electrical conductivity of the thermoplastic polymer composition. Conductive agents may include, for example, carbon black and carbon fibers. Some conductive agents, such as carbon black, may also impart color to the thermoplastic polymer composition and articles formed from the thermoplastic polymer composition.

[0062] In embodiments where the thermoplastic polymer composition further comprises one or more additives, the thermoplastic polymer composition may comprise, based on the total weight of the thermoplastic polymer composition, greater than 0 wt.% and less than or equal to 10 wt.% of the one or more additives. For example, the thermoplastic polymer composition may comprise the one or more additives in an amount greater than 0 wt.% and less than or equal to 10 wt.%, greater than 2 wt.% and less than or equal to 10 wt.%, greater than 4 wt.% and less than or equal to 10 wt.%, greater than 6 wt.% and less than or equal to 10 wt.%, greater than 8 wt.% and less than or equal to 10 wt.%, greater than 0 wt.% and less than or equal to 9 wt.%, greater than 0 wt.% and less than or equal to 7 wt.%, greater than 0 wt.% and less than or equal to 5 wt.%, greater than 0 wt.% and less than or equal to 3 wt.%, greater than 0 wt.% and less than or equal to 1 wt.%,or any range or combination of ranges formed from these endpoints. In embodiments, the thermoplastic polymer composition may be free or substantially free of additives. In one or more embodiments, the thermoplastic polymer composition may be free or substantially free of fluorine.

[0063] Referring still to FIG. 1, the article 100 may comprise a polyalphaolefin composition 120. The polyalphaolefin composition 120 may be disposed on at least a portion of the first surface 112 of the substrate 110. The polyalphaolefin composition 120 may have a viscosity greater than or equal to 6 centistokes (cSt) and less than or equal to 165 cSt, at a temperature of 100 °C. The viscosity of the polyalphaolefin composition 120 is measured according to ASTMD445. In one or more embodiments, the polyalphaolefin composition 120 may have a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, greater than or equal to 10 cSt and less than or equal to 165 cSt, greater than or equal to 20 cSt and less than or equal to 165 cSt, greater than or equal to 30 cSt and less than or equal to 165 cSt, greater than or equal to 40 cSt and less than or equal to 165 cSt, greater than or equal to 50 cSt and less than or equal to 165 cSt, greater than or equal to 60 cSt and less than or equal to 165 cSt, greater than or equal to 70 cSt and less than or equal to 165 cSt, greater than or equal to 80 cSt and less than or equal to 165 cSt, greater than or equal to 90 cSt and less than or equal to 165 cSt, greater than or equal to 100 cSt and less than or equal to 165 cSt, greater than or equal to 110 cSt and less than or equal to 165 cSt, greater than or equal to 120 cSt and less than or equal to 165 cSt, greater than or equal to 130 cSt and less than or equal to 165 cSt, greater than or equal to 140 cSt and less than or equal to 165 cSt, greater than or equal to 150 cSt and less than or equal to 165 cSt, greater than or equal to 6 cSt and less than or equal to 160 cSt, greater than or equal to 6 cSt and less than or equal to 150 cSt, greater than or equal to 6 cSt and less than or equal to 140 cSt, greater than or equal to 6 cSt and less than or equal to 130 cSt, greater than or equal to 6 cSt and less than or equal to 120 cSt, greater than or equal to 6 cSt and less than or equal to 110 cSt, greater than or equal to 6 cSt and less than or equal to 100 cSt, greater than or equal to 6 cSt and less than or equal to 90 cSt, greater than or equal to 6 cSt and less than or equal to 80 cSt, greater than or equal to 6 cSt and less than or equal to 70 cSt, greater than or equal to 6 cSt and less than or equal to 60 cSt, greater than or equal to 6 cSt and less than or equal to 50 cSt, greater than or equal to 6 cSt and less than or equal to 40 cSt, greater than or equal to 6 cSt and less than or equal to 30 cSt, greater than or equal to 6 cSt and less than or equal to 20 cSt, greater than or equal to 6 cSt and less than or equal to 10 cSt, or any range or combination of ranges formed from these endpoints.

[0064] Without intending to be bound by theory, the viscosity of the polyalphaolefin composition 120 may ensure that the polyalphaolefin composition 120 is not mechanically shed from the surface of the substrate 110 or dissolved in conventional solvents. The presence of a liquid / liquid interface between the polyalphaolefin composition 120 of the article 100 and fluid contained within the article 100 may contribute to low fluid retention of the article 100 and solvent resistance of the article 100. For example, if the viscosity of the polyalphaolefin composition 120 is too low (i.e., less than 6 cSt), then the polyalphaolefin composition 120 may be easily shed from the surface of the substrate 110. This may reduce the solvent resistance of the article 100. If the viscosity of the polyalphaolefin composition 120 is too high (i.e., greater than 165 cSt), then it may be difficult to coat the substrate with the polyalphaolefin composition 120. This may result in an inferior liquid / liquid interface between the article 100 and fluids contained within the article, leading to increased fluid retention and decreased solvent resistance.

[0065] In one or more embodiments, the polyalphaolefin composition 120 comprises a polyalphaolefin having the structure (CH2CHR)n, where R is an alkyl group comprising greater than or equal to 4 carbon atoms and less than or equal to 21 carbon atoms, and where n is greater than or equal to 4 and less than or equal to 32. For example, R may be any alkyl group comprising 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 21 carbon atoms. As another example, n may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32. In embodiments, n may be greater than or equal to 6 and less than or equal to 14. The alkyl groups are not necessarily limited. In embodiments, the alkyl group may be linear or branched. In embodiments, the alkyl group may be cyclic or acyclic. It should be understood that R is not necessarily the same alkyl group in every monomer of the polyalphaolefin. Some monomers of the polyalphaolefin may have different R groups than other monomers of the polyalphaolefin, provided that R is an alkyl group comprising greater than or equal to 4 carbon atoms and less than or equal to 21 carbon atoms. Without intending to be bound by theory, the distribution of the chain lengths of the R groups may contribute to the viscosity of the polyalphaolefin composition. For example, if the R groups are too similar in length, then the polyalphaolefin composition may crystallize, increasing the viscosity or even resulting in a solid composition. As previously described, such an increased viscosity may increase the fluid retention and decrease the solvent resistance of articles comprising the polyalphaolefin composition.

[0066] In one or more embodiments, the polyalphaolefin composition 120 comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol. For example, in embodiments, the average molecular weight of the polyalphaolefin may be greater than or equal to 600 g / mol and less than or equal to 4500 g / mol, greater than or equal to 600 g / mol and less than or equal to 4000 g / mol, greater than or equal to 600 g / mol and less than or equal to 3500 g / mol, greater than or equal to 600 g / mol and less than or equal to 3000 g / mol, greater than or equal to 600 g / mol and less than or equal to 2500 g / mol, greater than or equal to 600 g / mol and less than or equal to 2000 g / mol, greater than or equal to 1000 g / mol and less than or equal to 4500 g / mol, greater than or equal to 1000 g / mol and less than or equal to 4000 g / mol, greater than or equal to 1000 g / mol and less than or equal to 3500 g / mol, greater than or equal to 1000 g / mol and less than or equal to 3000 g / mol, greater than or equal to 1000 g / mol and less than or equal to 2500 g / mol, greater than or equal to 1000 g / mol and less than or equal to 2000 g / mol, greater than or equal to 1400 g / mol and less than or equal to 4500 g / mol, greater than or equal to 1400 g / mol and less than or equal to 4000 g / mol, greater than or equal to 1400 g / mol and less than or equal to 3500 g / mol, greater than or equal to 1400 g / mol and less than or equal to 3000 g / mol, greater than or equal to 1400 g / mol and less than or equal to 2500 g / mol, greater than or equal to 1400 g / mol and less than or equal to 2000 g / mol, greater than or equal to 1800 g / mol and less than or equal to 4500 g / mol, greater than or equal to 1800 g / mol and less than or equal to 4000 g / mol, greater than or equal to 1800 g / mol and less than or equal to 3500 g / mol, greater than or equal to 1800 g / mol and less than or equal to 3000 g / mol, greater than or equal to 1800 g / mol and less than or equal to 2500 g / mol, or even greater than or equal to 1800 g / mol and less than or equal to 2000 g / mol, or any range or combination of ranges formed from these endpoints.

[0067] Without intending to be bound by theory, if the average molecular weight of the polyalphaolefin is too great then the polyalphaolefin composition 120 may not be a liquid or may have too great a viscosity. In such scenarios, the fluid retention of articles comprising the polyalphaolefin composition 120 may be increased and the solvent resistance may be decreased.

[0068] In one or more embodiments, the polyalphaolefin composition 120 comprises greater than or equal to 90 wt.% of the polyalphaolefin, based on the total weight of the polyalphaolefin composition 120. For example the, polyalphaolefin composition 120 maycomprise greater than or equal to 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, or even 99 wt.% of the polyalphaolefin, based on the total weight of the polyalphaolefin composition 120. In one or more embodiments, the polyalphaolefin composition 120 may consist essentially of or consist of the polyalphaolefin. In some embodiments, the polyalphaolefin composition 120 is free or substantially free of fluorine.

[0069] In one or more embodiments, the article 100 comprises a fluid retention less than a similar article lacking the polyalphaolefin composition 120. As described herein, a “similar article lacking the polyalphaolefin composition 120” refers to an article that is identical to the article comprising the polyalphaolefin composition 120 in both structure and composition, except that the polyalphaolefin composition 120 of the article is replaced with the material forming the substrate 110 in the “similar article lacking the polyalphaolefin composition 120.”

[0070] Embodiments of the article 100 described herein may be resistant to certain solvents, including polar solvents, such as ethanol, isopropanol, dimethyl sulfoxide (DMSO), and acetone. As described herein, an article may be “solvent resistant” when contacting the article with the solvent does not substantially alter the chemistry or structure that provides low fluid retention to the article during normal use. For example, a pipette tip may be “solvent resistant” when the pipette tip is used to draw and subsequently dispense a solvent, where the solvent does not alter the composition or structure of the pipette tip such that fluid retention is reduced. In embodiments, the polyalphaolefin composition 120 may have a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt. Without intending to be bound by theory, when the viscosity of the polyalphaolefin composition 120 is greater than or equal to 6 cSt and less than or equal to 165 cSt, the polyalphaolefin composition 120 is not easily mechanically shed from the substrate 110 or dissolved by conventional solvents. This may allow the article to maintain low fluid retention, even after exposure to conventional solvents.

[0071] The article 100 is not necessarily limited. The article 100 may be any article where low fluid retention is desired. In one or more embodiments, the article 100 may be a pipette tip, a bag, a tube, or a spheroid plate. In some embodiments, the article 100 is a pipette tip.

[0072] Referring now to FIG. 2, the article 100 may be a pipette tip 200. The pipette tip 200 may comprise a liquid containment portion 210 and an attachment portion 220. The liquidcontainment portion 210 of the pipette tip 200 defines a volume 230 that may hold a liquid sample, when the pipette tip 200 is in use. The attachment portion 220 of the pipette tip 200 refers to a portion of the pipette tip 200 that may contact a pipette.

[0073] In one or more embodiments, the substrate 110 may form at least a portion of the pipette tip 200. The first surface 112 of the substrate 110 may be an interior surface of the pipette tip 200. For example, in the liquid containment portion 210 of the pipette tip 200, the first surface 112 of the substrate 110 may face the volume 230 of the pipette tip 200 that may contain a liquid sample, when the pipette tip 200 is used. In some embodiments, the second surface 114 of the substrate 110 may be an outer surface of the pipette tip 200. For example, the second surface 114 of the substrate 110 may face away from the volume 230 of the pipette tip 200.

[0074] Still referring to FIG. 2, the polyalphaolefin composition 120 may be disposed on at least a portion of the first surface of the substrate 110 in the liquid containment portion 210 of the pipette tip 200. In one or more embodiments, at least 90% of the first surface 112 of the substrate 110 in the liquid containment portion 210 of the pipette tip 200 is in direct contact with the polyalphaolefin composition 120. For example, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or even 99% of the first surface 112 of the substrate 110 in the liquid containment portion 210 of the pipette tip 200 is in direct contact with the polyalphaolefin composition 120. In some embodiments, all or substantially all of the first surface 112 of the substrate 110 in the liquid containment portion 210 of the pipette tip 200 is in direct contact with the polyalphaolefin composition 120. Without intending to be bound by theory, the polyalphaolefin composition 120 disposed on the substrate 110 may give the pipette tip 200 low fluid retention in the liquid containment portion 210 of the pipette tip 200. Low fluid retention in the liquid containment portion 210 of the pipette tip 200 may reduce loss of pipetted samples due to a thin film of sample being retained on the wall of the pipette tip 200.

[0075] Articles formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, or even less, or at any other value less than or equal to 10%, of green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test. The fluid retention testis described further below. As used herein, “green food dye” refers to McCormick’s® green food dye or an equivalent. In one embodiment, an article formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 10% of green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test. In another embodiment, an article formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 5% of green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test. In another embodiment, an article formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 2.5% of green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test. In another embodiment, an article formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 1 % of a green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test. In yet another embodiment, an article formed into a pipette tip with the polyalphaolefin composition in direct contact with the liquid containment portion of the pipette tip may retain less than or equal to 0.5% of green food dye that is aspirated into the article and then dispensed as determined by a fluid retention test.

[0076] As described herein, “a fluid retention test” for a pipette tip is measured by the following method using gravimetric testing. The fluid used for the test is McCormick® green food dye or an equivalent. A vessel that will hold fluid for use in the fluid retention test is weighed on a high precision analytical balance scale (an analytical balance scale that has precision to at least three decimals) and the weight of the vessel is recorded as the vessel weight. Fluid for the fluid retention test is then placed into the weighed vessel and the vessel with the fluid is weighed and the value is recorded as the vessel with fluid weight. The pre-cycle fluid weight is determined by subtracting the vessel weight from the vessel with fluid weight. Next, an article in the form of a 200 pL pipette tip having a polyalphaolefin composition as described herein is attached to a pipettor and then 200 pL of the fluid from the vessel is drawn up (aspirated) into the pipette tip using the pipette. The volume of fluid in the vessel is greater than the volume aspirated into the pipette tip. After 30 seconds, the fluid in the pipette tip is then dispensed back into the same vesselit was drawn from. The vessel containing the dispensed fluid is then weighed and the weight is recorded as the post-cycle weight. The post-cycle fluid weight is then determined by subtracting the vessel weight from the post-cycle weight. Next, the post-cycle fluid weight is subtracted from the pre-cycle fluid weight, and then that value is divided by the pre-cycle fluid weight. The resultant value is multiplied by 100 to yield the percentage of the fluid retained by the pipette tip.

[0077] In one or more embodiments, the first surface 112 of the substrate 110 in the attachment portion 220 of the pipette tip 200 may be free or substantially free from the polyalphaolefin composition 120. Without intending to be bound by theory, if the polyalphaolefin composition is disposed on the first surface 112 of the substrate 110 in the attachment portion 220 of the pipette tip 200, then the pipette tip 200 may too easily slide off of a pipette. In some cases, pipette tips are held on a pipette by friction. However, some polyalphaolefin compositions disposed on the substrate may result in a low enough coefficient of friction that the pipette tip may too easily slide off of the pipette. Inadvertent removal of the pipette tip from the pipette may result in loss or contamination of samples and may increase the difficulty of using the pipette.

[0078] Methods for forming articles 100 described herein are not necessarily limited. In some embodiments, articles described herein may be formed by injection molding, blow molding, extrusion, compression molding, or any other suitable processes.

[0079] In one or more embodiments, a method of forming an article 100 may comprise coating at least a portion of a mold with the polyalphaolefin composition. The mold may be coated by any suitable means. For example, the polyalphaolefin composition may be sprayed onto at least a portion of the mold. In such embodiments, a thermoplastic polymer composition may be disposed into the mold. The thermoplastic polymer composition may be disposed into the mold after the at least a portion of the mold is coated with the polyalphaolefin composition. The thermoplastic polymer composition may be formed outside the mold, before it is disposed into the mold. For example, the thermoplastic polymer composition may be formed by adding one or more thermoplastic polymers, and optionally, one or more additives, each of which are previously described. The thermoplastic polymer composition may then be disposed into the mold and subsequently solidified within the mold to form the article. The article may then be removed fromthe mold. Embodiments of the articles that may be formed by this method are described in detail hereinabove.

[0080] In one or more embodiments, a method of forming an article 100 may comprise solidifying a thermoplastic polymer composition within a mold to form a substrate 110. The thermoplastic polymer composition may be formed outside the mold, before it is disposed into the mold. For example, the thermoplastic polymer composition may be formed by adding one or more thermoplastic polymers, and optionally, one or more additives, each of which are previously described. The thermoplastic polymer composition may then be disposed into the mold, and subsequently solidified within the mold to form the substrate 110. The substrate 110 may be removed from the mold. As previously described, the substrate 110 may comprise a first surface 112. At least a portion of the first surface 112 of the substrate 110 may be coated with a polyalphaolefin composition 120 to form an article 100.EXAMPLES

[0081] The embodiments described herein will be further clarified by the following examples.Example 1 — Qualitative Test of the Fluid Retention of Pipette Tips

[0082] The fluid retention of two pipette tips was qualitatively analyzed. The first pipette tip was a polypropylene pipette tip having an interior surface that was not coated with a polyalphaolefin composition. The second pipette tip was a polypropylene pipette tip where the interior surface was coated with a polyalphaolefin composition. The polypropylene used to form the pipette tips had a melt index (L) greater than or equal to 10 g / mol and less than or equal to 75 g / mol, as measured according to ASTM method DI 238 at 190 °C and 2.16 kg. Green McCormick food coloring was aspirated into each pipette tip and subsequently dispensed from each pipette tip.

[0083] FIG. 3 depicts the McCormick food coloring held within the first pipette tip. FIG. 4 depicts the first pipette tip after the McCormick food coloring was dispensed from the first pipette tip. As shown in FIG. 4, the McCormick food coloring was retained on the inner surface of the first pipette tip. In contrast, FIG. 5 depicts the second pipette tip after dispensing the McCormickfood coloring. As shown in FIG. 5, no food coloring was visibly retained within the pipette tip after the food coloring was dispensed. The qualitative fluid retention test exemplifies that pipette tips comprising a polyalphaolefin coating exhibit low fluid retention for low surface tension fluids, such as food coloring.Example 2 — Solubility of a Polyalphaolefin Composition in Isopropyl Alcohol

[0084] The solubility of a polyalphaolefin composition in isopropyl alcohol was qualitatively analyzed. A 0.5 mb sample of a polyalphaolefin composition was mixed with 2 mL of isopropyl alcohol. The mixture was agitated to form an emulsion of polyalphaolefin composition in isopropyl alcohol. The emulsion is depicted in FIG. 6. The emulsion was allowed to settle for 8 hours, which resulted in the separation of polyalphaolefin composition and isopropyl alcohol. The separated emulsion is depicted in FIG. 7. After 8 hours, the fine droplets of polyalphaolefin composition remained suspended in the isopropyl alcohol. Despite relatively low volume and high surface area, these droplets of polyalphaolefin composition did not dissolve in the isopropyl alcohol, as demonstrated by light scattering the isopropyl alcohol phase.

[0085] The present disclosure is directed to various embodiments of articles comprising a substrate and a polyalphaolefin composition and methods of making such articles. The substrate may comprise a first surface and the polyalphaolefin composition may be disposed on at least a portion of the first surface of the substrate. The polyalphaolefin composition may comprise a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 150 °C. The specified viscosity of the polyalphaolefin composition described herein may ensure that the polyalphaolefin is not mechanically shed from the surface of the substrate or dissolved in conventional solvents, such as isopropyl alcohol. The articles comprising the polyalphaolefin compositions described herein may be non-fluorinated articles having low fluid retention.

[0086] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

CLAIMS1. An article comprising: a substrate comprising a first surface; and a polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, the polyalphaolefin composition comprising a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

2. The article of claim 1, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

3. The article of claim 1 or claim 2, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

4. The article of any one of claims 1 to 3, wherein the polyalphalolefin composition comprises a polyalphaolefin having a structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

5. The article of claim 4, wherein the polyalphaolefin composition comprises greater than or equal to 90 wt.% of the polyalphaolefin, based on a total weight of the polyalphaolefin composition.

6. The article of any one of claims 1 to 5, wherein the substrate comprises a thermoplastic polymer composition.

7. The article of claim 6, wherein the thermoplastic polymer composition comprises polypropylene, polystyrene, polymethylmethacrylate, polyvinyl chloride, polycarbonate,polysulfone, polyester, polyamide, polystyrene butadiene copolymers, fully hydrogenated styrenic polymers, polyurethanes, polyethylene, polymethyl pentene, polylactic acid, polybutylene succinate, polyhydroxyalkamoate, or a combination thereof.

8. The article of claim 6 or claim 7, wherein the thermoplastic polymer composition further comprises one or more additives selected from the group consisting of an antioxidant, a clarifying agent, a nucleating agent, an antistatic agent, a colorant, a radiation stability agent, and a conductive agent.

9. The article of claim 8, wherein the thermoplastic polymer composition comprises greater than 0 wt.% and less than or equal to 10 wt.% of the one or more additives.

10. The article of any one of claims 1 to 9, wherein the article comprises a fluid retention of less than or equal to 10% as measured by a fluid retention test.

11. The article of any one of claims 1 to 9, wherein the article comprises a fluid retention of less than or equal to 5% as measured by a fluid retention test.

12. The article of any one of claims 1 to 9, wherein the article comprises a fluid retention of less than or equal to 1% as measured by a fluid retention test.

13. The article of any one of claims 1 to 12, wherein the polyalphaolefin composition is free or substantially free of fluorine.

14. The article of any one of claims 1 to 13, wherein the article is selected from the group consisting of a pipette tip, a bag, a tube, and a spheroid plate.

15. The article of claim 14, wherein the article is the pipette tip.

16. The article of claim 15, wherein the pipette tip comprises a liquid containment portion and an attachment portion, and wherein the first surface of the substrate is an interior surface of the pipette tip.

17. The article of claim 16, wherein the polyalphaolefin composition is disposed on at least a portion of the first surface of the substrate in the liquid containment portion of the pipette tip.

18. The article of claim 16 or claim 17, wherein at least 90% of the first surface of the substrate in the liquid containment portion of the pipette tip is in direct contact with the polyalphaolefin composition.

19. The article of any one of claims 16 to 18, wherein the first surface of the substrate in the attachment portion of the pipette tip is substantially free from the polyalphaolefin composition.

20. A method of forming an article, the method comprising: coating at least a portion of a mold with a polyalphaolefin composition; disposing a thermoplastic polymer composition into the mold; solidifying the thermoplastic polymer composition within the mold to form an article; and removing the article from the mold; wherein the article comprises: a substrate comprising a first surface; and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, wherein the polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

21. The method of claim 20, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

22. The method of claim 20 or claim 21, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

23. The method of any one of claims 20 to 22, wherein the polyalphalolefin composition comprises a polyalphaolefin having the structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

24. The method of any one of claims 20 to 23, wherein the polyalphaolefin composition is free or substantially free of fluorine.

25. The method of any one of claims 20 to 24, wherein the formed article comprises a fluid retention of less than or equal to 2.5% as measured by a fluid retention test.

26. The method of any one of claims 20 to 25, wherein the article comprises a pipette tip.

27. A method of forming an article, the method comprising: solidifying a thermoplastic polymer composition within a mold to form a substrate, wherein the substrate comprises a first surface; and coating at least a portion of the first surface of the substrate with a polyalphaolefin composition to form an article, wherein the article comprises: the substrate; and the polyalphaolefin composition disposed on at least a portion of the first surface of the substrate, wherein the polyalphaolefin composition comprises a viscosity greater than or equal to 6 cSt and less than or equal to 165 cSt, as measured according to ASTM D445 at a temperature of 100 °C.

28. The method of claim 27, wherein the polyalphaolefin composition comprises a polyalphaolefin comprising an average molecular weight greater than or equal to 600 g / mol and less than or equal to 4500 g / mol.

29. The method of claim 27 or claim 28, wherein the first surface of the substrate comprises a roughness (Ra) less than 25 nm.

30. The method of any one of claims 27 to 29, wherein the polyalphalolefin composition comprises a polyalphaolefin having the structure (CH2CHR)n, wherein R is an alkyl group comprising greater than or equal to 4 and less than or equal to 21 carbon atoms and n is greater than or equal to 4 and less than or equal to 32.

31. The method of any one of claims 27 to 30, wherein the polyalphaolefin composition is free or substantially free of fluorine.

32. The method of any one of claims 27 to 31, wherein the formed article comprises a fluid retention of less than or equal to 2.5% as measured by a fluid retention test.

33. The method of any one of claims 27 to 32, wherein the article comprises a pipette tip.

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