Non-fluorinated low retention additives

Abstract

Fluorine and siloxane-free compositions for manufacturing molded pipette tips that exhibit improved expulsion of liquid samples from the tips. A non-fluorinated composition may include an organo-modified siloxane, a triglyceride ester, an organo phosphinite, and a carrier resin. A non-fluorinated, siloxane-free composition may include a triglyceride, an organo phosphinite, an aluminum oxide, and a carrier resin. The disclosed compositions may increase the hydrophobicity of a resulting product including but not limited to fiber, nonwoven fabric, and / or products produced by injection molding.

Description

NON-FLUORINATED LOW RETENTION ADDITIVESTECHNICAL FIELD

[0001] This application claims the benefit of U.S. provisional application Serial No. 63 / 513,075 filed July 11, 2023, the disclosure of which is hereby incorporated in its entirety' by reference herein.TECHNICAL FIELD

[0002] Disclosed embodiments relate to compositions and methods for enhancing low retention properties of molded pipette tips.BACKGROUND

[0003] Micropipettes are utilized in the biological, medical, and chemical fields to accurately measure small amounts of liquid. Micropipettes are typically used with disposable plastic tips. For the measurements to be accurate, the liquid must be fully expelled from the tips. Certain liquids, such as viscous liquids, are more difficult to expel. Materials or additives that improve expulsion of such liquids from the tips have been used to produce low-retention tips. Low retention tips commonly include fluorinated compounds. Such compounds may potentially leach into experimental samples. Additionally, these compounds are harmful to human health and the environment. There is thus a need for low-retention tips that improve expulsion of liquids without using toxic chemicals.

[0004] In at least an aspect, a non-fluorinated composition for manufacturing molded pipette tips may be provided. The composition may comprise an organo-modified siloxane; a triglyceride ester; an organo phosphinite; and a carrier resin. The composition may comprise 5-20% by weightof a triglyceride ester; 1-10% by weight of an organo-modified siloxane; 0.05-0.2% by weight of an organo phosphinite; and 65-95% by weight of a carrier resin. The composition does not include a fluorine-based component.

[0005] In at least another aspect, a fluorine-free, siloxane-free composition for manufacturing molded pipette tips may be provided. The composition may comprise 5 to 25 wt% of a triglyceride, 0.05 to 0.2 wt% of an organo phosphinite, 5 to 20 wt% of an aluminum oxide, and 65 to 95 wt% of a carrier resin, wherein the composition does not include a fluorine-based component. The composition also does not include a siloxane-based component.

[0006] In at least another aspect, a method of manufacturing a molded pipette tip with improved expulsion of a liquid from the pipette tip may be provided. The method may comprise mixing together 1 to 10 wt% of an organo-modified siloxane; 5 to 20 wt% of a triglyceride ester; 0.05 to 0.2 wt% of an organo phosphinite; and 65 to 95 wt% of a carrier resin. The method may also include heating the mixture to about 200 to about 475 °F, extruding the mixture, cooling the mixture, forming the mixture into pellets to form a masterbatch, mixing together 1 to 7 % of the masterbatch and 85 to 99% of a base resin, heating the masterbatch and the base resin to form a mixture, and feeding the mixture through an injection press to form a molded pipette tip.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIGURE 1 illustrates a graph showing contact angle measurements for tips manufactured with the compositions described herein.

[0008] FIGURE 2 illustrates a graph showing contact angle measurements for tips manufactured with the compositions described herein.

[0009] FIGURE 3 illustrates images of tips manufactured with and without the compositions described herein used to pipette a stained glycol solution.

[0010] FIGURE 4 illustrates images of tips manufactured with and without the compositions described herein used to pipette a stained glycol solution.

[0011] FIGURE 5 illustrates images of tips manufactured without or with the compositions described herein included at a 4% or 8% let down rate used to pipette a food coloring solution.DETAILED DESCRIPTION

[0012] As required, detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

[0013] Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and / or use are to be understood as modified by the word "about" in describing the broadest scope of the disclosure. Practice within the numerical limits stated is generally preferred.

[0014] It must also be noted that, as used in the specification and the appended aspects, the singular form "a," "an," and "the" comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

[0015] As used herein, the term “and / or” means that either all or only one of the elements of said group may be present. For example, “A and / or B” shall mean “only A, or only B, or both A and B”. In the case of “only A”, the term also covers the possibility that B is absent, i.e. “only A, but not B”.

[0016] It is also to be understood that this disclosure is not limited to the specific embodiments and methods described below, as specific components and / or conditions may, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present disclosure and is not intended to be limiting in any way.

[0017] The term “comprising” is synonymous with “including,” “having,” “containing,” or “characterized by.” These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps.

[0018] The phrase “composed of’ means “including” or “consisting of.” Typically, this phrase is used to denote that an object is formed from a material.

[0019] With respect to the terms “comprising,” “consisting of,” and “consisting essentially of,” where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

[0020] The term “one or more” means “at least one” and the term “at least one” means “one or more.” The terms “one or more” and “at least one” include “plurality” and “multiple” as a subset. In a refinement, “one or more” includes “two or more.”

[0021] It should also be appreciated that integer ranges explicitly include all intervening integers. For example, the integer range 1-10 explicitly includes I, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Similarly, the range 1 to 100 includes 1, 2, 3, 4. . . . 97, 98, 99, 100. Similarly, when any range is called for, intervening numbers that are increments of the difference between the upper limit and the lower limit divided by 10 can be taken as alternative upper or lower limits. For example, if the range is 1.1. to 2.1 the following numbers 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 can be selected as lower or upper limits.

[0022] The term “extruder” as used herein means a machine used to extrude viscous substances, including but not limited to polymers, into high quality structured products by controlling the processing conditions.

[0023] The term “extrusion” as used herein means the process of forcing melted polymer pellets or granules through a die with an opening.

[0024] The following examples illustrate the various embodiments of the present disclosure. Those skilled in the art will recognize many variations that are within the spirit of the present disclosure and scope of the aspects.

[0025] Micropipettes are commonly used in molecular biology, microbiology, chemistry, and medical testing labs to measure and transfer small amounts of liquids. The measurement and successful transfer of such liquids must be highly exact and reproducible. To measure and transfer liquid using a micropipette, a disposable plastic tip is commonly placed over the bottom end of the micropipette. The measurement dial of the micropipette is set at the desired volume, the plunger is pressed down, and the tip is placed into the liquid. The plunger is then slowly released to draw the liquid up into the tip. The tip is then placed into the receptacle into which the sample is to be released. Pressing the plunger all the way down, releases the liquid sample into the receptacle.

[0026] While the majority of the liquid is released, a portion of it may remain behind. With more viscous liquids, such as liquid samples having detergents or polyethylene glycol for example, more of the liquid may be left behind. Retention of the liquid sample may result in reduced accuracy and reproducibility of measurements. Additionally, particles such as cells, DNA, RNA, and proteins may also interact with the tip material and be retained in the tip. For these reasons, low- retention tips have been developed.

[0027] Low-retention tips are either formed from or coated with materials that increase the hydrophobicity of the interior of the tip, thereby increasing the efficiency with which liquid samples are expelled from the tips. Low retention tips may be manufactured using a variety of techniques including diamond polishing the surfaces of tip molds, using plastic additives, dipping the tips into chemicals that modify the surface of the tips, or other methods that increase hydrophobicity.

[0028] Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are defined by the PFAS Act of 2019 as any compound with at least one fully fluorinated carbon. These compounds are increasingly being regulated due to their high persistence and harmful impact on both the environment and on human health. Low-retention pipette tips are commonly manufactured using PFAS. In addition to the potential negative impacts on human health and the environment, PFAS from fluorinated tips can leak into samples which can negatively impact experiments. For these reasons, there is a need for low-retention pipette tips that function similarly to tips containing fluorinated compounds without including such compounds.

[0029] Siloxanes may also be used in plastics additives. Siloxane is a functional group having an inorganic backbone with the silicon-oxygen-silicon (Si-O-Si) linkage. Each silicon atom may carry two organic groups, typically methyl, ethyl, or phenyl groups. Siloxane polymers are called silicones. Siloxane polymers are ubiquitous in the modem world as they are components of many consumer products including pharmaceutical products, lotions and shampoos. Siloxane polymers can also be found in polyurethane cushions, paints and coatings, nautical sealants, aerospace equipment, dielectric barriers, and even cooking oil.

[0030] While siloxanes have been used for many years in cosmetic products as well as in a wide array of other products, the potential toxicity of siloxanes and siloxane-based compounds is still being studied. Siloxanes can be environmentally persistent. This property confers both useful and potentially undesired effects. For instance, many siloxane-based products do not break down readily in the environment. This can cause them to accumulate in the environment and potentially affect wildlife particularly aquatic wildlife. Solid silicone products made from siloxanes do not shed or break down into microplastics, so they can be a healthier alternative to plastics that produce microplastics that accumulate in the bodies of animals and humans. Given concerns about bioaccumulation of siloxanes and about potential toxicity, there is also a need for low-retention pipette tips that include neither fluorinated compounds nor siloxane-based compounds without sacrificing function.

[0031] In at least one aspect, a composition for manufacturing non-fluorinated low-retention micropipette tips is provided. The composition may comprise organo modified siloxane, triglyceride ester, and organo phosphite incorporated in a polypropylene system to enhance the low retention properties of molded pipette tips. The composition may replace fluorinated polymers and be a non-fluorine based, PF AS free low-retention additive. At the proper usage levels, the composition may achieve hydrophobic properties with contact angle measurements of 108° to 109°. The composition may also be compliant with all regulatory and FDA requirements. Embodiments of the composition may include an additive or a fully formulated compound that may be used to manufacture molded pipette tips with improved expulsion of a liquid from the pipette tip as measured by contact angle measurements. The composition according to certain embodiments may provide a non-fluorinated alternative for producing low-retention pipette tips that reduces experimental contamination from PFAS in the tips and leaching of PFAS fromdiscarded tips into the environment. According to other embodiments, the composition may provide a non-fluorinated siloxane-free alternative for producing low-retention pipette tips.

[0032] Disclosed embodiments of the composition may comprise triglyceride ester, organo- modified siloxane, organic phosphinite, aluminum oxide, and a polypropylene family resin as a carrier resin. Examples of suitable carrier resins include but are not limited to homopolypropylene, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or polypropylene.

[0033] The composition may comprise about 5 to about 20 wt% of triglyceride ester. For example, the composition may comprise about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt% of triglyceride ester. Amounts higher than about 20 wt% may lead to processing issues. Amounts lower than about 5 wt% may lead to less hydrophobicity than is required for the composition to produce low-retention pipette tips. The triglyceride ester may be derived from palm oil or from vegetable oils. The ester may be derived from acids including but not limited to stearic or oleic acids.

[0034] The composition may comprise about 1 to about 10 wt% of organo-modified siloxane. For example, the composition may comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt% of organo-modified siloxane.

[0035] The composition may further comprise about 0.05 to about 0.2 wt% of organic phosphinite.For example, the composition may comprise 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0,.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.20 wt% of organic phosphinite. The organic phosphinite may act as a stabilizer during processing.

[0036] The composition may additionally comprise about 65 to about 95 wt% of polypropylene family resin. For example, the composition may comprise 65, 70, 75, 80, 85, 90, or 95 wt% of polypropylene family resin.

[0037] Disclosed embodiments of the composition may be used as a masterbatch, in which it is mixed with a base resin during processing in a chosen ratio of composition to resin, as well as optional components including but not limited to, flame retardants, UV protective additives, slips, antiblocks, scents, antioxidants, pigments, antifogs, antistatics, dispersing agents, waxes, claryfmg agents, reinforcements such as glass fiber or carbon fiber, fillers, clarifying agents, process aids,and wetting agents. The composition may also be used as a fully formulated compound with the masterbatch and resin both present together, along with optional components including but not limited to, flame retardants, UV protective additives, slips, antiblocks, scents, antioxidants, pigments, antifogs, antistatics, dispersing agents, waxes, claryfing agents, reinforcements such as glass fiber or carbon fiber, fillers, clarifying agents, process aids, and wetting agents. Disclosed embodiments of the composition may be used with phthalate-based or non-phthalate-based applications.

[0038] In addition to producing molded low-retention pipette tips, disclosed embodiments of the composition may be used in the following non-limiting applications where higher hydrophobicity may be required: fiber production, nonwoven fabric production, and injection molding.

[0039] The composition may be used as a masterbatch additive at a letdown rate of about 1-7%. For example, the composition may be used as a masterbatch additive at a letdown rate of 1, 2, 3, 4, 5, 6, or 7%. A letdown rate of 5%, for example, corresponds to 5% of composition added to 95% of prime resin. Prime resin or base resin corresponds to the resin supplied by the user.

[0040] To generate the useable form of the composition, the triglyceride ester, organo-modified siloxane, organic phosphinite, aluminum oxide, and the carrier resin may be heated and mixed together. The mixture may be heated to about 200 to about 475°F. The mixture may then be extruded using a single screw or a twin screw extruder, for example. The screw speed may be from about 150 to about 500 rpm. The extruded mixture may then be cooled and formed into flakes, granules, powders, pellets, or other suitable masterbatch forms for use in injection molding, and / or other suitable applications.

[0041] The useable form of the composition may be generated using batch processes including but not limited to a sandwich method. For example, the sandwich method may be used to mix the components of the composition in the mixer. The organo-modified siloxane and the triglyceride for example, may be sandwiched in between resin. Half of the resin may be weighed and added to the mixer first. Then the organo-modified siloxane may be measured and added next. After, the triglyceride may be measured and added. Finally, the other half of the resin may be weighed and added to the mixer. The mixer may be a sack mixer. The temperatures to which the compositionis heated as well as the speed of the screw / s may be optimized to particular extruders. The organo- modified siloxane and the triglyceride may also be melted and fed into the extruder as a melt,

[0042] A molded low retention pipette tip which is for example a pipette tip with improved expulsion of liquid from the pipette tip may be manufactured by adding 1-7% of the composition according to at least an embodiment and a base resin to a hopper. The composition and the base resin may be added in pellet form. The composition pellets and the base resin pellets as well as any optional additives may be heated and melted and mixed together to form a mixture. The mixture may be fed through an extruder to form a blend which may subsequently be added to a hopper, heated, melted, and fed through an injection press to form a molded low retention pipette tip. Alternatively, the mixture may be fed through an injection press to form a molded low retention pipette tip.

[0043] Inclusion of disclosed embodiments of the composition during the manufacturing of molded pipette tips may produce pipette tips with improved expulsion of liquid samples from a pipette tip as measured by contact angle according to ASTM D5946. Inclusion of disclosed embodiments of the composition may also generally increase hydrophobicity of a resulting product including but not limited to fiber, nonwoven fabric, and / or products produced by injection molding.

[0044] According to additional embodiments, a composition for manufacturing non-fluorinated, siloxane-free low-retention micropipette tips is provided. The composition may comprise a triglyceride, an aluminum oxide, an organic phosphinite, and a carrier resin. For example, the composition may comprise about 5 to about 25, or 7 to 22, or 10 to 20 wt% of triglyceride. For example, the composition may comprise about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 wt% of triglyceride. Amounts higher than about 25 wt% may lead to processing issues. Amounts lower than about 5 wt% may lead to less hydrophobicity than is required for the composition to produce low-retention pipette tips. The triglyceride may be derived from palm oil or from vegetable oils. For example, the triglyceride may be derived from fully hydrogenated palm oil.

[0045] The composition may additionally comprise about 5 to about 20, or 5 to 15, or 5 to 10 wt% of aluminum oxide. For example, the composition may comprise about 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19, or 20 wt% of aluminum oxide. Amounts higher than 20 wt% or lower than 5 wt% may negatively affect performance, processing, and / or cost.

[0046] The composition may further comprise about 0.05 to about 0.2, or 0.75 to 0.15, or 0.9 to 0.11 wt% of an organic phosphinite. For example, the composition may comprise 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0,.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.20 wt% of organic phosphinite. The organic phosphinite may act as a stabilizer during processing. The organic phosphinite may be Bis(2-4-Dicumylphenyl)pentaerythritol Diphosphite for example. Amounts less than 0.05 may result in the production of black specs. Amounts higher than 0.2 may increase manufacturing costs.

[0047] The composition may additionally comprise about 65 to about 95 wt% of polypropylene family resin. For example, the composition may comprise 65, 70, 75, 80, 85, 90, or 95 wt% of polypropylene family resin.

[0048] The composition may additionally comprise about 5 to 20, 7 to 17, or 10 to 15 wt% surfactant derivatives. For example, the composition may additionally comprise about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt% surfactant derivatives. The surfactant derivatives may be a single surfactant derivative or a mixture of more than one surfactant derivatives.

[0049] Disclosed embodiments of the composition may be used as a masterbatch, in which it is mixed with a base resin during processing in a chosen ratio of composition to resin, as well as optional components including but not limited to, flame retardants, UV protective additives, slips, antiblocks, scents, antioxidants, pigments, antifogs, antistatics, dispersing agents, waxes, claryfmg agents, reinforcements such as glass fiber or carbon fiber, fillers, clarifying agents, process aids, and wetting agents. The composition may also be used as a fully formulated compound with the additive and resin both present together, along with optional components including but not limited to, flame retardants, UV protective additives, slips, antiblocks, scents, antioxidants, pigments, antifogs, antistatics, dispersing agents, waxes, claryfing agents, reinforcements such as glass fiber or carbon fiber, fillers, clarifying agents, process aids, and wetting agents.

[0050] In addition to producing molded low-retention pipette tips, disclosed embodiments of the composition may be used in the following non-limiting applications where higher hydrophobicity may be required: fiber production, nonwoven fabric production, and injection molding.

[0051] The composition may be used as a masterbatch additive at a letdown rate of about 1-7%. For example, the composition may be used as a masterbatch additive at a letdown rate of 1, 2, 3, 4, 5, 6, or 7%. A letdown rate of 5%, for example, corresponds to 5% of composition added to 95% of prime resin. Prime resin or base resin corresponds to the resin supplied by the user. For example, prime or base resin may correspond to resin used by the manufacturer of a molded pipette tip in the manufacturing of the pipette tip.

[0052] To generate the useable form of the composition, the triglyceride, organo phosphinite, aluminum oxide, the carrier resin, and optionally the surfactant derivatives, may be heated and mixed together. The mixture may be heated to about 200 to about 475°F. The mixture may then be extruded using a single screw or a twin screw extruder, for example. The screw speed may be from about 150 to about 500 rpm. The extruded mixture may then be cooled and formed into flakes, granules, powders, pellets, or other suitable masterbatch forms for use in injection molding, and / or other suitable applications.

[0053] The useable form of the fluorine-free siloxane-free composition may be generated using batch processes including but not limited to a sandwich method. For example, the sandwich method may be used to mix the components of the composition in the mixer. The triglyceride for example, may be sandwiched in between resin. Half of the resin may be weighed and added to the mixer first. Then the triglyceride may be measured and added. Finally, the other half of the resin may be weighed and added to the mixer. The mixer may be a sack mixer. The temperatures to which the composition is heated as well as the speed of the screw / s may be optimized to particular extruders. The triglyceride component may also be melted and fed into the extruder as a melt.

[0054] EXAMPLES

[0055] Example 1: A non-limiting example of the composition for use in manufacturing low- retention micropipette tips is as follows:% in formula byIngredient weight Chemical NameHydrophobic10.001 additive TRIGLYCERIDEHomopolypropylene.Resin 84.902 35MFROrgano modifiedAnti-scratch 5.003 Siloxane4 Stabilizer 0.10 Organo PhosphiniteMFR refers to the melt flow rate of the resin.

[0056] Example 2: An alternate non-limiting example of the composition for use in manufacturing low-retention micropipette tips is as follows:,x% in formula by Ingredient . . weightJChemical NameHydrophobic1 additive TRIGLYCERIDE Homopolypropylene,2 Resin 79.90 35MFR,Cera“ic10.003 powder Alumium Oxide4 Stabilizer 0.10 Organo PhosphiniteMFR refers to the melt flow rate of the resin.

[0057] Example 3: Contact angle measurements of micropipette tips manufactured using the composition in Example 1:

[0058] The contact angle for three distinct samples of tips produced using the composition from Example 1, at a 5% letdown rate was measured according to ASTM D5946. The measurements are static contact angle measurements.Left Right Average1 108.93 109.01 108.972 108.24 108.05 108.153 108.29 107.97 108.13Mean 108.49 108.34 108.42Left Right Average1 106.89 106.63 106.762 108.15 108.52 108.343 108.45 107.53 107.99Mean 107.83 107.56 107.70Left Right Average1 108.63 108.99 108.812 108.83 107.49 108.163 107.92 108.36 108.14Mean 108.46 108.28 108.37

[0059] Example 4: Contact angle measurements of micropipette tips manufactured using the composition in Example 4:

[0060] The contact angle for three distinct samples of tips produced using the composition from Example 2, at a 5% letdown rate was measured according to ASTM D5946. The measurements are static contact angle measurements.Left Right Average1 107.53 108.30 107.922 108.43 108.40 108.423 108.91 109.39 109.15Mean 108.29 108.70 108.49Left Right Average1 108.25 108.08 108.172 108.82 108.88 108.853 107.78 107.36 107.57Mean 108.28 108.11 108.20Left Right Average1 108.82 108.46 108.642 107.86 107.84 107.853 108.11 110.08 109.10Mean 108.26 108.79 108.53

[0061] Example 5: Oven aging tests

[0062] Oven aging is a standard test method for accelerated warehouse aging according to ASTM Fl 980. The tips manufactured using the compositions in Examples 1 and 2 at a 5% letdown rate were aged for 1 week, 2 weeks, 3 weeks or 4 weeks, after which time the oven aging test was performed. Contact angles were measured as a control to compare to unexposed specimens.

[0063] Oven aging measurements for the composition from Example 1 :0 week Left Right Average1 108.84 109.02 108.932 109.19 109.12 109.163 110.14 109.72 109.93Mean 109.39 109.29 109.341 week Left Right Average1 108.28 108.44 108.362 109.26 109.02 109.143 108.26 108.91 108.59Mean 108.60 108.79 108.702 week Left Right Average1 109.46 109.57 109.522 109.39 109.54 109.473 109.03 109.68 109.36Mean 109.29 109.60 109.453 week Left Right Average1 109.19 109.51 109.352 108.68 108.52 108.603 108.50 108.58 108.54Mean 108.79 108.87 108.834 week Left Right Average1 107.70 106.10 106.902 106.19 105.77 105.983 106.70 106.20 106.45 Mean 106.86 106.02 106.44

[0064] Oven aging measurements for the composition from Example 2:0 week Left Right Average1 109.87 110.02 109.952 109.01 108.53 108.773 109.91 110.11 110.01Mean 109.60 109.55 109.581 week Left Right Average1 108.66 109.19 108.932 109.07 108.98 109.033 109.43 109.67 109.55Mean 109.05 109.28 109.172 week Left Right Average1 107.98 107.91 107.952 108.62 109.45 109.043 109.05 108.83 108.94Mean 108.55 108.73 108.643 week Left Right Average1 106.36 107.55 106.962 109.66 110.02 109.843 107.94 107.44 107.69Mean 107.99 108.34 108.164 week Left Right Average1 106.50 107.80 107.152 107.70 108.60 108.153 108.50 106.60 107.55Mean 107.57 107.67 107.62[00651 Example 6: Contact angles and optical properties

[0066] Contact angles were measured for an additional sample of micropipette tips manufactured using the composition from Examples 1 and 2 at a 5% letdown rate. Optical properties including percent transmission, haze, and clarity were measured from molded plaques of the same materialused for the contact angle measurements. %T means percent transmission. The measurements for % transmission and haze were obtained according to ASTM DI 003.

[0067] Contact measurements and optical properties for the composition from Example 1 :Left Right Average1 108.84 109.02 108.932 109.19 109.12 109.163 110.14 109.72 109.934 108.95 109.25 109.105 109.31 109.53 109.42Mean 109.29 109.33 109.34% T Haze Clarity69 101 8.2

[0068] Contact measurements and optical properties for the composition from Example 2:Left Right Average1 109.87 110.02 109.952 109.01 108.53 108.773 109.91 110.11 110.014 109.95 108.86 109.415 109.71 108.08 108.90Mean 109.69 109.12 109.58% T Haze Clarity69 98.5 9.6

[0069] Example 7: Contact angle measurements with organic solvents

[0070] Contact angles were measured for tips manufactured with the compositions from Examples1 and 2, as well as an established fluorinated low-retention additive (Fluor) and 100% homopolypropylene as a control (Control). The compositions from Examples 1 and 2 were used at a 5% letdown rate, and the fluorinated additive was used at a 4% letdown rate. The organic solvents listed in the first column were each pipetted using the tips, and the contact angles weremeasured. A graph of the results is shown in Figure 1. The properties of the tested organic solvents are as follows: Isopropanol (polar, limited organic character), 50% and >95%; Methanol (polar, limited organic character), 50% and >95%; N-Butanol (weakly polar, moderate organic character), 50% and >95%; Acetonitrile (polar), >95%; DMSO (highly polar), >95%; Chloroform (nonpolar), >95%.

[0071] Control Fluor Example 1 Example 2 50%Isopropanol 25.82 60.67 48.9 48.341666750%Acetonitrile 46.11 71.81 65.3 65.211666750% Methanol 67.86 89.69 82.4 81.2799% Butanol 34.11 44.84 38.3 34.2599% DMSO 63.96 84.86 74.9 74.9416667

[0072] Example 8: Contact angle measurements with surfactants

[0073] Contact angles were measured for tips manufactured with the compositions from Examples 1 and 2, as well as an established fluorinated low-retention additive (Fluor), and 100% homopolypropylene as a control (Control). The compositions from Examples 1 and 2 were used at a 5% letdown rate, and the fluorinated additive was used at a 4% letdown rate. Water plus each surfactant listed in the first column were pipetted using the tips, and the contact angles were measured. A graph of the results is shown in Figure 2. Surfactants substantially reduce surface tension and were thus tested for the ability of the tips to repel and quantitatively recover such solutions during dispensing.

[0074] Control Fluor Example 1 Example 21% Tween 20 62.36 87.9466667 77.42 76.2933333 1% SDS 61.80 87.9466667 73.13 67.5683333 1% NP-4O 44.69 82.105 68.8016667 61.3816667

[0075] Example 9: Testing retention of glycol solution

[0076] Tips manufactured using the compositions from Examples 1 (Bl) and 2 (B2), as well as the fluorinated additive from Examples 7 and 8 at a 3% letdown rate. A stock tip manufactured with a fluorinated additive was used as a control (Al). An additional tip (Invista) was tested as well. This tip was manufactured with base resin with no additive. The retention rates were tested using glycol solution. The results are shown in Figures 3 and 4. The dark droplets inside the tips represent glycol solution that was not successfully expelled. More dark drops indicates more retention.

[0077] Example 10: An example formula for a fluorine-free, siloxane-free composition according to an embodiment. The formula does not contain any fluorine-containing components. The formula does not contain any siloxane-containing components.Amount Product Name Chemical Name22.5% PA-6112 PALSGAARD 6112 Triglycerides fully hydrogenated palm oil10% FL-805 AEROXIDE ALU C 805 Aluminum oxideBis(2-4-Dicumylphenyl)pentaerythritol0.1% AO-9228 DOVERPHOS S 9228 Diphosphite 67.4% Resin 752 3944MR PP Polypropylene, 60 MFRMFR refers to the melt flow rate of the resin.

[0078] Example 11: A: An example formula for a fluorine-free, siloxane-free composition according to an embodiment. The formula does not contain any fluorine-containing components. The formula does not contain any siloxane-containing components. B: A similar formula but with organo-modified siloxane instead of the triglycerides present in Formula A for comparison.A:Amount Product Name Chemical Name15% PA-6225B PW-6522B Surfactant derivatives15% PA-GTSB EKOLITE FLEX GTS B Triglycerides fully hydrogenated palm oil5% FL-805 AEROXIDE ALU C 805 Aluminum oxideBis(2-4-Dicumylphenyl)pentaerythritol0.1% AO-9228 DOVERPHOS S 9228 Diphosphite 64.9% Resin 752 3944MR PP Polypropylene, 60 MFRMFR refers to the melt flow rate of the resin.Amount Product Name Chemical Name20% PA-6522 PW-6522B Surfactant Derivatives5% PA-L TEGOMER ANTISCRATCH L Organo-modified Siloxane5% FL-805 AEROXIDE ALU C 805 Aluminum oxideBis(2-4-Dicumylphenyl)pentaerythritol0.1% AO-9228 DOVERPHOS S 9228 Diphosphite 64.9% Resin 752 3944MR PP Polypropylene, 60 MFRMFR refers to the melt flow rate of the resin.

[0079] Example 12: Static contact angle measurements:

[0080] Contact angles were measured for tips manufactured using the masterbatch of Example 10 at the listed letdown rates. Three measurements plus the average of the three measurements are listed for each sample. The solution pipetted during the test was water.2%PPM142603 110.16 110.51 110.335109.87 109.25 109.56110.26 110.02 110.14Average 110.10 109.93 110.01 3% PPM142603 108.59 108.35 108.47109.66 110.34 110109.69 110.32 110.005Average 109.31 109.67 109.49 4% PPM142603 112.68 108.52 110.6109.66 109.65 109.655108.91 110.73 109.82Average 110.42 109.63 110.03 6% PPM142603 109.76 109.03 109.395109.66 109.47 109.565109.52 109.06 109.29Average 109.65 109.19 109.42 8%PPM142603 109.72 110.36 110.04109.66 110.44 110.05109.56 109.42 110.43Average 109.65 110.07 109.86

[0081] Example 13: Oven aging tests:

[0082] Oven aging is a standard test method for accelerated warehouse aging according to ASTM Fl 980. The tips manufactured using the masterbatch composition of Example 10 at the listed letdown rates were aged for 0 weeks, 3 days, or 1 week, after which time the oven aging test was performed. Contact angles were measured as a control to compare to unexposed specimens. Contact angles were measured for a control sample as well as three test samples (indicated below) produced using the composition according to embodiments.

[0083] Oven aging test measurements:

[0084] At time 0:

[0085] After 3 days:100%ControlLeft Right Average98.76 97.86 98.312 98.85 97.76 98.313 98.69 97.91 98.30Mean 98.77 97.84 98.31Test 1 - 2% NF2R2Left Right Average1 102.72 103.18 102.952 102.73 103.14 102.943 102.76 103.12 102.94Mean 102.74 103.15 102.94Test 2 - 3% NF2R2Left Right Average1 105.83 105.34 105.592 105.70 105.32 105.513 105.82 105.28 105.55Mean 105.78 105.31 105.55Test 3 - 4% NF2R2Left Right Average1 105.84 106.28 106.062 105.83 106.27 106.053 105.86 106.22 106.04Mean 105.84 106.26 106.05

[0086] After 1 week:100%ControlLeft Right Average1 95.73 97.53 96.632 98.82 98.58 98.703 96.31 93.65 94.98Mean 96.95 96.59 96.77Test 1 - 2% NF2R2Left Right Average1 106.99 105.93 106.462 107.14 106.92 107.033 105.67 105.73 105.70Mean 106.60 106.19 106.40Test 2 - 3% NF2R2Left Right Average1 108.13 107.85 107.992 108.98 108.98 108.983 106.96 107.53 107.25Mean 108.02 108.12 108.07Test 3 - 4% NF2R2Left Right Average1 108.37 107.02 107.702 109.12 109.95 109.543 108.59 109.62 109.11Mean 108.69 108.86 108.78[00871 Example 14: Testing retention of glycol solution:

[0088] Tips manufactured using the compositions from Example 10 at either a 4% or 8% letdown rate, as well as a control tip and a tip manufactured using a fluorinated additive. The retention rates were tested using a food coloring solution. (McCormick® Green Food Color, which is a mixture of propylene glycol and water + FD&C Yellow and blue). The results are shown in Figure 5. The dark droplets inside the tips represent solution that was not successfully expelled. More dark drops indicates more retention. LT represents a tip manufactured without any low retention additive. LR represents a tip manufactured with a fluorinated low retention additive.

[0089] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosure. Rather, the words used in thespecification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A composition for use in manufacturing molded pipette tips comprising:1 to 10 wt% of an organo-modified siloxane; 5 to 20 wt% of a triglyceride ester; 0.05 to 0.2 wt% of an organo phosphinite; and 65 to 95 wt% of a carrier resin, wherein the composition does not include a fluorine-based component.

2. The composition of claim 1 , further comprising 4 to 12 wt% of an aluminum oxide.

3. The composition of claim 1 , wherein the carrier resin is homopolypropylene.

4. The composition of claim 1, wherein the triglyceride is derived from palm oil.

5. The composition of claim 1, wherein the composition is added to a base resin to manufacture a molded pipette tip.

6. The composition of claim 5, wherein addition of the composition to a base resin at a letdown rate of 1-7% produces a molded pipette tip with improved expulsion of a liquid from the pipette tip as measured by a contact angle measurement according to ASTM D5946.

7. A blend comprising 1 to 7% of the composition of claim 1 , and 85 to 99% of a base resin, wherein the blend when heated and added to an injection press produces a molded pipette tip with improved expulsion of a liquid from the pipette tip as measured by a contact angle measurement according to ASTM D5946.

8. The blend of claim 7, further comprising 4 to 12 wt% of an aluminum oxide.

9. A composition for use in manufacturing molded pipette tips comprising:5 to 25 wt% of a triglyceride, 0.05 to 0.2 wt% of an organo phosphinite, 5 to 20 wt% of an aluminum oxide, and 65 to 95 wt% of a carrier resin, wherein the composition does not include a fluorine-based component.

10. The composition of claim 9, further comprising one or more surfactant derivatives.

11. The composition of claim 9, wherein the triglyceride is derived from palm oil.

12. The composition of claim 9, wherein the composition is added to a base resin to manufacture a molded pipette tip.

13. The composition of claim 12, wherein addition of the composition to a base resin at a letdown rate of 1-7% produces a molded pipette tip with improved expulsion of a liquid from the pipette tip as measured by a contact angle measurement according to ASTM D5946.

14. A blend comprising 1 to 7% of the composition of claim 9, and 85 to 99% of a base resin, wherein the blend when heated and added to an injection press produces a molded pipette tip with improved expulsion of a liquid from the pipette tip as measured by a contact angle measurement according to ASTM D5946.

15. The blend of claim 14, further comprising one or more surfactant derivatives.

16. A method of manufacturing a molded pipette tip with improved expulsion of a liquid from the pipette tip comprising: mixing together 1 to 10 wt% of an organo-modified siloxane; 5 to 20 wt% of a triglyceride ester; 0.05 to 0.2 wt% of an organo phosphinite; and 65 to 95 wt% of a carrier resin; heating the mixture to about 200 to about 475°F; extruding the mixture;cooling the mixture; forming the mixture into pellets to form a masterbatch; mixing together 1 to 7 % of the masterbatch and 85 to 99% of a base resin; heating the masterbatch and the base resin to form a mixture; and feeding the mixture through an injection press to form a molded pipette tip.

17. The method of claim 16, further comprising mixing 4 to 12 wt% of an aluminum oxide together with the organo-modified siloxane, the triglyceride ester, the organo phosphinite, and the carrier resin.

18. The method of claim 16, wherein the carrier resin is homopolypropylene.

19. The method of claim 16, wherein the triglyceride is derived from palm oil.

20. A method of manufacturing a molded pipette tip with improved expulsion of a liquid from the pipette tip comprising: mixing 1 to 7% of the composition of claim 9 with 85 to 99 percent of a base resin; and feeding the mixture through an injection press to form a molded pipette tip.

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