Non-oil self-lubricating silicones and methods of producing the same

Abstract

Compositions disclosed herein comprise a silicone rubber base composition comprising a vinyl silicone, a crosslinker comprising a pendant-only hydride silicone having an average silicon hydride (Si-H) content of at least 1 mmol / g, an inhibitor, a transition metal catalyst complex, and from about 0.2 wt.% to about 2 wt.%, based on a total weight of the composition, of a primary unsaturated fatty acid amide having a C=C double bond. Post-cured silicone products formed from the compositions are also provided.

Description

NON-OIL SELF-LUBRICATING SILICONES AND METHODS OF PRODUCING THESAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all benefit of U.S. Provisional Patent Application No. 63 / 672,196, filed on July 16, 2024, the entire disclosure of which is fully incorporated herein by reference.FIELD

[0002] The present disclosure relates to polymeric compositions and, more particularly, to polymeric compositions including self-lubricating silicone-based compositions.BACKGROUND

[0003] Silicone tubing is widely used in healthcare applications due to its biocompatibility, chemical resistance, optical transparency, and good mechanical performance over a wide range of temperatures. However, conventional silicone-based articles exhibit a tacky surface and static charge that can easily attract dust and other debris. For example, as a patient moves about a facility, silicone tubing (e.g., IV tubing) may drag on the floor and pick up dirt and dust. Manufacturers have previously attempted to reduce the tackiness of the silicone-based articles by applying a coating. However, such coatings typically only work for a short period of time before wearing away and losing performance.

[0004] Moreover, conventional silicone-based articles may also exhibit blocking (e.g., sticking to itself) as a result of the tackiness. Although lubricious coatings or oils have been used to address this issue, there remains the issue of the wear of the coating and loss of performance over time. In addition, conventional slip agents tend to migrate very quickly, particularly upon curing of the silicone-based composition.

[0005] Accordingly, there remains a need for alternative silicone-based compositions that exhibit reduced tack.SUMMARY

[0006] The following is a brief summary of subject matter that is described in greater detail herein. This summary is not intended to be limiting as to the scope of the claims.

[0007] According to a first aspect of the present disclosure, a composition comprises a silicone rubber base composition comprising a vinyl silicone; a crosslinker comprising a pendant-only hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram; an inhibitor; a transition metal catalyst complex; and from about 0.2 wt.% to about 2 wt.%, based on a total weight of the composition, of a primary unsaturated fatty acid amide with a C=C double bond. A molar ratio between Si-H groups of the crosslinker and vinyl groups of the silicone rubber base composition is at least 1.5 : 1. A silicone product formed from the composition and following a postcure treatment at one of the following temperature and time conditions: 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours, has a dynamic coefficient of friction of less than 0.7 and the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3 when measured on a dry and smooth stainless steel surface.

[0008] In a second aspect of the present disclosure, a composition comprises the composition of the first aspect, wherein the molar ratio between the Si-H groups of the crosslinker and the vinyl groups of the silicone rubber base composition is at least 4: 1.

[0009] In a third aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the crosslinker further comprises a hybrid hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram, and wherein the pedant-only hydride silicone contributes at least 20 mol.% of the total Si-H groups in the composition.

[0010] In a fourth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, further comprising a multi-functional trialkoxysilane additive.

[0011] In a fifth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the pedant-only hydride silicone contributes more than 90 mol.% of the total Si-H groups in the composition.

[0012] In a sixth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein a total number of moles of Si-H groups in the composition is greater than or equal to a sum of moles of vinyl groups in the base composition, moles of the unsaturated fatty acid amide, and moles of trialkoxy silane.

[0013] In a seventh aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the multi-functional trialkoxysilane is selected from the group consisting of epoxy-containing trialkoxysilane, vinyl-containing trialkoxysilane, (meth)acry late- containing trialkoxysilane, and combinations thereof.

[0014] In an eighth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein multi-functional trialkoxysilane is an epoxy-containing trialkoxysilane.

[0015] In a ninth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the primary unsaturated fatty acid amide is erucamide.

[0016] In a tenth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the transition metal catalyst complex comprises platinum.

[0017] In an eleventh aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the silicone rubber base composition further comprises a silicone resin selected from the group consisting of a methyl silicone, an -OH silicone, a phenyl silicone, a fluorosilicone, and combinations thereof.

[0018] In a twelfth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the silicone rubber base composition further comprises a silica.

[0019] In a thirteenth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the silicone rubber base composition further comprises a silicone plasticizer.

[0020] In a fourteenth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the silicone plasticizer comprises polydimethyl siloxane (PDMS).

[0021] In a fifteenth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, wherein the inhibitor is selected from the group consisting of ethynyl cyclohexanol, dimethyl fumarate, dimethyl maleate, and acetylenic alcohol.

[0022] In a sixteenth aspect of the present disclosure, a composition comprises the composition of any preceding aspect, further comprising one or more additives selected from the group consisting of colorants, carbon blacks, anti-static additives, anti-dust additives, mineral fillers, heat stabilizers, acid acceptors, adhesion promoters, tackifiers, mold releases, flame retardants, silicas, silicates, green strength additives, tensile modifiers, antimicrobial additive, and combinations thereof.

[0023] In a seventeenth aspect, a post-cured silicone product is formed from the composition according to any preceding aspect.

[0024] According to an eighteenth aspect, a post-cured silicone product is formed from a composition and subjected to a post-cure treatment. The composition comprises a silicone rubber base composition comprising a vinyl silicone; a crosslinker comprising a pendant-only hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram; an inhibitor; a transition metal catalyst complex; and from about 0.2 wt.% to about 2 wt.%, based on a total weight of the composition, of a primary unsaturated fatty acid amide with a C=C double bond. A molar ratio between Si-H groups of the crosslinker and vinyl groups of the silicone rubber base composition is at least 1.5: 1. The post-cure treatment is carried out one of the following temperature and time conditions: 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours. The post-cured silicone product has an average dynamic coefficient of friction of less than 0.7, and the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3, when measured on a dry and smooth stainless steel surface.

[0025] In a nineteenth aspect of the present disclosure, a post-cured silicone product comprises the post-cured silicone product of the seventeenth or eighteenth aspects, wherein the post-cured silicone product has an average dynamic coefficient of friction of less than 0.5.

[0026] In a twentieth aspect of the present disclosure, a post-cured silicone product comprises the post-cured silicone product of any one of the seventeenth through nineteenth aspects, wherein the post-cured silicone product has an instantaneous Shore A hardness of greater than 30 when measured in accordance with ASTM D2240.

[0027] In a twenty-first aspect of the present disclosure, a post-cured silicone product comprises the post-cured silicone product of any one of the seventeenth through twentieth aspects, wherein the post-cured silicone product has a transmission of greater than 60% when measured in accordance with ASTM DI 003.

[0028] In a twenty-second aspect of the present disclosure, a post-cured silicone product comprises the post-cured silicone product of any one of the seventeenth through twenty-first aspects, wherein the post-cured silicone product has a haze of less than 110% when measured in accordance with ASTM DI 003.

[0029] The above summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and / or methods discussed herein. This summary isnot an extensive overview of the systems and / or methods discussed herein. It is not intended to identify key / critical elements or to delineate the scope of such systems and / or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.BRIEF DESCRPTION OF THE DRAWING

[0030] The general inventive concepts, as well as embodiments and advantages thereof, are described in greater detail, by way of example, with reference to the drawing in which:

[0031] The Figure is a graph of the pull force (in Newtons (N); y-axis) as a function of displacement (in mm; x-axis) during a coefficient of friction test for Sample SI and Comparative Sample C5, as shown and described in the Examples.DETAILED DESCRIPTION

[0032] Disclosed herein are self-lubricating silicone compositions including a silicone rubber base composition, a transition metal catalyst system, and a fatty acid amide-based slip agent. The silicone rubber base composition includes at least one vinyl silicone. The transition metal catalyst system generally includes a transition metal catalyst complex, a crosslinker, and an inhibitor. The crosslinker includes a pendant-only hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / g. The fatty acid amide-based slip agent is a primary unsaturated fatty acid amide with a C=C double bond. Silicone products formed from the composition and subjected to a postcure treatment at 205 °C for 2 hours has a relative dynamic coefficient of friction of less than 50% as compared to a post-cured silicone product formed from a composition not including the primary unsaturated fatty acid amide but is otherwise identical. Other advantages are possible and contemplated and may be realized based on the following disclosure.

[0033] The terminology as set forth herein is for description of the various aspects only and should not be construed as limiting the disclosure as a whole. All references to singular characteristics or limitations of the present disclosure shall include the corresponding plural characteristic or limitation, and vice versa, unless otherwise specified or clearly implied to the contrary by the context in which the reference is made. Unless specified otherwise, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the description and the appended claims, the singular forms “a,” “an,” and “the” are inclusive of their plural forms, unless the context clearly indicates otherwise.

[0034] Unless otherwise expressly defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art.

[0035] Unless otherwise expressly stated, it not intended that any method disclosed herein be construed as requiring that its steps be performed in a specific order, nor that any article set forth herein be construed as requiring specific orders or orientations to its individual components.

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

[0037] Any composition described in the present disclosure can comprise, consist of, or consist essentially of the essential elements of the disclosure as described herein, as well as any additional or optional element described herein, or which is otherwise useful in polymeric compositions.

[0038] All percentages, parts, and ratios as used herein are by weight of the total blend on an “dry” basis, i.e., without solvents, unless otherwise specified.

[0039] All ranges and parameters, including but not limited to percentages, parts, and ratios, disclosed herein are understood to encompass any and all sub-ranges assumed and subsumed therein, and every number between the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 1 to 6.1, or 2.3 to 9.4), and to each integer (1, 2, 3, 4, 5, 6, 7, 8, 9, and 10) contained within the range. 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 embodiments includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the 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.

[0040] The term “wt.%,” as described herein, refers to the weight fraction of the individual component based on a total weight of the polymeric composition, unless otherwise noted.

[0041] Additionally, as used herein, the term “exemplary” is intended to mean serving as an illustration or example of something, and is not intended to indicate a preference.

[0042] As used herein, the term “thermoset” refers to a polymer that is irreversibly hardened through a curing process.

[0043] In various aspects provided herein, a composition is disclosed that includes a silicone rubber base composition, a transition metal catalyst system, and a fatty acid amide. Post-cured silicone product made from the composition may exhibit an average dynamic coefficient of friction of less than 50% as compared to a post-cured silicone product made from a composition that does not include the fatty acid amide but is otherwise identical. Products made through curing of the composition may have reduced surface tack without the use of a coating or oil. Other advantages may be realized, depending on the particular aspects, which will now be described in greater detail.Silicone Rubber Base Composition

[0044] As set forth above, the self-lubricating silicone composition can comprise a silicone rubber base composition. The silicone rubber base composition can be a high-consistency silicone rubber, also known as solid silicone rubber, a liquid silicone rubber (LSR) base composition, or a paste silicone rubber base composition. In general, the silicone rubber base composition is cured at elevated temperatures with either organic peroxides through a free-radical based curing process or a transition metal catalyst through a hydrosilylation process. In various aspects, the silicone rubber base composition comprises at least one vinyl silicone. The silicone rubber base composition may, in aspects, also include at least one silicone plasticizer and silica.

[0045] The silicone may further comprise another silicone component in addition to the vinyl silicone that is selected from the group consisting of a methyl silicone, an -OH silicone, a phenyl silicone, a fluorosilicone, and combinations thereof. The silicone may be in the form of a silicone gum or silicone fluid. In aspects of the disclosure, the total amount of silicone (including the vinyl silicone and other, optional silicones, but excluding the silica and plasticizer components) is included in the silicone rubber base composition in an amount of from about 10 wt.% to about 90 wt.%, based on a total weight of the composition. For example, the silicone rubber base composition may include from about 10 wt.% to about 90 wt.%, from about 10 wt.% to about 80 wt.%, from about 10 wt.% to about 70 wt.%, from about 10 wt.% to about 60 wt.%, from about 10 wt.% to about 50 wt.%, from about 20 wt.% to about 90 wt.%, from about 20 wt.% to about 80 wt.%, from about 20 wt.% to about 70 wt.%, from about 20 wt.% to about 60 wt.%, from about 20wt.% to about 50 wt.%, from about 30 wt.% to about 90 wt.%, from about 30 wt.% to about 80 wt.%, from about 30 wt.% to about 70 wt.%, from about 30 wt.% to about 60 wt.%, from about 30 wt.% to about 50 wt.%, from about 40 wt.% to about 90 wt.%, from about 40 wt.% to about 80 wt.%, from about 40 wt.% to about 70 wt.%, or from about 40 wt.% to about 60 wt.%, from about 40 wt.% to about 50 wt.% silicone, based on a total weight of the composition, including any and all ranges and subranges therein.

[0046] Silica may be included in the silicone rubber base composition in an amount of from about 2 wt.% to about 80 wt.%, based on a total weight of the composition. For example, the silicone rubber base composition may include from about 2 wt.% to about 80 wt.%, from about 2 wt.% to about 70 wt.%, from about 2 wt.% to about 60 wt.%, from about 2 wt.% to about 50 wt.%, from about 2 wt.% to about 40 wt.%, from about 2 wt.% to about 30 wt.%, from about 2 wt.% to about 20 wt.%, from about 5 wt.% to about 80 wt.%, from about 5 wt.% to about 70 wt.%, from about 5 wt.% to about 60 wt.%, from about 5 wt.% to about 50 wt.%, from about 5 wt.% to about 40 wt.%, from about 5 wt.% to about 30 wt.%, from about 5 wt.% to about 20 wt.%, from about 10 wt.% to about 80 wt.%, from about 10 wt.% to about 70 wt.%, from about 10 wt.% to about 60 wt.%, from about 10 wt.% to about 50 wt.%, from about 10 wt.% to about 40 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 20 wt.%, from about 15 wt.% to about 80 wt.%, from about 15 wt.% to about 70 wt.%, from about 15 wt.% to about 60 wt.%, from about 15 wt.% to about 50 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 30 wt.%, from about 15 wt.% to about 20 wt.%, from about 20 wt.% to about 80 wt.%, from about 20 wt.% to about 70 wt.%, from about 20 wt.% to about 60 wt.%, from about 20 wt.% to about 50 wt.%, from about 20 wt.% to about 40 wt.%, or from about 20 wt.% to about 30 wt.%, of the silica, based on a total weight of the composition, including any and all ranges and subranges therein. However, it should be understood that, in some aspects, the silicone rubber base composition may not include silica.

[0047] In any of the aspects described herein, the silicone plasticizer may comprise a mono- or poly-siloxane containing methyl, vinyl, hydroxyl, or phenyl groups, or a combination thereof. In aspects, the silicone plasticizer has a molecular weight of from about 0.1 g / mol to about 300,000 g / mol. For example, the silicone plasticizer may have a molecular weight of from about 0.1 g / mol to about 300,000 g / mol, from about 0.1 g / mol to about 250,000 g / mol, from about 0.1 g / mol to about 200,000 g / mol, from about 0.1 g / mol to about 150,000 g / mol, from about 0.1 g / mol to about 100,000 g / mol, from about 0.1 g / mol to about 50,000 g / mol, from about 1 g / mol to about 300,000 g / mol, from about 1 g / mol to about 250,000 g / mol, from about 1 g / mol to about 200,000 g / mol,from about 1 g / mol to about 150,000 g / mol, from about 1 g / mol to about 100,000 g / mol, from about 1 g / mol to about 50,000 g / mol, from about 10 g / mol to about 300,000 g / mol, from about 10 g / mol to about 250,000 g / mol, from about 10 g / mol to about 200,000 g / mol, from about 10 g / mol to about 150,000 g / mol, from about 10 g / mol to about 100,000 g / mol, from about 10 g / mol to about 50,000 g / mol, from about 100 g / mol to about 300,000 g / mol, from about 100 g / mol to about 250,000 g / mol, from about 100 g / mol to about 200,000 g / mol, from about 100 g / mol to about 150,000 g / mol, from about 100 g / mol to about 100,000 g / mol, from about 100 g / mol to about 50,000 g / mol, from about 1,000 g / mol to about 300,000 g / mol, from about 1,000 g / mol to about 250,000 g / mol, from about 1,000 g / mol to about 200,000 g / mol, from about 1,000 g / mol to about 150,000 g / mol, from about 1,000 g / mol to about 100,000 g / mol, from about 1,000 g / mol to about 50,000 g / mol, from about 10,000 g / mol to about 300,000 g / mol, from about 10,000 g / mol to about 250,000 g / mol, from about 10,000 g / mol to about 200,000 g / mol, from about 10,000 g / mol to about 150,000 g / mol, from about 10,000 g / mol to about 100,000 g / mol, or from about 10,000 g / mol to about 50,000 g / mol, including any and all ranges and subranges therein.

[0048] In any of the aspects described herein, the silicone plasticizer may comprise polydimethylsiloxane (PDMS).

[0049] In aspects of the disclosure, the silicone plasticizer is included in the silicone rubber base composition in an amount of from about 0.1 wt.% to about 20 wt.%, based on a total weight of the composition. For example, the silicone plasticizer may be included in the silicone rubber base composition in an amount of from about 0.1 wt.% to about 20 wt.%, from about 0.1 wt.% to about 15 wt.%, from about 0.1 wt.% to about 10 wt.%, from about 0.1 wt.% to about 7.5 wt.%, from about 0.1 wt.% to about 5 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.5 wt.% to about 20 wt.%, from about 0.5 wt.% to about 15 wt.%, from about 0.5 wt.% to about 10 wt.%, from about 0.5 wt.% to about 7.5 wt.%, from about 0.5 wt.% to about 5 wt.%, from about 0.5 wt.% to about 2 wt.%, from about 1 wt.% to about 20 wt.%, from about 1 wt.% to about 15 wt.%, from about 1 wt.% to about 10 wt.%, from about 1 wt.% to about 7.5 wt.%, from about 1 wt.% to about 5 wt.%, from about 1 wt.% to about 2 wt.%, from about 2 wt.% to about 20 wt.%, from about 2 wt.% to about 15 wt.%, from about 2 wt.% to about 10 wt.%, from about 2 wt.% to about 7.5 wt.%, from about 2 wt.% to about 5 wt.%, from about 5 wt.% to about 20 wt.%, from about 5 wt.% to about 15 wt.%, from about 5 wt.% to about 10 wt.%, or from about 5 wt.% to about 7.5 wt.%, based on a total weight of the composition, including any and all ranges and subranges therein.However, it should be understood that, in some aspects, the silicone rubber base composition may not include silicone plasticizer.Transition Metal Catalyst System

[0050] In aspects, the self-lubricating silicone composition may include a transition metal catalyst system effective to cure the silicone rubber base composition. The transition metal catalyst system may comprise a nickel, platinum, rhodium, palladium, or other suitable transition metal. Transition metal catalyst systems are particularly well-suited for compositions intended for use in healthcare applications due to the fact that, unlike peroxide-catalyzed systems, transition metal catalysts systems do not produce harmful or undesirable by-products and the resulting product may exhibit less shrinkage. In general, the transition metal catalyst system includes a transition metal catalyst complex, a crosslinker, and an inhibitor.

[0051] The transition metal catalyst complex may be selected from the group of organo metal compounds, salts, or metals, having the ability to catalyze hydrosilylation. The metal may be selected from the group consisting of nickel, iridium, rhodium, ruthenium, osmium, palladium, and platinum compounds. In aspects, the transition metal catalyst complex can be a complex of any form of nickel, iridum, rhodium, or platinum. In aspects including a platinum catalyst, the catalyst complex can be any form of platinum (0), (II), or (IV) compounds. For example, the transition metal catalyst may be a Pt-alkenyl complex, such as alkenyl, cycloalkenyl, alkenylsiloxane, or the like. Particular transition metal catalyst complexes that may be used are those conventionally known and used in the art.

[0052] The amount of transition metal catalyst complex included in the self-lubricating silicone composition is not particularly limited, so long as there is a sufficient amount to accelerate the hydrosilylation at the desired temperature and within the desired temperature in the presence of the other ingredients of the composition. The amount of transition metal catalyst complex included will also depend on the particular catalyst complex and the amount of inhibiting compounds. In general, the transition metal catalyst complex may be included in the self-lubricating silicone composition in an amount of from 0.001 wt.% to about 7 wt.%, based on a total weight of the composition. For example, the composition may include the transition metal catalyst complex in an amount of from about 0.001 wt.% to about 7 wt.%, from about 0.001 wt.% to about 5 wt.%, from about 0.001 wt.% to about 2 wt.%, from about 0.001 wt.% to about 1 wt.%, from about 0.001 wt.% to about 0.5 wt.%, from about 0.01 wt.% to about 7 wt.%, from about 0.01 wt.% to about 5 wt.%, from about 0.01 wt.% to about 2 wt.%, from about 0.01 wt.% to about 1 wt.%, from about0.01 wt.% to about 0.5 wt.%, from about 0.1 wt.% to about 7 wt.%, from about 0.1 wt.% to about 5 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.1 wt.% to about 1 wt.%, from about 0.1 wt.% to about 0.5 wt.%, from about 1 wt.% to about 7 wt.%, from about 1 wt.% to about 5 wt.%, or from about 1 wt.% to about 2 wt.%, based on the total weight of the composition, including any and all ranges and subranges therein.

[0053] In general, platinum catalyst complexes suitable for use in any of the aspects herein include a neat platinum catalyst in an inert liquid carrier. In aspects, the platinum catalyst complex includes metal platinum in an amount of from about 0.1 wt.% to about 10 wt.%, based on a total weight of the platinum catalyst complex. For example, the platinum catalyst complex may include metal platinum in an amount of from about 0.1 wt.% to about 10 wt.%, from about 0.1 wt.% to about 8 wt.%, from about 0.1 wt.% to about 6 wt.%, from about 0.1 wt.% to about 4 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.5 wt.% to about 10 wt.%, from about 0.5 wt.% to about 8 wt.%, from about 0.5 wt.% to about 6 wt.%, from about 0.5 wt.% to about 4 wt.%, from about 0.5 wt.% to about 2 wt.%, from about 1 wt.% to about 10 wt.%, from about 1 wt.% to about 8 wt.%, from about 1 wt.% to about 6 wt.%, from about 1 wt.% to about 4 wt.%, from about 1 wt.% to about 2 wt.%, from about 1.5 wt.% to about 10 wt.%, from about 1.5 wt.% to about 8 wt.%, from about 1.5 wt.% to about 6 wt.%, from about 1.5 wt.% to about 4 wt.%, or from about 1.5 wt.% to about 2 wt.%, based on a total weight of the platinum catalyst complex, including any and all ranges and subranges therein.

[0054] The crosslinker included in the platinum catalyst system of may be selected from the group consisting of a hybrid hydride silicone, a pendant-only hydride silicone, and combinations thereof. As used herein, a “hybrid hydride silicone” refers to a hydride silicone with Si-H groups present at both a terminal location and at least one pendant location on the silicone chain. As used herein, a “pendant-only hydride silicone” refers to a hydride silicone with Si-H groups present only at one or more pendant locations on the silicone chain. The crosslinker may comprise, for example, methylhydrogen siloxane-dimethyl siloxane copolymer with methyl terminal groups (a pendant- only hydride silicone) or a hydride-terminated methylhydrogen siloxane-dimethyl siloxane copolymer (a hybrid hydride silicone). A variety of suitable crosslinkers are available and known to those skilled in the art, including, for example, ANDISIL® XL- 1342 (a hybrid hydride silicone available from AB Specialty Silicones) and DOWSIL™ 6-3570 (a pendant-only hydride silicone available from The Dow Chemical Company).

[0055] In aspects, the crosslinker has an average Si-H content of at least 1 mmol / g. For example, the crosslinker may have an average Si-H content of from 1 mmol / g to 15 mmol / g, from1 mmol / g to 12 mmol / g, from 1 mmol / g to 10 mmol / g, from 2 mmol / g to 15 mmol / g, from 2 mmol / g to 12 mmol / g, from 2 mmol / g to 10 mmol / g, from 3 mmol / g to 15 mmol / g, from 3 mmol / g to 12 mmol / g, or from 3 mmol / g to 10 mmol / g. In certain aspects, the crosslinker has an average Si-H content of from 3 mmol / g to 10 mmol / g, which may provide an Si-H content effective to provide improved efficiency in the curing process. In some aspects, the crosslinker is a pendant- only hydride silicone that contributes at least 20 mol.%, at least 30 mol.%, at least 40 mol.%, or at least 50 mol.% of the total amount of Si-H groups in the composition. In some aspects, the crosslinker is a pendant-only hydride silicone that contributes greater than about 50 mol.%, greater than about 60 mol.%, greater than about 70 mol.%, or even greater than about 99 mol.% of the total amount of Si-H groups in the composition. In any of the aspects disclosed herein, the crosslinker may further comprise a hybrid hydride silicone with a silicon-hydride content of at least 1 mmol / g, provided that the pendant-only hydride silicone contributes at least 20 mol.% of the total Si-H groups in the composition, as set forth above.

[0056] In aspects of the disclosure, the crosslinker is included in the self-lubricating silicone composition in an amount of from about 0.1 wt.% to about 8 wt.%, based on a total weight of the composition. For example, the self-lubricating silicone composition may include from about 0.1 wt.% to about 8 wt.%, from about 0.1 wt.% to about 6 wt.%, from about 0.1 wt.% to about 4 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.5 wt.% to about 8 wt.%, from about 0.5 wt.% to about 6 wt.%, from about 0.5 wt.% to about 4 wt.%, from about 0.5 wt.% to about 2 wt.%, from about 1 wt.% to about 8 wt.%, from about 1 wt.% to about 6 wt.%, from about 1 wt.% to about 4 wt.%, from about 1 wt.% to about 2 wt.%, from about 1.5 wt.% to about 8 wt.%, from about 1.5 wt.% to about 6 wt.%, from about 1.5 wt.% to about 4 wt.%, or from about 1.5 wt.% to about 2 wt.% of the crosslinker, based on a total weight of the composition, including any and all ranges and subranges therein. It is also contemplated that the crosslinker may be included in the composition in an amount greater than 8 wt.% in some aspects in order to provide a sufficient silicone hydride (Si-H) content to the composition.

[0057] In various aspects herein, the crosslinker is included in the self-lubricating silicone composition in an amount such that a molar ratio between a number of moles of Si-H groups of the crosslinker to a number of moles of vinyl groups in the silicone rubber base composition is at least 1.5: 1. For example, the molar ratio between a number of moles of Si-H groups of the crosslinker to a number of moles of vinyl groups in the silicone rubber base composition may be greater than or equal to 1.5: 1, greater than or equal to 1.7: 1, greater than or equal to 2: 1, greater than or equal to 2.3: 1, greater than or equal to 2.5: 1, greater than or equal to 2.7: 1, greater than orequal to 3: 1, greater than or equal to 3.3: 1, greater than or equal to 3.5: 1, greater than or equal to 3.7 : 1 , or even greater than or equal to 4 : 1.

[0058] In aspects, the crosslinker may be included in an amount to provide an Si-H group content of from about 0.1 wt.% to about 10 wt.%, based on a total weight of the self-lubricating silicone composition. For example, the crosslinker may be included in the composition in an amount to provide an Si-H group content of from about 0.1 wt.% to about 10 wt.%, from about 0.1 wt.% to about 8 wt.%, from about 0.1 wt.% to about 6 wt.%, from about 0.1 wt.% to about 4 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.5 wt.% to about 10 wt.%, from about 0.5 wt.% to about 8 wt.%, from about 0.5 wt.% to about 6 wt.%, from about 0.5 wt.% to about 4 wt.%, from about 0.5 wt.% to about 2 wt.%, from about 1 wt.% to about 10 wt.%, from about 1 wt.% to about 8 wt.%, from about 1 wt.% to about 6 wt.%, from about 1 wt.% to about 4 wt.%, from about 1 wt.% to about 2 wt.%, from about 1.5 wt.% to about 10 wt.%, from about 1.5 wt.% to about 8 wt.%, from about 1.5 wt.% to about 6 wt.%, from about 1.5 wt.% to about 4 wt.%, or from about 1.5 wt.% to about 2 wt.%, based on a total weight of the composition, including any and all ranges and subranges therein.

[0059] In any of the aspects disclosed herein, the inhibitor may comprise ethynyl cyclohexanol, dimethyl fumarate, dimethyl maleate, or an acetylenic alcohol.

[0060] In aspects, the inhibitor is included in the self-lubricating silicone composition in an amount of from about 0.001 wt.% to about 3 wt.%. For example, the inhibitor may be included in the self-lubricating silicone composition in an amount of from about 0.001 wt.% to about 3 wt.%, from about 0.001 wt.% to about 2 wt.%, from about 0.001 wt.% to about 1 wt.%, from about 0.001 wt.% to about 0.5 wt.%, from about 0.01 wt.% to about 3 wt.%, from about 0.01 wt.% to about 2 wt.%, from about 0.01 wt.% to about 1 wt.%, from about 0.01 wt.% to about 0.5 wt.%, from about 0.1 wt.% to about 3 wt.%, from about 0.1 wt.% to about 2 wt.%, from about 0.1 wt.% to about 1 wt.%, from about 0.1 wt.% to about 0.5 wt.%, from about 1 wt.% to about 3 wt.%, or from about 1 wt.% to about 2 wt.%, based on the total weight of the composition, including any and all ranges and subranges therein.Fatty Acid Amide-Based Slip Agent

[0061] As described above, the composition further includes at least one fatty acid amide-based slip agent. In general, a fatty acid amide has the following structure:O ' IbN R where R is a C3-C27 alkyl moiety. R can be saturated, mono-unsaturated, or poly-unsaturated, and may be linear or branched. The fatty acid amide may be, for example, a primary unsaturated fatty acid amide. The composition may include a single fatty acid amide-based slip agent, or a blend of at least two different fatty acid amide-based slip agents. In aspects, the fatty acid amide comprises a primary unsaturated fatty acid amide with a C=C double bond in the R group. The C=C double bond may be a cis bond or a trans bond. The primary unsaturated fatty acid may be selected from erucamide, oleamide, elaidamide, linoleamide, and combinations thereof.

[0062] In aspects of the disclosure, the fatty acid amide-based slip agent is included in the selflubricating silicone composition in an amount of from about 0.2 wt.% to about 2.0 wt.%, based on a total weight of the composition. For example, the fatty acid amide-based slip agent may be present in the composition in an amount of from about 0.2 wt.% to about 2.0 wt.%, from about 0.3 wt.% to about 2.0 wt.%, from about 0.5 wt.% to about 2.0 wt.%, from about 0.7 wt.% to about 2.0 wt.%, from about 1.0 wt.% to about 2.0 wt.%, from about 1.3 wt.% to about 2.0 wt.%, from about 1.5 wt.% to about 2.0 wt.%, from about 0.2 wt.% to about 1.7 wt.%, from about 0.3 wt.% to about 1.7 wt.%, from about 0.5 wt.% to about 1.7 wt.%, from about 0.7 wt.% to about 1.7 wt.%, from about 1.0 wt.% to about 1.7 wt.%, from about 1.3 wt.% to about 1.7 wt.%, from about 0.2 wt.% to about 1.5 wt.%, from about 0.3 wt.% to about 1.5 wt.%, from about 0.5 wt.% to about 1.5 wt.%, from about 0.7 wt.% to about 1.5 wt.%, from about 1.0 wt.% to about 1.5 wt.%, from about 1.3 wt.% to about 1.5 wt.%, from about 0.2 wt.% to about 1.3 wt.%, from about 0.3 wt.% to about 1.3 wt.%, from about 0.5 wt.% to about 1.3 wt.%, from about 0.7 wt.% to about 1.3 wt.%, from about 1.0 wt.% to about 1.3 wt.%, from about 0.2 wt.% to about 1.0 wt.%, from about 0.3 wt.% to about 1.0 wt.%, from about 0.5 wt.% to about 1.0 wt.%, or from about 0.7 wt.% to about 1.0 wt.%, based on a total weight of the composition, including any and all ranges and subranges therein.Multi-Functional Trialkoxysilane Additive

[0063] In any of the aspects described herein, the self-lubricating silicone composition may include a multi-functional trialkoxysilane additive. Without being bound by theory, it is believed that there is a molecular interaction between the multi-functional trialkoxysilane additive and the fatty acid amide through a hydrogen-bonding mechanism or a chemical reaction. The hydrogenbonding mechanism may occur between the hydrogen-acceptor group (e.g., an epoxy group) of themulti-functional trialkoxysilane additive and a hydrogen of the -NH2 end group of the primary unsaturated fatty acid amide. The hydrosilylation reaction may also occur between the C=C double bond of an unsaturated fatty acid amide and the Si-H group of the hydride silicone crosslinker in the presence of a transition metal catalyst at a slower reaction rate than that of the hydrosilylation between the vinyl groups of the vinyl silicone component and the crosslinker. Such interactions may still anchor the fatty acid amide-based slip agent to the surface of the silicone rubber composition if the interactive species are both available at the surface, thereby enabling the composition to retain the slip agent following curing or a post-curing step of the silicone rubber.

[0064] The multi-functional trialkoxysilane additive may comprise an epoxy-containing trialkoxysilane, a vinyl-containing trialkoxysilane, a (meth)acrylate-containing trialkoxysilane, or combinations thereof. Example multi-functional trialkoxysilane additives include, by way of example and not limitation, glycidoxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, methyltriacetoxysilane, bis(trimethoxysilyl)hexane, and methyltriethoxysilane, and combinations thereof. Commercially available multi-functional trialkoxysilane additives include those marketed under the tradenames XIAMETER™, including XIAMETER™ OFS-6040 and XIAMETER™ OFS-6106 (available from The Dow Chemical Company), and Z-6040 and Z-6106 (available from The Dow Chemical Company), for example. In aspects provided herein, the particular multi-functional trialkoxysilane additive may be selected based, at least in part, on the specific properties of the final silicone product, such as bonding to specific materials or target durometer.

[0065] The multi-functional trialkoxysilane additive may be included in the self-lubricating silicone composition in an amount of from about 0.2 wt.% to about 5.0 wt.%, based on a total weight of the composition. For example, the multi-functional trialkoxysilane additive may be included in the composition in an amount of from about 0.2 wt.% to about 5.0 wt.%, from about 0.3 wt.% to about 5.0 wt.%, from about 0.5 wt.% to about 5.0 wt.%, from about 0.8 wt.% to about 5.0 wt.%, from about 1.0 wt.% to about 5.0 wt.%, from about 1.5 wt.% to about 5.0 wt.%, from about 2.0 wt.% to about 5.0 wt.%, from about 2.5 wt.% to about 5.0 wt.%, from about 3.0 wt.% to about 5.0 wt.%, from about 3.5 wt.% to about 5.0 wt.%, from about 0.2 wt.% to about 4.5 wt.%, from about 0.3 wt.% to about 4.5 wt.%, from about 0.5 wt.% to about 4.5 wt.%, from about 0.8 wt.% to about 4.5 wt.%, from about 1.0 wt.% to about 4.5 wt.%, from about 1.5 wt.% to about 4.5 wt.%, from about 2.0 wt.% to about 4.5 wt.%, from about 2.5 wt.% to about 4.5 wt.%, from about 3.0 wt.% to about 4.5 wt.%, from about 3.5 wt.% to about 4.5 wt.%, from about 0.2 wt.% to about 4.0 wt.%, from about 0.3 wt.% to about 4.0 wt.%, from about 0.5 wt.% to about 4.0 wt.%, fromabout 0.8 wt.% to about 4.0 wt.%, from about 1.0 wt.% to about 4.0 wt.%, from about 1.5 wt.% to about 4.0 wt.%, from about 2.0 wt.% to about 4.0 wt.%, from about 2.5 wt.% to about 4.0 wt.%, from about 3.0 wt.% to about 4.0 wt.%, from about 3.5 wt.% to about 4.0 wt.%, from about 0.2 wt.% to about 3.5 wt.%, from about 0.3 wt.% to about 3.5 wt.%, from about 0.5 wt.% to about 3.5 wt.%, from about 0.8 wt.% to about 3.5 wt.%, from about 1.0 wt.% to about 3.5 wt.%, from about1.5 wt.% to about 3.5 wt.%, from about 2.0 wt.% to about 3.5 wt.%, from about 2.5 wt.% to about3.5 wt.%, from about 3.0 wt.% to about 3.5 wt.%, from about 0.2 wt.% to about 3.0 wt.%, from about 0.3 wt.% to about 3.0 wt.%, from about 0.5 wt.% to about 3.0 wt.%, from about 0.8 wt.% to about 3.0 wt.%, from about 1.0 wt.% to about 3.0 wt.%, from about 1.5 wt.% to about 3.0 wt.%, from about 2.0 wt.% to about 3.0 wt.%, from about 2.5 wt.% to about 3.0 wt.%, from about 0.2 wt.% to about 2.5 wt.%, from about 0.3 wt.% to about 2.5 wt.%, from about 0.5 wt.% to about 2.5 wt.%, from about 0.8 wt.% to about 2.5 wt.%, from about 1.0 wt.% to about 2.5 wt.%, from about1.5 wt.% to about 2.5 wt.%, or from about 2.0 wt.% to about 2.5 wt.%, based on a total weight of the composition, including any and all ranges and subranges therein.

[0066] In any of the aspects disclosed herein, the multi-functional trialkoxy silane additive and the fatty acid amide-based slip agent are included in the composition such that a molar ratio between a total number of moles of Si-H groups in the composition is greater than or equal to a sum of the number of moles of vinyl groups in the base composition, the number of moles of the unsaturated fatty acid amide, and the number of moles of trialkoxy silane in the composition.Properties and Articles

[0067] In any of the aspects described herein, in addition to the components described hereinabove, one or more additives can be incorporated into the self-lubricating silicone composition. Additives can include, by way of example and not limitation, colorants and dyes, carbon blacks, anti-static agents, anti-dust agents, mineral fillers, heat stabilizers, acid acceptors, adhesion promoters, tackifiers, mold releases, flame retardant / resistance additives, silicas and silicates, green strength additives, tensile modifiers, scavengers, antimicrobial additives, and any other additive known and used in the art.

[0068] As described hereinabove, in various aspects, a masterbatch can be formed by melting the fatty acid amide-based slip agent, a silicone carrier, and, optionally, a filler. The masterbatch can include the fatty acid amide-based slip agent in an amount of from about 0.5 wt.% to about 75 wt.%, and the silicone carrier in an amount of from about 10 wt.% to about 80 wt.%, based on a total weight of the masterbatch.

[0069] For example, the fatty acid amide-based slip agent may be included in the masterbatch in an amount of from about 0.5 wt.% to about 75 wt.%, from about 0.5 wt.% to about 70 wt.%, from about 0.5 wt.% to about 60 wt.%, from about 0.5 wt.% to about 50 wt.%, from about 0.5 wt.% to about 40 wt.%, from about 0.5 wt.% to about 30 wt.%, from about 0.5 wt.% to about 20 wt.%, from about 5 wt.% to about 75 wt.%, from about 5 wt.% to about 70 wt.%, from about 5 wt.% to about 60 wt.%, from about 5 wt.% to about 50 wt.%, from about 5 wt.% to about 40 wt.%, from about 5 wt.% to about 30 wt.%, from about 5 wt.% to about 20 wt.%, from about 10 wt.% to about 75 wt.%, from about 10 wt.% to about 70 wt.%, from about 10 wt.% to about 60 wt.%, from about 10 wt.% to about 50 wt.%, from about 10 wt.% to about 40 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 20 wt.%, from about 15 wt.% to about 75 wt.%, from about 15 wt.% to about 70 wt.%, from about 15 wt.% to about 60 wt.%, from about 15 wt.% to about 50 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 30 wt.%, or from about 15 wt.% to about 20 wt.%, based on a total weight of the masterbatch, including any and all ranges and subranges therein.

[0070] The silicone carrier may be included in the masterbatch in an amount of from about from about 10 wt.% to about 80 wt.%, from about 10 wt.% to about 70 wt.%, from about 10 wt.% to about 60 wt.%, from about 10 wt.% to about 50 wt.%, from about 10 wt.% to about 40 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 20 wt.%, from about 15 wt.% to about 80 wt.%, from about 15 wt.% to about 70 wt.%, from about 15 wt.% to about 60 wt.%, from about 15 wt.% to about 50 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 30 wt.%, from about 15 wt.% to about 20 wt.%, from about 20 wt.% to about 80 wt.%, from about 20 wt.% to about 70 wt.%, from about 20 wt.% to about 60 wt.%, from about 20 wt.% to about 50 wt.%, from about 20 wt.% to about 40 wt.%, from about 20 wt.% to about 30 wt.%, from about 25 wt.% to about 80 wt.%, from about 25 wt.% to about 70 wt.%, from about 25 wt.% to about 60 wt.%, from about 25 wt.% to about 50 wt.%, from about 25 wt.% to about 40 wt.%, or from about 25 wt.% to about 30 wt.%, based on a total weight of the masterbatch, including any and all ranges and subranges therein.

[0071] In some aspects, the masterbatch may also include a filler. The filler may comprise, silicas, silicates, hydrates, talc, limestone, sand, carbonates, carbon black, treated versions of any of the foregoing, or combinations thereof. The filler, when used, may be included in the masterbatch in an amount of from about 0.1 wt.% to about 66 wt.%, based on a total weight of the masterbatch. For example, the filler may be included in the masterbatch in an amount of from about 0.1 wt.% to about 66 wt.%, from about 0.1 wt.% to about 60 wt.%, from about 0.1 wt.% toabout 50 wt.%, from about 0.1 wt.% to about 40 wt.%, from about 0.1 wt.% to about 30 wt.%, from about 0.1 wt.% to about 20 wt.%, from about 0.5 wt.% to about 66 wt.%, from about 0.5 wt.% to about 60 wt.%, from about 0.5 wt.% to about 50 wt.%, from about 0.5 wt.% to about 40 wt.%, from about 0.5 wt.% to about 30 wt.%, from about 0.5 wt.% to about 20 wt.%, from about 1 wt.% to about 66 wt.%, from about 1 wt.% to about 60 wt.%, from about 1 wt.% to about 50 wt.%, from about 1 wt.% to about 40 wt.%, from about 1 wt.% to about 30 wt.%, from about 1 wt.% to about 20 wt.%, from about 5 wt.% to about 66 wt.%, from about 5 wt.% to about 60 wt.%, from about 5 wt.% to about 50 wt.%, from about 5 wt.% to about 40 wt.%, from about 5 wt.% to about 30 wt.%, from about 5 wt.% to about 20 wt.%, from about 10 wt.% to about 66 wt.%, from about 10 wt.% to about 60 wt.%, from about 10 wt.% to about 50 wt.%, from about 10 wt.% to about 40 wt.%, from about 10 wt.% to about 30 wt.%, from about 10 wt.% to about 20 wt.%, from about 15 wt.% to about 66 wt.%, from about 15 wt.% to about 60 wt.%, from about 15 wt.% to about 50 wt.%, from about 15 wt.% to about 40 wt.%, from about 15 wt.% to about 30 wt.%, or from about 15 wt.% to about 20 wt.%, based on a total weight of the masterbatch, including any and all ranges and subranges therein.

[0072] Alternatively, the fatty acid amide-based slip agent can be added to the silicone rubber base composition and the transition metal catalyst system without creation of a separate masterbatch. The fatty acid amide-based slip agent, silicone rubber base composition, and the transition metal catalyst system can be mixed or blended in any suitable way to form the composition.

[0073] An article may be formed from the composition using any suitable method of molding or forming the composition, including, for example, injection molding, compression molding, dispenser molding, extrusion, and transfer molding. In aspects, the formed composition may be press cured and, optionally, subjected to a post-cure treatment to form a cured silicone product. The post-cure treatment can be carried out at an elevated temperature. For example, the postcuring treatment can be performed at about 150 °C for about 30 minutes, or at about 205 °C for about 2 hours to about 4 hours, or at about 35 °C for about 8 hours. In any of the aspects disclosed herein, the post-curing treatment may be performed at 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours. Other time and temperature combinations for the post-cure treatment are contemplated and possible.

[0074] In any of the aspects described herein, the article may be a pharmaceutical package (e.g., a syringe), a stopper, a valve (e.g., a slit valve), tubing (e.g., catheter tubing or IV tubing), a seal or gasket, a cable jacket, a septum, or the like. The article may be incorporated into consumerdevices, medical devices, electric devices, or the like. The article may also be incorporated into parts used in assembly processes for transportation applications and the like.

[0075] In various aspects, the post-cured silicone product may have an average dynamic coefficient of friction of less than 1, less than 0.7, or less than 0.5 when measured using a dry, smooth steel substrate. For example, the post-cured silicone product may have an average dynamic coefficient of friction of from about 0.2 to about 0.9, from about 0.3 to about 0.7, or from about 0.4 to about 0.6, including any and all ranges and subranges therein.

[0076] Additionally, in various aspects, the post-cured silicone product may have an average dynamic coefficient of friction and an average static coefficient of friction such that the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3 when measured on a dry and smooth stainless steel surface. For example, the post-cured silicone product, following a post-cure treatment at one of the following temperature and time conditions: 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours, may have a ratio of the dynamic coefficient of friction and static coefficient of friction of less than or equal to 1.3, less than or equal to 1.2, or even less than or equal to 1.1.

[0077] The post-cured silicone product formed from the self-lubricating silicone compositions described herein may have a relative dynamic coefficient of friction of less than about 70% as compared to a post-cured silicone product formed from a composition not including the primary unsaturated fatty acid amide but that is otherwise identical when the product is subjected to a postcure treatment at 205 °C for 2 hours. The relative dynamic coefficient of friction can be calculated by dividing the average dynamic coefficient of friction of the post-cured silicone product formed from the composition described herein by the average dynamic coefficient of friction of the postcured silicone product formed from the composition not including the primary unsaturated fatty acid amide (e.g., the control) and multiplying by 100. In aspects, the relative dynamic coefficient of friction may be less than about 70%, less than about 65%, less than about 60%, less than about 55%, less than about 55%, less than about 50%, less than about 45%, less than about 40%, less than about 35%, or less than about 30%. In aspects, the relative dynamic coefficient of friction may be from about 20% to about 50%, from about 20% to about 40%, or from about 20% to about 30%, including any ranges and subranges therein.

[0078] In any of the aspects described herein, the post-cured silicone product may have an instantaneous Shore A hardness of greater than 30 when measured in accordance with ASTM D2240. For example, the post-cured silicone product may have an instantaneous Shore A hardnessof from 30 to about 80, from about 40 to about 78, from about 50 to about 76, or from about 70 to about 75, including any ranges and subranges therein. Following an up to 10 second delay, the post-cured silicone product may have a Shore A hardness of greater than 30 when measured in accordance with ASTM D2240. For example, the post-cured silicone product may have a Shore A hardness after an up to 10 second delay of from about 30 to about 75, from about 55 to about 75 or from about 58 to about 72, including any ranges and subranges therein.

[0079] The post-cured silicone product may exhibit a stress at 50% strain of greater than about 165 psi at 20 in / min when measured in accordance with ASTM D412 (die C). For example, the post-cured silicone product may exhibit a stress at 50% strain from about 165 psi to about 320 psi, from about 168 psi to about 250 psi, or from about 170 psi to about 200 psi, including any ranges and subranges therein. In aspects, the post-cured silicone product may exhibit a stress at 50% strain from about 171 psi to about 190 psi.

[0080] In any of the aspects disclosed herein, the post-cured silicone product may exhibit a tensile elongation at break of greater than 400%, when measured in accordance with ASTM D412 (die C) at 20 in / min. For example, the post-cured silicone product may exhibit a tensile elongation at break of greater than 350%, when measured in accordance with ASTM D412 (die C) at 20 in / min. In aspects, the post-cured silicone product may exhibit a tensile elongation at break of greater than about 675%, greater than about 700%, or even greater than about 725%.

[0081] The post-cured silicone product may also exhibit a tensile strength at break of greater than 1000 psi when measured in accordance with ASTM D412 (die C) at 20 in / min. For example, the post-cured silicone product may exhibit a tensile strength at break of from about 1050 psi to about 1250 psi, from about 1075 psi to about 1200 psi, from about 1080 psi to about 1175 psi, or from about 1100 psi to about 1170 psi, including any ranges and subranges therein.

[0082] It is contemplated that, in any of the aspects disclosed herein, the stress at 50% strain, tensile elongation at break, and / or the tensile strength at break of the post-cured silicone product may have values outside of the ranges disclosed above. However, it should be understood that these values are comparable to that of a post-cured silicone product that does not include primary unsaturated fatty acid amide but is otherwise identical.

[0083] In any of the aspects disclosed herein, the post-cured silicone product may exhibit a transmission of greater than 60% when measured in accordance with ASTM D1003. For example, the post-cured silicone product may exhibit a transmission of from about 60% to about 90%, fromabout 68% to about 85%, or from about 70% to about 73%, including any ranges and subranges therein.

[0084] The post-cured silicone product may also exhibit a haze of less than 110% when measured in accordance with ASTM D1003. For example, the post-cured silicone product may exhibit a haze of from about 50% to about 110%, from about 55% to about 105%, or from about 60% to about 103%, including any ranges and subranges therein.

[0085] In general, the cured silicone product exhibits a silky feel both prior to and following a post cure treatment as well as a decreased dust pick up as compared to a cured silicone product made from a composition that does not include the primary unsaturated fatty acid amide but is otherwise identical.

[0086] The general inventive concepts have been described above both generally and with regard to various specific aspects. Although the general inventive concepts have been set forth in what are believed to be exemplary illustrative aspects, a wide variety of alternatives will be apparent to those of skill in the art from reading this disclosure. The general inventive concepts are not otherwise limited, except for those instances when presented in specific claims.EXAMPLES

[0087] The following examples are included for the purposes of illustration, and do not limit the scope of the general inventive concepts described herein.

[0088] The materials provided in Table 1 below were used in the examples described herein. A conventional platinum cure silicone compound was employed as a base for each of the compositions, which included a vinyl silicone base, a vinyl-containing silicone gum, an inhibitor masterbatch, and a platinum catalyst masterbatch.Table 1.

[0089] Several compositions were prepared, including eleven control (Cl-Cl l) and eight example compositions according to the aspects described herein (S1-S8). The compositions are provided in Tables 2-4 below, in which the values are reported as wt.%.Table 2.Table 3.Table 4.

[0090] For each of the compositions, the number of various moles of functional groups were calculated, along with certain ratios. Values are reported in Table 5 as moles per 100 grams of the composition. Ratios are reported in Table 6.Table 5.Table 6.*C10 and Cl 1 do not contain unsaturated fatty acid amide or epoxy-containing silane

[0091] Hardness was measured in accordance with ASTM D2240. Average transmission and average haze were measured in accordance with ASTM DI 003. Hardness, transmission, and haze were measured following a post-cure treatment at 300 °F for 4 hours. Static coefficient of friction and dynamic coefficient of friction were measured according to an internal method using a dry, smooth steel substrate. The results are reported in Tables 7-9 below.Table 7.Table 8.*Value reported is ±0.25 as results were inconsistent.Table 9.

[0092] As shown in Tables 7-9, each of Samples S1-S8, when cured at one of the following temperature and time conditions: 148 °C (300 °F) for 4 hours or 176 °C (350 °F) for 2 hours or 205 °C (400 °F) for 2 hours, had an average dynamic coefficient of friction of less than 0.7 when measured on a dry and smooth stainless steel surface, and the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3. Notably, Sample S6, when postcured at 300 °F (148 °C) for 4 hours, has demonstrated a dynamic COF of 0.36, and the ratio between its dynamic COF and its static COF of only 1.1, meaning it has a durable lubricious surface with low COF.

[0093] The Figure is a graph of the pull force (in Newtons (N); y-axis) as a function of displacement (in mm; x-axis) for Comparative Sample C5 and Sample SI, each following a postcure treatment at 350 °F for 2 hours, during a coefficient of friction test performed in accordance with ASTM D1894-14). As shown in the FIG., Comparative Sample C5 shows a monotonically increasing curve of the pull force versus displacement, and the calculated ratio between its dynamic coefficient of friction and its static coefficient of friction is 1.5 indicating the lubricating effect of the fatty acid amide-based slip agent has gradually deteriorated during the test. This behavior may be explained by partial loss of the fatty acid amide additive from the sample surface to the testing substrate (z.e., stainless steel substrate) when the sample surface was subject to the rubbing action between the sample surface and the testing substrate in the COF test. The loss of the slip agent in the test would correspond to poor durability of lubricious effect of the slip agent at the sample’s surface, which may be undesirable for the silicone parts that are potentially subject to repetitive surface rubbing in the field applications.

[0094] On the other hand, Sample SI shows a much flatter curve of the pull force versus displacement during the COF test and the calculated ratio between its dynamic coefficient of friction and its static coefficient of friction is 1.1, indicating the lubricating effect of the fatty acid amide-based slip agent has been retained during the test. This behavior may be explained by restricted loss of the fatty acid amide additive from the sample surface to the testing substrate in the test, which is likely due to the chemical coupling between the unsaturated fatty acid amide and the excess amount of Si-H group that happened in the post-curing step at the sample’s surface. Accordingly, a lower ratio between dynamic coefficient of friction and static coefficient of friction of a post-cured sample corresponds to a better durability of the lubricating effect of the post-cured part.

[0095] Every document cited herein is incorporated herein by reference in its entirety unless otherwise specified. The citation of any document is not to be construed as an admission that it is prior art with respect to any invention disclosed or claimed herein. To the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

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

Claims

CLAIMSWhat is claimed is:

1. A composition comprising: a silicone rubber base composition comprising a vinyl silicone; a crosslinker comprising a pendant-only hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram; an inhibitor; a transition metal catalyst complex; and from about 0.2 wt.% to about 2 wt.%, based on a total weight of the composition, of a primary unsaturated fatty acid amide with a C=C double bond; wherein a molar ratio between Si-H groups of the crosslinker and vinyl groups of the silicone rubber base composition is at least 1.5: 1; and wherein a silicone product formed from the composition and following a post-cure treatment at one of the following temperature and time conditions: 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours, has a dynamic coefficient of friction of less than 0.7 and the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3 when measured on a dry and smooth stainless steel surface.

2. The composition according to claim 1, wherein the molar ratio between the Si-H groups of the crosslinker and the vinyl groups of the silicone rubber base composition is at least 4: 1.

3. The composition according to claim 1 or claim 2, wherein the crosslinker further comprises a hybrid hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram, and wherein the pedant-only hydride silicone contributes at least 20 mol.% of the total Si- H groups in the composition.

4. The composition according to any one of claims 1-3, further comprising a multifunctional trialkoxysilane additive.

5. The composition according to claim 4, wherein the pedant-only hydride silicone contributes more than 90 mol.% of the total Si-H groups in the composition.

6. The composition according to claim 4 or claim 5, wherein a total number of moles ofSi-H groups in the composition is greater than or equal to a sum of moles of vinyl groups in the base composition, moles of the unsaturated fatty acid amide, and moles of trialkoxy silane.

7. The composition according to any one of claims 4-6, wherein the multi-functional trialkoxysilane is selected from the group consisting of epoxy-containing trialkoxysilane, vinylcontaining trialkoxysilane, (meth)acrylate-containing trialkoxysilane, and combinations thereof.

8. The composition according to any one of claims 4-7, wherein multi-functional trialkoxysilane is an epoxy-containing trialkoxysilane.

9. The composition according to any preceding claim, wherein the primary unsaturated fatty acid amide is erucamide.

10. The composition according to any preceding claim, wherein the transition metal catalyst complex comprises platinum.

11. The composition according to any preceding claim, wherein the silicone rubber base composition further comprises a silicone resin selected from the group consisting of a methyl silicone, an -OH silicone, a phenyl silicone, a fluorosilicone, and combinations thereof.

12. The composition according to any preceding claim, wherein the silicone rubber base composition further comprises a silica.

13. The composition according to any preceding claim, wherein the silicone rubber base composition further comprises a silicone plasticizer.

14. The composition according to claim 13, wherein the silicone plasticizer comprises polydimethyl siloxane (PDMS).

15. The composition according to any preceding claim, wherein the inhibitor is selected from the group consisting of ethynyl cyclohexanol, dimethyl fumarate, dimethyl maleate, and acetylenic alcohol.

16. The composition according to any preceding claim, further comprising one or more additives selected from the group consisting of colorants, carbon blacks, anti-static additives, anti-dust additives, mineral fillers, heat stabilizers, acid acceptors, adhesion promoters, tackifiers, mold releases, flame retardants, silicas, silicates, green strength additives, tensile modifiers, antimicrobial additive, and combinations thereof.

17. A post-cured silicone product formed from the composition according to any preceding claim.

18. A post-cured silicone product formed from a composition and subjected to a post-cure treatment, the composition comprising: a silicone rubber base composition comprising a vinyl silicone; a crosslinker comprising a pendant-only hydride silicone with a silicon-hydride (Si-H) content of at least 1 mmol / gram; an inhibitor; a transition metal catalyst complex; and from about 0.2 wt.% to about 2 wt.%, based on a total weight of the composition, of a primary unsaturated fatty acid amide with a C=C double bond; wherein a molar ratio between Si-H groups of the crosslinker and vinyl groups of the silicone rubber base composition is at least 1.5: 1; wherein the post-cure treatment is carried out at one of the following temperature and time conditions: 148 °C for 4 hours, or 176 °C for 2 hours, or 205 °C for 2 hours; and wherein the post-cured silicone product has an average dynamic coefficient of friction of less than 0.7, and the ratio between the dynamic coefficient of friction and static coefficient of friction is not greater than 1.3, when measured on a dry and smooth stainless steel surface.

19. The post-cured silicone product according to claim 17 or claim 18, wherein the postcured silicone product has an average dynamic coefficient of friction of less than 0.5.

20. The post-cured silicone product according to any one of claims 17-19, wherein the post-cured silicone product has an instantaneous Shore A hardness of greater than 30 when measured in accordance with ASTM D2240.

21. The post-cured silicone product according to any one of claims 17-20, wherein the post-cured silicone product has a transmission of greater than 60% when measured in accordance with ASTM DI 003.

22. The post-cured silicone product according to any one of claims 17-21, wherein the post-cured silicone product has a haze of less than 110% when measured in accordance with ASTM DI 003.

Images