Low friction coefficient polymer composition

Abstract

The polymer composition comprises a vinyl polymer having a density of 0.926 g / cc to 0.970 g / cc as measured according to ASTM D792 and a polydimethylsiloxane having a weight-average molecular weight of 550,000 g / mol to 650,000 g / mol as measured according to gel permeation chromatography. The composition does not contain polydimethylsiloxane having a weight-average molecular weight of 30,000 g / mol to 300,000 g / mol as measured according to gel permeation chromatography.

Description

Technical Field

[0001] This disclosure generally relates to polymer compositions, and more specifically to polymer compositions exhibiting a low coefficient of friction. Background Technology

[0002] Introduction

[0003] Wires and cables are typically blown in and / or pushed into existing conduits and tubing to increase fiber density within the structure. This maximizes the use of both new and existing infrastructure. For wires and cables to be installed effectively in this manner, the polymer composition of the sheath on the wires and cables needs to have a low coefficient of friction (“COF”). A low COF of the polymer composition ensures that the wires and cables do not resist sliding along surfaces during installation. Typically, for maximum effectiveness in the application, the polymer composition of the sheath needs to exhibit an unaged COF of 0.25 or less, as measured according to ASTM D1894.

[0004] Various additives have been explored to reduce the COF of polymer compositions. One example of such additive is a slip agent. Slip agents act as lubricants on the surface of the polymer composition during processing or in the use environment. These slip agents typically work by migrating or blooming onto the surface of the polymer composition, where they provide a COF-reducing coating. Advantageously, the concentration of the slip agent at the surface results in a lower overall amount of slip agent required in the polymer material. Examples of slip agents include erucamide and low molecular weight siloxanes.

[0005] Typically, the slip agent within the polymer composition will bloom over time, thus reducing the sheath's ability to exhibit low COF. Premature blooming of the slip agent is detrimental because prolonged storage of the polymer composition after manufacturing but before wire or cable installation can cause the COF to deteriorate to an unusable level. Therefore, the polymer composition must also typically exhibit a COF of 0.25 as measured according to ASTM D1894 after aging at 55°C for 336 hours (i.e., "aged COF").

[0006] Attempts have also been made to use higher molecular weight polydimethylsiloxanes (“PDMS”) to reduce the coefficient of friction of polymer compositions. For example, U.S. Patent Application US2020 / 0199336A1 (“336 Publication”) discloses a composition using a slip agent blend comprising a first PDMS having a weight-average molecular weight (“Mw”) of 30,000 g / mol to less than 300,000 g / mol; and a second PDMS having a Mw of 300,000 g / mol to 2,000,000 g / mol, wherein the composition has a COF of 0.25. The 336 Publication shows that using only PDMS having a Mw of 300,000 g / mol to 2,000,000 g / mol (e.g., CS1 and CS2) in low-density polyethylene exhibits high COFs of 0.65 and 0.70, respectively.

[0007] In light of the foregoing, it is surprising to discover polymer compositions that use a single polydimethylsiloxane with a Mw of 550,000 g / mol to 650,000 g / mol but are capable of achieving an unaged COF of 0.25 or lower and an aged COF of 0.25 or lower. Summary of the Invention

[0008] The present invention provides a polymer composition using a single polydimethylsiloxane having a Mw of 550,000 g / mol to 650,000 g / mol, but capable of achieving an unaged COF of 0.25 or lower and an aged COF of 0.25 or lower.

[0009] This invention is a result of the discovery that the aforementioned properties can be achieved by using PDMS with a Mw of 550,000 g / mol to 650,000 g / mol in polymer compositions comprising vinyl polymers having a density of 0.926 g / cc to 0.970 g / cc. Without being bound by theory, it is believed that the Mw and viscosity of PDMS result in uniform dispersion within the vinyl polymer during melt blending. This uniform dispersion of PDMS provides an unaged COF of 0.25. Furthermore, the semi-crystalline domains of the vinyl polymer and the Mw of PDMS act as a resistive agent against PDMS migration over time, thereby maintaining an aged COF of 0.25, unlike compositions that rely on additive blooming.

[0010] The polymer composition can be specifically used to form sheaths for wires and cables.

[0011] According to a first feature of this disclosure, the polymer composition comprises a vinyl polymer having a density of 0.926 g / cc to 0.970 g / cc as measured according to ASTM D792 and a polydimethylsiloxane having a weight-average molecular weight of 550,000 g / mol to 650,000 g / mol as measured according to gel permeation chromatography. The composition does not contain polydimethylsiloxane having a weight-average molecular weight of 30,000 g / mol to 300,000 g / mol as measured according to gel permeation chromatography.

[0012] According to a second feature of this disclosure, the polymer composition comprises 90% by weight or more of a vinyl polymer based on the total weight of the polymer composition.

[0013] According to a third feature of this disclosure, the polymer composition comprises 10% by weight or less of polydimethylsiloxane based on the total weight of the polymer composition.

[0014] According to the fourth feature of this disclosure, the vinyl polymer has a density of 0.926 g / cc to 0.940 g / cc as measured according to ASTM D792.

[0015] According to the fifth feature of this disclosure, the polymer composition comprises a fatty acid amide.

[0016] According to the sixth feature of this disclosure, the polymer composition is free of fatty acid amides.

[0017] According to the seventh feature of this disclosure, the polymer composition further comprises a second polydimethylsiloxane having a weight-average molecular weight of 2,000 g / mol to 15,000 g / mol as measured by gel permeation chromatography.

[0018] According to the eighth feature of this disclosure, the polymer composition exhibits an unaged coefficient of friction of 0.25 or less as measured according to ASTM D1894.

[0019] According to the ninth feature of the invention, the polymer composition exhibits an aging coefficient of friction of 0.25 or less as measured according to ASTM D1894 after aging at 55°C for 336 hours.

[0020] According to a tenth feature of this disclosure, a coated conductor includes a conductor and a polymer composition disposed around the conductor. Detailed Implementation

[0021] As used herein, the term “and / or” when used in a list of two or more items means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may contain A alone; contain B alone; contain C alone; contain A and B in combination; contain A and C in combination; contain B and C in combination; or contain A, B, and C in combination.

[0022] Unless otherwise stated, all ranges include the endpoints.

[0023] A test method refers to the most recent test method as of the priority date of this document, unless the date is indicated by a two-digit test method number with a hyphen. References to test methods include references to both the testing association and the test method number. Test method organizations are referenced by one of the following abbreviations: ASTM refers to ASTM International (formerly known as the American Society for Testing and Materials); IEC refers to the International Electrotechnical Commission; EN refers to European Standards; DIN refers to the German Institute for Standardization; and ISO refers to the International Organization for Standardization.

[0024] As used herein, unless otherwise stated, the term weight percentage (“wt%”) means the weight percentage of a component relative to the total weight of the polymer composition.

[0025] The melt index (I²) values ​​in this document refer to those measured according to ASTM Method D1238 at 190°C and 2.16 kg, and are provided in grams eluted per 10 minutes (“g / 10 min.”). 21 The value refers to the value determined according to ASTM method D1238 at 190 degrees Celsius (°C) and a mass of 21.6 kg, and is provided in grams eluted per 10 minutes (g / 10 min).

[0026] The density values ​​in this document refer to those determined according to ASTM D792 at 23°C and are provided in grams per cubic centimeter (“g / cc”).

[0027] As used herein, the term “shrinkage rate” refers to the cyclic temperature (or field) shrinkage rate of a sheath or other outer material as measured according to IEC 60811-503 (shrinkage test of outer sheath).

[0028] As used herein, the Chemical Abstracts Service Registry Number (“CAS#”) refers to a unique numerical identifier recently assigned to a chemical compound by the Chemical Abstracts Service from the priority date of this document.

[0029] polymer composition

[0030] The polymer composition comprises a vinyl polymer and polydimethylsiloxane. The polymer composition exhibits both unaged COF and aged COF. As used herein, an unaged COF is the COF exhibited by the polymer composition without any intentional aging or testing delay after its manufacture. An aged COF, as used herein, is the COF exhibited by the polymer composition after being held at 55°C for 336 hours (i.e., two weeks) and before heating, without any intentional delay or aging.

[0031] The unaged COF of the polymer composition may be 0.01 or higher, or 0.02 or higher, or 0.04 or higher, or 0.06 or higher, or 0.08 or higher, or 0.10 or higher, or 0.12 or higher, or 0.14 or higher, or 0.16 or higher, or 0.18 or higher, or 0.20 or higher, or 0.22 or higher, or 0.24 or higher, while simultaneously being 0.25 or lower, or 0.24 or lower, or 0.22 or lower, or 0.20 or lower, or 0.18 or lower, or 0.16 or lower, or 0.14 or lower, or 0.12 or lower, or 0.10 or lower, or 0.08 or lower, or 0.06 or lower, or 0.04 or lower, or 0.02 or lower, as measured according to ASTM D1894.

[0032] The aging COF of the polymer composition may be 0.01 or higher, or 0.02 or higher, or 0.04 or higher, or 0.06 or higher, or 0.08 or higher, or 0.10 or higher, or 0.12 or higher, or 0.14 or higher, or 0.16 or higher, or 0.18 or higher, or 0.20 or higher, or 0.22 or higher, or 0.24 or higher, while simultaneously being 0.25 or lower, or 0.24 or lower, or 0.22 or lower, or 0.20 or lower, or 0.18 or lower, or 0.16 or lower, or 0.14 or lower, or 0.12 or lower, or 0.10 or lower, or 0.08 or lower, or 0.06 or lower, or 0.04 or lower, or 0.02 or lower, as measured according to ASTM D1894.

[0033] The polymer composition may have a concentration of 0.940 g / cc or greater, or 0.941 g / cc or greater, or 0.942 g / cc or greater, or 0.943 g / cc or greater, or 0.944 g / cc or greater, or 0.945 g / cc or greater, or 0.946 g / cc or greater, or 0.947 g / cc or greater, or 0.948 g / cc or greater, or 0.949 g / cc or greater, or 0.950 g / cc or greater, or 0.951 g / cc or greater, or 0.952 g / cc or greater, or 0.953 g / cc or greater, or 0.954 g / cc or greater, while... Density of 0.955 g / cc or less, or 0.954 g / cc or less, or 0.953 g / cc or less, or 0.952 g / cc or less, or 0.951 g / cc or less, or 0.950 g / cc or less, or 0.949 g / cc or less, or 0.948 g / cc or less, or 0.947 g / cc or less, or 0.946 g / cc or less, or 0.945 g / cc or less, or 0.944 g / cc or less, or 0.943 g / cc or less, or 0.942 g / cc or less, or 0.941 g / cc or less, as measured according to ASTM D792.

[0034] The polymer composition may exhibit a cyclic shrinkage of 3.0% or less, as measured according to the test methods provided in the Examples section. For example, the polymer composition may exhibit 3.0% or less, or 2.9% or less, or 2.8% or less, or 2.7% or less, or 2.6% or less, or 2.5% or less, or 2.4% or less, or 2.3% or less, or 2.2% or less, or 2.1% or less, or 2.0% or less, or 1.9% or less, or 1.8% or less, or 1.7% or less, or 1.6%. Cyclic contraction of 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, or 0.1% or less.

[0035] The polymer composition may exhibit a 24-hour shrinkage rate of 1.00% or less, as measured according to the test methods provided in the Examples section. For example, the polymer composition may exhibit a 24-hour shrinkage rate of 1.00% or less, or 0.95% or less, or 0.90% or less, or 0.85% or less, or 0.80% or less, or 0.75% or less, or 0.70% or less, or 0.65% or less, or 0.60% or less, or 0.55% or less, or 0.50% or less, or 0.45% or less, or 0.40% or less, or 0.35% or less, or 0.30% or less, or 0.25% or less, or 0.20% or less, or 0.15% or less, or 0.10% or less, or 0.05% or less.

[0036] The polymer composition may have a concentration of 0.1 g / 10 min or greater, or 0.3 g / 10 min or greater, or 0.5 g / 10 min or greater, or 0.7 g / 10 min or greater, or 0.8 g / 10 min or greater, or 0.9 g / 10 min or greater, or 1.0 g / 10 min or greater, or 1.5 g / 10 min or greater, or 2.0 g / 10 min or greater, or 2.5 g / 10 min or greater, or 3.0 g / 10 min or greater, or 3.5 g / 10 min or greater, or 4.0 g / 10 min or greater, or 4.5 g / 10 min or greater, or 5.0 g / 10 min or greater, or 5.5 g / 10 min or greater, or 6.0 g / 10 min or greater, or 6.5 g / 10 min or greater, or 7.0 g / 10 min. min. or greater, or 7.5g / 10 min. or greater, or 8.0g / 10 min. or greater, or 8.5g / 10 min. or greater, or 9.0g / 10 min. or greater, or 9.5g / 10 min. or greater, while simultaneously 10.0g / 10 min. or less, or 9.5g / 10 min. or less, or 9.0g / 10 min. or less, or 8.5g / 10 min. or less, or 8.0g / 10 min. or less, or 7.5g / 10 min. or less, or 7.0g / 10 min. or less, or 6.5g / 10 min. or less, or 6.0g / 10 min. or less, or 5.5g / 10 min. or less, or 5.0g / 10 min. or less, or 4.5g / 10 min. or less, or 4.0g / 10 Melt index (I2) of min. or less, or 3.5g / 10 min. or less, or 3.0g / 10 min. or less, or 2.5g / 10 min. or less, or 2.0g / 10 min. or less, or 1.5g / 10 min. or less, or 1.0g / 10 min. or less, or 0.9g / 10 min. or less, or 0.8g / 10 min. or less, or 0.7g / 10 min. or less, or 0.5g / 10 min. or less, or 0.3g / 10 min. or less.

[0037] The polymer composition may have a high melt index (I) of 50 g / 10 min or greater, or 55 g / 10 min or greater, or 60 g / 10 min or greater, or 65 g / 10 min or greater, or 70 g / 10 min or greater, or 75 g / 10 min or greater, or 80 g / 10 min or greater, or 85 g / 10 min or greater, or 90 g / 10 min or greater, or 95 g / 10 min or greater, while simultaneously having a high melt index (I) of 100 g / 10 min or less, or 95 g / 10 min or less, or 90 g / 10 min or less, or 85 g / 10 min or less, or 80 g / 10 min or less, or 75 g / 10 min or less, or 65 g / 10 min or less, or 60 g / 10 min or less, or 55 g / 10 min or less. 21 ).

[0038] The polymer composition may have a melt flow ratio (I0) of 70 or greater, or 75 or greater, or 80 or greater, or 85 or greater, or 90 or greater, or 95 or greater, or 100 or greater, or 105 or greater, while simultaneously having a melt flow ratio (I0) of 110 or less, or 105 or less, or 100 or less, or 95 or less, or 90 or less, or 85 or less, or 80 or less, or 75 or less. 21 / I2).

[0039] Vinyl polymer

[0040] As described above, the polymer composition comprises a vinyl polymer. As used herein, a "vinyl" polymer is a polymer in which more than 50% by weight of the monomer is ethylene, but other comonomers may also be used. The vinyl polymer may include ethylene and one or more C3-C... 20 α-Olefin comonomers, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Vinyl polymers may have a unimodal or multimodal molecular weight distribution and may be used alone or in combination with one or more other types of vinyl polymers (e.g., blends of two or more vinyl polymers that differ from each other in monomer composition and content, catalytic preparation method, molecular weight, molecular weight distribution, density, etc.). If blends of vinyl polymers are used, the polymers can be blended by any in-reactor or post-reactor method.

[0041] As measured using nuclear magnetic resonance (NMR) or Fourier transform infrared (FTIR) spectroscopy, the vinyl polymer may contain 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, or 91% or more, or 92% or more, or 93% or more, or 94% or more, or 95% or more, or 96% or more, or 97% or more, or 97.5% or more. The vinyl polymer may contain 98% or more, or 99% or more, while simultaneously containing 99.5% or less, or 99% or less, or 98% or less, or 97% or less, or 96% or less, or 95% or less, or 94% or less, or 93% or less, or 92% or less, or 91% or less, or 90% or less, or 85% or less, or 80% or less, or 70% or less, or 60% or less ethylene. Other units of the vinyl polymer may include C3 α-olefins, or C4 α-olefins, or C6 α-olefins, or C8 α-olefins, or C... 10 α-olefins, or C 12 α-olefins, or C 16 α-olefins, or C 18 α-olefins, or C 20 α-olefins, such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

[0042] The polymer composition may comprise 80% or more, 85% or more, 90% or more, or 91% or more, or 92% or more, or 93% or more, or 94% or more, or 95% or more, or 96% or more, or 97% or more, or 97.5% or more, while simultaneously comprising 98% or less, or 97% or less, or 96% or less, or 95% or less, or 94% or less, or 93% or less, or 92% or less, or 91% or less, or 90% or less, or 85% or less of a vinyl polymer based on the total weight of the polymer composition.

[0043] Vinyl polymers have densities ranging from 0.926 g / cc to 0.970 g / cc as measured according to ASTM D792. For example, vinyl polymers may have densities of 0.926 g / cc or greater, or 0.928 g / cc or greater, or 0.930 g / cc or greater, or 0.932 g / cc or greater, or 0.934 g / cc or greater, or 0.936 g / cc or greater, or 0.938 g / cc or greater, or 0.940 g / cc or greater, or 0.942 g / cc or greater, or 0.944 g / cc or greater, or 0.946 g / cc, as measured according to ASTM D792. Or greater, or 0.948g / cc or greater, or 0.950g / cc or greater, or 0.952g / cc or greater, or 0.954g / cc or greater, or 0.956g / cc or greater, or 0.958g / cc or greater, or 0.960g / cc or greater, or 0.962g / cc or greater, or 0.964g / cc or greater, or 0.966g / cc or greater, or 0.968g / cc or greater Meanwhile, the concentrations are 0.970 g / cc or less, or 0.968 g / cc or less, or 0.966 g / cc or less, or 0.964 g / cc or less, or 0.962 g / cc or less, or 0.960 g / cc or less, or 0.958 g / cc or less, or 0.956 g / cc or less, or 0.954 g / cc or less, or 0.952 g / cc or less, or 0.950 g / cc or less. Density of 0.948 g / cc or less, or 0.946 g / cc or less, or 0.944 g / cc or less, or 0.942 g / cc or less, or 0.940 g / cc or less, or 0.938 g / cc or less, or 0.936 g / cc or less, or 0.934 g / cc or less, or 0.932 g / cc or less, or 0.930 g / cc or less, or 0.928 g / cc or less.

[0044] polydimethylsiloxane

[0045] The polymer composition comprises polydimethylsiloxane. PDMS can be unsubstituted or substituted. "Substituted PDMS" is PDMS in which at least one methyl group of the PDMS is substituted by a substituent. Non-limiting examples of substituents include halogen atoms (such as chlorine, fluorine, bromine, and iodine); groups containing halogen atoms (such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl groups); groups containing oxygen atoms (such as hydroxyl groups, alkoxy groups (such as methoxy and ethoxy groups), (meth)acrylic acid epoxy groups, and carboxyl groups); groups containing nitrogen atoms (such as amino, amide, and cyano functional groups); groups containing sulfur atoms (such as mercapto groups); hydrogen; C2-C 10 Alkyl groups (such as ethyl groups); C2-C 10 Alkynyl groups; alkenyl groups (such as vinyl and allyl groups); aryl groups (such as phenyl and substituted phenyl groups); cycloalkyl groups (such as cyclohexyl groups); and combinations thereof. The substituted methyl group can be a terminal methyl group or a non-terminal methyl group. Non-limiting examples of suitable substituted PDMS include trialkylsilyl-terminated PDMS, wherein at least one alkyl group is C2-C. 10 Alkyl; dialkyl hydroxysilyl-terminated PDMS; dialkyl hydrogen silyl-terminated PDMS; dialkyl alkenyl silyl-terminated PDMS; dialkyl vinyl silyl-terminated PDMS, dimethyl hydroxysilyl-terminated PDMS and dimethyl vinyl silyl-terminated PDMS.

[0046] PDMS has a weight-average molecular weight of 550,000 g / mol to 650,000 g / mol as measured by gel permeation chromatography as described in more detail below. For example, PDMS may have a weight-average molecular weight of 550,000 g / mol or greater, or 560,000 g / mol or greater, or 570,000 g / mol or greater, or 580,000 g / mol or greater, or 590,000 g / mol or greater, or 600,000 g / mol or greater, or 610,000 g / mol or greater, or 620,000 g / mol or greater, or 630,000 g / mol or greater, or 640,000 g / mol or greater, as measured by gel permeation chromatography. The polymer composition contains a molecular weight (Mw) of 650,000 g / mol or less, or 640,000 g / mol or less, or 630,000 g / mol or less, or 620,000 g / mol or less, or 610,000 g / mol or less, or 600,000 g / mol or less, or 590,000 g / mol or less, or 580,000 g / mol or less, or 570,000 g / mol or less, or 560,000 g / mol or less. The polymer composition does not include or otherwise does not contain polydimethylsiloxane having a weight-average molecular weight of 30,000 g / mol to 300,000 g / mol as measured by gel permeation chromatography. As used herein, the term "free of" is defined as meaning that the polymer composition contains 0.01% by weight or less of the material it does not contain.

[0047] The polymer composition may contain PDMS in amounts of 0.1% or more, 0.5% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, or 9% or more, based on the total weight of the polymer composition, while simultaneously containing 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less.

[0048] Second polydimethylsiloxane

[0049] The polymer composition may comprise a second polydimethylsiloxane having a lower Mw than that of PDMS having an Mw of 550,000 g / mol to 650,000 g / mol. The second PDMS may be substituted or unsubstituted and may be end-capped with any of the aforementioned substances.

[0050] The second PDMS has a weight-average molecular weight of 2,000 g / mol to 15,000 g / mol as measured by gel permeation chromatography. For example, the PDMS may have a weight-average molecular weight of 2,000 g / mol or greater, or 3,000 g / mol or greater, or 4,000 g / mol or greater, or 5,000 g / mol or greater, or 6,000 g / mol or greater, or 7,000 g / mol or greater, or 8,000 g / mol or greater, or 9,000 g / mol or greater, or 10,000 g / mol or greater, or 11,000 g / mol or greater, or 12,000 g / mol or greater, or 13,000 g / mol or greater, or 14,000 g / mol or greater, as measured by gel permeation chromatography. Mw of g / mol or greater, and simultaneously 15.00 g / mol or less, or 14.000 g / mol or less, or 13.000 g / mol or less, or 12.000 g / mol or less, or 11.000 g / mol or less, or 10.000 g / mol or less, or 9.000 g / mol or less, or 8.000 g / mol or less, or 7.000 g / mol or less, or 6.000 g / mol or less, or 5.000 g / mol or less, or 4.000 g / mol or less, or 3.000 g / mol or less.

[0051] The polymer composition may contain PDMS in amounts of 0.1% or more, 0.5% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, or 9% or more, based on the total weight of the polymer composition, while simultaneously containing 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less.

[0052] Fatty acid amide

[0053] The polymer composition may or may not contain fatty acid amides. "Fatty acid amide" refers to a molecule corresponding to structure (I):

[0054] Structure (I)

[0055] Where R is C3 to C 27 Alkyl moiety. R can be C 11 To C 25 or C 15 To C 23Alkyl moiety. R can be C 21 Alkyl moiety. R can be saturated, monounsaturated, or polyunsaturated. Specific examples of suitable fatty acid amides include, but are not limited to, erucamide, oleamide, palmitamide, stearamide, and behenamide. Additionally, fatty acid amides can be mixtures of two or more fatty acid amides.

[0056] The polymer composition may contain 0.05% or more by weight, or 0.1% or more by weight, or 0.2% or more by weight, or 0.3% or more by weight, or 0.4% or more by weight, or 0.5% or more by weight, or 0.6% or more by weight, or 0.7% or more by weight, or 0.8% or more by weight, or 0.9% or more by weight, or 1.0% or more by weight, or 1.1% or more by weight, or 1.2% or more by weight, or 1.3% by weight, based on the total weight of the polymer composition. Fatty acid amides of % or more by weight, or 1.4% or more by weight, while simultaneously 1.5% or less by weight, or 1.4% or less by weight, or 1.3% or less by weight, or 1.2% or less by weight, or 1.0% or less by weight, or 0.9% or less by weight, or 0.8% or less by weight, or 0.7% or less by weight, or 0.6% or less by weight, or 0.5% or less by weight, or 0.4% or less by weight, or 0.3% or less by weight, or 0.2% or less by weight.

[0057] additive

[0058] The polymer composition may contain additional additives in the following forms: antioxidants, processing aids, coupling agents, ultraviolet stabilizers (including UV absorbers), antistatic agents, carbon black, additional nucleating agents, slip agents, lubricants, viscosity control agents, tackifiers, anti-blocking agents, surfactants, bulking agents, acid removers, flame retardants, and metal passivators. The polymer composition may contain 0.01% to 5% by weight of one or more additional additives. Additives may be added alone as pure components, in combination, and / or added to one or more masterbatches.

[0059] The polymer composition comprises one or more hindered amine light stabilizers. HALS are chemical compounds containing amine functional groups that are used as stabilizers in plastics and polymers. These compounds may be derivatives of tetramethylpiperidine and are primarily used to protect polymers from free radical oxidation caused by exposure to UV light. HALS may include one or more of the following: poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol-alt-1,4-succinic acid) (CAS# 65447-77-0); bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (CAS# 52829-07-9); di-(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl) malonate (CAS# 63843-89-0); bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (CAS# 52829-07-9). 129757-67-1); poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl]-[(2,2,6,6-tetramethyl-4-piperidinyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piperidinyl)imino] (CAS# 71878-19-8); 1,3,5-triazine-2,4,6-triamine, N,N'''-1,2-ethanediylbis[N-[3-[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl]amino]propyl]-N',N''-dibutyl-N',N''-bis(1,2,2,6,6-pentamethyl -4-piperidinyl)- (CAS#106990-43-6); 1,6-hexanediamine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-, a polymer of 2,4,6-trichloro-1,3,5-triazine, and the reaction product of N-butyl-1-butylamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinylamine (CAS#192268-64-7). An example of HALS can be found under the trade name TINUVIN. TM 622 and CHIMASSORB TM944 was commercially available from BASF, Ludwigshafen, Germany. The polymer composition may contain HALS at a concentration of 0.1 wt% to 1.0 wt% based on the total weight of the polymer composition. For example, the polymer composition may contain HALS at a concentration of 0.1 wt% or more, or 0.2 wt% or more, or 0.3 wt% or more, or 0.4 wt% or more, or 0.5 wt% or more, or 0.6 wt% or more, or 0.7 wt% or more, or 0.8 wt% or more, or 0.9 wt% or more, while simultaneously containing 1.0 wt% or less, or 0.9 wt% or less, or 0.8 wt% or less, or 0.7 wt% or less, or 0.6 wt% or less, or 0.5 wt% or less, or 0.4 wt% or less, or 0.3 wt% or less, or 0.2 wt% or less.

[0060] The polymer composition may contain one or more particulate fillers, such as glass fibers or various mineral fillers (including nanocomposites). Fillers (particularly those with elongated or small flake-like particles providing a high aspect ratio (length / thickness)) improve modulus and post-extrusion shrinkage properties. The median size or d50 of the filler may be less than 20 µm, less than 10 µm, or less than 5 µm. The filler may be surface-treated to promote wetting or dispersion in the polymer composition. Specific examples of suitable fillers include, but are not limited to, calcium carbonate, silica, quartz, fused silica, talc, mica, clay, kaolin, wollastonite, feldspar, aluminum hydroxide, and graphite. Based on the total weight of the polymer composition, the filler may be included in the polymer composition in an amount ranging from 2% to 30% by weight or from 5% to 30% by weight.

[0061] Processing aids may include metal salts of fluoropolymers such as polytetrafluoroethylene or fluorinated ethylene propylene; carboxylic acids such as zinc stearate and calcium stearate; fatty acids such as stearic acid, oleic acid, or erucic acid; fatty amides such as stearamide, oleamide, erucic acid, or N,N'-ethylenebis-stearamide; polyethylene wax; oxidized polyethylene wax; polymers of ethylene oxide; copolymers of ethylene oxide and propylene oxide; plant waxes; petroleum waxes; nonionic surfactants; silicone fluids; and polysiloxanes.

[0062] Antioxidants can include hindered phenols, such as tetra[methylene(3,5-di-tert-butyl-4-hydroxycinnamate)]methane; bis[(β-(3,5-di-tert-butyl-4-hydroxybenzyl)methylcarboxyethyl)]-sulfides, 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-thiobis(2-tert-butyl-5-methylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), and thiodiethylenebis(3,5-di-tert-butyl-4-hydroxy)-hydrocinnamate; phosphites and phosphonites. Such as tris(2,4-di-tert-butylphenyl) phosphite and di-tert-butylphenyl-phosphite; thiolated compounds such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearate thiodipropionate; various siloxanes; polymers of 2,2,4-trimethyl-1,2-dihydroquinoline, n,n'-bis(1,4-dimethylpentyl-p-phenylenediamine), alkylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, diphenyl-p-phenylenediamine, mixed diaryl-p-phenylenediamine and other hindered amine degradation inhibitors or stabilizers.

[0063] Formulation and coating of conductors

[0064] Components of a polymer composition can be added to a batch or continuous mixer to form a melt-blended composition. Components can be added in any order, or one or more masterbatches can be prepared first for blending with other components. Melt blending can be carried out at temperatures above the melting point of the highest-melting polymer. The melt-blended composition can then be fed into an extruder or injection molding machine, or molded through a die into the desired article, or converted into granules, tapes, strips, films, or some other form for storage or preparation of material to be supplied to the next forming or processing step. Optionally, if formed into granules or some similar configuration, the granules, etc., can be coated with an anti-sticking agent to facilitate handling during storage.

[0065] Examples of mixing equipment include internal batch mixers, such as BANBURY. TM or BOLLING TM Internal mixer. Alternatively, a continuous single-screw or twin-screw mixer, such as FARRELL, can be used. TM Continuous mixer, WERNER TM and PLEIDERER TM Twin-screw mixer or BUSS TM Kneading continuous extruder. The type of mixer used and the operating conditions of the mixer will affect the properties of the composition, such as viscosity, volume resistivity, and surface smoothness of the extrusion.

[0066] The coated conductor can be made from a polymer composition. The coated conductor includes a conductor and a coating. The coating comprises the polymer composition. The polymer composition is at least partially disposed around the conductor to create the coated conductor. The conductor may include a conductive metal or an optically transparent structure.

[0067] A method for preparing a coated conductor includes mixing a polymer composition in an extruder and heating it to the melt temperature of at least the polymer components to form a polymer melt blend, and then coating the polymer melt blend onto a conductor. The term "on" includes direct or indirect contact between the polymer melt blend and the conductor. The polymer melt blend is in an extrudable state.

[0068] A polymer composition is disposed on and / or around a conductor to form a coating. The coating may be one or more inner layers, such as an insulating layer. The coating may completely or partially cover or otherwise surround or encapsulate the conductor. The coating may be the only component surrounding the conductor. Alternatively, the coating may be a layer of a multi-layered sheath or outer layer encapsulating the conductor. The coating may be in direct contact with the conductor. The coating may be in direct contact with the insulating layer surrounding the conductor.

[0069] Example

[0070] Material

[0071] EP1 is a medium-density polyethylene containing carbon black and having a density of 0.945 g / cc and a melt flow rate of 0.75 g / 10 min at 190°C. EP1 is available from The Dow Chemical Company, Midland, Michigan.

[0072] EP2 is a medium-density polyethylene with a density of 0.935 g / cc and a melt flow rate of 0.65 g / 10 min at 190°C. EP2 is available from Dow Chemical Company, Midland, Michigan.

[0073] EP3 is a UNIPOL product with a density of 0.935 g / cc and a melt flow rate of 0.79 g / 10 min at 190 °C. TM II. Bimodal medium-density polyethylene.

[0074] PA can be the product name DYNAMAR TM FX 5912 is a fluoropolymer processing aid purchased from 3M Company, Saint Paul, Minnesota, USA.

[0075] Si Gum is a blend of 35% by weight polydimethylsiloxane, which is dimethylvinylsiloxy-terminated, with the remainder being EP2. PDMS for Si Gum is available from Dow Chemical Company, Midland, Michigan.

[0076] Si Liquid is a blend of 5% by weight polydimethylsiloxane, which is trimethylsiloxy-terminated and has a Mw between 5,000 g / mol and 12,000 g / mol as measured by gel permeation chromatography, with the remainder being EP2. PDMS for Si Liquid is available from Dow Chemical Company, Midland, Michigan.

[0077] FAA is erucamide with CAS number 112-84-5 and can be used as crodamide. TM ER was acquired from Croda, East Yorkshire, United Kingdom.

[0078] CB is a carbon black masterbatch containing 45% carbon black by weight and can be used as an AXELERON masterbatch. TM GP A-0037 BK CPD was purchased from Dow Chemical Company in Midland, Michigan.

[0079] Sample preparation

[0080] Examples (“IE”) 1-6 and Comparative Examples (“CE”) 1-4 of the present invention were tested in a small laboratory at BANBURY with a standard biplane polyethylene rotor. TM Prepared in an internal batch mixer (1.2 kg). All materials from the example were added simultaneously and mixed until the drip temperature reached 160°C. Prepared in a BANBURY mixer with a standard biplane polyethylene rotor. TM IE7, IE8, CE5, and CE6 were prepared on an internal mixer. All materials were added simultaneously and mixed until the dropping temperature reached 175°C.

[0081] The plates of the examples were prepared by compressing molded granules on a preheated hand-operated press at 180°C. These granules were placed in a 1.905 mm die. The examples were heated to 180°C for four minutes, then pressed for three minutes at 3.45 MPa, followed by three minutes at 17.24 MPa. The examples were cooled in the press at 15°C / min and then conditioned according to test requirements. The plates intended for heat aging were placed in a preheated oven at 55°C and removed after 336 hours. The plates were then conditioned for 24 hours at 23°C and 50% relative humidity prior to testing.

[0082] A sheath with a wall thickness of 0.8 mm was prepared by extruding the polymer composition onto the conductor at 91 m / min using a 6.35 cm wire extrusion line from Davis-Standard at 180°C–240°C. The conductor was removed, and the sheath sample was conditioned at room temperature for 24 hours prior to shrinkage testing.

[0083] Test methods

[0084] Gel permeation chromatography: The weight-average molecular weight of polydimethylsiloxane was measured using GPC (Viscotek™ GPC Max) with triple detection capability. The Viscotek™ TDA305 unit was equipped with a differential refractometer, an online differential pressure viscometer, and low-angle light scattering (LALS: 7° and 90° detection angles). The mobile phase was toluene HPLC grade. The column was a two-column PL gel mixed C (7.5) column from Varian. 300mm, 5µm particle size) and PL Gel Guard columns (7.5) from Varian. The column was 300 mm long, with 5 fractions of injection volume, a flow rate of 1 mL / min, and a run time of 37 min. The column and detector temperature was 40 °C. The software used was Omnisec 4.6.1 (Viscotek™). The detector was calibrated by injecting a known concentration of narrow-band polystyrene standard (Mw 68, 100 g / mol).

[0085] According to ASTM D1238, I2 (2.16 kg at 190°C) and I 21 The melt index (“MI”) of 21.6 kg at 190°C. The melt flow rate is I. 21 Divide by the melt index ratio (“MFR”) of I2.

[0086] Density was tested on a 1.27 mm thick compression-molded sample according to ASTM D792.

[0087] The coefficient of friction was measured using a tribometer according to ASTM D1894. The substrate for measuring the COF of the samples was high-density polyethylene sheet. A new substrate was used for each sample. Samples were conditioned at 23°C and 50% relative humidity for 48 hours prior to testing.

[0088] Cyclic temperature shrinkage tests were performed on sheath samples removed from the conductor after wire production. Cyclic temperature shrinkage was performed by conditioning the sheath samples in an oven at a heating rate of 0.5°C / min from 40°C to 100°C. The samples were held at 100°C for 60 minutes, then the temperature was reduced back to 40°C at a rate of 0.5°C / min. The sheath was held at 40°C for 20 minutes, and this temperature cycle was repeated 4 times for a total of 5 cycles. The shrinkage rate was reported as the percentage change in sheath length from before to after the test, measured using a ruler accurate to 1.6 mm on a 61 cm long sample. Twenty-four-hour (“24 Hr”) shrinkage was measured by removing the conductor from the wire sample, cutting a 1.22 m (4 ft) sample, and measuring the length of the sample after storage at 23°C for 24 hours.

[0089] The PDMS content is calculated by multiplying the weight % of PDMS in Si Gum or Si Liquid by the weight % of Gum or Liquid in the examples.

[0090] result

[0091] Table 1 provides the composition and characteristics of IE1-8 and CE1-CE6. When specified, "nm" indicates that the characteristic was not measured.

[0092] Table 1

[0093]

[0094] Table 1 (continued)

[0095]

[0096] As can be seen from Table 1, the incorporation of organosilicon raw rubber in IE1-IE3 allows the compositions to exhibit an unaged COF of less than 0.25, while also demonstrating COF stability, as evidenced by the aged COF of IE1-IE4, which is also less than 0.25. Although IE4-6 shows that low molecular weight organosilicon and erucamide can be advantageously added, CE2-CE6 shows that without polydimethylsiloxane with a weight-average molecular weight of 550,000 g / mol to 650,000 g / mol, these compositions do not meet the unaged COF requirement or do not exhibit COF stability after aging.

Claims

1. A polymer composition comprising: 80% by weight or more of a vinyl polymer having a density of 0.926 g / cc to 0.970 g / cc as measured according to ASTM D792; and 10% by weight or less of polydimethylsiloxane having a weight-average molecular weight of 550,000 g / mol to 650,000 g / mol as measured by gel permeation chromatography, wherein the composition does not contain polydimethylsiloxane having a weight-average molecular weight of 30,000 g / mol to 300,000 g / mol as measured by gel permeation chromatography.

2. The polymer composition of claim 1, wherein the polymer composition comprises 90% by weight or more of the vinyl polymer based on the total weight of the polymer composition.

3. The polymer composition of claim 1, wherein the polymer composition comprises 0.5% by weight or more of the polydimethylsiloxane based on the total weight of the polymer composition.

4. The polymer composition of claim 1, wherein the vinyl polymer has a density of 0.926 g / cc to 0.940 g / cc as measured according to ASTM D792.

5. The polymer composition according to claim 1, wherein the polymer composition comprises a fatty acid amide.

6. The polymer composition according to claim 1, wherein the polymer composition is free of fatty acid amides.

7. The polymer composition according to claim 6, wherein the polymer composition further comprises: A second polydimethylsiloxane having a weight-average molecular weight of 2,000 g / mol to 15,000 g / mol as measured by gel permeation chromatography.

8. The polymer composition according to any one of claims 1-7, wherein the polymer composition exhibits an unaged coefficient of friction of 0.25 or less as measured according to ASTM D1894.

9. The polymer composition of claim 8, wherein the polymer composition exhibits an aging coefficient of friction of 0.25 or less as measured according to ASTM D1894 after aging at 55°C for 336 hours.

10. The polymer composition according to any one of claims 1-7, wherein the polymer composition comprises 98% by weight or less of the vinyl polymer based on the total weight of the polymer composition.

11. A coated conductor, the coated conductor comprising: conductors; and The polymer composition according to claim 1 is disposed around the conductor.

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