WO2015119943A1

WO2015119943A1 - Ice-phobic compositions

Info

Publication number: WO2015119943A1
Application number: PCT/US2015/014245
Authority: WO
Inventors: Srijanani Bhaskar; Mark Andrew Harmer
Original assignee: E. I. Du Pont De Nemours And Company
Priority date: 2014-02-07
Filing date: 2015-02-03
Publication date: 2015-08-13

Abstract

The disclosure relates to composition having very low adhesion levels to ice. The compositions are dispersions of a lubricant in a polymer. The lubricant in polymer compositions can provide a surface that has very low levels of adhesion to ice even after many cycles of icing/ice removal.

Description

TITLE

ICE-PHOBIC COMPOSITIONS FIELD OF THE DISCLOSURE

[01] The present disclosure is directed toward a composition comprising, or consisting essentially of, a solid polymer and a lubricant dispersed in the polymer, wherein the composition has a very low adhesion to ice. The composition comprises specific polymers and a perfluoropolyether lubricant dispersed in the polymer.

BACKGROUND OF DISCLOSURE

[02] The accumulation of ice on surfaces is a major problem, especially in cold climates. The build-up of ice creates unsafe conditions and the resulting costs of the icing events can run into the billions of dollars.

[03] Ice formation can affect a broad range of structures and substrates, including airplanes, wind turbines, power transmission lines and towers, off-shore and marine structures, solar panels, automobiles and buildings. Many industries have set tolerances for ice accumulating on structures and should the amount of ice exceed the tolerances, the damage to the structure can be severe. In the case of power transmission lines and power transmission towers, accumulating ice can cause power outages due to the weight of the accumulated ice.

[04] The aviation industry has several well-known methods to deal with icing issues while an aircraft is on the ground and during flight. The methods used on the ground can include spraying a de-icing fluid on the surfaces to remove the ice and to delay the formation of new ice. Such methods require large amounts of de-icing fluids, which can be expensive and cause environmental concerns. During flight, several anti-icing methods can be used depending upon the type and size of the aircraft. While they are necessary, these in-flight systems can be expensive and require regular maintenance.

[05] There is a need for a system or process which would prevent the formation of ice from such structures. If ice formation cannot be completely prevented, then the system should reduce the adhesion of ice to the substrate which in turn would require less energy to remove the ice.

SUMMARY OF THE DISCLOSURE

[06] The present disclosure relates to a composition comprising or consisting essentially of a solid polymer and a lubricant dispersed in the polymer, wherein the solid polymer is a polysiloxane, an

ethylene/methacrylate copolymer or a

tetrafluoroethylene/hexafluoropropylene copolymer and wherein the weight ratio of the solid polymer to lubricant is in the range of from 85:15 to 100:150.

[07] The present disclosure also relates to a substrate coated with a layer of the composition and to methods of preventing the accumulation of ice on the surface of the substrate.

DETAILED DESCRIPTION

[08] The features and advantages of the present disclosure will be more readily understood, by those of ordinary skill in the art from reading the following detailed description. It is to be appreciated that certain features of the disclosure, which are, for clarity, described above and below in the context of separate embodiments, may also be provided in combination in a single element. Conversely, various features of the disclosure that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination. In addition, references to the singular may also include the plural (for example, "a" and "an" may refer to one or more) unless the context specifically states otherwise.

[09] The use of numerical values in the various ranges specified in this application, unless expressly indicated otherwise, are stated as

approximations as though the minimum and maximum values within the stated ranges were both proceeded by the word "about". In this manner, slight variations above and below the stated ranges can be used to achieve substantially the same results as values within the ranges. Also, the disclosure of these ranges is intended as a continuous range including each and every value between the minimum and maximum values. [10] As used herein, the term "lubricant" means an oil or grease. In some embodiments, the oil or grease is a perfluoropolyether, wherein the perfluoropolyether comprises or consists essentially of repeat units derived from tetrafluoroethylene oxide, hexafluoropropylene oxide or a

combination thereof. The peril uoropolyethers have a number average molecular weight in the range of from 250 to 20,000 and are typically liquids, i.e., oils, at room temperature. The perfluoropolyether oils can be combined with various thickeners to form perfluoropolyether greases. The thickening agents can be, for example, polytetrafluoroethylene particles. As is known in the art, an oil is a liquid at room temperature while a grease is a semi-solid at room temperature.

[11] The present disclosure relates to a composition comprising or consisting essentially of a solid polymer and a lubricant dispersed in the polymer. The composition provides a surface that has a very low adhesion to ice and is able to retain the low adhesion even after many cycles of ice accumulation and removal from the surface of the

composition. As used herein the phrase "average ice adhesion" means the force required to separate ice adhered to the composition. The average ice adhesion is measured as a shear stress and can be measured according to the following test;

i) a layer of the composition is applied to an aluminum plate; ϋ) a cuvette is placed onto the composition;

ill) one-half of a cubic centimeter of water is placed into the cuvette so that the water contacts the composition, and the water is cooled to -20°C to form ice;

iv) a shear stress is applied to the cuvette in a direction that is parallel to the applied layer of composition; and determining the force required to separate the ice from the composition.

The method is repeated at least three times and the results are averaged to determine the average ice adhesion. In some embodiments, the average ice adhesion is the average of a minimum of 5 trials, and, in other embodiments, the average ice adhesion is the average of a minimum of 8 trials. In various embodiments, the average ice adhesion is less than 1 .76 kg/cm² or less than 1 .41 kg/cm² (20 psi) or less than 1 .33 kg/cm² (19 psi) or less than 1 .26 kg/cm² (18 psi) or less than 1 .20 kg/cm² (17 psi) or less than 1 .12 kg/cm² (16 psi) or less than 1 .05 kg/cm² (15 psi), or less than 0.98 kg/cm² (14 psi) or less than 0.91 kg/cm² (13 psi) or less than 0.84 kg/cm² (12 psi) or less than 0.77 kg/cm² (1 1 psi) or less than 0.70 kg/cm² (10 psi) or less than 0.63 kg/cm² (9 psi) or less than 0.56 kg/cm² (8 psi) or less than 0.49 kg/cm² (7 psi) or less than 0.42 kg/cm² (6 psi) or less than 0.35 kg/cm² (5 psi). In each embodiment, the force required to separate the ice from the composition is the shear stress as measured by the test outlined above.

[12] The solid polymer can be a polysiloxane polymer, an

ethylene/methacrylate copolymer or a

tetrafluoroethylene/hexafluoropropylene copolymer. In some

embodiments, the solid polymer is a crosslinked polymer, while in other embodiments, the solid polymer is a thermoplastic

tetrafluoroethylene/hexafluoropropylene copolymer with no crosslinking.

[13] The solid polymer can be a crosslinked polysiloxane polymer. In some embodiments, the polysiloxane polymer can be formed by the crosslinking of a monomer mixture, wherein the monomer mixture is polyvinyl terminated polydimethylsiloxane, a polymethylvinyl terminated silica, methylhydrogen siloxane, and tetramethyl tetravinyl

cyclotetrasiloxane. A suitable example is commercially available as SYLGARD® 184 silicone elastomer and is available from Dow Corning, Midland, Michigan. To produce the desired composition with the crosslinked polysiloxane polymer, the monomer mixture and the lubricant are combined in the desired proportion. The mixture is then blended and polymerized and/or crosslinked to form the desired composition. The polysiloxane/lubricant crosslinked composition forms a heterogeneous system consisting of encapsulated domains of the lubricant dispersed in the crosslinked polymer.

[14] The solid polymer can also be a crosslinked ethylene/methacrylate copolymer. In some embodiments, the ethylene/methacrylate copolymer can be a VAMAC^® elastomer, available from E.I. du Pont de Nemours and Company, Wilmington, Delaware. VAMAC^® elastomers are copolymers that are produced by the polymerization of ethylene, methacrylic monomers and amine-curable monomers. To produce the desired composition with the ethylene/methacrylate copolymers, a mixture of the copolymer, the lubricant and the curing agent is formed. After removal of at least a portion of the solvent, a period of thermal curing forms the desired composition consisting of domains of the lubricant dispersed in the crosslinked polymer.

[15] The solid copolymer can also be a

tetrafluoroethylene/hexafluoropropylene (TFE/HFP) copolymer. Suitable examples of the TFE/HFP copolymer can be produced according to procedures found in US Patent Number 5,478,905. To produce the desired composition, a solution of the TFE/HFP copolymer can be blended with the lubricant. The mixture can then be cast onto a substrate and at least a portion of the solvent can then be removed to form a layer of the composition on the substrate. In some embodiments, the composition can be heated to remove at least a portion of the solvent. Heating of the composition forms a heterogeneous system consisting of encapsulated domains of the lubricant dispersed in the polymer.

[16] Crosslinked polymers, for example, crosslinked polysiloxane polymers and crosslinked ethylene/ methacrylate polymers can be utilized in the composition. Commercially available crosslinkable polymers, such as SYLGARD^® and VAMAC^® polymers are packaged in at least two components, wherein at least one of the components is the crosslinking or curing agent. The manufacturer will set the ratio of one component to the other, i.e., the ratio of the film forming binder to the crosslinking or curing agent. In some embodiments, the ratio of the uncrosslinked polymer and/or monomer to the crosslinking agent can be in the range of from 5:1 to 50:1 , wherein the ratio is based on the weight of each component. In other embodiments, the weight ratio can be in the range of from 10:1 to 30:1 .

[17] The lubricant is a perfluoropolyether based lubricant. Suitable lubricants are available from E.I. du Pont de Nemours and Company as FLUOROGUARD^® and KRYTOX^® lubricants. These perfluoropolyether lubricants have repeat units derived from tetrafluoroethylene oxide or hexafluoropropylene oxide, homopolymers of tetrafluoroethylene oxide or copolymers of hexafluoropropylene oxide and tetrafluoroethylene oxide. In some embodiments, the lubricants are homopolymers of

hexafluoropropylene oxide. Perfluoropolyether lubricants can be formulated to be oils or greases. Greases can utilize the same

perfluoropolyethers while further comprising a thickening agent, such as, for example, polytetrafluoroethylene particles. The polytetrafluoroethylene particles can have an average diameter in the range of from 10 to 500 nanometers.

[18] The composition comprises the solid polymer and the lubricant in a polymer to lubricant weight ratio in a range of from 85:15 to 100:150. In other embodiments, the weight ratio of the polymer to lubricant can be in the range of from 75:25 to 100:125. In still further embodiments, the weight ratio of the polymer to lubricant can be in the range of from 60:40 to 40:60.

[19] Typically, the mixture of the solid polymer and the lubricant is a solution or a relatively homogeneous mixture. Upon solvent removal and/or curing, the lubricant forms discrete domains dispersed in the solid polymer. The discrete domains can have an average diameter in the range of from 100 nanometers to 30 micrometers, which can be

determined using, for example, electron microscopy. Furthermore, dynamic mechanical analysis of the composition reveals two glass transition temperatures, one corresponding to the solid polymer and the other corresponding to the lubricant.

[20] The present disclosure also relates to a substrate coated with a layer of the composition. The composition can be formed directly on the substrate or a layer of the composition can be formed which can then be adhered to the substrate. While it is important that the composition remain permanently bound to the substrate during use, any number of methods can be employed to achieve this adhesion. The methods or adhesive agents used to achieve adhesion are known and can be used provided that they do not interfere with the mechanical properties of the substrate or composition or inadvertently increase the strength of the ice adhesion. In some embodiments, the substrate can be a coated or uncoated metal substrate. In other embodiments, the substrate, comprising a layer of the composition can include, for example, an airplane wing, airplane body, wind turbine blade, wind turbine, power transmission line, power

transmission tower, oil rig, marine structure, marine vessel, bridge, vehicle, building, radio antenna, cell phone tower, solar panel or a combination thereof.

[21] The present disclosure also relates to a method of preventing the accumulation of ice on the surface of a substrate comprising the steps of;

1 ) providing a substrate that is free from ice; and

2) applying the composition of the present disclosure to at least a

portion of the substrate

The method can further comprise the steps of;

3) allowing ice to accumulate on at least a portion of the composition; and

4) applying a force to the substrate, to the composition, to the ice or to a combination thereof.

The composition has an average ice adhesion of less than 1 .76 kg/cm² when a shear stress is applied to the ice on the composition according to the following test;

i) a layer of the composition is adhered to a horizontally

situated aluminum plate;

ii) a cuvette is placed onto the layer of composition;

iii) one-half cubic centimeter of water is placed into the cuvette so that the water contacts the composition, and the water is cooled to -20°C to form ice;

iv) a shear stress is applied to the cuvette in a direction that is parallel to the applied layer of composition.

The force necessary to separate the ice from the composition is recorded as the value of the ice adhesion. This process is repeated at least three times and the average of each of the trials is recorded as the average ice adhesion. In other embodiments, the test is repeated at least 5 times in order to calculate the average ice adhesion. EXAMPLES

[22] Unless otherwise noted, all ingredients are available from the Sigma-Aldrich Company, St. Louis, Missouri.

[23] SYLGARD^® 184 silicone dispersion is available from Dow Corning, Midland, Michigan.

[24] VAMAC^® elastomer, FLUOROGUARD^® PCA lubricant, KRYTOX^® lubricant and VITON® fluoroelastomers are all available from E.I. du Pont de Nemours and Company, Wilmington, Delaware.

[25] NUSIL™ R1009 silicone dispersion, is available from NuSil, Inc., Carpinteria, California.

[26] FLUORINERT® FC-40 fluorinated solvent is available from 3M, St. Paul, Minnesota.

[27] 1 ,3,5-triallyl-1 ,3,5-triazine-2,4,6(1 H,3H,5H)-trione and 2,5-dimethyl- 2,5-di(tert-butylperoxy)hexane are both available from Vanderbilt

Chemicals, Norwalk, Connecticut.

[28] Ice Adhesion measurements

[29] The ice adhesion of the various compositions was tested using the following procedure. The compositions were coated onto an aluminum plate mounted onto a cold stage (TE Technology Inc., Model #CP200TT) according to the procedures given below. Eight 1 cm² cuvettes were placed randomly on the composition and 0.5 cubic centimeters of deionized water was added to the cuvettes so that the water contacted the applied layer of composition. The cold stage was then programmed to - 20°C at 1 .5°C/minute from room temperature. The circular head of a force gauge (Mark 10 Inc., Series 3) mounted on a syringe pump (Harvard Inc., Model #33) was placed close to, but not touching one of the cuvettes and within about 1 millimeter from the bottom of the cuvette. The syringe pump was turned on so that the force gauge moved toward the cuvette at about 0.029 millimeters/second. The ice adhesion was calculated by the reading on the force gauge divided by the cross sectional area of the ice in contact with the layer of composition. The process was repeated for the remaining cuvettes and the average ice adhesion value was calculated. [30] Preparation of Composition #1

[31] 35.2 grams of SYLGARD^® 184 (base:crosslinker ratio of 10:1 by weight) and 30 grams of FLUOROGUARD^® PCA lubricant were blended together using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum in order to remove air bubbles and then coated onto an aluminum plate using a 635 micrometer (25 mil) drawn down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 305 micrometers.

[32] Preparation of Comparative Composition A

[33] A sample of SYLGARD^® 184 (base:crosslinker ratio of 10:1 by weight) was subjected to a partial vacuum in order to remove air bubbles and coated onto an aluminum plate using a 635 micrometer (25 mil) drawn down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 31 1 micrometers.

[34] Preparation of Composition #2

[35] 35.2 grams of SYLGARD^® 184 (base:crosslinker ratio of 10:1 by weight) and 30 grams of FLUOROGUARD^® PCA lubricant were blended together using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum in order to remove air bubbles and then coated onto an aluminum plate using a 1270 micrometer (50 mil) drawn down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 624 micrometers.

[36] Preparation of Comparative Composition B

[37] A sample of SYLGARD^® 184 (base:crosslinker ratio of 10:1 by weight) was subjected to a partial vacuum in order to remove air bubbles and then coated onto an aluminum plate using a 1270 micrometer (50 mil) drawn down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 582 micrometers. [38] Preparation of Composition #3

[39] 33 grams of SYLGARD^® 184 (base:crosslinker ratio of 10:1 by weight) and 7 grams of FLUOROGUARD^® PCA lubricant were blended together using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum in order to remove air bubbles and then coated onto an aluminum plate using a 508 micrometer (20 mil) drawn down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 488 micrometers.

[40] Preparation of Composition #4

[41] 10 grams of SYLGARD^® 184 (base:crossl inker ration of 30:1 by weight) and 10 grams of KRYTOX^® GPL 202 lubricant were blended together using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum to remove air bubbles and coated onto an aluminum plate using a 1270 micrometer (50 mil) draw down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 604 micrometers.

[42] Preparation of Composition #5

[43] 10 grams of SYLGARD^® 184 (base:crossl inker ration of 30:1 by weight) and 10 grams of KRYTOX^® GPL 202 lubricant were blended together using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum in order to remove air bubbles and then coated onto an aluminum plate using a 254 micrometer (10 mil) draw down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 164 micrometers.

[44] Preparation of Composition #6

[45] 10 parts by weight of VAMAC^® VMX 4017 was dissolved in acetone to form a 20 weight percent solution. To this was mixed 0.1 1 parts by weight of 6-(aminohexyl) carbamic acid and 2.5 parts by weight of KRYTOX^® VPF 16350 lubricant, and the mixture was stirred. A portion of the acetone was removed by heating the solution to 70°C for 5 minutes. The remaining mixture was then coated onto an aluminum plate using a draw down bar. The composition was then cured under pressure (48.2 kilopascal) at 175°C for 10 minutes in a laboratory press (Carver Inc) to give a sample having a thickness of about 200 micrometers.

[46] Preparation of Comparative Composition C

[47] 10 parts by weight of VAMAC^® VMX 4017 ethylene-acrylic elastomer was dissolved in acetone to give a 20 weight percent solution. This was mixed with 0.1 1 parts by weight of 6-(aminohexyl)carbamic acid. A portion of the acetone was removed by heating the mixture to 70°C for 5 minutes. The remaining mixture was coated onto an aluminum plate using a draw down bar. The composition was then cured under pressure (48.2 kilopascal) at 175°C for 10 minutes in a laboratory press (Carver Inc.) to give a film having a thickness of about 227 micrometers.

[48] Preparation of Composition #7 (HFP/TFE copolymer)

[49] A copolymer of hexafluoropropylene and tetrafluoroethylene was produced according to the process given in US 5,478,905. The copolymer had a hexafluoropropylene content of 52.7 weight percent and 47.3 weight percent of tetrafluoroethylene, a weight average molecular weight of 428,000, a number average weight of 137,000 and a melt index of 1 .6 grams/minute at 297°C with a 5 kilogram weight. The copolymer was dissolved in FLUORINERT^® FC-40 fluorinated solvent to produce a 3 percent by weight solution. KRYTOX^® lubricant was added to this solution to give a solution that had 3 percent by weight of the lubricant. A layer of the mixture was applied to an aluminum plate using a 127 micrometer (5 mil) drawn down blade and the film was allowed to dry in air for 1 hour. The film was then heated for 2 hours in a 120°C oven. This composition was tested for average ice adhesion over 1 1 cycles.

[50] Preparation of Comparative Composition D

[51] A film of NUSIL™ R1009 silicone dispersion was prepared according to the manufacturer's directions. The dispersion was coated onto an aluminum panel in order to form a film that had a thickness of about 147 micrometers (5.8 mil).

[52] Preparation of Comparative Composition E

[53] Preparation of high oleic soybean methyl ester [54] A 20 liter jacketed reactor equipped with a mechanical stirrer, reflux condenser, thermometer and a nitrogen inlet was charged with 12.0 kg of high oleic soybean oil (prepared according to US 5,981 ,781 and

containing triglycerides of the following fatty acids: palmitic acid (6.5 wt%), stearic acid (4.1 wt%), oleic acid (74.8 wt%), linoleic acid (7.6 wt%) and linolenic acid (2.8 wt%)), 3.0 kg anhydrous methanol and 15 grams of sodium carbonate. The mixture was heated to reflux (pot temperature of about 70° to 80°C) under nitrogen and then stirred at reflux for 3 hours. After refluxing for 3 hours, the reaction mixture was cooled to near room temperature, the stirrer was turned off and the layers allowed to separate overnight. The bottom glycerol layer was removed. An additional 1 .0 gram of sodium carbonate was added to the reactor and the mixture was refluxed for an additional 2 hours. The reaction was cooled to 25°C, the stirrer was turned off and the layers were allowed to separate. The bottom glycerol layer was removed. The crude ester product was transferred to a 22 liter round bottom flask equipped with a mechanical stirrer,

thermometer and a still head connected to a vacuum pump and trap.

Methanol was distilled out under vacuum while keeping the pot

temperature below 50°C. The distillation pot was then cooled to room temperature under nitrogen and the crude high oleic soybean methyl ester was used as is.

[55] Preparation of high oleic soybean ester oil

[56] A 12 liter round bottom flask was equipped with a mechanical stirrer, internal temperature control, a nitrogen source and a distillation head connected to a vacuum pump and a heating mantle. The system was purged with nitrogen for one hour. The reaction flask was charged with 7.0 kilograms of the crude high oleic soybean methyl ester, 17.5 grams of solid sodium methoxide and 880 grams of trimethylolpropane. The reaction mixture was stirred at room temperature and 5 mm Hg absolute pressure was slowly applied to the reactor to avoid foaming and/or bubbling. The vacuum pump was equipped with a dry ice trap in order to collect the methanol from the reaction. After the vacuum was established, the mixture was heated to 70°C and then slowly increased in 20°C increments to a final temperature of 190°C. Each time the temperature of the reaction was increased, the temperature was held until the bubbling had subsided. The reaction was held at 190°C for one hour until the bubbling had stopped. The reaction mixture was cooled to room temperature and the product was used as is.

[57] 90 parts by weight of SYLGARD^® 184 (base:crosslinker ratio of 30:1 ) was blended with 10 parts by weight of the high oleic soybean ester oil using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum to remove air bubbles and was coated onto an aluminum plate using a 1270 micrometer (50 mil) draw down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 571 micrometers.

[58] Preparation of Comparative Composition F

[59] 75 parts by weight of SYLGARD^® 184 (base:crosslinker ratio of 30:1 ) was blended with 25 parts by weight of the high oleic soybean ester oil using a spatula to form a homogeneous mixture. The resulting mixture was subjected to a partial vacuum in order to remove air bubbles and then was coated onto an aluminum plate using a 1270 micrometer (50 mil) draw down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 586 micrometers.

[60] Preparation of Comparative Composition G

[61] 0.36 grams of 1 ,3,5-triallyl-l ,3,5-triazine-2,4,6(1 H,3H,5H)-trione and 0.18 grams of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added to 34 grams of a 35.5 percent by weight solution of uncured VITON^® A500 fluoroelastomer in acetone. This mixture was stirred thoroughly and the resulting mixture was coated onto an aluminum plate using a 254 micrometer (10 mil) draw down bar and heated for 10 minutes in a 140°C convection oven to obtain a film having a thickness of 127 micrometers.

[62] Preparation of Comparative Composition H

[63] 4 grams of KRYTOX^® TLF 16350 lubricant was added to 15 grams of Comparative composition G. This mixture was stirred thoroughly and the resulting mixture was coated onto an aluminum plate using a 254 micrometer (10 mil) draw down bar and heated for 10 minutes in a 140°C convection oven to obtain a film having a thickness of 127 micrometers. [64] Preparation of Comparative Composition I

[65] 0.36 grams of 1 ,3,5-triallyl-l ,3,5-triazine-2,4,6(1 H,3H,5H)-trione and 0.18 grams of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added to 30 grams of a 40 percent by weight solution of uncured VITON^®

GFLT600S fluoroelastomer in acetone. This mixture was stirred thoroughly and the resulting mixture was coated onto an aluminum plate using a 254 micrometer (10 mil) draw down bar and heated for 10 minutes in a140°C convection oven to obtain a film having a thickness of 127 micrometers.

[66] Preparation of Comparative Composition J

[67] 4 grams of KRYTOX® TLF 16350 lubricant was added to 14 grams of comparative composition I. This mixture was thoroughly stirred and the resulting mixture was coated onto an aluminum plate using a 254 micrometer (10 mil) draw down bar and heated for 10 minutes in a 140°C convection oven to obtain a film having a thickness of 127 micrometers.

[68] The compositions were tested to determine their average ice adhesion according to the procedure given above. The results of the test are found in TABLE 1 .

TABLE 1

[69] The results show that composition according to the present disclosure show ice adhesion values lower than that of a generally accepted commercial standard, NUSIL™ R1009, comparative D.

Comparative compositions A, B and C show that without the lubricant, the polymers themselves have high levels of ice adhesion when compared to the analogous polymers with the lubricant. Comparative examples E and F show that the choice of lubricant is important. The lubricant used in E and F is a synthetic lubricant that is not based on the desired

perfluoropolyether lubricant and results in compositions that have high levels of ice adhesion. Comparative Composition G shows an example of a vinylidene fluoride/hexafluoropropylene fluoroelastomer, VITON^® A500, which has high adhesion to ice. The addition of the KRYTOX^® lubricant, Comparative composition H, increases the ice adhesion. Comparative examples I and J show that while the addition of KRYTOX^® lubricant to a different grade of VITON^® fluoroelastomer decreases the ice adhesion, the ice adhesion is still unacceptably high. [70] In order to determine whether the lubricant in polymer compositions are able to retain their low levels of adhesion to ice over several cycles, the compositions were tested over 10 or 1 1 cycles of ice adhesion. To test the ability to retain the levels of adhesion, the ice adhesion procedure given above was conducted and the average ice adhesion was calculated for cycle #1 . For cycle #2, the cuvettes were placed on the same spots as they were for cycle #1 or as closely as was possible to the spots used for cycle #1 . The ice adhesion test was then conducted again and the average ice adhesion value was determined for cycle #2. This process was continued until 10 or 1 1 cycles had been completed. The results of the tests are shown in TABLE 2.

[71] Preparation of Composition #8

[72] The polysiloxane/KRYTOX^® composition from Composition #5 was applied to an aluminum plate using a 254 micrometer (10 mil) draw down bar. The composition was then heated for 45 minutes in a 100°C convection oven to give a sample having a thickness of about 178 micrometers. This composition was tested for average ice adhesion over 10 cycles.

TABLE 2

[73] The results of this test show that compositions according to the present disclosure are able to retain their low levels of ice adhesion over at least 10 trials.

Claims

CLAIMS What is claimed is:

1 . A composition comprising a solid polymer and a lubricant dispersed in the polymer, wherein the solid polymer is a polysiloxane, an

ethylene/methacrylate copolymer or a

2. The composition of claims 1 wherein the solid polymer is a crosslinked polymer, wherein the ratio of uncrosslinked polymer and/or monomer to crosslinking agent used to form the crosslinked polymer is in the range of from 5:1 to 50:1 .

3. The composition of any one of claims 1 or 2 wherein the lubricant further comprises polytetrafluoroethylene particles.

4. The composition of any one of claims 1 , 2 or 3 wherein the lubricant forms discrete domains dispersed in the solid polymer.

5. The composition of any one of claims 1 , 2, 3 or 4 wherein the lubricant is present in the solid polymer in discrete domains, and wherein the average diameter of the domains in the range of from 100 nanometers to 30 micrometers.

6. The composition of any one of claims 1 , 2, 3, 4 or 5 wherein the crosslinked polymer is a crosslinked polydimethylsiloxane polymer or a crosslinked ethylene/methacrylate copolymer.

7. The composition of any one of claims 1 , 2, 3, 4, 5 or 6 wherein the composition has an average ice adhesion of less than 1 .76 kg/cm² when a shear stress is applied to ice adhered to a layer of the composition according to the following test;

i) a layer of the composition is applied to an aluminum plate; ii) a cuvette is placed onto the composition;

iii) one-half cubic centimeter of water is placed into the cuvette so that the water contacts the composition, and the water is cooled to -20°C to form ice; and

iv) a shear stress is applied to the ice in a direction that is

parallel to the applied layer of composition.

8. The composition of any one of claims 3, 4, 5, 6 or 7 wherein the polytetrafluoroethylene particles have an average diameter in the range of from 10 to 500 nanometers.

9. The composition of any one of claims 1 , 2, 3, 4, 5, 6, 7 or 8 wherein the weight ratio of the solid polymer to lubricant is in the range of from 85:15 to 100:150.

10. The composition of any one of claims 1 , 2, 3, 4, 5, 6, 7, 8 or 9 wherein the lubricant is a perfluoropolyether.

A substrate coated by a layer of the composition of any one of 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10.

12. The substrate of claim 1 1 wherein the substrate is a coated or uncoated metal substrate.

13. The substrate of any one of claims 1 1 or 12 wherein the substrate is an airplane wing, airplane body, wind turbine blade, wind turbine, power transmission line, power transmission tower, oil rig, marine structure, marine vessel, bridge, vehicle, building, radio antenna, cell phone tower or solar panel.

14. A method of preventing the accumulation of ice on the surface of a substrate comprising the steps of;

1 ) providing a substrate that is free from ice; and

2) applying the composition of any one of claims 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 to at least a portion of the substrate.

15. The method of claim 14 wherein the method further comprises the steps of;

3) allowing ice to accumulate on at least a portion of the

composition; and

16. The method of claim 14 or 15 wherein the substrate is an airplane wing, airplane body, wind turbine blade, wind turbine, power transmission line, power transmission tower, oil rig, marine structure, marine vessel, bridge, vehicle, building, radio antenna, cell phone tower or solar panel.