WO2019222574A1

WO2019222574A1 - Polymer articles comprising mineral fillers

Info

Publication number: WO2019222574A1
Application number: PCT/US2019/032779
Authority: WO
Inventors: Chinmay PESHAVE
Original assignee: Imerys Usa, Inc.
Priority date: 2018-05-18
Filing date: 2019-05-17
Publication date: 2019-11-21

Abstract

The present disclosure includes provides articles and methods of making thereof. The articles may comprise one or more polymers (e.g., rubber) and mineral fillers (e.g., metakaolin). The mineral fillers may prevent or delay the degradation of the polymers in the articles.

Description

POLYMER ARTICLES COMPRISING MINERAL FILLERS

CLAIM FOR PRIORITY

[0001] This PCT International Application claims the benefit of priority of U.S.

Provisional Patent Application No. 62/673,363, filed May 18, 2018, the subject matter of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate generally to articles comprising polymers, e.g., rubber, and mineral fillers, and methods of making thereof.

BACKGROUND

[0003] Exposure to chloride ions and heavy metals can induce degradation of polymers such as natural rubber and synthetic rubber over time. Other environmental factors such as ultraviolet light or heat can also induce degradation of the polymers. The degradation of polymers may cause damage to articles made from the polymers, e.g., weakening their structural integrity or decreasing tensile strength. Thus, there is a need to develop polymers less susceptible to degradation and/or better able to maintain durability over time.

SUMMARY OF THE DISCLOSURE

[0004] The present disclosure includes methods for protecting articles comprising one or more polymers from degradation. For example, the present disclosure includes a method that comprises incorporating metakaolin into the polymer(s) as a filler, the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin; wherein the polymer(s) may be exposed to an external agent

(or a combination of external agents) that promotes degradation; and wherein the metakaolin may react with the external agent(s) to delay or prevent degradation of the article. The metakaolin may have a shape factor of at least 20. For example, the metakaolin may have a shape factor ranging from 30 to 100 or from 50 to 80, In some examples, a particle size distribution of the metakaolin may have a dso diameter ranging from about 0.5 pm to about

10.0 pm as measured by Sedigraph. In at least one example, the article may have a metakaolin loading ranging from about 3% to about 65% by weight of the polymer. In some examples, the article may be a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

[0005] According to some aspects of the present disclosure, the external agent(s) may comprise an ion present in water with a hardness of at least 15 parts per million. In some examples, the external agent(s) may comprise chloride or a metal. In certain examples, the external agent(s) may comprise iron, copper, zinc, or an alloy thereof, or a combination thereof.

[0006] In some examples, the article may be exposed to radiation, and the metakaolin may absorb at least a portion of the radiation to prevent or delay formation of cracks in the article. In certain examples, the article may be exposed to UV radiation, and the metakaolin may absorb at least a portion of the UV radiation with a DE value of the polymer no greater than 3. In at least one example, the article may maintain at least 70% tensile strength over a period of at least six months. In another example, the article may maintain at least 70% tensile strength after aging at 70 °C for 7 days. In another example, the article may maintain at least 70% tensile strength after aging at 90 °C for 14 days. [0007] According to some aspects of the present disclosure, the polymer(s) may comprise natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof. For example, the polymer(s) may comprise styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof. In some cases, the polymer(s) may further comprise paraffin, an antioxidant, sulfur peroxide, zinc oxide, stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

[0008] Further provided herein are methods of making an article. For example, the methods may comprise combining a polymer or two or more polymers with metakaolin to form a mixture, wherein the metakaolin may comprise from about 10% to about 30% by weight soluble alumina, relative to the total weight of the metakaolin; and forming the mixture into an article; wherein, when the polymer is exposed to an external agent (or multiple external agents) that promotes degradation, the metakaolin may react with the external agent to delay or prevent degradation of the article. The metakaolin may have a shape factor of at least 20. For example, the metakaolin may have a shape factor ranging from 30 to 100 or from 50 to 80. In some examples, a particle size distribution of the metakaolin may have a dso diameter ranging from about 0.5 pm to about 10.0 pm as measured by Sedigraph. In some examples, the mixture may comprise a metakaolin loading ranging from 3% to about 65% by weight of the polymer. In some aspects, the article may be a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component. [0009] According to some aspects of the present disclosure, the polymer(s) may comprise natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof. For example, the polymer(s) may comprise styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof. In some cases, the mixture may further comprise at least one additive chosen from paraffin, an antioxidant, sulfur peroxide, zinc oxide, a stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

[0010] In some examples, forming the mixture into the article may comprise compression molding, injection molding, or extrusion. In at least one example, the article may be a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component. In another example, the article may maintain at least 70% tensile strength over a period of at least six months! In another example, the article may maintain at least 70% tensile strength after aging at 70 °C for 7 days. In another example, the article may maintain at least 70% tensile strength after aging at 90 °C for 14 days. In certain examples, when the article is exposed to UV radiation, the metakaolin may absorb at least a portion of the UV radiation to maintain a DE value of the polymer no greater than 3.

[0011] Also provided herein are articles comprising polymers. For example, the articles may comprise at least one polymer; and metakaolin incorporated into the polymer(s), the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin; wherein when the article is exposed to one or more external agents that promote degradation. For example, the metakaolin may react with the external agent(s) to delay or prevent degradation of the article. The metakaolin may have a shape factor of at least 20. For example, the metakaolin may have a shape factor ranging from 30 to 100 or from 50 to 80. In some examples, the metakaolin may have a soluble alumina content ranging from about 10% to about 30% by weight, or from about 12% to about 28%, or from about 14% to about 26%, or from about 18% to about 24%, or from about 20% to 24% by weight. In some examples, a particle size distribution of the metakaolin may have a dso diameter ranging from about 0.5 pm to about 10 pm as measured by Sedigraph. In some examples, the article may have a metakaolin loading ranging from 3% to 65% by weight of the polymer(s).

[0012] According to some aspects of the present disclosure, the polymer(s) may comprise natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof For example, the polymer(s) may comprise styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

[0013] Embodiments and various aspects of the present disclosure are illustrated in the following detailed description and the accompanying figures. Various features shown in the figures are not drawn to scale. [0014] FIG. 1 shows shape factor and soluble alumina content of kaolin and metakaolin as discussed in the examples.

DETAILED DESCRIPTION

[0015] Particular aspects of the present disclosure are described in greater detail below. The terms and definitions provided herein control, if in conflict with terms and/or definitions incorporated by reference.

[0016] As used herein, the terms“comprises,”“comprising,” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, composition, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, composition, article, or apparatus. The term“exemplary” is used in the sense of“example” rather than“ideal.”

[0017] As used herein, the singular forms“a, >i « an,” and“the” include plural reference unless the context dictates otherwise. The terms“approximately” and“about” refer to being nearly the same as a referenced number or value. As used herein, the terms “approximately" and“about” should be understood to encompass ± 5% of a specified amount or value.

[0018] The present disclosure includes articles comprising one or more polymers and one or more fillers. In some examples, the filler(s) may delay or prevent the degradation of the polymer(s), e.g., degradation due to exposure of the polymer(s) to environmental species, heat, and/or radiation. In at least one example, the filler(s) may comprise metakaolin that has a shape factor of at least 20 and a soluble alumina content ranging from 10% to 30% by weight. [0019] Further disclosed herein are methods of making the articles. The methods may comprise combining one or more polymers and one or more minerals to form a mixture.

Also disclosed herein are methods of protecting the articles from degradation induced by exposure to external agents such as metals, ions, heat, and/or radiation. The methods may comprise incorporating one or more fillers (e.g., minerals such as metakaolin) into polymer articles. The articles herein may be or comprise components useful for various applications, such as vehicles (e.g., automotive components), household appliances, commercial appliances, industrial equipment, and/or laboratory equipment. Exemplary articles according to the present disclosure include, but are not limited to, hoses, belts, washers, O-rings, diaphragms, pipes, linings, stops, and gaskets. In some examples herein, the articles may be exposed to environmental conditions that are corrosive, oxidizing, ionizing, and/or abrasive, wherein the chemical composition of the articles help to protect the article against degradation and/or maintain the integrity of the article over time.

[0020] The articles herein may comprise one or more polymers. Exemplary polymers that may be used in the articles include, but are not limited to, natural rubber, natural rubber blends, synthetic rubber, synthetic rubber blends, thermoplastics, polyvinyl chloride, styrene- butadiene, neoprene rubber, polyisoprene, ethylene propylene diene monomer,

polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, fluorinated rubber, chlorinated rubber, hydrogenated nitrile rubber, epichlorohydrin, polyisobutylene, polysiloxane, polypropylene, polyethylene, polyester, any copolymers thereof any derivatives thereof, and any combinations thereof. In at least one example, the article comprises one or more polymers chosen from rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, or any combinations thereof. [0021] The articles herein may comprise from about 0.1% to about 100% by weight of the polymer(s), e.g., ranging from about 10% to about 90%, from about 20% to about 80%, from about 30% to about 70%, or from about 40% to about 60% by weight of the polymer(s) with respect to the total weight of the articles.

[0022] The articles herein may comprise one or more minerals. The mineral(s) may be used as fillers, for example, in at least a portion of the article or throughout the article

(e.g., in the bulk polymer(s) forming in the article). According to some aspects of the present disclosure, the mineral(s) may comprise or be derived from a natural or synthetic clay, such as a kaolin clay. Exemplary minerals that can be included in the articles herein include, but are not limited to, kaolin, metakaolin, mica, talc, zeolites, and any combinations thereof. In at least one example, the mineral comprises metakaolin. In some cases, the mineral(s) may comprise one or more additives, such as, for example, aluminum phosphates, aluminum silicates salts (e.g., sodium aluminum silicates such as zeolites), and combinations thereof. In some examples, the mineral(s) may comprise one or more minerals of the feldspar group (including, e.g., metakaolin), optionally in combination with one or more zeolites. According to some aspects of the present disclosure, the articles may comprise only one mineral, such as, e.g., metakaolin. Alternatively, the articles may comprise a combination (e.g., a mixture) of two or more minerals, such as, e.g., a mixture of metakaolin and talc.

[0023] The minerals herein may have a shape factor that provides desired

characteristics for the articles. For example, the minerals may have a relatively high shape factor, e.g., a shape factor greater than 10. The shape factor may provide in-plane strength to the articles, e.g., providing for high dimensional stability. As used herein, the term“shape factor” refers to a measure of an average value (on a weight average basis) of the ratio of mean particle diameter to particle thickness for a population of particles of varying size and shape. Shape factor may be measured using the electrical conductivity method and apparatus described in U.S. Patent No. 5,576,617 (also referred to as PANACEA (particle assessment

[by] natural alignment [and] conductivity effect analysis)). In this method, the electrical conductivity of a folly dispersed aqueous suspension of the particles is measured as they flow through an elongated tube. Measurements of the electrical conductivity are taken between (a) a pair of electrodes separated from one another along the longitudinal axis of the tube, and (b) a pair of electrodes separated from one another across the transverse width of the tube. The shape factor of the particulate material is determined from the difference between these two conductivity measurements. Higher shape factors generally describe materials that are more platy.

[0024] The minerals suitable for the articles and methods herein may have a shape factor of at least 10, at least 20, at least 40, at least 60, at least 80, at least 90, at least 100, at least 125, at least 150, or at least 200. In some cases, the article may comprise at least one mineral having a shape factor ranging from about 10 to about 200, e.g., from about 20 to about 200, from about 20 to about 100, from about 30 to about 100, from about 50 to about

80, from about 50 to about 60, or from about 40 to about 60. In at least one example, the mineral(s) may have a shape factor from about 50 to about 80. In at least one example, the mineral(s) may have a shape factor from about 30 to about 100.

[0025] The minerals may have a particle size distribution suitable for use in the articles. For example, the minerals may have a dio diameter as measured by Sedigraph ranging from about 0.2 pm to about 4.0 pm, from about 0.2 pm to about 1.0 pm, from about 0.5 pm to about 1.5 pm, from about 1.0 pm to about 2.0 pm, from about 1.5 pm to about 2.5 pm, from about 2.0 pm to about 3.0 pm, from about 2.5 pm to about 3.5 pm, or from about

3.0 mih to about 4.0 pm. In some examples, the minerals may have dso diameter as measured by Sedigraph ranging from about 0.1 pm to about 50 pm, from about 0.5 pm to about 40 pm, from about 0.5 pm to about 10 pm, from about 0.5 pm to about 7.5 pm, from about 0.5 pm to about 5 pm, from about 1.0 pm to about 5.0 pm, from about 1.0 pm to about 3.5 pm, from about 1 pm to about 10 pm, from about 5 pm to about 15 pm, from about 10 pm to about 20 pm, from about 15 pm to about 25 pm, from about 20 pm to about 30 pm, from about 25 pm to about 35 pm, or from about 30 pm to about 40 pm. In at least one example, the minerals may have a dso from about 1.0 pm to about 5.0 pm. In some examples, the minerals may have a d»o diameter as measured by Sedigraph ranging from about 15 pm to about 50 pm, from about 15 pm to about 25 pm, from about 20 pm to about 30 pm, from about 25 pm to about 35 pm, from about 30 pm to about 40 pm, from about 35 pm to about 45 pm, or from about 40 pm to about 50 pm. The particle size distribution of the minerals described herein may be measured by sedimentation of minerals in a fully dispersed condition in an aqueous medium using a Sedigraph 5100 machine as supplied by Micromeritics Instruments Corporation, Norcross, Ga., USA. Such a machine may provide measurements and a plot of the cumulative percentage by weight of particles having a size, referred to as the“equivalent spherical diameter” (e.s.d.), less than given e.s.d. values. The mean particle size dio is the value determined in this way of the particle e.s.d. at which there are 10% by. weight of the particles which have an e.s.d. less than that dio value. The mean particle size dso is the value determined in this way of the particle e.s.d. at which there are 50% by weight of the particles which have an e.s.d. less than that dso value. The mean particle size dso is the value determined in this way of the particle e.s.d. at which there are 90% by weight of the particles which have an e.s.d. less than that dgo value. In at least one example, from about 95% to about 100% by weight of the particles have an e.s.d. less than 10 pm. In another example, from about 40% to about 80% by weight of the particles have an e.s.d. less than 2 pm.

[0026] Without intending to be bound by theory, it is believed that the mineral(s) may delay, decrease, or prevent the degradation of the polymer(s), e.g., degradation induced by exposure to degradation-causing external agents. The degradation of the polymer(s) may at least partially cause damage to the articles, such as, for example, crack formation, discoloration, hardening, softening, loss of other physical and/or chemical properties, or any combinations thereof.

[0027] Examples of the degradation-causing external agents include, but are not limited to, heat, radiation (e.g., ultraviolet radiation, infrared radiation, and/or visible light radiation), hard water and components thereof (e.g., dissolved minerals, including one or more cations and/or anions such as Ca²⁺, Mg^24-, Al³⁺, Ba²*, Sr^2-1, Fe²*, Fe³*, Zn²⁺, Mn²*, Cl^',

CO3² , HCO3^", BCh^3", PO4^3", SiO*^4-, etc.), metals and/or salts or alloys thereof (e.g., Fe, Cu,

Zn, Mn, Co, Co salts, Ag, Ca, Ti, Ni, Mg, Al, V, Mg, W, brass, etc.), ions, oil, grease, acids, wet conditions (e.g., water, moisture, condensation), atmospheric components such as nitrogen oxides (NO, NO2), ozone, free radicals (e.g., OH^", HO2^', organic radicals, etc.), sulfate aerosols, organic aerosols, and any combinations thereof. The degradation-causing agents may be external to the polymer but internal to the article, such as brass-coated steel cords used as reinforcement material in rubber tires, high-pressure hydraulic hoses, and heavy-duty conveyor belts. In at least one example, the degradation-causing components may comprise combinations of any or all of the degradation-causing metal components and any or all of the degradation-causing ions described herein. [0028] In some examples, the external agent(s) may comprise hard water or a component thereof. The term“hard water” as used herein refers to water having a divalent ion content of more than 10 parts per million (ppm). In some examples, the hard water may have a hardness of at least 10 ppm, at least 15 ppm, at least 17 ppm, at least 20 ppm, at least

40 ppm, at least 60 ppm, at least 80 ppm, at least 100 ppm, at least 120 ppm, at least 140 ppm, at least 160 ppm, at least 180 ppm, or at least 200 ppm. In at least one example, the hard water may have a hardness of at least 15 ppm. In some examples, the hard water may have a hardness ranging from about 1 ppm to about 7000 ppm, from about 1 ppm to about 17 ppm, from about 17 ppm to about 60 ppm, from about 60 ppm to about 120 ppm, from about 120 ppm to about 180 ppm, from about 180 ppm to about 400 ppm, or from about 6000 ppm to about 7000 ppm.

[0029] In some examples, the external agent(s) may comprise one or more metals.

Examples of such metals include, but are not limited to, iron, copper, zinc, manganese, cobalt, silver, calcium, titanium, nickel, magnesium, aluminum, vanadium, barium, lead, cadmium, antimony, any alloys thereof, and any combinations thereof. In at least one example, the metals comprise an alloy such as, for example, an alloy of copper and zinc, e.g., brass. In some examples, the metals may comprise heavy metals.

[0030] In some examples, the external agent(s) may comprise one or more ions. The ion(s) may include ions of any metal described herein. In some cases, the ion(s) may include non-metal ions, such as, for example, fluoride ions, chloride ions, and/or bromide ions. In some examples, the external agent(s) may comprise hard water that includes one or more of the metal(s) and/or one or more of the ion(s). [0031] The minerals incorporated into the articles herein may comprise one or more constituents capable of reacting (or otherwise interacting) with one or more of the external agents, e.g., to thereby reduce the level(s) or decreasing the effect of one or more of the external agents. According to some aspects of the present disclosure, for example, the mineral(s) may comprise alumina, e.g., soluble alumina. Without intending to be bound by theory, it is believed that the soluble alumina present in such mineral(s), may delay or prevent polymer degradation associated with exposure to external agents. For example the soluble alumina may scavenge radicals and/or participate in ion exchange to counteract the attack of external agents.

[0032] In some examples, the article may comprise at least one mineral having a soluble alumina content ranging from about about 10% to about 30% by weight, or from about 12% to about 28%, or from about 14% to about 26%, or from about 18% to about

24%, or from about 20% to 24% by weight . For example, the article may comprise metakaolin having a soluble alumina content ranging from 10% to about 30% by weight. In at least one example, the article comprises metakaolin having a soluble alumina content ranging from 20% to about 24% by weight.

[0033] The amount of soluble alumina content may be measured using nitric acid. In an exemplary method, 100 milligrams of a sample is measured using an analytical balance and transferred to a 16 mm x 150 mm test tube with a screw-on cap. 10 mL of concentrated nitric acid is added to the test tube, which is capped loosely. The test tube is then heated in a water bath (with a temperature of 100 °C± 2C°) for 4 hours and allowed to cool down. The top part of the test tube is filled with deionized water and the solution in the test tube is then filtered through ashless filter paper into a 100 mL volumetric flask. A control sample is also prepared using concentrated nitric acid. The flask is then filled to the 100 mL mark and the solution is analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-

AES), using various dilution of a 1000 ppm aluminum standard solution as standards. The soluble alumina content is then calculated using the following equation:

[0034] According to some aspects of the present disclosure, the article may comprise from about 0.1% to about 100% by weight of mineral(s), with respect to the total weight of the polymers) in the article. For example, the mineral(s) may be present as a filler material in the polymer(s) of the article in an amount ranging from about 1% to about 80%, from about 3% to about 65%, from about 1% to about 20%, from about 10% to about 30%, from about 20% to about 40%, from about 30% to about 50%, from about 40% to about 60%, from about 50% to about 70%, or from about 60% to about 80% by weight relative to the total weight of the poIymer(s). In at least one example, the articles may have a total mineral content (mineral loading) ranging from about from about 3% to about 65% by weight. In some examples, the mineral loading may be metakaolin loading.

[0035] The articles herein may farther comprise one or more additives. Examples of additives that can be used in the articles include, but are not limited to, paraffin, antioxidants, sulfur peroxide, zinc oxide, stearic acid, flame retardants, plasticizers, thermal stabilizers, processing aids, anti-blocking agents, ultraviolet light stabilizers, quenchers, colorants, mold release agents, lubricants, antistatic agents, and any combinations thereof.

[0036] According to some aspects of the present disclosure, the articles may comprise one or more plasticizers. Exemplary plasticizers include, but are not limited to, phthalate ester, phosphate ester, ethoxyated soybean oil, epoxidized soybean oil, adipate plasticizers, epoxidized propylene glycol disoyate, dioctyl phthalate, dioctyl terphalate, dioctyl adipate, dibutyl sebacate, dinonyl phthalate, glyceryl stearates, and any combinations thereof. The articles may further comprise one or more thermal stabilizers. Exemplary thermal stabilizers include, but are not limited to, carboxylic acid metal soaps (e.g., barium, calcium, cadmium, zinc and/or lead carboxylates), esters or mercaptides of alkyl tin, epoxy compounds, and any combinations thereof. In at least one example, the thermal stabilizers may comprise barium/zinc thermal stabilizers, e.g., barium/zinc carboxylic acid metal soaps.

[0037] The articles herein may be of any type, e.g., the articles for use in various applications. For example, the articles may include hoses, belts, washers, O-rings, pipes, linings, stoppers, gaskets, automotive components (e.g., for general purpose applications in automobiles), and any combinations thereof. The articles herein may comprise components of household appliances, commercial appliances, industrial equipment, and/or laboratory equipment.

[0038] Also disclosed herein are methods of making articles. The methods may include combining one or more polymers and one or more minerals to form a mixture. The

%

methods optionally may also include adding one or more additives to the mixture. The method of making the articles may further include forming the mixture of polymers) and mineral(s) into an article. Formation of the article may be performed by molding (e.g., compression molding, injection molding, etc.) or extrusion, among other techniques for shaping polymers.

[0039] The mineral fillers suitable for the articles herein may be prepared, e.g., based on the desired particle size, shape, and/or composition. In cases where the minerals) comprise metakaolin, the metakaolin may be prepared by processing a kaolin clay. In at least one example, such methods may produce metakaolin that has a shape factor ranging from about 20 to about 100, e.g., from about 30 to about 80, from about 40 to about 60, from about

45 to about 60, from about 50 to about 60, or from about 50 to about 55. The metakaolin may have a soluble alumina content ranging from about about 10% to about 30% by weight, or from about 12% to about 28%, or from about 14% to about 26%, or from about 18% to about 24%, or from about 20% to 24% by weight.

[0040] The methods of making metakaolin may comprise calcining kaolin clay at a suitable temperature and for an appropriate amount of time. The temperature and time may be sufficient to remove some of the water content from kaolin. In some examples, the method of making metakaolin may comprise calcining kaolin at a temperature ranging from about 500 °C to about 900 °C, e.g., from about 550 °C to about 850 °C, from about 600 °C to about 800 °C, from about 650 °C to about 750 °C, or from about 680 °C to about 720 °C. In some examples, the method of making metakaolin may comprise calcining kaolin for a time ranging from about 30 minutes to about 120 minutes, from about 40 minutes to about 110 minutes, from about 50 minutes to about 100 minutes, from about 60 minutes to about 90 minutes, from about 50 minutes to about 70 minutes, or from about 80 minutes to about 110 minutes. Such conditions may produce metakaolin having a shape factor of at least 20.

[0041] The kaolin clay used for making the metakaolin herein may comprise hyper platy kaolin clay (e.g., kaolin having a shape factor of at least 50). According to some aspects of the present disclosure, the shape factor of the kaolin clay may be reduced after calcination (e.g., when the kaolin clay is made into metakaolin). However, the reduced shape factor of the resulting metakaolin may be equal to or greater than 20. [0042] Further provided herein are methods for delaying or preventing the degradation of the articles. The methods may comprise incorporating one or more minerals into the articles (e.g., incorporating the mineral(s) into polymers) forming all or a portion of the articles). In some examples, the mineral(s) may be used as a filler material. In at least one example, the methods may comprise incorporating metakaolin into polymer articles as a filler.

[0043] Without intending to be bound by theory, it is believed that the mineral filler(s) may interact, e.g., react, with or otherwise reduce the level or effect of degradation- causing external agents present in the article. In at least one example, incorporating the fillers) into the articles may be performed when the articles are made.

[0044] In some examples, the polymer material of an article may be exposed to chloride ions in the external environment, which may attack methyl groups in the side chains of the polymer, e.g., the side chain of diene component of ethylene propylene diene monomer rubber. Due to chlorination of the methyl groups on the polymer, the crosslink density and hardness of the polymers may increase over time. This chemical modification of the polymer, in turn, may lead to the formation of cracks in the articles containing the polymers.

The mineral(s) present in the polymer according to the present disclosure may be available to scavenge the chloride ions, inhibit chlorination, and delay or prevent the crack formation and other degradation effects caused by the chloride ions. In some examples, the mineral(s) present in the article may have an ion exchange capacity that prevents metal ions from causing oxidation of the polymer(s).

[0045] According to some aspects of the present disclosure, the mineral(s) may have low transmittance in the ultraviolet, visible, and/or photosynthetically active radiation (PAR) regions. The mineral(s) may also have high infrared (IR) absorbency (e.g., in mid-far IR region). These properties of the mineral(s) may reduce crack formation, discoloration, and other degradation effects caused by radiations to the articles. In some examples, when the articles are exposed to radiation (e.g., ultraviolet radiation), the mineral(s) may absorb at least a portion of the radiation. For example, the mineral(s) may absorb at least 5%, at least 10%, at least 20%, at least 40%, at least 60%, or at least 80% of the radiation. In some cases, the mineral(s) may absorb from about 1% to about 20%, from about 10% to about 30%, from about 20% to about 40%, from about 30% to about 50%, from about 40% to about 60%, from about 50% to about 70%, or from about 60% to about 80% of the ultraviolet and/or IR radiation to which the article is exposed. The mineral may also be treated with a polymer, such as 2-Amino-2-Methyl-l -Propanol (AMP), to lower the transmitance in the UV visible and IR ranges.

[0046] Additionally or alternatively, the mineral(s) incorporated into the articles may help prevent or delay a change of color of the article, e.g., a change of color of the polymeifs) from which the article is formed. The effect on reducing color change may be at least partially due to the absorbance of radiation by the mineral(s). Color changes may be quantified according to the Cielab system that quantifies color changes based on the DE value. In general, a smaller DE value indicates a lower level of color change. The Cielab system expresses DE according to the following formula:

Equation 2 ·

In this formula, AL refers to the change in darkness or lightness (positive AL means that the articles have become darker and negative AL means that the articles have become lighter). Aa refers to the change of color in the red-green axis (positive means color change towards red range and negative towards green range) and Ab refers to color changes in the blue- yellow axis (positive color change means towards yellow range and negative toward blue range).

[0047] According to some aspects of the present disclosure, when made and/or treated with the methods provided herein, the articles may maintain a DE value of no greater than 5, no greater than 4, no greater than 3, no greater than 2, or no greater than 1. In some examples, the articles may maintain a DE value ranging from about 0.1 to about 5, from about

1 to about 3, from about 1 to about 2, or from about 2 to about 3.

[0048] When made and/or treated with the methods provided herein, the articles may maintain a dimensional stability (e.g., tensile strength) of at least 50%, at least 60%, at least

70%, at least 80%, at least 90%, at least 95%, or at least 99% after an aging process. In some examples, the aging may be performed at about 70 °C for at least 7 days. Alternatively or additionally, the aging process may be performed at about 90 °C for 14 days. In at least one example, the articles may maintain a dimensional stability of at least 70% after such aging process(es). The term“dimensional stability” as used herein refers to the ability of the articles to maintain their structural integrity, particularly upon exposure to degradation- causing external agents. The dimensional stability may comprise the dimensional stability under stress such as, for example, tensile, tear, compression, heat, or any combinations thereof. The dimensional stability may be presented as elongation at break, impact strength, hardness of the material, heat deflection temperature, load deflection point, or any combinations thereof. In some examples, the articles may maintain a dimensional stability with less than 20%, less than 15%, less than 10%, less than 5%, or less than 1% expansion or shrinkage over a temperature range of at least 30°C (e.g., a range of 20°C to 50°C, 50°C to

90°C, 40°C to 80°C, or 20°C to 90°C).

[0049] In some examples, incorporating the mineral(s) into the polymer of an article may provide for less than 40%, less than 35%, less than 30%, less than 25%, or less than 20% change in mechanical strength properties over a period of six months, or a period of six months to one year. Such mechanical properties may include, for example, tensile strength, tear strength, flexural modulus, elongation at break, and hardness. For example, articles comprising at least one mineral as disclosed herein may exhibit less than 30% change in at least one mechanical strength property over a period of six months or one year. In at least one example, the dimensional stability may comprise tensile strength. The tensile strength may be measured following American Society for Testing and Materials (ASTM) standard D412. In another example, the dimensional stability may comprise tear strength. The tear strength may be measured following ASTM D624,

[0050] Aspects of the present disclosure are further illustrated by reference to the following, non-limiting numbered paragraphs describing exemplary embodiments.

[0051] 1. A method of protecting an article comprising a polymer from degradation, the method comprising: incorporating metakaolin into the polymer as a filler, the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin; wherein the polymer is exposed to an external agent that promotes degradation; and wherein the metakaolin reacts with the external agent to delay or prevent degradation of the article.

[0052] 2. The method according to paragraph 1, wherein the metakaolin has a shape factor of at least 20. [0053] 3. The method according to paragraph 1 or 2, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80.

[0054] 4. The method according to any of paragraphs 1 -3, wherein the external agent is an ion present in water with a hardness of at least 15 parts per million.

[0055] 5. The method according to any of paragraphs 1-4, wherein the external agent comprises chloride or a metal.

[0056] 6. The method according to any of paragraphs 1-5, wherein the external agent comprises iron, copper, zinc, or an alloy thereof.

[0057] 7. The method according to any of paragraphs 1-6, wherein the article is exposed to radiation, and the metakaolin absorbs at least a portion of the radiation to prevent or delay formation of cracks in the article.

[0058] 8. The method according to any of paragraphs 1-7, wherein the article is exposed to UV radiation, and the metakaolin absorbs at least a portion of the UV radiation with a DE value of the polymer no greater than 3.

[0059] 9. The method according to any of paragraphs 1-8, wherein the article maintains at least 70% tensile strength over a period of at least six months.

[0060] 10. The method according to any of paragraphs 1-9, wherein the article maintains at least 70% tensile strength after aging at 70 °C for 7 days.

[0061] 11. The method according to any of paragraphs 1-10, wherein the article maintains at least 70% tensile strength after aging at 90 °C for 14 days.

[0062] 12. The method according to any of paragraphs 1-11, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10.0 pm as measured by Sedigraph. [0063] 13. The method according to any of paragraphs 1-12, wherein the article has a metakaolin loading ranging from about 3% to about 65% by weight of the polymer.

[0064] 14. The method according to any of paragraphs 1-13, wherein the polymer comprises natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

[0065] 15. The method according to any of paragraphs 1-14, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic robber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile robber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

[0066] 16. The method according to any of paragraphs 1-15, wherein the polymer further comprises paraffin, an antioxidant, sulfur peroxide, zinc oxide, stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

[0067] 17. The method according to any of paragraphs 1-16, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

[0068] 18. A method of making an article, the method comprising: combining a polymer with metakaolin to form a mixture, wherein the metakaolin comprises from about 10% to about 30% by weight soluble alumina, relative to the total weight of the metakaolin; and forming the mixture into an article; wherein, when the polymer is exposed to an external agent that promotes degradation, the metakaolin reacts with the external agent to delay or prevent degradation of the article. [0069] 19. The method according to paragraph 18, wherein the metakaolin has a shape factor of at least 20.

[0070] 20. The method according to paragraph 18 or 19, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80.

[0071] 21. The method according to any of paragraphs 18-20, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10.0 pm as measured by Sedigraph.

[0072] 22. The method according to any of paragraphs 18-21, wherein the mixture has a metakaolin loading ranging from 3% to about 65% by weight of the polymer.

[0073] 23. The method according to any of paragraphs 18-22, wherein the polymer comprises natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

[0074] 24. The method according to any of paragraphs 18-23, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

[0075] 25. The method according to any of paragraphs 18-24, wherein the mixture further comprises at least one additive chosen from paraffin, an antioxidant, sulfur peroxide, zinc oxide, a stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

[0076] 26. The method according to any of paragraphs 18-25, wherein forming the mixture into the article comprises compression molding, injection molding, or extrusion. [0077] 27. The method according to any of paragraphs 18-26, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

[0078] 28. The method according to any of paragraphs 18-27, wherein the article maintains at least 70% tensile strength over a period of at least six months.

[0079] 29. The method according to any of paragraphs 18-28, wherein the article maintains at least 70% tensile strength after aging at 70 °C for 7 days.

[0080] 30. The method according to any of paragraphs 18-29, wherein the article maintains at least 70% tensile strength after aging at 90 °C for 14 days.

[0081] 31. The method according to any of paragraphs 18-30, wherein when the article is exposed to UV radiation, the metakaolin absorbs at least a portion of the UV radiation to maintain a DE value of the polymer no greater than 3.

[0082] 32. An article made by a method according to any of paragraphs 18-31.

[0083] 33. An article comprising: a polymer, and metakaolin incorporated into the polymer, the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin; wherein when the article is exposed to an external agent that promotes degradation, the metakaolin reacts with the external agent to delay or prevent degradation of the article.

[0084] 34. The article according to paragraph 33, wherein the metakaolin has a shape factor of at least 20.

[0085] 35. The article according to paragraph 33 or 34, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80. [0086] 36. The article according to any of paragraphs 33-35, wherein the metakaolin has a soluble alumina content ranging from about 20% to about 24% by weight.

[008h 37. The article according to any of paragraphs 33-36, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10 pm as measured by Sedigraph.

[0088] 38. The article according to any of paragraphs 33-37, wherein the article has a metakaolin loading ranging from 3% to 65% by weight of the polymer.

[0089] 39. The article according to any of paragraphs 33-38, wherein the polymer comprises natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

[0090] 40. The article according to any of paragraphs 33-39, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber,

epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

[0091] 41. The article according to any of paragraphs 33-40, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

[0092] The following examples are intended to illustrate the present disclosure without, however, being limiting in nature. It is understood that the present disclosure encompasses additional embodiments consistent with the foregoing description and following examples. EXAMPLE

[0093] Hyper platy kaolin clay (shape factor = 100) was used to prepare metakaolin.

The kaolin was calcined at about 700°C for 90 minutes. Samples were taken after 30 minutes, 60 minutes, and 90 minutes of the calcination process. Shape factors and soluble alumina contents of the kaolin and the three samples were measured. The results are shown in FIG. 1. Characteristics of the kaolin and the metakaolin sample at 90 minutes are reported in Tables 1 and 2 below. Particle size distributions were measured by laser diffraction

(Malvern Zetasizer, Malvern Instruments) for metakaolin only, and by sedimentation (Sedigraph 5100, Micromeritics Instruments) for both kaolin and metakaolin. The shape factors of the metakaolin and the kaolin were measured by PANACEA.

[0094] The chemical composition of the metakaolin by X-ray fluorescence is shown in Table 2 below, as well as the loss on ignition (LOI) measured at 1050°C as an indication of water content.

[0095] Other aspects and embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein.

[0096] It is intended that the specification and examples therein be considered as exemplary only, with a true scope and spirit of the present disclosure being indicated by the following claims.

Claims

CLAIMS What is claimed is;

1. A method of protecting an article comprising a polymer from degradation, the method comprising:

incorporating metakaolin into the polymer as a filler, the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin;

wherein the polymer is exposed to an external agent that promotes degradation; and wherein the metakaolin reacts with the external agent to delay or prevent degradation of the article.

2. The method of claim 1, wherein the metakaolin has a shape factor of at least 20.

3. The method of claim 1, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80.

4. The method of claim 1, wherein the external agent is an ion present in water with a hardness of at least 15 parts per million.

5. The method of claim I, wherein the external agent comprises chloride or a metal.

6. The method of claim 1, wherein the external agent comprises iron, copper, zinc, or an alloy thereof.

7. The method of claim 1, wherein the article is exposed to radiation, and the metakaolin absorbs at least a portion of the radiation to prevent or delay formation of cracks in the article.

8. The method of claim 1, wherein the article is exposed to UV radiation, and the metakaolin absorbs at least a portion of the UV radiation with a DE value of the polymer no greater than 3.

9. The method of claim 1 , wherein the article maintains at least 70% tensile strength over a period of at least six months.

10. The method of claim 1, wherein the article maintains at least 70% tensile strength after aging at 70 °C for 7 days.

11. The method of claim 1 , wherein the article maintains at least 70% tensile strength after aging at 90 °C for 14 days.

12. The method of claim 1, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10.0 pm as measured by Sedigraph.

13. The method of claim 1, wherein the article has a metakaolin loading ranging from about 3% to about 65% by weight of the polymer.

14. The method of claim 1, wherein the polymer comprises natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

15. The method of claim 1, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacryJic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber, epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

16. The method of claim 1, wherein the polymer further comprises paraffin, an antioxidant, sulfur peroxide, zinc oxide, stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

17. The method of claim 1, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

18. A method of making an article, the method comprising:

combining a polymer with metakaolin to form a mixture, wherein the metakaolin comprises from about 10% to about 30% by weight soluble alumina, relative to the total weight of the metakaolin; and

forming the mixture into an article;

wherein, when the polymer is exposed to an external agent that promotes degradation, the metakaolin reacts with the external agent to delay or prevent degradation of the article.

19. The method of claim 18, wherein the metakaolin has a shape factor of at least 20.

20. The method of claim 18, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80.

21. The method of claim 18, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10.0 pm as measured by Sedigraph.

22. The method of claim 18, wherein the mixture has a metakaolin loading ranging from 3% to about 65% by weight of the polymer.

23. The method of claim 18, wherein the polymer comprises natural rubber, a natural robber blend, synthetic robber, a synthetic robber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

24. The method of claim 18, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber, epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

25. The method of claim 18, wherein the mixture further comprises at least one additive chosen from paraffin, an antioxidant, sulfur peroxide, zinc oxide, a stearic acid, a flame retardant, a plasticizer, a thermal stabilizer, or a combination thereof.

26. The method of claim 18, wherein forming the mixture into the article comprises compression molding, injection molding, or extrusion.

27. The method of claim 18, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.

28 The method of claim 18, wherein the article maintains at least 70% tensile strength over a period of at least six months.

29. The method of claim 18, wherein the article maintains at least 70% tensile strength after aging at 70 °C for 7 days.

30. The method of claim 18, wherein the article maintains at least 70% tensile strength after aging at 90 °C for 14 days.

31. The method of claim 18, wherein when the article is exposed to UV radiation, the metakaolin absorbs at least a portion of the UV radiation to maintain a DE value of the polymer no greater than 3.

32* An article comprising:

a polymer; and metakaolin incorporated into the polymer, the metakaolin having a soluble alumina content ranging from about 10% to about 30% by weight, relative to the total weight of the metakaolin;

wherein when the article is exposed to an external agent that promotes degradation, the metakaolin reacts with the external agent to delay or prevent degradation of the article.

33. The article of claim 32, wherein the metakaolin has a shape factor of at least 20.

34. The article of claim 32, wherein the metakaolin has a shape factor ranging from 30 to 100 or from 50 to 80.

35. The article of claim 32, wherein the metakaolin has a soluble alumina content ranging from about 20% to about 24% by weight.

36. The article of claim 32, wherein a particle size distribution of the metakaolin has a dso diameter ranging from about 0.5 pm to about 10 pm as measured by Sedigraph.

37. The article of claim 32, wherein the article has a metakaolin loading ranging from 3% to 65% by weight of the polymer.

38. The article of claim 32, wherein the polymer comprises natural rubber, a natural rubber blend, synthetic rubber, a synthetic rubber blend, a thermoplastic, polyvinyl chloride, or a combination thereof.

39. The article of claim 32, wherein the polymer comprises styrene-butadiene, ethylene propylene diene monomer, polychloroprene, chlorosulfonyl polyethylene, acrylonitrile butadiene, polyacrylic rubber, ethylene acrylic rubber, a fluorinated rubber, a chlorinated rubber, a hydrogenated nitrile rubber, epichlorohydrin, polyisobutylene, polysiloxane, or a combination thereof.

40. The article of claim 32, wherein the article is a hose, a belt, a washer, an O-ring, a pipe, a lining, a stopper, a gasket, or an automotive component.