Patent Application
20240287295
Embodiments of the present disclosure are generally related to thermoset articles, and are specifically related to thermoset articles of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, and silicone rubber having increased high temperature oil resistance while providing the desired compression set and coefficient of friction.
Non-crosslinked thermoplastic elastomers may have desirable ambient mechanical and thermal properties, such as tensile strength at break, tensile elongation at break, and compression set. However, these articles may not have the high temperature (e.g., greater than or equal to 100° C.) chemical resistance (e.g., oil resistance), high temperature heat resistance (e.g. compression set), and the silky feeling (e.g., low coefficient of friction) necessary for certain applications in the healthcare, automotive, industrial and electronic fields.
Accordingly, a continual need exists for improved thermoset articles that have increased high temperature oil resistance while providing the compression set and the coefficient of friction for the aforementioned applications.
Embodiments of the present disclosure are directed to thermoset articles comprising a crosslinked reaction product of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, silicone rubber, and silane, which have increased high temperature oil resistance while providing the desired compression set and coefficient of friction.
According to one embodiment, a thermoset article is provided. The thermoset article comprises the crosslinked reaction product of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, silicone rubber, and silane. The silicone rubber has at least one vinyl functional group. At least one of the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, and the silicone rubber is silane grafted and silane crosslinked. The silane crosslinking is at least one of intramolecular silane crosslinking and intermolecular silane crosslinking
Additional features and advantages of the embodiments described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description, which follows and the claims.
Reference will now be made in detail to various embodiments of thermoset articles, specifically thermoset articles comprising the crosslinked reaction product of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, silicone rubber, and silane. The silicone rubber has at least one vinyl functional group. At least one of the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, and the silicone rubber is silane grafted and silane crosslinked. The silane crosslinking is at least one of intramolecular silane crosslinking and intermolecular silane crosslinking.
The disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the subject matter to those skilled in the art.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in the disclosure herein is for describing particular embodiments only and is not intended to be limiting.
Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.
As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.
The term “wt %,” as described herein, refers to the weight fraction of the individual reactants of the formulation used to produce the crosslinked reaction product that comprises the thermoset article, unless otherwise noted. For simplicity purposes, “wt %” will be referred to throughout as the amount in the thermoset article.
The term “melt flow rate,” as described herein, refers to the ability of a material's melt to flow under pressure as measured according to ASTM D1238 at the given temperature and given weight.
The term “density,” as described herein, refers to the mass per unit volume of a material as measured according to ASTM D792 at 23° C.
The term “specific gravity,” as described herein, refers to the ratio of the density of a material to the density of water as measured according to ASTM D792 at 23° C.
The term “Mooney viscosity,” as described herein, refers to the viscosity reached after a rotor rotates for a given time interval at the specified temperature as measured according to ASTM D1646.
The term “yield,” as described herein, refers to the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior.
The term “tensile strength at yield,” as described herein, refers to the maximum stress that a material can withstand while being stretched before it begins to change shape permanently as measured according to ASTM D638 at 23° C. and a rate of strain of 0.85 mm/s.
The term “tensile elongation at yield,” as described herein, refers to the ratio between the increased length and initial length at the yield point as measured according to ASTM D638 at 23° C. and a rate of strain of 0.85 mm/s.
The term “tensile strength at break,” as described herein, refers to the maximum stress that a material can withstand while stretching before breaking as measured according to ASTM D638 at 23° C. and a rate of strain of 0.85 mm/s.
The term “tensile elongation at break,” as described herein, refers to the ratio between increased length and initial length after breakage as measured according to ASTM D638 at 23° C. and a rate of strain of 0.85 mm/s.
The term “Shore A hardness,” as described herein, refers to the hardness of a material as measured according to ASTM D2240.
The term “compression set,” as described herein, refers to the ability of a material to return to its original thickness after prolonged compressive stress as measured according to ASTM D395 at the temperature indicated.
The term “maintained compression set,” as described herein, refers to a compression set of a thermoset article as described herein that is within 10% of a compression set of a thermoset article that does not include silicone rubber.
The term “silky feeling,” as described herein, refers to a tactile sensation one experiences when touching a silk fabric.
The term “melting point,” as described herein, is measured using differential scanning calorimetry (DSC).
The term “thermoset article,” as described herein, refers to an article including crosslinking that is irreversible such that the article cannot successfully be remolded or reheated after initial heat-forming or molding.
The term “silane grafted,” as described herein, refers to the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, or the silicone rubber having a silane side chain connected to the polymer main chain. The grafted silane allow the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, or the silicone rubber to intramolecular silane crosslink or intermolecular silane crosslink.
The term “intramolecular silane crosslinking,” as described herein, refers to silane crosslinking that occurs when the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, or the silicone rubber crosslinks with itself.
The term “intermolecular silane crosslinking,” as described herein, refers to silane crosslinking that occurs when the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, or the silicone rubber crosslinks with another of the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, or the silicone rubber.
The term “copolymer,” as described herein, refers to a polymer formed when two or more monomers are linked in the same chain.
The term “ethylene propylene diene rubber,” as described herein, may be used interchangeably with “ethylene propylene diene polymer.”
The term “thermoplastic polyolefin,” as described herein, refers to a highly crystalline (i.e., greater than or equal to 40% crystalline) blend including a thermoplastic domain, optionally an amorphous elastomer or rubber domain, and optionally a filler.
The term “polyolefin elastomer,” as described herein, refers to a low crystalline (i.e., less than or equal to 25% crystalline) blend including a thermoplastic domain, an amorphous elastomer or rubber domain, and optionally a filler.
As discussed hereinabove, non-crosslinked thermoplastic elastomers may have desirable ambient mechanical and thermal properties, such as tensile strength at break, tensile elongation at break, and compression set. However, these articles may not have the high temperature (e.g., greater than 100° C.) chemical resistance (e.g., oil resistance), high temperature heat resistance (e.g. compression set), and the silky feeling (e.g., low coefficient of friction) necessary for certain applications in the healthcare, automotive, industrial and electronic fields.
Disclosed herein are thermoset articles, which mitigate the aforementioned problems. Specifically, the thermoset articles disclosed herein comprise a crosslinked reaction product of: thermoplastic polyolefin; at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber; silicone rubber; and silane, which results in an oil resistant thermoset article having maintained compression set and low coefficient of friction. At least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber is silane grafted and silane crosslinked. The silane crosslinking is at least one of intramolecular silane crosslinking and intermolecular silane crosslinking. This occurrence of silane crosslinking, along with the specific amounts of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, and silicone rubber, produces a thermoset article having improved high temperature oil resistance and maintained compression set and low coefficient of friction as compared to a conventional non-crosslinked thermoplastic polyolefin elastomeric article.
The thermoset articles disclosed herein may generally be described as the crosslinked reaction product of: thermoplastic polyolefin; at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber; silicone rubber; and silane.
As described hereinabove, the presence and specific amount of thermoplastic polyolefin, along with at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber and silicone rubber, produces a thermoset article having improved high temperature oil resistance and maintained compression set and low coefficient of friction.
Various thermoplastic polyolefins are considered suitable for the present thermoset articles. In embodiments, the thermoplastic polyolefin may comprise polypropylene, polyethylene, or a combination thereof.
In embodiments, the polypropylene may comprise a polypropylene homopolymer (i.e., composed of propylene monomers) or a polypropylene copolymer having greater than 50 wt % propylene monomer and an additional comonomer such as C2 and C4-C12 alpha olefins.
In embodiments, the polyethylene may comprise a polyethylene homopolymer (i.e., composed of ethylene monomers) or a polyethylene copolymer having greater than 50 wt % ethylene monomer and an additional comonomer, such as C3-C12 alpha olefins.
In embodiments, the thermoplastic polyolefin is at least one of high density polyethylene (e.g., greater than or equal to 0.940 g/cm3) or a crystalline polypropylene with a percent crystallinity of at least about 60%.
In embodiments, the thermoplastic polyolefin is included in amounts greater than 5 wt %. In embodiments, the amount of thermoplastic polyolefin may be limited (e.g., less than or equal to 30 wt %). In embodiments, the amount of thermoplastic polyolefin in the thermoset article may be greater than or equal to 5 wt %, greater than or equal to 8 wt %, greater than or equal to 10 wt %, greater than or equal to 12 wt %, or even greater than or equal to 14 wt %. In embodiments, the amount of thermoplastic polyolefin in the thermoset article may be less than or equal to 30 wt %, less than or equal to 25 wt %, less than or equal to 23 wt %, less than or equal to 21 wt %, or even less than or equal to 19 wt %. In embodiments, the amount of thermoplastic polyolefin in the thermoset article may be from 5 wt % to 30 wt %, from 5 wt % to 25 wt %, from 5 wt % to 23 wt %, from 5 wt % to 21 wt %, from 5 wt % to 19 wt %, from 8 wt % to 30 wt %, from 8 wt % to 25 wt %, from 8 wt % to 23 wt %, from 8 wt % to 21 wt %, from 8 wt % to 19 wt %, from 10 wt % to 30 wt %, from 10 wt % to 25 wt %, from 10 wt % to 23 wt %, from 10 wt % to 21 wt %, from 10 wt % to 19 wt %, from 12 wt % to 30 wt %, from 12 wt % to 25 wt %, from 12 wt % to 23 wt %, from 12 wt % to 21 wt %, from 12 wt % to 19 wt %, from 14 wt % to 30 wt %, from 14 wt % to 25 wt %, from 14 wt % to 23 wt %, from 14 wt % to 21 wt %, or even from 14 wt % to 19 wt %, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the polypropylene may comprise a melt flow rate (230° C./2.16 kg) greater than or equal to 0.1 g/10 min, greater than or equal to 0.5 g/10 min, greater than or equal to 1 g/10 min or even greater than or equal to 3 g/10 min. In embodiments, the polypropylene may comprise a melt flow rate (230° C./2.16 kg) less than or equal to 10 g/10 min or even less than or equal to 5 g/10 min. In embodiments, the polypropylene may comprise a melt flow rate (230° C./2.16 kg) from 0.1 g/10 min to 10 g/10 min, from 0.1 g/10 min to 5 g/10 min, from 0.5 g/10 min to 10 g/10 min, from 0.5 g/10 min to 5 g/10 min, from 1 g/10 min to 10 g/10 min, from 1 g/10 min to 5 g/10 min, from 3 g/10 min to 10 g/10 min, or even from 3 g/10 min to 5 g/10 min, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoplastic polyolefin may comprise a density greater than or equal to 0.80 g/cm3 or even greater than or equal to 0.85 g/cm3. In embodiments, the thermoplastic polyolefin may comprise a density less than or equal to 1.10 g/cm3 or even less than or equal to 1.00 g/cm3. In embodiments, the thermoplastic polyolefin may comprise a density from 0.80 g/cm3 to 1.10 g/cm3, from 0.80 g/cm3 to 1.00 g/cm3, from 0.85 g/cm3 to 1.10 g/cm3, or even from 0.85 g/cm3 to 1.00 g/cm3, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoplastic polyolefin may have a melting point greater than or equal to 100° C., greater than or equal to 110° C., or even greater than or equal to 120° C.
In embodiments, the thermoplastic polyolefin may comprise a tensile strength at yield greater than or equal to 25 MPa or even greater than or equal to 30 MPa. In embodiments, the thermoplastic polyolefin may comprise a tensile strength at yield less than or equal to 45 MPa or even less than or equal to 40 MPa. In embodiments, the thermoplastic polyolefin may comprise a tensile strength at yield from 25 MPa to 45 MPa, from 25 MPa, to 40 MPa, from 30 MPa to 45 MPa, or even from 30 MPa to 40 MPa, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoplastic polyolefin may comprise a tensile elongation at yield greater than or equal to 3% or even greater than or equal to 5%. In embodiments, the thermoplastic polyolefin may comprise a tensile elongation at yield less than or equal to 20% or even less than or equal to 15%. In embodiments, the thermoplastic polyolefin may comprise a tensile elongation at yield from 3% to 20%, from 3% to 15%, from 5% to 20%, or even from 5% to 15%, or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the thermoplastic polyolefin are available under the FORMOLENE brand from Formosa Plastics, such as polypropylene homopolymer grade 1102KR. Table 1 shows certain properties of FORMOLENE 1102KR.
As described hereinabove, the presence and specific amount of at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, along with thermoplastic polyolefin and silicone rubber, produces a thermoset article having improved high temperature oil resistance and maintained compression set and low coefficient of friction.
The ethylene alpha-olefin polyolefin elastomer is the polymerized reaction product of ethylene and C3-C12 olefins. For example, in embodiments, the ethylene alpha-olefin copolymer may comprise ethylene-octene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, or a combination thereof.
The ethylene propylene diene rubber is the polymerized reaction product of ethylene, propylene, and diene. The ethylene propylene diene rubber may comprise one or more of ethylidene norbornene, dicyclopentadiene, and vinyl norbornene.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber is included in amounts greater than or equal to 20 wt %. In embodiments, the amount of the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may be limited (e.g., less than or equal to 90 wt %). In embodiments, the amount of the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber in the thermoset article may be greater than or equal to 20 wt %, greater than or equal to 25 wt %, or even greater than or equal to 30 wt %. In embodiments, the amount of the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber in the thermoset article may be less than or equal to 90 wt %, less than or equal to 70 wt %, less than or equal to 50 wt %, less than or equal to 45 wt %, or even less than or equal to 40 wt %. In embodiments, the amount of the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber in the thermoset article may be from 20 wt % to 90 wt %, from 20 wt % to 70 wt %, from 20 wt % to 50 wt %, from 20 wt % to 45 wt %, from 20 wt % to 40 wt %, from 25 wt % to 90 wt %, from 25 wt % to 70 wt %, from 25 wt % to 50 wt %, from 25 wt % to 45 wt %, from 25 wt % to 40 wt %, from 30 wt % to 90 wt %, from 30 wt % to 70 wt %, from 30 wt % to 50 wt %, from 30 wt % to 45 wt %, or even from 30 wt % to 40 wt %, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a melt flow rate (190° C./2.16 kg) greater than or equal to 0.1 g/10 min or even greater than or equal to 0.25 g/10 min. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a melt flow rate (190° C./2.16 kg) less than or equal to 3 g/10 min or even less than or equal to 1 g/10 min. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a melt flow rate (190° C./2.16 kg) from 0.1 g/10 min to 3 g/10 min, from 0.1 g/10 min to 1 g/10 min, from 0.25 g/10 min to 3 g/10 min, or even from 0.25 g/10 min to 1 g/10 min, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a density greater than or equal to 0.80 g/cm3 or even greater than or equal to 0.85 g/cm3. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a density less than or equal to 0.95 g/cm3 or even less than or equal to 0.90 g/cm3. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a density from 0.80 g/cm3 to 0.95 g/cm3, from 0.80 g/cm3 to 0.90 g/cm3, from 0.85 g/cm3 to 0.95 g/cm3, or even from 0.85 g/cm3 to 0.90 g/cm3, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a Mooney viscosity (ML 1+4, 125° C.) greater than or equal to 30, greater than or equal to 50, or even greater than or equal to 70. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may have a Mooney viscosity (ML 1+4, 125° C.) less than or equal to 150, less than or equal to 125, or even less than or equal to 100. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a Mooney viscosity (ML 1+4, 125° C.) from 30 to 150, from 30 to 125, from 30 to 100, from 50 to 150, from 50 to 125, from 50 to 100, from 70 to 150, from 70 to 125, or even from 70 to 100, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile strength at break greater than or equal to 1 MPa or even greater than or equal to 2 MPa. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile strength at break less than or equal to 10 MPa or even less than or equal to 5 MPa. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile strength at break from 1 MPa to 10 MPa, from 1 MPa to 5 MPa, from 2 MPa to 10 MPa, or even from 2 MPa to 5 MPa, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile elongation at break greater than or equal to 750% or even greater than or equal to 1000%. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile elongation at break less than or equal to 1750% or even less than or equal to 1500%. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a tensile elongation at break from 750% to 1750%, from 750% to 1500%, from 1000% to 1750%, or even from 1000% to 1500%, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a Shore A hardness greater than or equal to 40 or even greater than or equal to 45. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a Shore A hardness less than or equal to 60 MPa or even less than or equal to 65 MPa. In embodiments, the ethylene alpha-olefin polyolefin elastomer and/or the ethylene propylene diene rubber may comprise a Shore A hardness from 40 to 60, from 40 to 55, from 45 to 60, or even from 45 to 55, or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the ethylene alpha-olefin polyolefin elastomer may include the ENGAGE brand from the Dow Chemical Company, such as grade XLT 8677. Similarly, the ethylene propylene diene rubber may be available under the NORDEL brand from Dow Chemical Company, such as grade IP 4785HM. Table 2 shows certain properties of ENGAGE XLT 8677 and NORDEL IP 4785HM.
As described hereinabove, the presence and specific amount of the silicone rubber, along with thermoplastic polyolefin and at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, produces a thermoset article having improved high temperature oil resistance and maintained compression set and low coefficient of friction. In particular, silicone rubber may impart a silky feeling (e.g., low coefficient of friction) to the thermoset article.
In embodiments, the silicone rubber may comprise at least one vinyl functional group. In embodiments, the vinyl functional group is selected for peroxide curing. In embodiments, the silicone rubber comprises high consistency silicone rubber. In embodiments, the silicone rubber may comprise polydimethylsiloxane.
In embodiments, the silicone rubber is included in amounts greater than or equal to 1 wt % such that the thermoset article has a silky feeling (e.g., low coefficient of friction). In embodiments, the amount of silicone rubber in the thermoset article may be limited (e.g., less than or equal to 50 wt %). In embodiments, the amount of silicone rubber in the thermoset article may be greater than or equal to 1 wt %, greater than or equal to 3 wt %, greater than or equal to 5 wt %, greater than or equal to 10 wt %, or even greater than or equal to 20 wt %. In embodiments, the amount of silicone rubber in the thermoset article may be less than or equal to 50 wt %, less than or equal to 45 wt %, less than or equal to 40 wt %, less than or equal to 35 wt %, or even less than or equal to 30 wt %. In embodiments, the amount of silicone rubber in the thermoset article may be from 1 wt % to 50 wt %, from 1 wt % to 45 wt %, from 1 wt % to 40 wt %, from 1 wt % to 35 wt %, from 1 wt % to 30 wt %, from 3 wt % to 50 wt %, from 3 wt % to 45 wt %, from 3 wt % to 40 wt %, from 3 wt % to 35 wt %, from 3 wt % to 30 wt %, from 5 wt % to 50 wt %, from 5 wt % to 45 wt %, from 5 wt % to 40 wt %, from 5 wt % to 35 wt %, from 5 wt % to 30 wt %, from 10 wt % to 50 wt %, from 10 wt % to 45 wt %, from 10 wt % to 40 wt %, from 10 wt % to 35 wt %, from 10 wt % to 30 wt %, from 20 wt % to 50 wt %, from 20 wt % to 45 wt %, from 20 wt % to 40 wt %, from 20 wt % to 35 wt %, or even from 20 wt % to 30 wt %, or any and all sub-ranges formed from any of these endpoint.
Suitable commercial embodiments of the silicone rubber are available under the GENIOPLAST PELLET brand from Wacker Chemie AG, such as grade S.
As stated hereinabove, at least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber is silane grafted and silane crosslinked. The occurrence of silane crosslinking results in a thermoset article having improved high temperature oil resistance.
Various silanes are considered suitable for the present thermoset articles. In embodiments, the silane may comprise vinyl trialkoxysilane. For example, in embodiments, the silane may comprise vinyl trimethoxysilane, vinyl triethoxysilane, or a combination thereof.
In embodiments, the silane is included in amounts greater than or equal to 0.5 wt % such that at least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber is silane grafted and silane crosslinked to produce a thermoset article having improved oil resistance. In embodiments, the amount of silane may be limited (e.g., less than or equal to 5 wt %). In embodiments, the amount of silane in the thermoset article may be greater than or equal to 0.5 wt %, greater than or equal to 1 wt %, or even greater than or equal to 2 wt %. In embodiments, the amount of silane in the thermoset article may be less than or equal to 5 wt % or even less than or equal to 3 wt %. In embodiments, the amount of silane in the thermoset article may be from 0.5 wt % to 5 wt %, from 0.5 wt % to 3 wt %, from 1 wt %, to 5 wt %, from 1 wt % to 3 wt %, from 2 wt % to 5 wt %, or even from 2 wt % to 3 wt %, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the silane may have a specific gravity greater than or equal to 0.9 or even greater than or equal to 0.95. In embodiments, the silane may have a specific gravity less than or equal to 1.05 or even less than or equal to 1. In embodiments, the silane may have a specific gravity from 0.9 to 1.05, from 0.9 to 1, from 0.95 to 1.05, or even from 0.95 to 1, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the silane may have a boiling point greater than or equal to 75° C. or even greater than or equal to 100° C. In embodiments, the silane may have a boiling point less than or equal to 150° C. or even less than or equal to 125° C. In embodiments, the silane may have a boiling point from 75° C. to 150° C., from 75° C. to 125° C., from 100° C. to 150° C., or even from 100° C. to 125° C., or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the silane are available under the SILQUEST brand from Momentive, such as grade A-171.
In embodiments, the silane may be included in a solution comprising organic peroxide such that the silane is better dispersed within the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and/or the silicone rubber, leading to improved silane grafting and silane crosslinking. In embodiments, the organic peroxide may comprise dicumyl peroxide. In embodiments, the amount of organic peroxide in the thermoset article may be greater than or equal to 0.05 wt % or even greater than or equal to 0.1 wt %. In embodiments, the amount of organic peroxide in the thermoset article may be less than or equal to 1 wt % or even less than or equal to 0.5 wt %. In embodiments, the amount of organic peroxide in the thermoset article may be from 0.05 wt % to 1 wt %, from 0.05 wt % to 0.5 wt %, from 0.1 wt % to 1 wt %, or even from 0.1 wt % to 0.5 wt %, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the organic peroxide may have a density greater than or equal to 1 g/cm3 or even greater than or equal to 1.05 g/cm3. In embodiments, the organic peroxide may have a density less than or equal to 1.2 g/cm3 or even less than or equal to 1.15 g/cm3. In embodiments, the organic peroxide may have a density from 1 g/cm3 to 1.2 g/cm3, from 1 g/cm3 to 1.15 g/cm3, from 1.05 g/cm3 to 1.2 g/cm3, or even from 1.05 g/cm3 to 1.15 g/cm3, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the organic peroxide may have a boiling point greater than or equal to 75° C. or even greater than or equal to 100° C. In embodiments, the organic peroxide may have a boiling point less than or equal to 150° C. or even less than or equal to 125° C. In embodiments, the organic peroxide may have a boiling point from 75° C. to 150° C., from 75° C. to 125° C., from 100° C. to 150° C., or even from 100° C. to 125° C., or any and all sub-ranges formed from any of these endpoints. In embodiments, the organic peroxide may decompose at a temperature lower than the boiling point of the organic peroxide.
Suitable commercial embodiments of the organic peroxide are available under the PERKADOX brand from AkzoNobel, such as grade BC-FF.
As described herein, the occurrence of silane crosslinking, along with the specific amounts of thermoplastic polyolefin, at least one of the ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, and silicone rubber, produces a thermoset article having increased high temperature oil resistance while providing the desired compression set and coefficient of friction.
In embodiments, at least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber may be silane grafted and silane crosslinked. In embodiments, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber and the silicone rubber may be silane crosslinked.
In embodiments, the silane crosslinking is at least one of intramolecular silane crosslinking and intermolecular silane crosslinking. For example, in embodiments, at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber may be silane crosslinked to the silicone rubber.
In embodiments, the thermoset article may comprise a thermoplastic polyolefin phase comprising the thermoplastic polyolefin and a rubber phase comprising the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber and the silicone rubber. In embodiments, the amount of the rubber phase (i.e., amount of the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber+the amount of the silicone rubber) in the thermoset article may be greater than or equal to 25 wt %, greater than or equal to 30 wt %, greater than or equal to 35 wt %, or even greater than or equal to 40 wt %. In embodiments, the amount of the rubber phase in the thermoset article may be less than or equal to 70 wt % or even less than or equal to 65 wt %. In embodiments, the amount of the rubber phase in the thermoset article may be from 25 wt % to 70 wt %, from 25 wt % to 65 wt %, from 30 wt % to 70 wt %, from 30 wt % to 65 wt %, from 35 wt % to 70 wt %, from 35 wt % to 65 wt %, from 40 wt % to 70 wt %, or even from 40 wt % to 65 wt %, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoset article may have a compression set (100° C.) greater than or equal to 20%, greater than or equal to 25% or even greater than or equal to 30%. In embodiments, the thermoset article may have a compression set (100° C.) less than or equal to 45% or even less than or equal to 40%. In embodiments, the thermoset article may have a compression set (100° C.) from 250% to 45%, from 20% to 40%, from 25% to 45%, from 25% to 40%, from 30% to 45%, or even from 30% to 40%, or any or all sub-ranges formed from any of these endpoints.
In embodiments, the thermoset article may have a Shore A hardness greater than or equal to 35, greater than or equal to 45, greater than or equal to 55, greater than or equal to 60, or even greater than or equal to 65. In embodiments, the thermoset article may have a Shore A hardness less than or equal to 95, less than or equal to 90, or even less than or equal to 85. In embodiments, the thermoset article may have a Shore A hardness from 35 to 95, from 35 to 90, from 35 to 85, from 45 to 95, from 45 to 90, from 45 to 85, from 55 to 95, from 55 to 90, from 55 to 85, from 60 to 95, from 60 to 90, from 60 to 85, from 65 to 95, from 65 to 90, or even from 65 to 85, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoset article may have a tensile strength at break greater than or equal to 2 MPa, greater than or equal to 3 MPa, or even greater than or equal to 4 MPa. In embodiments, the thermoset article may have a tensile strength at break less than or equal to 10 MPa, less than or equal to 9 MPa, or even less than or equal to 8 MPa. In embodiments, the thermoset article may have a tensile strength at break from 2 MPa to 10 MPa, from 2 MPa to 9 MPa, from 2 MPa to 8 MPa, from 3 MPa to 10 MPa, from 3 MPa to 9 MPa, from 3 MPa to 8 MPa, from 4 MPa to 10 MPa, from 4 MPa to 9 MPa, or even from 4 MPa to 8 MPa, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoset article may have a tensile elongation at break greater than or equal to 25%, greater than or equal to 50%, greater than or equal to 75%, or even greater than or equal to 100%. In embodiments, the thermoset article may have a tensile elongation at break less than or equal to 300% or even less than or equal to 250%. In embodiments, the thermoset article may have a tensile elongation at break from 25% to 300%, from 25% to 250%, from 50% to 300%, from 50% to 250%, from 75% to 300%, from 75% to 250%, from 100% to 300%, or even from 100% to 250%, or any and all sub-ranges formed from any of these endpoints.
In embodiments, the thermoset article may include a thermoplastic polyolefin comprising polypropylene homopolymer; 20 wt % to 90 wt % of the ethylene alpha-olefin polyolefin elastomer, the ethylene alpha-olefin polyolefin elastomer comprising ethylene-octene copolymer; and 1 wt % to 50 wt % of the silicone rubber.
In embodiments, the thermoset article may include 31 wt % to 41 wt % of the ethylene-octene copolymer; and 10 wt % to 35 wt % of the silicone rubber.
In embodiments, the thermoset article may include a thermoplastic polyolefin comprising polypropylene homopolymer; 25 wt % to 41 wt % of the ethylene propylene diene rubber; and 1 wt % to 35 wt % of the silicone rubber.
As exemplified in the Examples section below, the thermoset articles described herein comprising a crosslinked reaction product of thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, silicone rubber, and silane have improved high temperature oil resistance while having a maintained compression set.
In embodiments, the thermoset article may comprise a moisture cure catalyst to initiate silane crosslinking of at least one of the thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, and the silicone rubber.
In embodiments, the moisture cure catalyst may comprise organotin (e.g., dibutalin dilaurate), carboxylic acids, metal complex compounds (e.g., metal carboxylates), aluminum triacetyl acetonate, nickel tetraacetyl acetonate, chromium hexaacetyl acetonate, titanium tetraacetyl acetonate, and metal alkoxides (e.g., aluminum ethoxide, aluminum propoxide, titanium ethoxide, titanium propoxide), or a combination thereof.
In embodiments, the catalyst is blended with the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, the silicone rubber, and the silane during silane grafting. In other embodiments, the catalyst is added to the extruded formulation wherein at least one of the thermoplastic polyolefin, at least one of ethylene alpha-olefin polyolefin elastomer and ethylene propylene diene rubber, and the silicone rubber is silane grafted. The at least one of the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, and the silicone rubber that is silane grafted will crosslink upon exposure to moisture (e.g., air).
In embodiments, the thermoset articles described herein may further comprise compatibilizer. The compatibilizer may react or be compatible with the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber to alter the dissimilar phases and improve the compatibility of the thermoset article.
In embodiments, the compatibilizer may comprise a copolymer of ethylene and a polar comonomer, such as ethylene-vinyl acetate.
In embodiments, the amount of compatibilizer in the thermoset article may be greater than or equal to 5 wt %, greater than or equal to 7 wt %, or even greater than or equal to 9 wt %. In embodiments, the amount of compatibilizer in the thermoset article may be less than or equal to 35 wt %, less than or equal to 30 wt %, or even less than or equal to 25 wt %. In embodiments, the amount of compatibilizer in the thermoset article may be from 5 wt % to 35 wt %, from 5 wt % to 30 wt %, from 5 wt % to 25 wt %, from 7 wt % to 35 wt %, from 7 wt % to 30 wt %, from 7 wt % to 25 wt %, from 9 wt % to 35 wt %, from 9 wt % to 30 wt %, or even from 9 wt % to 25 wt %, or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the compatibilizer are available under the ELVAX brand from Dow Chemical Company, such as grade 265.
In embodiments, the thermoset articles described herein may further comprise such that to reduce hardness and improve flow.
In embodiments, the plasticizer may comprise non-polar plasticizer (e.g., mineral oil).
In embodiments, the amount of plasticizer in the thermoset article may be greater than or equal to 20 wt %, greater than or equal to 25 wt %, or even greater than or equal to 30 wt %. In embodiments, the amount of plasticizer in the thermoset article may be less than or equal to 60 wt, less than or equal to 50 wt %, or even less than or equal to 45 wt %. In embodiments, the amount of plasticizer in the thermoset article may be from 20 wt % to 60 wt %, from 20 wt % to 50 wt %, from 20 wt % to 45 wt %, from 25 wt % to 60 wt %, from 25 wt % to 50 wt %, from 25 wt % to 45 wt %, from 30 wt % to 60 wt %, from 30 wt % to 50 wt %, or even from 30 wt % to 45 wt %, or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the plasticizer are available under the PURETOL brand from Petro-Canada, such as grade PSO 380.
In embodiments, the thermoset article may further comprise an additive. In embodiments, the additive may comprise adhesion promoters; biocides; anti-fogging agents; anti-static agents; blowing and foaming agents; bonding agents and bonding polymers; polar copolymers (e.g., ethylene-vinyl acetate (EVA), ethylene butyl acrylate (EBA), or ethyl methacrylate (EMA)); dispersants; flame retardants and smoke suppressants; mineral fillers; initiators; lubricants; micas; pigments, colorants, and dyes; processing aids; release agents; silanes, titanates, and zirconates; slip and anti-blocking agents; stearates; ultraviolet light absorbers; viscosity regulators; waxes; or combinations thereof.
In embodiments, the mineral filler may comprise calcium carbonate, talc, or a combination thereof.
In embodiments, the amount of additive in the thermoset article greater than 0 wt %, greater than or equal to 2 wt %, or even greater than or equal to 4 wt %. In embodiments, the amount of additive in the thermoset article may be less than or equal to 15 wt % or even less than or equal to 10 wt %. In embodiments, the amount of additive in the thermoset article may be from greater than 0 wt % to 15 wt %, from greater than 0 wt % to 10 wt %, from 2 wt % to 15 wt %, from 2 wt % to 10 wt %, from 4 wt % to 15 wt %, from 4 wt % to 10 wt %, or any and all sub-ranges formed from any of these endpoints.
Suitable commercial embodiments of the additive are available under the VICRON brand from Mineral Technologies Inc., such as grade 25-11; and under the MISTRON brand from Imerys, such as grade Vapor R.
In embodiments, the thermoset article described herein may be made with a batch process or continuous process.
In embodiments, the components of the thermoset article, including: the thermoplastic polyolefin; at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber; and the silicone rubber may be added to an extruder (27 MM Leistriz Twin Extruder (L/D 52)) and blended. In embodiments, silane is added to the blend such that at least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber is silane grafted. In embodiments, the blending (e.g., in the barrel of the extruder) may be carried out at a temperature from 150° C. to 220° C.
Blending (also known as compounding) devices are well known to those skilled in the art and generally include feed means, especially at least one hopper for pulverulent materials and/or at least one injection pump for liquid materials; high-shear blending means, for example a co-rotating or counter-rotating twin-screw extruder, usually comprising a feed screw placed in a heated barrel (or tube); an output head, which gives the extrudate its shape; and means for cooling the extrudate, either by air cooling or by circulation of water. The extrudate is generally in the form of rods continuously exiting the device and able to be cut or formed into granules. However, other forms may be obtained by fitting a die of desired shape on the output die.
In embodiments, the shaped, silane-grafted blend may be cured such that at least one of the thermoplastic polyolefin, the ethylene alpha-olefin polyolefin elastomer, the ethylene propylene diene rubber, and the silicone rubber is silane crosslinked. In embodiments, a moisture cure catalyst may be added to initiate silane crosslinking of at least one of the thermoplastic polyolefin, the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber, and the silicone rubber. In embodiments, the catalyst is blended with: the thermoplastic polyolefin; the at least one of the ethylene alpha-olefin polyolefin elastomer and the ethylene propylene diene rubber; the silicone rubber; and the silane during silane grafting. In other embodiments, the catalyst is added at the extrusion step.
Table 3 below shows sources of ingredients used to form the thermoset articles of Comparative Examples C1 and C2 and Examples E1-E7.
Table 4 below shows the formulations used to form and the certain properties of Comparative Examples C1 and C2 and Examples E1 to E7. To prepare the comparative and exemplary thermoset plaques, the components of the formulations listed in Table 4 were added into a 27 MM Leistriz Twin Extruder (L/D 52) and blended at a barrel temperature of 193° F. and a rate of 5 rotations per second. The mixed formulation was extruded at a speed of 5 g/s. The extruded formulation was blended with 3% tin catalyst master match (MB). MB has a polyether carrier with 1.5% dibutylin dilaurate (MARK 1038, Galata Chemicals). The blended formulation was injection molded (i.e., shaped) to form a plaque. The plaque was conditioned at 90° C. and 90% relative humidity for 24 hours prior to measuring the properties listed in Table 4.
To measure the “oil immersion weight increase” listed in Table 4, the plaque having a diameter of 39 mm and a thickness of 3 mm was weighed and then immersed in IRM 903 oil for 3 days at 125° C. After immersion, the plaque was weighed and the weight percentage increase was calculated.
As shown in Table 4, Examples E1-E3, thermoset articles including thermoplastic polyolefin (FORMOLENE 1102KR), ethylene alpha-olefin polyolefin elastomer (ENGAGE XLT 8677), and silicone rubber (GENIOPLAST PELLET S), showed a reduced oil immersion weight increase of 84%, 84%, 88%, and 93%, respectively, as compared to Comparative Example C1, a thermoset article including FORMOLENE 1102KR and ENGAGE XLT 8677 without GENIOPLAST PELLET S, which had an oil immersion weight increase of 172%. Additionally, Examples E1-E3 had a maintained compression set of 27%, 30%, 30%, and 30%, respectively, as compared to Comparative Example C1, which had a compression set of 29%. Moreover, Examples E1-E3 had a silky feeling. As indicated by Comparative Example C1 and Examples E1-E3, including silicone rubber having at least one vinyl functional group with polyolefin and ethylene alpha-olefin polyolefin elastomer results in a high temperature oil resistant thermoset article having a maintained compression set as compared to a thermoset article that does not include silicone rubber and a silky feeling.
As further shown in Table 4, Examples E4-E7, thermoset articles including FORMOLENE 1102KR, ethylene propylene diene rubber (NORDEL IP 4785HM), and GENIOPLAST PELLET S, showed a reduced oil immersion weight increase of 74%, 80%, 72%, and 65%, respectively, as compared to Comparative Example C2, a thermoset article including FORMOLENE 1102KR and NORDEL IP 4785HM without GENIOPLAST PELLET S, which had an oil immersion weight increase of 93%. Additionally, Examples E4-E7 had a maintained compression set of 39%, 36%, 38%, and 38%, respectively, as compared to Comparative Example C2, which had a compression set of 29%. Moreover, Examples E4-E7 had a silky feeling. As indicated by Comparative Example C2 and Examples E4-E7, including silicone rubber having at least one vinyl functional with polyolefin and ethylene propylene diene rubber results in a high temperature oil resistant thermoset article having a maintained compression set as compared to a thermoset article that does not include silicone rubber and a silky feeling.
It will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/216,742 bearing Attorney Docket Number 1202104 and filed on Jun. 30, 2021, which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/035497 | 6/29/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63216742 | Jun 2021 | US |
