Elastomer composition

Abstract

The current invention relates to an elastomer composition comprising one or more fluorine-free elastomers, wherein said elastomer composition has an outgassing value of less than 10-6 mbar*l / (s*cm²) for water and hydrocarbons.

Description

[0001] ELASTOMER COMPOSITION

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an elastomer composition comprising one or more fluorine-free elastomers, and the production thereof. Said fluorine-free elastomers are suitable for use in vacuum application, especially with low outgassing requirements.

[0004] BACKGROUND

[0005] In the semiconductor industry, but also in scientific equipment, defense, and aerospace, vacuum systems are often used. Typically fluorinated elastomers based on crude polymers such as FKM, FFKM, FEPM are applied to seal vacuum applications due to the inherently low outgassing performance of fluorinated crude polymers. Said polymers are typically the main contributor to outgassing performance and hence essential to achieve low outgassing performance. The low outgassing of fluorinated crude polymers and formulations thereof is mostly related to the polymerization and post-polymerization treatment during polymer manufacturing. Fluorinated elastomeric products for vacuum application are formulated and manufactured using general clean manufacturing practices known to those skilled in the art.

[0006] However, fluorinated elastomers belong to a group of man-made substances called Per- and polyfluoroalkyl substances (PFAS), often dubbed "forever chemicals" due to their resistance to degradation, present numerous challenges, including environmental persistence, bioaccumulation, and significant human health risks. While fluorinated elastomers themselves meet the OECD standard criteria for polymers of low concern, the manufacturing process of monomers and polymers Their use has led to global contamination of water, soil, and living organisms. This contamination, alongside the difficulty of removing PFAS from the environment and the variability in regulatory standards across jurisdictions, complicates efforts to mitigate their impact. Furthermore, the future supply (and reliability thereof) of fluorinated polymers is under pressure due to legislative pressure, increasing litigation, public pressure against manufacturing. Typically, commercially available fluorine-free crude polymers contain significant contents of hydrocarbon and / or water contamination which render these materials unsuitable for low outgassing elastomer formulations.

[0007] JP2005314685 and US20120043687 both disclose purification methods based on the use of an inert gas.

[0008] The present invention aims to resolve at least some of the problems and disadvantages mentioned above.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention and embodiments thereof serve to provide a solution to one or more of above-mentioned disadvantages. To this end, the present invention relates to an elastomer composition according to claim 1.

[0011] The outgassing of volatile matter (e.g. water, hydrocarbons, halogenated hydrocarbons, silicon containing molecules) from materials in vacuum, especially where optical devices are present, can lead to (irreversible) surface contamination which directly effects the functioning of the optical devices. The invention provides a solution, wherein fluorine-containing materials are avoided, but the above mentioned disadvantages are still avoided.

[0012] The invention presents a viable solution to the problem of high outgassing rates in fluorine-free elastomers. It offers a practical and efficient method of reducing the contaminants in these elastomers, thereby lowering the outgassing value of the final elastomer composition. The invention offers a preferred alternative to fluorinated elastomers, while still maintaining low outgassing rates, which is can be important for the performance of high-end vacuum systems.

[0013] Preferred embodiments of the composition are shown in any of the claims 2 to 6. A specific preferred embodiment relates to an invention according to claim 5. It has been found possible to produce a elastomer composition with very low outgassing values, while avoiding fluorine-containing materials. In a second aspect, the present invention relates to a use according to claim 8 and 9. More particular, the use as described herein provides for application in high- vacuum systems.

[0014] In a third aspect, the present invention relates to a method for producing an elastomer composition according to claim 10. Preferred embodiments of the method are shown in any of the claims 11 to 16.

[0015] DETAILED DESCRIPTION OF THE INVENTION

[0016] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0017] As used herein, the following terms have the following meanings:

[0018] The term "elastomer composition", as used herein, is synonym to "rubber product" or "elastomer product" and refers to a mixture or formulation that includes one or more types of elastomers. The elastomer composition as defined herein is to be understood as a ready for use product. The elastomer composition as described herein is to be understood as a vulcanized elastomer composition. The composition classifies as an elastomer composition according to the terminology disclosed in ASTM D-1566.

[0019] The term "crude elastomer", as used herein, is synonym to "crude polymer", "base elastomer" or "base polymer" and refers to the raw, non-vulcanized polymers that form the basis of the elastomer composition. In this context, crude elastomers are the base materials that, once combined with other ingredients and subjected to vulcanization, produce elastomers and thus the final elastomer composition.

[0020] "Outgassing" refers to the release of gas that was previously trapped, dissolved, frozen, absorbed, or adsorbed in some material. The term "outgassing value", as used herein, refers to a measure of the rate at which gas is released from a solid or liquid material under vacuum conditions, typically expressed in units of mbar*l / (s*cm2). This can be measured with a Residual Gas Analysis (RGA) measurement as described in 15020175:2018. The term "hydrocarbons", as used herein, refers to organic compounds consisting entirely of hydrogen and carbon atoms, which can vary in molecular weight and structure.

[0021] The term "mass", as used herein, refers to the mass of a molecule, measured in atomic mass units (m / z), indicating the size of the molecule. The mass is measured according to ISO 14291:2012. In m / z, m stands for mass and z stands for charge number of ions. In mass analysis, an electron is taken from molecules to create single charged ions. If two electrons are removed, double charged ions are produced. The number of electrons removed is the charge number (for positive ions), m / z represents mass divided by charge number and since z is almost always 1 with GCMS, the m / z value is considered to be the mass.

[0022] The term "Shore A hardness", as used herein, refers to a scale used to measure the hardness of elastomeric materials, indicating their resistance to indentation. The shore A hardness is measure according to ISO 48-4:2018.

[0023] The term "high-vacuum applications", as used herein, refers to uses or environments where a high degree of vacuum (low pressure) is required, such as in certain industrial or scientific settings.

[0024] The term "vulcanizing agents", as used herein, refers to chemicals used to crosslink polymer chains in the elastomer, thereby enhancing its properties such as strength, elasticity, and thermal stability.

[0025] The term "vulcanizing", as used herein, refers to the process of chemically crosslinking elastomers using vulcanizing agents leading to an elastomer according to ASTM D-1566.

[0026] The term "thermoplastic elastomers", as used herein, refers to a class of polymers that are crosslinked by physical crosslinks and therefore exhibit both thermoplastic and elastomeric properties, which are preferably not included in the compositions described herein.

[0027] The term "refractories" refers to photoactive halogenated (e.g. Cl, Br, F), silicon, and sulfur containing organic molecules that under influence of (extreme) ultraviolet irradiation can form high reactive radicals. Refractories combined with other condensed organic molecules can cause (near) irreversible accumulation of chemically bound contamination onto optics.

[0028] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0029] "Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0030] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0031] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0032] The expression "% by weight", "weight percent", "%wt" or "wt%", here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation.

[0033] Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.

[0034] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention.

[0035] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0036] In a first aspect, the invention provides an elastomer composition. The elastomer composition comprises one or more elastomers, preferably one elastomer.

[0037] In an embodiment, the elastomer composition comprises one or more fluorine-free elastomers, preferably one fluorine-free elastomer. The term "fluorine-free elastomers", as used herein, refers to a class of elastomeric materials that do not contain fluorine atoms in their respective molecular or polymeric structure.

[0038] A "fluorine-free" elastomer refers to an elastomer that comprises at most 1 weight percent (wt.%) of fluorine, preferably at most 0.1 wt.% of fluorine, more preferably at most 0.01 wt.% of fluorine, even more preferably at most 0.001 wt.% of fluorine, even more preferably at most 0.0001 wt.% (1 ppm) of fluorine. The elastomers could also be described as PFAS-free.

[0039] An elastomer composition devoid of fluorine presents significant environmental and health benefits, primarily due to the reduced potential for bioaccumulation and persistence in ecosystems associated with fluorinated compounds. These materials are easier to dispose of and recycle, aligning with growing environmental sustainability goals. In an embodiment, the fluorine-free elastomer is also a silicone-free elastomer. Similarly, a "silicone-free" elastomer refers to an elastomer that comprises at most 1 weight percent (wt.%) of silicone, preferably at most 0.1 wt.% of silicone, more preferably at most 0.01 wt.% of silicone, even more preferably at most 0.001 wt.% of silicone, even more preferably at most 0.0001 wt.% (1 ppm) of silicone. Silicone elastomers often contain volatile organic refractories that can lead to issues with outgassing, a process where gases are released under vacuum or during heating, potentially leading to contamination of sensitive environments or optical devices. The term "silicone" as used herein refers to organic (poly)siloxanes. The term "silicone-free elastomers", as used herein, refers to a class of elastomeric materials that do not contain silicone molecules in their respective molecular or polymeric structure.

[0040] In other words, the elastomer composition comprises one or more elastomers essentially free of fluorine and optionally silicone. In other words, the elastomer composition comprises one or more elastomers comprising at most 0.001 wt.% of fluorine and at most 0.001 wt.% of silicone.

[0041] In an embodiment, the elastomer composition comprises one or more elastomers chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), neoprene rubber (CR), and combinations thereof. In a further embodiment, the elastomer composition comprises one elastomer chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), and neoprene rubber (CR).

[0042] In an embodiment, said one or more fluorine-free elastomers are chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), neoprene rubber (CR), and combinations thereof. In a further embodiment, the elastomer composition comprises one fluorine-free elastomer chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), and neoprene rubber (CR).

[0043] These types of elastomers are preferably formulated with ingredients which do not contain refractories and are thus very suitable for the current application.

[0044] The fluorine-free elastomers are preferably not elastomers which require sulfur vulcanization, such as NR, IR, BR, SBR, NBR, HR. Sulfur vulcanization leads to potential outgassing of refractories and are best avoided.

[0045] In a particularly preferred embodiment, the invention provides an elastomer composition comprising one or more fluorine-free elastomers, wherein said elastomer composition has an outgassing value of less than 10’6mbar*l / (s*cm2) for water and hydrocarbons.

[0046] The outgassing of volatile matter (e.g. water, hydrocarbons, halogenated hydrocarbons, silicon containing molecules) from materials in vacuum, especially where optical devices are present, can lead to (irreversible) surface contamination which directly effects the functioning of the optical devices. The invention provides a solution, wherein fluorine-containing materials are avoided, but the above mentioned disadvantages are still avoided.

[0047] Preferably the elastomer composition has an outgassing value of less than 10’6mbar*l / (s*cm2) for water.

[0048] In an embodiment, said elastomer composition has an outgassing value for water of less than 10’6mbar*l / (s*cm2), preferably of less than 9xl0-7mbar*l / (s*cm2), more preferably of less than 8xl0-7mbar*l / (s*cm2), even more preferably of less than 7xl0-7mbar*l / (s*cm2), even more preferably of less than 6xl0-7mbar*l / (s*cm2), even more preferably of less than 5xl0-7mbar*l / (s*cm2), even more preferably of less than 4xl0-7mbar*l / (s*cm2), even more preferably of less than 3xl0-7 mbar*l / (s*cm2), even more preferably of less than 2xl0-7mbar*l / (s*cm2), even more preferably of less than IxlO-7mbar*l / (s*cm2), even more preferably of less than 5xl0-8mbar*l / (s*cm2).

[0049] In another or a further embodiment, said elastomer composition has an outgassing value for water of between 1010and 10’6mbar*l / (s*cm2), preferably of between 1010and 10’6mbar*l / (s*cm2), preferably of between 1010and 9xl0-7mbar*l / (s*cm2), more preferably of between 1010and 8xl0-7mbar*l / (s*cm2), even more preferably of between 1010and 7xl0-7mbar*l / (s*cm2), even more preferably of between 1010and 6xl0-7mbar*l / (s*cm2), even more preferably of between 10’10and 5xl0-7mbar*l / (s*cm2), even more preferably of between 1010and 4xl0-7mbar*l / (s*cm2), even more preferably of between 1010and 3xl0-7mbar*l / (s*cm2), even more preferably of between 1010and 2xl0-7mbar*l / (s*cm2), even more preferably of between 1010and IxlO-7mbar*l / (s*cm2), even more preferably of between 1010and 5xl0-8mbar*l / (s*cm2).

[0050] Water vapor is a significant contaminant in vacuum systems. High levels of outgassing can degrade the vacuum quality, making it difficult to achieve and maintain the high-vacuum conditions required for sensitive processes and experiments. Water vapor can condense on cold surfaces within vacuum systems, such as sensors and optical components, impairing their performance. In presence of radicals and electrons, water can chemosorb onto surfaces. Condensation and chemisorption can lead to measurement inaccuracies, optical distortion, or even physical damage due to accumulated contamination over time.

[0051] Water vapor can react with materials within the vacuum system, leading to corrosion or degradation of metal components and seals. This can compromise the integrity of the system and reduce the lifespan of its components.

[0052] In processes that require pure vacuum conditions, such as thin film deposition or surface analysis techniques, the presence of water vapor can interfere with the chemical reactions or deposition processes, leading to defects or reduced quality of the final product. High outgassing rates can necessitate more frequent maintenance and cleaning of vacuum systems to remove contaminants and restore optimal performance. This increases operational downtime and costs. The elastomers used in this embodiment are also preferably free of refractories, such as halogenated, silicon, and sulfur containing molecules, which can cause severe contamination in vacuum systems.

[0053] Preferably the elastomer composition has an outgassing value of less than 10’6mbar*l / (s*cm2) for hydrocarbons, more preferably less than 10’7mbar*l / (s*cm2), even more preferably less than 10’8mbar*l / (s*cm2), even more preferably less than 10’9mbar*l / (s*cm2).

[0054] Hydrocarbons can be divided in volatile and non-volatile hydrocarbons. Volatile hydrocarbons are defined as hydrocarbons with a mass between 45 and 100 m / z. Non-volatile hydrocarbons are defined as hydrocarbons with a mass between 101 and 200 m / z.

[0055] In an embodiment, said elastomer composition has an outgassing value for volatile hydrocarbons (hydrocarbons with a mass between 45 and 100 m / z) of less than 10’9mbar*l / (s*cm2), preferably of less than 9x1010mbar*l / (s*cm2), more preferably of less than 8x1010mbar*l / (s*cm2), even more preferably of less than 7x1010mbar*l / (s*cm2), even more preferably of less than 6x1010mbar*l / (s*cm2), even more preferably of less than 5x1010mbar*l / (s*cm2), even more preferably of less than 4x1010mbar*l / (s*cm2), even more preferably of less than 3x1010mbar*l / (s*cm2), even more preferably of less than 2x1010mbar*l / (s*cm2), even more preferably of less than 1x1010mbar*l / (s*cm2), even more preferably of less than 5x1011mbar*l / (s*cm2).

[0056] In another or a further embodiment, said elastomer composition has an outgassing value for volatile hydrocarbons (hydrocarbons with a mass between 45 and 100 m / z) of between 1013and 10’9mbar*l / (s*cm2), preferably of between 1013and 9x1010mbar*l / (s*cm2), more preferably of between 1013and 8x1010mbar*l / (s*cm2), even more preferably of between 1013and 7x1010mbar*l / (s*cm2), even more preferably of between 1013and 6x1010mbar*l / (s*cm2), even more preferably of between 1013and 5x1010mbar*l / (s*cm2), even more preferably of between 1013and 4x1010mbar*l / (s*cm2), even more preferably of between 1013and 3x1010mbar*l / (s*cm2), even more preferably of between 1013and 2xlO10mbar*l / (s*cm2), even more preferably of between 1013and 1x1010mbar*l / (s*cm2), even more preferably of between 1013and 5x1011mbar*l / (s*cm2). Volatile hydrocarbons can easily vaporize and contaminate the vacuum environment. This contamination can degrade the purity of the vacuum, affecting processes that rely on ultra-clean conditions, such as semiconductor fabrication or surface science studies. In scientific equipment, where precision and accuracy are paramount, the presence of volatile hydrocarbons can introduce errors in measurements and analyses. This is particularly critical in mass spectrometry and electron microscopy, where background signals from hydrocarbons can obscure or interfere with the analysis of samples. For optical components, this can mean reduced clarity or changes in refractive index, affecting the performance of the equipment.

[0057] Hydrocarbons in a vacuum system can undergo chemical reactions under certain conditions, such as in the presence of plasma or when exposed to high-energy radiation. These reactions can produce residues or corrosive compounds, leading to degradation of vacuum system components. Furthermore, managing a vacuum system with high hydrocarbon outgassing involves more frequent maintenance, such as cleaning and degassing components, to maintain the desired vacuum levels. This increases operational complexity and costs, while also potentially reducing system uptime.

[0058] In an embodiment, said elastomer composition has an outgassing value for nonvolatile hydrocarbons (hydrocarbons with a mass between 101 and 200 m / z) of less than 1010mbar*l / (s*cm2), preferably of less than 9x1011mbar*l / (s*cm2), more preferably of less than 8x1011mbar*l / (s*cm2), even more preferably of less than 7x1011mbar*l / (s*cm2), even more preferably of less than 6x1011mbar*l / (s*cm2), even more preferably of less than 5x1011mbar*l / (s*cm2), even more preferably of less than 4x1011mbar*l / (s*cm2), even more preferably of less than 3x1011mbar*l / (s*cm2), even more preferably of less than 2x1011mbar*l / (s*cm2), even more preferably of less than 1x1011mbar*l / (s*cm2), even more preferably of less than 5x1012mbar*l / (s*cm2).

[0059] In another or a further embodiment, said elastomer composition has an outgassing value for volatile hydrocarbons (hydrocarbons with a mass between 45 and 100 m / z) of between 1014and 1010mbar*l / (s*cm2), preferably of between 1014and 9x1011mbar*l / (s*cm2), more preferably of between 1014and 8x1011mbar*l / (s*cm2), even more preferably of between 1014and 7x1011mbar*l / (s*cm2), even more preferably of between 1014and 6x1011mbar*l / (s*cm2), even more preferably of between 1014and 5x1011mbar*l / (s*cm2), even more preferably of between 1014and 4x1011mbar*l / (s*cm2), even more preferably of between 1014and 3x1011 mbar*l / (s*cm2), even more preferably of between 1014and 2x1011mbar*l / (s*cm2), even more preferably of between 1014and 1x1011mbar*l / (s*cm2), even more preferably of between 1014and 5x1012mbar*l / (s*cm2).

[0060] Non-volatile hydrocarbons have a lower tendency to evaporate compared to their volatile counterparts, but their presence in a vacuum system can still significantly degrade the vacuum quality. Over time, these hydrocarbons can accumulate on surfaces, making it increasingly difficult to achieve and maintain the high vacuum levels required for certain precise operations. In scientific and manufacturing equipment where ultra-high vacuum conditions are necessary, such as in mass spectrometry, surface analysis techniques, or high resolution lithography, the presence of non-volatile hydrocarbons can lead to contamination. This contamination can interfere with experimental results or the manufacturing process, leading to reduced yield or compromised data integrity. Non-volatile hydrocarbons can condense and form thin films on cooler surfaces within the vacuum system, including critical components and sensors. This can impair the function of these components, necessitating more frequent cleaning and maintenance, and can also affect the performance of the equipment, such as reducing sensitivity or accuracy.

[0061] While non-volatile hydrocarbons are less likely to participate in fast chemical reactions due to their larger size and lower volatility, they can still undergo slow reactions or contribute to the formation of residues when exposed to energetic stimuli in the vacuum system. This can lead to the degradation of vacuum chamber materials and surfaces. Systems with high outgassing rates of non-volatile hydrocarbons may require additional measures to control contamination, such as more sophisticated vacuum pumps, frequent system bake-outs, or the use of getters to absorb unwanted species. These measures increase the complexity and cost of maintaining the vacuum system.

[0062] In a specific embodiment, said elastomer composition has an outgassing value of less than 10’6mbar*l / (s*cm2), preferably less than 5xl0-7mbar*l / (s*cm2) for water, an outgassing value of less than 10’9mbar*l / (s*cm2), preferably less than 4x1010mbar*l / (s*cm2) for volatile hydrocarbons, and an outgassing value of less than 1010mbar*l / (s*cm2), preferably less than 3x1011mbar*l / (s*cm2) for non-volatile hydrocarbons. In a further specific embodiment, said elastomer composition has an outgassing value of less than 10’6mbar*l / (s*cm2), preferably less than 5xl0-7mbar*l / (s*cm2) for water, an outgassing value of less than 2x1010mbar*l / (s*cm2) for volatile hydrocarbons, and an outgassing value of less than 1.5x1011mbar*l / (s*cm2) for non-volatile hydroca rbons.

[0063] In an embodiment, the hardness of said elastomer composition is between 30 and 100 shore A.

[0064] Having an elastomer composition with a Shore A hardness between 30 and 100 offers a balanced combination of flexibility and stiffness, making it highly suitable for a wide range of applications, but especially sealing and gasket applications. Such a hardness level is particularly beneficial in applications requiring a tight seal against fluids or gases, as the elastomer can conform well to irregular surfaces or accommodate slight misalignments in assembly parts.

[0065] In an embodiment, said elastomer composition is (but not limited to) in the form of a molded product or extruded product, such as a seal, a bonded seal, a clamp, or a rubber-metal product, a bellow, an end-stop, a cord, a cable, or a hose.

[0066] In an embodiment, said elastomer composition is (but not limited to) in the form of a seal, a bonded seal, gasket, bellow, a clamp, or a rubber-metal product. This list should not be considered as being limitative, and it should be clear that the elastomer composition can be in the form of anything resembling a seal, a bonded seal, gasket, bellow, a clamp, or a rubber-metal product or having the same function as a seal, a bonded seal, gasket, bellow, a clamp, or a rubber-metal product.

[0067] In an embodiment, said one or more fluorine -free elastomers are substantially chemically crosslinked and not thermoplastic elastomers.

[0068] In a second aspect, the invention relates to the use of an elastomer composition as described herein.

[0069] The elastomer composition can be used in high-vacuum applications. Such vacuum systems are mainly used (but not limited to) in the semiconductor industry, scientific equipment, defense, and aerospace. Applications of elastomers include (but not limited to) seals (o-rings, gaskets, other shaped seals), molded parts, bellows, and rubber-to-metal bonded products (e.g. bonded seals, passive damping elements, cable clamps).

[0070] In other words, the elastomer composition can be used in a vacuum environment, wherein the pressure is at most 1 mbar.

[0071] In an embodiment, said high-vacuum applications are chosen from the list of: semiconductor industry, aerospace, optical devices, and scientific equipment.

[0072] In an embodiment, the composition is especially useful in the form of seals and the like, which can then be used in vacuum applications.

[0073] This composition is particularly beneficial in industries such as the semiconductor industry, scientific equipment, defense, and aerospace, where the functioning of optical devices can be directly affected by surface contamination caused by outgassing.

[0074] The reduction in outgassing contaminants improves the operational environment of optical devices in vacuum conditions. This enhancement in the operational environment directly impacts the lifespan and overall efficiency of the optical devices. It reduces the risk of surface contamination, which can lead to irreversible damage to the optical devices. This is particularly beneficial in industries such as the semiconductor industry, scientific equipment, defense, and aerospace, where vacuum systems are extensively used. The elastomer composition offers the significant advantage of reducing contamination in vacuum systems, thereby enhancing the performance and longevity of the systems. Furthermore, the use of fluorine-containing materials is avoided, addressing environmental and health concerns associated with these materials.

[0075] The invention thus provides a viable alternative to fluorinated elastomers, which are currently under scrutiny due to their contribution to PFAS release during manufacturing and end-of-life.

[0076] In a third aspect, the invention provides a method for producing an elastomer composition. Specifically, an elastomer composition comprising one or more fluorine- free elastomers, preferably one fluorine-free elastomer. The invention provides a method to produce elastomer compositions that have significantly reduced outgassing values. This method can significantly enhance longevity and performance of optical, vacuum-based systems, adding value to industries such as the semiconductor industry, where vacuum applications are frequently used. It has been found possible to produce an elastomer composition with very low outgassing values, while avoiding fluorine-containing materials.

[0077] The method is to be understood as being performed on one or more crude elastomers as starting polymers to obtain a vulcanized elastomer composition. As described above the term "crude elastomer" or "crude polymer" are synonyms and refer to the starting polymers of the method. Herein the fluorine-free crude elastomers correspond to the fluorine-free elastomers as described above obtained in the final elastomer composition.

[0078] Preferably the method comprises the step of granulating the one or more fluorine- free crude elastomers, prior to heating in vacuum. Outgassing is a diffusion-limited process, the surface to volume ratio of the crude elastomer is preferentially maximized for an efficient heat treatment in vacuum. Granulating the crude elastomers will increase the surface area, and will advantageously effect the subsequent vacuum treatment.

[0079] In an embodiment, the one or more fluorine-free crude elastomers have a d90 of between 0,1 and 100 mm, preferably between 1 and 50 mm.

[0080] In an embodiment, the method comprises further the step of heating the one or more fluorine-free crude elastomers in vacuum. It has been found that heating in vacuum effectively cleans the one or more fluorine-free crude elastomers, resulting in low outgassing values of the cleaned elastomers as well as the final elastomer composition.

[0081] In an embodiment, said heating in vacuum is carried out at a temperature of at least 100°C, preferably at least 110°C, more preferably at least 120°C, even more preferably at least 130°C, even more preferably at least 140°C, even more preferably at least 145°C.

[0082] In an embodiment, said heating in vacuum is carried out at a temperature of at most 200°C, preferably at most 190°C, more preferably at most 180°C, even more preferably at most 170°C, even more preferably at most 160°C, even more preferably at most 155°C.

[0083] In another or further embodiment, said heating in vacuum is carried out at a temperature of between 100 and 200°C, more preferably between 110 and 190°C, even more preferably between 120 and 180°C, even more preferably between 130 and 170°C, even more preferably between 140 and 160°C, even more preferably between 145 and 155°C.

[0084] This temperature allows effectively accelerating outgassing / removing contaminants, but also avoids thermal degradation of the material.

[0085] In an embodiment, said heating in vacuum is carried out at a pressure of at most 1 mbar, preferably at most 0.1 mbar, more preferably at most 0.05 mbar, even more preferably at most 0.01 mbar.

[0086] In another or further embodiment, said heating in vacuum is carried out at a pressure of between 10’7and 1 mbar, more preferably between 10’7and 0.1 mbar, even more preferably between 10’7and 0.05 mbar, even more preferably between 10’7and 0.01 mbar.

[0087] In an embodiment, said heating in vacuum is carried out at a temperature of at least 120°C, and a pressure of at most 0.1 mbar, preferably said heating in vacuum is carried out at a temperature of at least 150°C, and a pressure of at most 0.01 mbar.

[0088] In an embodiment, said heating in vacuum is carried out for at least 24 hours, preferably at least 48 hours, even more preferably at least 50 hours, even more preferably at least 55 hours. It has been found that this allows thorough cleaning of the crude elastomers. A longer vacuum period ensures deeper penetration into the material, effectively removing the contaminants.

[0089] After heating in vacuum, the cleaned / treated crude elastomers can be mixed with one or more vulcanizing agents and subsequently vulcanized. This can be done according to known vulcanizing processes.

[0090] Exemplary vulcanizing agents are sulfur, peroxides, metallic oxides, and acetoxysilane,. A preferred vulcanizing agent is peroxide. Preferable organic peroxides include, but not limited to, dicumyl peroxide, di-tert-butylperoxide, 2,5- dimethyl-2,5-di(tert-butyl peroxy) hexane.

[0091] In an embodiment, said one or more vulcanizing agents comprise a peroxide initiator and a coagent. A coagent is a compound used in conjunction with a primary initiator, such as a peroxide initiator, to enhance the crosslinking process during polymerization. Coagents are added to improve the efficiency of the crosslinking reaction, leading to better mechanical properties and performance of the final polymer product.

[0092] In an embodiment, the vulcanizing agents are mixed with the cleaned / treated crude elastomers in a ratio by weight of between 1 / 100 and 1 / 10.

[0093] In a particularly preferred embodiment, the method comprises the steps of: i. mixing one or more fluorine-free crude elastomers with one or more vulcanizing agents, and ii. vulcanizing the mixture obtained in step (i), wherein the one or more fluorine-free crude elastomers are heated in vacuum prior to step (i).

[0094] This heat treatment of the crude elastomer under vacuum before mixing with the ingredients is found to be effective in reducing the contaminants in the crude elastomers, which are a major contributor to the outgassing values of the final product.

[0095] In another or further particularly preferred embodiment, the method comprises the steps of: i. mixing one or more fluorine-free crude elastomers with one or more vulcanizing agents, and ii. vulcanizing the mixture obtained in step (i), wherein the one or more fluorine-free crude elastomers are heated in vacuum prior to step (i), wherein the one or more fluorine-free crude elastomers have a d90 of between 0,1 and 100 mm, preferably between 1 and 50 mm.

[0096] In an embodiment, said one or more fluorine-free crude elastomers are further mixed in step (i) with one or more additives chosen from: inorganic fillers, organic fillers, pigments, and carbon black. In an embodiment, a post-cure step and bake-out step is carried out after vulcanization. This can be done according to known post-cure and bake-out processes.

[0097] The post-cure and bake-out procedures remove volatile reacted peroxide fragments, further reducing the outgassing characteristics of the elastomer composition.

[0098] The post-cure process involves subjecting the vulcanized elastomer to an elevated temperature for an extended period. The elevated temperature during post-curing accelerates the completion of cross-linking reactions that may have been incomplete after the initial cure, leading to improved mechanical strength, thermal stability, and chemical resistance. It also helps in the further reduction of volatile compounds that could have been trapped within the material matrix, enhancing the product's performance in its final application.

[0099] The bake-out process is commonly used for rubber products in vacuum systems and components to remove residual gases and contaminants trapped within the materials and surfaces of the system. During a bake-out, the composition is heated under vacuum conditions, for a duration that can range from several hours to several days. In case of peroxide vulcanizing agents, the bake-out process will remove residual peroxides from the elastomer composition.

[0100] The method allows for the production of elastomeric components that meet the outgassing requirements of high-end vacuum systems, with outgassing values below the target values. The method provides for reducing outgassing contaminants in elastomer compositions for use in optical devices operating in vacuum conditions through the use of cleaned, fluorine-free elastomers. This method significantly enhances the lifespan and overall efficiency of the optical devices. Furthermore, this method is advantageous as it provides a solution to the potential future restrictions on the use of fluorinated elastomers, by offering an effective alternative in the form of cleaned, fluorine-free elastomers.

[0101] In another aspect, the invention could be described as providing a method of cleaning fluorine-free elastomers, the method comprising the step of heating the fluorine-free crude elastomers in vacuum as described herein. This heat treatment method effectively reduces the contaminants that originate from the polymerization production process of the elastomeric materials.

[0102] In an embodiment, the method of cleaning one or more fluorine-free crude elastomers comprises the steps of: i. granulating one or more fluorine-free crude elastomers, to obtain one or more fluorine-free crude elastomers have a d90 of between 0,1 and 100 mm, preferably between 1 and 50 mm. ii. heating said one or more fluorine-free crude elastomers in vacuum.

[0103] In another embodiment, the method of cleaning fluorine-free elastomers comprises the steps of: i. heating one or more fluorine-free crude elastomers in vacuum, wherein the one or more fluorine-free crude elastomers have a d90 of between 0,1 and 100 mm, preferably between 1 and 50 mm.

[0104] In another aspect, the invention provides cleaned fluorine-free crude elastomers which can be used in elastomer compositions as described herein. The cleaned fluorine-free elastomers are obtainable from the method as described herein.

[0105] In an embodiment, the cleaned fluorine-free crude elastomers have an outgassing value under vacuum conditions of less than 10’6mbar*l / (s*cm2), preferably less than 5xl0-7mbar*l / (s*cm2) for water and hydrocarbons.

[0106] Preferably the cleaned fluorine-free crude elastomers have an outgassing value under vacuum conditions of less than 10’6mbar*l / (s*cm2) for hydrocarbons, more preferably less than 10’7mbar*l / (s*cm2), even more preferably less than 10’8mbar*l / (s*cm2), even more preferably less than 10’9mbar*l / (s*cm2).

[0107] This method is primarily aimed at reducing the contaminants that are typically present in these elastomers, which are often responsible for high outgassing rates. The contaminants are usually byproducts of the polymerization production process.

[0108] The present invention will be now described in more details, referring to examples that are not limitative.

[0109] EXAMPLES

[0110] Methods A. RGA

[0111] Residual Gas Analysis (RGA) was conducted in accordance to ISO 20175:2018 to evaluate the outgassing characteristics of elastomeric components in deep vacuum (<1E-6mbar) using a D8iM NGQ-250 RGA device. A batch of five O-rings of dimensions 253,37 x 5,33 mm with a combined surface area of 615 cm2were measured using a high-sensitivity mass spectrometer at ambient temperature for 10 hours. The difference between the recorded partial and background pressure at each m / z data point yields the total outgassing for an elastomer. The partial pressures for water (e.g. 18 m / z), volatile organics (sum of 45 - 100 m / z), and non-volatile organics (sum of 101 - 200 m / z) are recorded. The partial pressures as disclosed were taken at 10 hours.

[0112] B. Determination of crude polymer contamination method by GCMS

[0113] The aim of the method is to detect (low molecular weight) contaminations present in commercially available crude elastomers by GCMS. Since polymer solutions cannot be injected directly onto a GCMS, the crude polymer is dissolved and the polymer is filtered out to yield a solution only containing low molecular weight contamination. Besides measuring total contamination, it is possible to observe the presence of low molecular weight refractories.

[0114] Sample preparation was performed by fully dissolving 0.2 g of crude polymer in 20 mL of GC ultra grade dichloromethane (DCM) for 24 hours resulting in a concentration of 10 mg / mL. Then the solution was filtered through a 0.2 pm PTFE filter using a transparent single-use syringe (HENKE-JECT). To quantify total content of contamination in solution, 1 ppm of 99% 1-octanol (Carl Roth), an internal standard, is added. GCMS was analyzed using a PerkinElmer GC 2400, following a method that employs a full scan analysis with a temperature gradient from 90°C to 310°C. All GCMS data is analyzed and peaks corresponding to contaminants originating from the crude polymer are integrated and compared to the internal standard to yield the total quantity of contamination.

[0115] C. Heat treatment under vacuum of crude elastomers

[0116] The heat treatment under vacuum for the crude elastomer was carried out by exposing a tray with granulated crude elastomer to high vacuum (<lxl0-2mbar, or even <lxl0-6mbar) at 150°C for approximately 60 hours. Since evaporation of volatiles is diffusion limited, the surface area of the crude elastomer is preferably maximized during heat treatment under vacuum to decrease the time necessary for the bake-out procedure. For example, granulates having a d90 of between 0,1 and 100 mm, preferably between 1 and 50 mm, can be used. This can be achieved by granulation.

[0117] D. Compounding method

[0118] All the elastomer composition compounds are mixed in a mill to prevent any external contamination. Initially, the vacuumed granulated elastomer as obtained by (C) is introduced into the mill. Once a flat slab is formed, the remaining powder ingredients are added. The compounds may comprise a filler, a pigment, a peroxide initiator, a coagent and / or carbon black.

[0119] E. Vulcanization method

[0120] Vulcanization to obtain the elastomer composition was performed by compression molding according to standard procedures known to those in the art. Vulcanization time and temperature are dependent on the specific compound formulation and were chosen according to the vulcanization curve as determined by a moving die rheometer (MDR) experiment. The compounded composition was vulcanized at least up to T90 before removal out of the tool. Subsequently all samples are subjected to a post-cure in an oven at 150°C for 2 hours at ambient pressure. A standard bakeout of all vulcanized items was carried out as known standard procedure to those skilled in the art.

[0121] Comparative example 1

[0122] The industry best practice for fluorinated elastomers (e.g. FKM, FEPM, FFKM, etc) to be used in vacuum include standard elastomer ingredient mixing of crude compound (e.g. on a two roll mill, internal mixer), thermoforming of crude compounds after mixing (e.g. calendaring, extrusion), manufacturing of cured products (e.g. compression molding, transfer molding, injection molding) and subsequent cleanroom cleaning including particle removal by means of (wet isopropanol) wiping and an oven treatment at high temperature (e.g. 150°C) and low pressure (vacuum) called a vacuum bake-out within the industry.

[0123] Fluorinated elastomers produced according to this manufacturing method, can achieve outgassing values which are accepted for use in (high) vacuum applications. Per- and polyfluoroalkyl substances (PFAS), often dubbed "forever chemicals" due to their resistance to degradation, present numerous challenges, including environmental persistence, bioaccumulation, and significant health risks such as cancer and liver damage. Their use has led to global contamination of water, soil, and living organisms. This contamination, alongside the difficulty of removing PFAS from the environment and the variability in regulatory standards across jurisdictions, complicates efforts to mitigate their impact.

[0124] It was found that when using these industry best practices, including vacuum bakeout, it is not possible to interchange fluorinated crude elastomers by non-fluorinated crude elastomers (e.g. EPDM, HNBR, EVM, AEM, BUR, CIIR, ...) and obtain low outgassing values.

[0125] When producing o-rings made out of EPDM, HNBR, AEM, BUR and CIIR, which were formulated with similar ingredients as fluorine containing rubber for high end vacuum systems, the EPDM, HNBR, AEM, BUR, and CIIR compounds had a strong smell at the end of the manufacturing process (after vacuum bakeout). As a result, it was not possible to measure residual outgassing (RGA) since the RGA oven itself would be severely contaminated. It was possible to measure RGA on the EVM compounds after bakeout since those materials did not have an observable smell. However, the RGA values were too high to be used in vacuum applications.

[0126] It was found that outgassing of elastomer compositions as measured by RGA increased significantly when replacing a fluorinated crude elastomer by a PFAS-free crude elastomer in an otherwise identical elastomer formulation and processing methods (e.g. including a vacuum bake-out after post curing) as known to those skilled in the art. Consequently, the PFAS-free crude elastomer is the largest contributor to outgassing when for example general semiconductor formulation guidelines are met. The results have indicated that most PFAS-free crude elastomers are significantly more contributing to outgassing than fluorinated crude elastomers. In particular the outgassing of hydrocarbon species is predominantly due to impurities, contamination, present in the crude elastomers.

[0127] Example 3

[0128] Figure 1 shows a GCMS trace of EPDM gum polymer contamination before (a) and after (b) a heat treatment at 150°C in vacuum for 60 hours.

[0129] Figure 2 shows the total content of contamination originating from the polymer as measured by GCMS for a selection of commercially available gum polymers before (to) and after (too) a heat treatment at 150°C in vacuum for 60 hours.

[0130] Figure 3 shows an example of time dependence of the total content of contamination as measured by GCMS of commercially available gum polymer during heat treatment at 150°C in vacuum. The data points represent single quantitative GCMS experiments. The curve is a non-linear curve-fit of the datapoints.

[0131] To gain insight into the outgassing in vacuum of elastomers generally RGA measurements are performed. However, excessive outgassing may lead to severe contamination of RGA equipment and is therefore not a suitable method to survey different crude, cleaned or formulated fluorine-free elastomers. As an indirect measure for outgassing, a gas chromatography and mass spectrometry (GCMS) method to comparatively survey low molecular weight impurities present in the crude polymer.

[0132] Contaminants present in crude and cleaned (heat treated) elastomers were measured according to method B. With this technique it is possible to determine that the extracted solution from the elastomers showed contaminants (probably resulting from the elastomer polymerization process). It was found that fluorinated elastomers contain significantly less volatile contaminants than (PFAS-free) hydrocarbon based elastomer (e.g. EPDM, HNBR, EVM, AEM, BUR, CIIR).

[0133] Outgassing involves two distinct physical processes, diffusion volatile (contaminants) from the material to the surface and evaporation from the surface. Outgassing processes are typically diffusion limited meaning that the larger the volume to surface area of a product the longer it takes to reach the same outgassing values. To that end, the inventors have found it best to start with (relatively) clean (read low volatile content) ingredients to be able to produce a product with low outgassing.

[0134] Thus, heating the elastomer in a vacuum was studied to clean the crude elastomers of contaminants. The GCMS based method showed that the vacuum treatment at high temperature resulted in a time dependent decrease in contaminants depending on the elastomer type. Figure 1 shows a GC-MS trace of an organic extract of EPDM (a) before and (b) after a heat treatment under vacuum at 150°C for 60 hours. The disappearance of peaks between 2.15 and 15 min shows that organic matter was removed from the polymer.

[0135] Based on this method it was possible to survey specific and total contamination of suitable crude elastomers for elastomer compositions for vacuum applications with low outgassing requirements. The effect of the heat treatment under vacuum was studied with the described quantitative GCMS method. Figure 2 shows the decrease in total contamination after heating various elastomers at 150°C in vacuum for 60 hours. In addition, Figure 3 shows that the total content of contamination in the crude elastomer decreases as a function of time. The total amount of contamination based on the specific crude polymer, with the GCMS method one skilled in the art is able to determine the required time in the vacuum for each crude elastomer.

[0136] To limit outgassing it is thus advantageous to clean the crude elastomers of volatile contamination prior to mixing with other ingredients and vulcanizing to obtain the elastomer composition. Herein, the removal of volatile contamination from the crude elastomer is successfully achieved by a heat treatment under vacuum before mixing with the other required ingredients.

[0137] Examples 4-8

[0138] Following methods C, D and E described above, fluorine-free crude elastomers (EPDM, HNBR, EVM) were heated in vacuum for 60h (150°C, <lxl0’2mbar). Then, an elastomer composition was formulated for a peroxide vulcanization with additional ingredients for high vacuum applications. These materials underwent a regular vulcanization, post-cure and bake-out procedure. Residual gas analysis of the elastomer compositions showed a low outgassing of water, volatile and nonvolatile hydrocarbons. This indicated the effectiveness of the initial heat treatment of the polymer under vacuum. The residual outgassing values of EPDM, EVM, and HNBR elastomer compositions are listed in table 1.

[0139] Table 1 - Outgassing of fluorine-free elastomer compositions of which the crude elastomers were heat treated under vacuum.

[0140] Compared to comparative example 2, wherein RGA measurements were not even possible for all elastomer formulations due to high outgassing, examples 4-8 show very low volatile and non-volatile outgassing values.

[0141] The present invention is in no way limited to the embodiments described in the examples and / or shown in the figures. On the contrary, methods according to the present invention may be realized in many different ways without departing from the scope of the invention.

[0142] The invention may thus be described according to the following embodiments:

[0143] 1. An elastomer composition comprising one or more fluorine-free elastomers, wherein said elastomer composition has an outgassing value of less than 10’ 6 mbar*l / (s*cm2) for water and hydrocarbons.

[0144] 2. Elastomer composition according to embodiment 1, wherein said one or more fluorine-free elastomers are chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), neoprene rubber (CR), and combinations thereof.

[0145] 3. Elastomer composition according to any of the previous embodiments, wherein said elastomer composition has an outgassing value of less than 10’ 9 mbar*l / (s*cm2) for hydrocarbons with a mass between 45 and 100 m / z, preferably an outgassing value of less than 4x1010mbar*l / (s*cm2).

[0146] 4. Elastomer composition according to any of the previous embodiments, wherein said elastomer composition has an outgassing value of less than 10’10mbar*l / (s*cm2) for hydrocarbons with a mass between 101 and 200 m / z, preferably an outgassing value of less than 3x1011mbar*l / (s*cm2). Elastomer composition according to any of the previous embodiments, wherein said elastomer composition has an outgassing value of less than 5xl0-7mbar*l / (s*cm2) for water, an outgassing value of less than 2x1010mbar*l / (s*cm2) for hydrocarbons with a mass between 45 and 100 m / z, and an outgassing value of less than 1.5x1011mbar*l / (s*cm2) for hydrocarbons with a mass between 101 and 200 m / z. Elastomer composition according to any of the previous embodiments, wherein said elastomer composition is in the form of a molded product or extruded product, such as a seal, a bonded seal, a clamp, a rubber-metal product, a bellow, an end-stop, a cord, a cable, or a hose. Elastomer composition according to any of the previous embodiments, wherein said one or more fluorine-free elastomers are not thermoplastic elastomers. Use of an elastomer composition according to any of embodiments 1 to 7 in high-vacuum applications. Use according to embodiment 8, wherein said high-vacuum applications are chosen from the list of: semiconductor industry, aerospace, optical devices, and scientific equipment. A method for production of an elastomer composition, wherein the method comprises the steps of: i. mixing one or more fluorine-free crude elastomers with one or more vulcanizing agents, and ii. vulcanizing the mixture obtained in step (i), characterized in that the one or more fluorine-free crude elastomers are heated in vacuum prior to step (i). Method according to embodiment 10, wherein said heating in vacuum is carried out at a temperature of at least 120°C, and a pressure of at most 0.1 mbar. Method according to embodiment 10, wherein said heating in vacuum is carried out at a temperature of at least 150°C, and a pressure of at most 0.01 mbar. Method according to any of embodiments 10 to 12, wherein said heating in vacuum is carried out for at least 24 hours, preferably at least 48 hours. Method according to any of embodiments 10 to 13, wherein said one or more fluorine-free crude elastomers are further mixed in step (i) with additives chosen from: inorganic fillers, organic fillers, pigments, and carbon black, wherein said one or more vulcanizing agents comprise a peroxide initiator and a coagent. Method according to any of embodiments 10 to 14, wherein a post-cure step and / or bake-out step is carried out after vulcanization.

Claims

CLAIMS1. An elastomer composition comprising one or more fluorine-free elastomers, wherein said elastomer composition has an outgassing value of less than 10’ 6 mbar*l / (s*cm2) for water and hydrocarbons.

2. Elastomer composition according to claim 1, wherein said one or more fluorine-free elastomers are chosen from the list of: ethylene-propylene diene monomer rubber (EPDM), ethylene-propylene monomer rubber (EPM), hydrogenated nitrile butadiene rubber (HNBR), epichlorohydrin rubber (ECO), bromo butyl rubber (BUR), chlorobutyl rubber (CIIR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene vinyl acetate rubber (EVM), chlorinated polyethylene rubber (CPE), neoprene rubber (CR), and combinations thereof.

3. Elastomer composition according to any of the previous claims, wherein said elastomer composition has an outgassing value of less than 10’9mbar*l / (s*cm2) for hydrocarbons with a mass between 45 and 100 m / z, preferably an outgassing value of less than 4x1010mbar*l / (s*cm2).

4. Elastomer composition according to any of the previous claims, wherein said elastomer composition has an outgassing value of less than 1010mbar*l / (s*cm2) for hydrocarbons with a mass between 101 and 200 m / z, preferably an outgassing value of less than 3x1011mbar*l / (s*cm2).

5. Elastomer composition according to any of the previous claims, wherein said elastomer composition has an outgassing value of less than 5xl0-7mbar*l / (s*cm2) for water, an outgassing value of less than 2x1010mbar*l / (s*cm2) for hydrocarbons with a mass between 45 and 100 m / z, and an outgassing value of less than 1.5x1011mbar*l / (s*cm2) for hydrocarbons with a mass between 101 and 200 m / z.

6. Elastomer composition according to any of the previous claims, wherein said elastomer composition is in the form of a molded product or extruded product, such as a seal, a bonded seal, a clamp, a rubber-metal product, a bellow, an end-stop, a cord, a cable, or a hose.

7. Elastomer composition according to any of the previous claims, wherein said one or more fluorine-free elastomers are not thermoplastic elastomers.

8. Use of an elastomer composition according to any of claims 1 to 7 in high- vacuum applications.

9. Use according to claim 8, wherein said high-vacuum applications are chosen from the list of: semiconductor industry, aerospace, optical devices, and scientific equipment.

10. A method for production of an elastomer composition, wherein the method comprises the steps of: i. mixing one or more fluorine-free crude elastomers with one or more vulcanizing agents, and ii. vulcanizing the mixture obtained in step (i), characterized in that the one or more fluorine-free crude elastomers are heated in vacuum prior to step (i).

11. Method according to claim 10, wherein said heating in vacuum is carried out at a temperature of at least 120°C, and a pressure of at most 0.1 mbar.

12. Method according to claim 10, wherein said heating in vacuum is carried out at a temperature of at least 150°C, and a pressure of at most 0.01 mbar.

13. Method according to any of claims 10 to 12, wherein said heating in vacuum is carried out for at least 24 hours, preferably at least 48 hours.

14. Method according to any of claims 10 to 13, wherein said one or more fluorine-free crude elastomers are further mixed in step (i) with additives chosen from: inorganic fillers, organic fillers, pigments, and carbon black, wherein said one or more vulcanizing agents comprise a peroxide initiator and a coagent.

15. Method according to any of claims 10 to 14, wherein a post-cure step and / or bake-out step is carried out after vulcanization.

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