JP2006213836A - Fluorocarbon elastomer composition cured with peroxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a thermoplastic vulcanized rubber using a peroxide curing system. <P>SOLUTION: This method includes a process for adding a peroxide masterbatch to the melt-blend of a fluorocarbon elastomer with a thermoplastic material. The peroxide masterbatch comprises ≥5 mass% of an organic peroxide, a fluorocarbon elastomer and a crosslinking agent having typically at least two sites of an olefinic unsaturation. The fluorocarbon elastomers in the melt-blend and in the peroxide masterbatch may be identical or different each other. The melt blend is added to the peroxide masterbatch, and the obtained composition is mixed for a sufficient time and at a sufficient temperature to achieve the curing of the fluorocarbon elastomer. By the use of the masterbatch, the peroxide curing agent for pre-dispersing the peroxide in the elastomer phase can quickly and uniformly be dispersed, thus giving the molded article having improved mechanical properties. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

(preface)
The present invention relates to dynamic vulcanization of fluorocarbon elastomers in thermoplastics. More particularly, the present invention relates to the use of organic peroxides as elastomer curing agents.

  Cured elastomers or rubbers have various physical properties that are useful in molded article applications. These properties include a high degree of flexibility, elasticity, and resistance to compressive strain. They themselves have applications in various applications such as seals and gaskets. Uncured elastomer or rubber is in the form of a resin or gum. In order to obtain a molded article having suitable elastomeric properties, the uncured resin is crosslinked or cured with various crosslinking agents.

  Conventional elastomers generally cure in a mold at a temperature and pressure suitable to form a cured or partially cured article. For high turnaround times and to save manufacturing costs, the part is generally removed from the mold prior to the cross-linking reaction that completes the cure. Under these conditions, the molded article undergoes a “post cure” process to further develop the elastomeric properties of the molded article.

  Dynamic vulcanizates are prepared by carrying out a crosslinking reaction while stirring or mixing the elastomer with the thermoplastic material. The thermoplastic material forms a continuous phase and the cured rubber particles are dispersed in the thermoplastic as a discontinuous phase. The composition dynamically vulcanizes with time to develop elastomeric properties. Typically, a cured or partially cured dynamic vulcanizate is transferred into a mold to prepare a molded article for applications such as seals and gaskets. Due to the same phenomenon of post cure, the cross-linking reaction can continue in the mold after the dynamic vulcanization process.

  Reactions that occur during the post-cure process generate heat. The generated heat can cause volatilization of the various components of the composition during the post cure stage. This volatilization can result in, for example, a porous cured product or a rough surfaced article. Physical properties such as tensile strength can work in reverse.

  In one aspect, post cure problems can be minimized by using fast reacting crosslinkers, such as organic peroxides, preferably in combination with organic crosslinkable molecules having two or more sites of olefinic unsaturation. Since peroxide-initiated curing is rapid, curing tends to be almost complete by the end of molding or, in the case of dynamic vulcanization, by the end of dynamic blending. In this manner, peroxide-initiated curing provides a molded article having faster turnaround times and desirable physical properties.

  Because the peroxide is added to the hot melt mixture of elastomer and thermoplastic, the peroxide may splash or bump upon addition. This can lead to the formation of a molded part with a porous or rough surface, much like the reaction during post cure as described above.

  Accordingly, it would be desirable to provide a method for curing fluorocarbon elastomers in a dynamic vulcanization process that uses a fast-curing peroxide-initiated curing system, but avoids the disadvantages described above.

(Overview)
In one embodiment, a high temperature peroxide is added to a melt blend of a fluorocarbon elastomer and a thermoplastic material to produce a thermoplastic vulcanizate (TPV) in a dynamic vulcanization process. Peroxides undergo only low levels of volatilization and decomposition due to their high temperature stability, leading to improved physical properties of TPV molded articles.

  In another embodiment, an advantage is provided in a process that includes adding a peroxide masterbatch to a melt blend of a fluorocarbon elastomer and a thermoplastic material. The melt blend contains a first portion of the fluorocarbon elastomer, while the peroxide masterbatch contains a second portion of the fluorocarbon elastomer. The fluorocarbon elastomer in the melt blend and in the peroxide masterbatch may be the same or different. After the peroxide masterbatch is added to the melt blend, the formulation is mixed for a sufficient time at a temperature sufficient to achieve cure of the fluorocarbon elastomer. The peroxide masterbatch contains 5% by weight or more of organic peroxide, further contains a fluorocarbon elastomer, and typically also contains a crosslinker containing at least two sites of olefinic unsaturation.

  Accordingly, a method for producing a molding polymer composition includes a step of melt blending a curable fluorocarbon elastomer and a thermoplastic material and a step of adding a curing composition containing a peroxide masterbatch to the melt blend. The cured composition, elastomer, and thermoplastic material are then heated while continuing to mix for a sufficient time and at a sufficient temperature to cure the fluorocarbon elastomer.

  Molded products that can be melt processed can be produced using this method. This molded article comprises a fluorocarbon elastomer and a thermoplastic dynamic vulcanizate of thermoplastic material. In some embodiments, the thermoplastic is a fluorine-containing thermoplastic resin. Molded articles produced by this process have elastomeric properties suitable for seals and gaskets. This property is advantageous over the properties of peroxide-cured articles that are generally produced by methods other than the masterbatch method. For example, in some embodiments, the tensile modulus of the molded article is greater than 10 Mpa, and in other embodiments, the tensile modulus is greater than 12 Mpa, or greater than 15 Mpa.

(Explanation)
The following description of the preferred embodiments is merely exemplary and is in no way intended to limit the invention, its application, or uses.

  Titles used herein (such as “Introduction” and “Summary”) are intended solely for the general construction of the topic within the disclosure of the present invention, and are intended for the present invention or any aspect thereof. It is not intended to limit the disclosure. In particular, the subject matter disclosed in the “Introduction” encompasses aspects of the technology within the scope of the present invention and does not constitute an enumeration of the prior art. The subject matter disclosed in the “Summary” is not an exclusive or complete disclosure of the full scope of the invention or any embodiment thereof.

  Citation of a reference herein does not constitute an admission that the reference is prior art or has any relevance to the patentability of the invention disclosed herein. All references cited in the description section of this specification are hereby incorporated by reference in their entirety.

  The description and specific examples, while indicating embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. Furthermore, the recitation of embodiments with defined features is not intended to exclude other embodiments with additional features or other embodiments that incorporate different combinations of defined features. Specific examples are provided for illustrative purposes of how to make and use the compositions of the present invention, and how to practice the methods of the present invention, and unless otherwise explicitly stated, It is not intended to be representative of those who did or did not perform the particular embodiments.

  As used herein, the terms “preferred” and “preferably” refer to embodiments of the invention that provide certain benefits under certain conditions. However, other embodiments may be preferred under the same or other conditions. Furthermore, the listing of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

  As used herein, the term “listed” and variations thereof excludes other similar items where listing of items in the list may also be useful in the materials, compositions, devices, and methods of this invention. It is intended to be non-limiting so as not to become.

  The terms “elastomeric material”, “elastomer” and the like refer to chemical compositions that are elastic or can be modified (ie, cured or cross-linked) to be elastic. Depending on the context, the term refers to an uncured or partially cured material that is not fully elastic, or a cured rubber-like material that is fully elastic. In some respects herein, the term is used with adjectives such as “cured”, “partially cured”, or “uncured” for clarity.

  The terms “curing agent”, “curative”, “curative agent”, etc., react with (uncured) elastomer to form a cured elastomer and its cured product Are used interchangeably to indicate a compound or composition that exhibits the resiliency. Depending on the context, the term is used to denote a crosslinking agent that can be used with an initiator (eg, triallyl isocyanurate) as well as a formal cure initiator (eg, a radical initiator such as a peroxide). . In some respects, the term “curing system” or the like is used to represent a combination of initiators and crosslinkers and optional additional components used for curing. It should be understood that the curing system is provided by the elastomer supplier (sometimes incorporated into the elastomer) and can often be used according to the manufacturer's instructions.

  In one embodiment, the method for producing a molded polymer composition comprises forming a mixture of a curable fluorocarbon elastomer and a thermoplastic material at a temperature above the melt flow temperature or melting point of the thermoplastic material, the mixture being a curable composition. And a step of heating while continuing to mix the cured composition, the elastomer, and the thermoplastic material. The cured composition includes an initiator having a half-life of 0.1 hours or more at a temperature of 180 ° C. or higher, and further includes a crosslinking agent. Preferably, the crosslinker contains at least two sites of olefinic unsaturation. In various embodiments, the initiator is an organic peroxide. In a preferred embodiment, the thermoplastic material comprises a fluorine-containing thermoplastic polymer.

  Fluorocarbon elastomers used in melt blends with thermoplastic materials include fluorine-containing polymers that cure under the action of peroxide-initiated crosslinkers to give a cured fluorocarbon rubber with elastomeric properties. Many different types of fluorocarbon elastomers are commercially available. In one embodiment, the fluorocarbon elastomer comprises a copolymer of vinylidene fluoride. In another embodiment, perfluororubbers based on polymers and copolymers of monomers that do not contain carbon hydrogen bonds can be used. Another class of fluorocarbon elastomers is provided by copolymers of tetrafluoroethylene and olefins such as propylene. In general, fluorocarbons also have a small amount of cure site monomer, described below, to promote curing with peroxide-initiated crosslinkers.

  In another embodiment, the present invention provides a method of making a melt processable fluorocarbon rubber composition, wherein the melt blend of the fluorocarbon elastomer and thermoplastic material of the first portion includes 5% by weight or more of an organic peroxide, and Adding a peroxide masterbatch comprising a second portion of the fluorocarbon elastomer; and the peroxide masterbatch, the first portion of the fluorocarbon elastomer, and the thermoplastic material sufficient to effect curing of the first and second fluorocarbon elastomers. A method is provided that includes mixing with heating for a time and at a sufficient temperature. In one embodiment, the method comprises injecting a composition comprising a first portion of a fluorocarbon elastomer and a thermoplastic material into a twin screw extruder with a first feeder; and a second downstream from the first feeder. Adding a master batch into the extruder with a feeder.

  The method can be performed by adding a peroxide masterbatch to the melt blend of the fluorocarbon elastomer and thermoplastic material of the first part. The peroxide masterbatch, the first portion of the fluorocarbon elastomer and the thermoplastic material are then heated while mixing at an effective temperature and at an effective temperature to cure the fluorocarbon elastomer. Thus, the method includes dynamic vulcanization of a fluorocarbon elastomer by peroxide curing in a thermoplastic material, preferably a fluorine-containing thermoplastic material.

  While the peroxide masterbatch is injected into the extruder at the second feeder downstream of the first feeder, the first portion of fluorocarbon elastomer and thermoplastic material can be added into the barrel of the twin screw extruder at the first feeder. . Continuous or semi-continuous processes for producing multipolymer compositions can be carried out in such a twin screw extruder.

  In one aspect, the addition of a peroxide curing agent in the form of a masterbatch having an elastomeric matrix phase leads to good uniformity and fast dispersion within the TPV peroxide curable main elastomeric phase. It also provides an effective use of curing agents by minimizing the volatilization of peroxide curing agents during TPV dynamic vulcanization, especially at high temperatures.

  In another embodiment, the present invention includes a peroxide cured dynamic vulcanizate of fluorocarbon elastomer and fluorine-containing thermoplastic material having a tensile modulus greater than 10 Mpa, preferably greater than 12 Mpa, more preferably greater than 15 Mpa. A molded product is provided. The TPV compound process, which is dynamically vulcanized with a peroxide batch containing a peroxide curing agent, improves the volatility of the peroxide curing agent by achieving a more homogeneously cured elastomer phase within the thermoplastic matrix phase and especially at elevated temperatures. Minimizing is thought to give better mechanical properties.

  Various types of fluoroelastomers can be used. One class of fluoroelastomers is given in ASTM-D 1418, “Standard conventions for rubber and rubber latex nomenclature”. The name FKM is given to fluororubbers that use vinylidene fluoride as a comonomer. Several types of FKM fluoroelastomers are commercially available. The first type can be chemically described as a copolymer of hexafluoropropylene and vinylidene fluoride. These FKM elastomers tend to have an advantageous combination of overall properties. Some commercial embodiments can utilize about 66% by weight fluorine. Another type of FKM elastomer can be described chemically as a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride. Such elastomers tend to have high heat resistance and good resistance to aromatic solvents. For example, those having 68-69.5% by weight fluorine are commercially available. Another FKM elastomer is chemically described as a terpolymer of tetrafluoroethylene, vinyl fluoride fluoride, and vinylidene fluoride. Such elastomers tend to have improved low temperature performance. In various embodiments, they can be utilized with 62-68% by weight fluorine. A fourth type of FKM elastomer is described as a terpolymer of tetrafluoroethylene, propylene, and vinylidene fluoride. Such FKM elastomers tend to have improved base resistance. Some commercial embodiments contain about 67% by weight fluorine. A fifth type of FKM elastomer may be described as a pentapolymer of tetrafluoroethylene, hexafluoropropylene, ethylene, vinyl fluoride ether and vinylidene fluoride. Such elastomers typically have improved base resistance and improved low temperature performance.

  Another class of fluorocarbon elastomers is named FFKM. These elastomers may be termed perfluoroelastomers because the polymer is fully fluorinated and does not contain carbon hydrogen bonds. As a group, FFKM fluoroelastomers tend to have excellent fluid resistance. They were first introduced by DuPont under the trade name Kalrez®. Additional suppliers include Daikin and Ausimont.

  A third class of fluorocarbon elastomers is named FTPM. Typical of this class is a copolymer of propylene and tetrafluoroethylene. This classification is characterized by high resistance to basic substances such as amines.

Fluorocarbon elastomers include commercially available copolymers of one or more fluorine-containing monomers, primarily vinylidene fluoride (VDF), hexafluoropropylene (HEP), tetrafluoroethylene (TFE), and perfluorovinyl ether (PFVE). Is mentioned. Preferred PFVEs include those having a C _1-8 perfluoroalkyl group, preferably a perfluoroalkyl group having 1 to 6 carbons, specifically perfluoromethyl vinyl ether and perfluoropropyl vinyl ether. In addition, the copolymer can also contain repeat units derived from olefins such as ethylene (Et) and propylene (Pr). The copolymer may further contain a relatively small amount of cure site monomer (CSM) as described below. Preferred copolymer fluorocarbon elastomers include VDF / HFP, VDF / HFP / CSM, VDF / HFP / TFE, VDF / HFP / TFE / CSM, VDF / PFVE / TFE / CSM, TFE / Pr, TFE / Pr / VDF, TFE. / Et / PFVE / VDF / CSM, TFE / Et / PFVE / CSM and TFE / PFVE / CSM. The elastomer name indicates the monomer from which the elastomer rubber is synthesized. In some embodiments, the elastomeric rubber generally provides a Mooney viscosity (ML1 + 10, large rotor at 121 ° C.) in the range of 15-160, and may be selected for a combination of flow and physical properties. Elastomer suppliers include Dyneon (3M), Asahi Glass Fluoropolymers, Solvay / Ausimont, DuPont, and Daikin.

  In various embodiments, the fluoroelastomer of the composition of the present invention also includes at least one halogenated cure site or reactive double bond due to the presence of copolymerized units of non-conjugated dienes. In various embodiments, the fluorocarbon elastomer contains up to 5 mol%, preferably up to 3 mol%, of repeating units derived from so-called cure site monomers.

  Cure site monomers are preferably selected from the group consisting of brominated, chlorinated, and iodinated olefins; brominated, chlorinated, and iodinated unsaturated ethers; and non-conjugated dienes. The halogenated cure site may be a copolymerized cure site monomer or halogen atom present at the terminal position of the fluoroelastomer polymer chain. Cure site monomers, reactive double bonds or halogenated end groups can react to form crosslinks.

The brominated cure site monomer may contain other halogens, preferably fluorine. Examples are bromotrifluoroethylene, 4-bromo-3,3,4,4-tetrafluorobutene-1 and others such as vinyl bromide, 1-bromo-2,2-difluoroethylene, perfluoroallyl bromide 4-bromo-1,1,2-trifluorobutene, 4-bromo-1,1,3,3,4,4, -hexafluorobutene, 4-bromo-3-chloro-1,1,3, 4,4-pentafluorobutene, 6-bromo-5,5,6,6-tetrafluorohexene, 4-bromoperfluorobutene-1 and 3,3-difluoroallyl bromide. Brominated unsaturated ether cure site monomers useful in the present invention include 2-bromo-perfluoroethyl perfluorovinyl ether and fluorinated compounds of classification CF ₂ Br—R _f —O—CF═CF ₂ (R _f is perfluoroalkylene) CF ₂ BrCF ₂ —O—CF═CF ₂ , and fluorovinyl ethers of the classification ROCF═CFBr or ROCBr═CF ₂ , where R is a lower alkyl group or a fluoroalkyl group, such as CH ₃ OCF═CFBr Alternatively, an ether such as CF ₃ CH ₂ OCF═CFBr may be mentioned.

Iodinated olefins can also be used as cure site monomers. Suitable iodinated monomers include those of the formula: CHR = CH-Z-CH ₂ CHR-I where R is -H or -CH ₃ ; Z is linear or branched, optionally one or more Of C ₁ -C ₁₈ (per) fluoroalkylene groups optionally containing ether oxygen atoms, or (per) fluoropolyoxyalkylene groups as disclosed in US Pat. No. 5,674,959) Examples include olefins. Other examples of useful iodinated cure site monomers are those of the formula: I (CH ₂ CF ₂ CF ₂ ) _n OCF═CF ₂ and ICH ₂ CF ₂ O [CF (as disclosed in US Pat. No. 5,717,036 CF ₃ ) CF ₂ O] _n CF═CF ₂ (where n = 1 to 3) and the like. Further, iodoethylene, 4-iodo-3,3,4,4-tetrafluorobutene-1; 3-chloro-4-iodo-3,4,4-trifluorobutene; 2-iodo-1,1,2 , 2-tetrafluoro-1- (vinyloxy) ethane; 2-iodo-1- (perfluorovinyloxy) -1,1,2,2-tetrafluoroethylene; 1,1,2,3,3,3-hexa Suitable including: fluoro-2-iodo-1- (perfluorovinyloxy) propane; 2-iodoethyl vinyl ether; 3,3,4,5,5,5-hexafluoro-4-iodopentene; and iodotrifluoroethylene Iodinated cure site monomers are disclosed in US Pat. No. 4,694,045.

  Examples of non-conjugated diene cure site monomers include 1,4-pentadiene, 1,5-hexadiene, 1,7-octadiene and others such as those disclosed in Canadian Patent 2,067,891. The preferred triene is 8-methyl-4-ethylidene-1,7-octadiene.

  Of the cure site monomers listed above, preferred compounds include 4-bromo-3,3,4,4-tetrafluorobutene-1; 4-iodo-3,3,4,4-tetrafluorobutene-1 And bromotrifluoroethylene.

  Additionally or alternatively, iodine, bromine or mixtures thereof may be present at the fluoroelastomer chain ends as a result of using a chain transfer agent or molecular weight modifier during the preparation of the fluoroelastomer. Such agents include iodine-containing compounds that result in iodine attached to one or both ends of the polymer molecule. Methylene iodide; 1,4-diiodoperfluoro-n-butane; and 1,6-diiodo-3,3,4,4, tetrafluorohexane are representative of such agents. Other iodinated chain transfer agents include 1,3-diiodoperfluoropropane; 1,4-diiodoperfluorobutane; 1,6-diiodoperfluorohexane; 1,3-diiodo-2-chloroperfluoropropane; 2-di (iododifluoromethyl) perfluorocyclobutane; monoiodoperfluoroethane; monoiodoperfluorobutane; and 2-iodo-1-hydroperfluoroethane. Diiodinated chain transfer agents are particularly preferred. Examples of brominated chain transfer agents include 1-bromo-2-iodoperfluoroethane; 1-bromo-3-iodoperfluoropropane; 1-iodo-2-bromo-1,1-difluoroethane and US Pat. No. 5,151,492. Others as disclosed are included.

  Additionally or alternatively, iodine, bromine or mixtures thereof may be present at the fluoroelastomer chain ends as a result of using a chain transfer agent or molecular weight modifier during the preparation of the fluoroelastomer. Such agents include iodine-containing compounds that result in iodine attached to one or both ends of the polymer molecule. Methylene iodide; 1,4-diiodoperfluoro-n-butane; and 1,6-diiodo-3,3,4,4, tetrafluorohexane are representative of such agents. Other iodinated chain transfer agents include 1,3-diiodoperfluoropropane; 1,4-diiodoperfluorobutane; 1,6-diiodoperfluorohexane; 1,3-diiodo-2-chloroperfluoropropane; 2-di (iododifluoromethyl) perfluorocyclobutane; monoiodoperfluoroethane; monoiodoperfluorobutane; and 2-iodo-1-hydroperfluoroethane. Diiodinated chain transfer agents are particularly preferred. Examples of brominated chain transfer agents include 1-bromo-2-iodoperfluoroethane; 1-bromo-3-iodoperfluoropropane; 1-iodo-2-bromo-1,1-difluoroethane and US Pat. No. 5,151,492. Others as disclosed are included.

  Low levels, preferably up to about 5 mol%, more preferably up to about 3 mol% of epoxy, carboxylic acid, carboxylic acid halide, carboxylic acid ester, carboxylate, sulfonic acid group, sulfonic acid alkyl ester, and sulfonic acid Other curing monomers that introduce functional groups such as salts can be used. Such monomers and curing are described, for example, in US Pat. No. 5,354,811 to Kamiya et al.

  Fluorocarbon elastomers based on cure site monomers are commercially available. Non-limiting examples include Viton GF, GLT-305, GLT-505, GBL-200, and GBL-900 grades from DuPont. Other examples include G-900 and LT series from Daikin, FX series and RE series from NOK, Tecnoflon P457 and P757 from Solvay.

  In some embodiments, the thermoplastic material comprises at least one fluorine-containing thermoplastic polymer, ie a fluororesin. The thermoplastic fluorine-containing polymer can be selected from a wide range of polymers and commercial products. The polymer is melt processable, that is, the polymer softens and flows when heated and can be easily processed with thermoplastic techniques such as injection molding, extrusion, compression molding, and blow molding. This material can be easily recycled by melting and reworking.

  The thermoplastic polymer may be fully fluorinated or partially fluorinated. Fully fluorinated thermoplastic polymers include copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether. A perfluoroalkyl group is preferably a group of 1 to 6 carbon atoms. Examples of copolymers are PFA (copolymer of TFE and perfluoropropyl vinyl ether) and MFA (copolymer of TFE and perfluoromethyl vinyl ether). Other examples of fully fluorinated thermoplastic polymers include copolymers of TFE and perfluoroolefins of 3 to 8 carbon atoms. Non-limiting examples include FEP (a copolymer of TFE and hexafluoropropylene).

  Partially fluorinated thermoplastic polymers include E-TFE (ethylene and TFE copolymer), E-CTFE (ethylene and chlorotrifluoroethylene copolymer), and PVDF (polyvinylidene fluoride). Many thermoplastic copolymers of vinylidene fluoride are also suitable thermoplastic polymers for the present invention. These include, but are not limited to, copolymers with perfluoroolefins such as hexafluoropropylene, and copolymers with chlorotrifluoroethylene. Thermoplastic terpolymers can also be used. This includes thermoplastic terpolymers of TFE, HFP, and vinylidene fluoride. Commercially available embodiments containing 59-76% by weight fluorine can be used. An example is Dyneon THV, which exhibits a melting point of about 120 ° C. to about 200 ° C. depending on the composition. In one embodiment, fluorinated fluororesins that are characterized by a melting point of about 105 ° C to about 160 ° C are particularly preferred. The use of this fairly low melting fluoropolymer allows the use of peroxide curing agents at low temperatures that minimize undesirable volatilization of the peroxide.

  Fluorine-free thermoplastic polymers can also be used. In one aspect, a thermoplastic material is a material whose melt viscosity can be measured at a temperature above its melting point, such as by ASTM D-1238 or D-2116.

  The thermoplastic material of the present invention can be selected to improve the properties of the rubber / thermoplastic material blend at high temperatures, particularly higher than 100 ° C., more preferably about 150 ° C. or higher. Such thermoplastic materials include those that maintain at least one physical property such as tensile strength, modulus, and elongation at break to an acceptable level at high temperatures. In a preferred embodiment, the thermoplastic material has high temperature physical properties (ie, high tensile strength, high modulus, and / or high elongation at break) that are superior to fluorocarbon elastomers (rubbers) cured at comparable temperatures. .

  The thermoplastic polymer material used in the present invention may be a thermoplastic elastomer. Thermoplastic elastomers have some physical properties of rubber, such as softness, flexibility and elasticity, but can be processed like thermoplastics. Upon cooling, the transition from melting to a solid rubber-like composition occurs very rapidly. This is in contrast to normal elastomers, which harden slowly when heated. Thermoplastic elastomers can be processed in conventional plastic equipment such as injection molding machines and extruders. Scrap can generally be easily recycled.

  Thermoplastic elastomers have a multiphase structure, and the phases are usually homogeneously mixed. In many cases, the phases are held together by grafting or block copolymerization. At least one phase is composed of a material that is hard at room temperature but is flowable when heated. Another phase is a softer material like rubber at room temperature.

  Some thermoplastic elastomers have an ABA block copolymer structure, where A represents a hard segment and B is a soft segment. Since most polymeric materials tend to be incompatible with each other, the hard and soft segments of thermoplastic elastomers tend to correlate to form hard and soft phases. For example, hard segments tend to form spherical regions or domains dispersed in a continuous elastomeric phase. At room temperature, this domain is hard and acts as a physical crosslink that ties the elastomeric chains together in a three-dimensional network. This domain tends to lose strength when the material is heated or dissolved in a solvent.

Other thermoplastic elastomers have a repeating structure represented by (AB) _n , and as described above, A represents a hard segment and B represents a soft segment.

  Many thermoplastic elastomers are known. Non-limiting examples of ABA type thermoplastic elastomers include polystyrene / polysiloxane / polystyrene, polystyrene / polyethylene-co-butylene / polystyrene, polystyrene / polybutadiene / polystyrene, polystyrene / polyisoprene / polystyrene, poly-α- Mention may be made of methylstyrene / polybutadiene / poly-α-methylstyrene, poly-α-methylstyrene / polyisoprene / poly-α-methylstyrene, and polyethylene / polyethylene-co-butylene / polyethylene.

Non-limiting examples of thermoplastic elastomers having a (A-B) _n repeating structure, polyamide / polyether, polysulfone / polydimethylsiloxane, polyurethane / polyester, polyurethane / polyether, polyester / polyether, polycarbonate / polydimethylsiloxane, And polycarbonate / polyether. Some of the most commonly commercially available thermoplastic elastomers contain polystyrene as the hard segment. Triblock elastomers can be utilized with polystyrene as the hard segment and either polybutadiene, polyisoprene, or polyethylene-co-butylene as the soft segment. Similarly, styrene butadiene repeat copolymers and polystyrene / polyisoprene repeat polymers are commercially available.

  The thermoplastic elastomer may have alternating blocks of polyamide and polyether. Such materials are commercially available from Atofina, for example under the trade name Pebax®. Polyamide blocks can be derived from copolymers of dibasic acid components and diamine components or can be prepared by homopolymerization of cyclic lactams. Polyether blocks are generally derived from homo- or copolymers of cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran.

  The thermoplastic polymer material can also be selected from solid, generally high molecular weight plastic materials. Preferably, the material is a crystalline or semi-crystalline polymer, and more preferably has a crystallinity of at least 25 percent as measured by differential scanning calorimetry. Amorphous polymers with reasonably high glass transition temperatures are also acceptable as thermoplastic polymer materials. Also, the thermoplastic preferably has a melting point or glass transition temperature in the range of about 80 ° C to about 350 ° C, but the melting point should generally be below the decomposition temperature of the thermoplastic vulcanizate.

  Non-limiting examples of thermoplastic polymers include polyolefin, polyester, nylon, polycarbonate, styrene-acrylonitrile copolymer, polyethylene terephthalate, polybutylene terephthalate, polyamide, polystyrene, polystyrene derivatives, polyphenylene oxide, polyoxymethylene, and fluorine-containing thermoplastic resins. Is mentioned.

Polyolefins include, but are not limited to, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, It is made by polymerizing α-olefins such as 5-methyl-1-hexene and mixtures thereof. Ethylene and propylene or ethylene, or propylene and 1-butene, 1-hexene, 1-octene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-1 Copolymers with other α-olefins such as -hexene or mixtures thereof are also conceivable. These homopolymers and copolymers, and blends thereof can be incorporated as the thermoplastic polymer material of the present invention.

  Polyester thermoplastics contain ester bond units in their polymer backbone. In one embodiment, they contain repeating units derived from a low molecular weight diol and a low molecular weight aromatic dibasic acid. Non-limiting examples include commercially available grades of polyethylene terephthalate and polybutylene terephthalate. Alternatively, the polyester can be based on an aliphatic diol and an aliphatic dibasic acid. Here, it is typically a copolymer of ethylene glycol or butanediol and adipic acid. In another embodiment, the thermoplastic polyester is a polylactone prepared by the polymerization of monomers containing both hydroxyl and carboxyl functions. A non-limiting example of this class of thermoplastic polyester is polycaprolactone.

  Polyamide thermoplastics contain repeated amide bonds within the polymer backbone. In one embodiment, the polyamide contains repeating units derived from a diamine and dibasic acid, such as the well known nylon 66 polymer of hexamethylene diamine and adipic acid. Other nylons have structures resulting from changes in the size of the diamine and dibasic acid components. Non-limiting examples include nylon 610, nylon 612, nylon 46, and nylon 6/66 copolymer. In another embodiment, the polyamide has a structure resulting from polymerizing monomers having both amine and carboxyl functionality. Non-limiting examples include nylon 6 (polycaprolactam), nylon 11, and nylon 12.

  Other polyamides made from diamines and dibasic acid components include high temperature aromatic polyamides containing repeat units derived from diamines and aromatic dibasic acids such as terephthalic acid. Examples of this commercially available include PA6T (a copolymer of hexanediamine and terephthalic acid) and PA9T (a copolymer of nonanediamine and terephthalic acid) sold by Kuraray under the trade name Genestar. Depending on the application, the melting point of the aromatic polyamide may be higher than the optimum temperature for thermoplastic processing. In such cases, the melting point can be lowered by preparing an appropriate copolymer. In a non-limiting example, for PA6T having a melting point of about 370 ° C., a moldable temperature of 320 ° C. is effectively obtained by including an effective amount of a non-aromatic dibasic acid such as adipic acid in the preparation of the polymer. The melting point can be lowered below.

  In another preferred embodiment, an aromatic based on a copolymer of an aromatic dibasic acid such as terephthalic acid and a diamine containing more than 6 carbon atoms, preferably containing 9 or more carbon atoms. Polyamide is used. The upper limit of the carbon chain length of the diamine is limited from a practical viewpoint by the availability of monomers suitable for polymer synthesis. In principle, suitable diamines include those having 7 to 20 carbon atoms, preferably in the range of 9 to 15 carbon atoms, more preferably in the range of 9 to 12 carbon atoms. Preferred embodiments include C9, C10, and C11 diamine based aromatic polyamides. Such aromatic polyamides are believed to exhibit a high level of solvent resistance based on the lipophilicity of carbon chains having more than 6 carbons. Where it is desirable to lower the melting point below the preferred molding temperature (typically 320 ° C. or lower), aromatic polyamides based on diamines with more than 6 carbons are effective with aromatic polyamides based on 6-carbon diamines as described above. An amount of non-aromatic dibasic acid can be included. Such an effective amount of dibasic acid must be sufficient to lower the melting point to the desired molding temperature range without unacceptably affecting the desired solvent resistance properties.

  Other non-limiting examples of high temperature thermoplastics include polyphenylene sulfide, liquid crystal polymers, and high temperature polyimides. Liquid crystal polymers are based on linear polymers that contain chemically repeating linear aromatic rings. Due to its aromatic structure, this material forms nematic molten domains with characteristic spacing detectable by X-ray diffraction. Examples of this material include copolymers of hydroxybenzoic acid or copolymers of ethylene glycol and linear aromatic diesters such as terephthalic acid or naphthalenedicarboxylic acid.

  Examples of the high temperature thermoplastic polyimide include a polymerization reaction product of an aromatic dianhydride and an aromatic diamine. They are commercially available from many suppliers. A typical example is a copolymer of 1,4-benzenediamine and 1,2,4,5-benzenetetracarboxylic dianhydride.

  The cured composition includes a radical initiator. Initiators are believed to function by first extracting hydrogen or halogen atoms from the fluorocarbon elastomer to produce free radicals that can crosslink. A crosslinking agent may be included in the cured composition. The cross-linking agent also includes at least two sites of olefinic unsaturation that react with free radicals on the fluorocarbon elastomer caused by the reaction of the initiator.

In various embodiments, the initiator has peroxide functionality. As examples of initiators, a wide variety of organic peroxides are known and are commercially available. Initiators including organic peroxides are activated over a wide range of temperatures. The activation temperature can be described by a parameter known as half-life. Typically, half-life values, such as 0.1 hours, 1 hour, and 10 hours, are given in degrees Celsius. For example, a T _1/2 of 0.1 hours at 143 ° C. represents that half of the initiator decomposes within 0.1 hours at that temperature. Organic peroxides with a T _1/2 of 0.1 hours at 118 ° C. to 228 ° C. are commercially available. Such peroxides have a half-life of at least 0.1 hour at the indicated temperature. The T _1/2 value indicates the kinetics of the initial reaction in cross-linking the fluorocarbon elastomer, that is, the decomposition of the peroxide to form a radical-containing intermediate.

In some embodiments, it is preferred to match the T _1/2 of the initiator, such as an organic peroxide, to the temperature of the molten material that is to be added into the cured composition. In various embodiments, the initiator has a thermal stability such that the half-life is at least 0.1 hours at a temperature of 180 ° C. or higher. In other embodiments, suitable initiators have a half-life of 0.1 hours at temperatures of 190 ° C or higher, or 200 ° C or higher. Non-limiting examples of peroxides and their 0.1 hour half-life T _1/2 include Trigonox 145-E85 (T _1/2 = 182 ° C), Trigonox M55 (T _1/2 = 183 ° C), Trigonox K-90 (T _1/2 = 195 ° C.), Trigonox A-W70 (T _1/2 = 207 ° C.), and Trigonox TAHP-W85 (T _1/2 = 228 ° C.). A non-limiting example of a non-peroxide initiator is Perkadox-30 (T _1/2 = 284 ° C.). Trigonox and Perkadox materials are commercial or developed products from AkzoNobel.

  Non-limiting examples of commercially available organic peroxides for initiating curing of fluorocarbon elastomers include: 4,4-di- (tert-butylperoxy) butyl valerate; tert-butyl peroxybenzoate; di-tert- Diamylyl peroxide; Di- (tert-butylperoxyisopropyl) benzene; 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane; tert-butylcumyl peroxide; 2,5, -dimethyl -2,5-di (tert-butylperoxy) hexyne-3; di-tert-butyl peroxide; 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane; , 1,3,3-tetramethylbutyl hydroperoxide; diisopropylbenzene monohydroperoxide; cumyl hydroperoxide; tert-butyl hydroperoxide; tert-amyl hydroperoxide; tert-butyl peroxyisobutyrate Tert-amyl peroxyacetate; tert-butylperoxystearyl carbonate; di (1-hydroxycyclohexyl) peroxide; ethyl 3,3-di (tert-butylperoxy) butyrate; and tert-butyl 3-isopropenylcumyl peroxide Can be mentioned.

  Non-limiting examples of crosslinking aids include triallyl cyanurate; triallyl isocyanurate; tri (methallyl) -isocyanurate; tris (diallylamine) -s-triazine, triallyl phosphite; N, N-diallylacrylamide; hexaallyl N, N, N ', N'-tetraallylterephthalamide; N, N, N', N'-tetraallylmalonamide; trivinyl isocyanurate; 2,4,6-trivinylmethyltrisiloxane And tri (5-norbornene-2-methylene) cyanurate. The crosslinking aid preferably contains at least two sites of olefinic unsaturation. These unsaturated sites react with free radicals generated on the fluorocarbon elastomer molecule to crosslink the elastomer. A commonly used crosslinking agent is triallyl isocyanurate (TAIC).

  In various embodiments, the cured fluorocarbon elastomer composition of the present invention is prepared by a process of dynamic vulcanization. Dynamic vulcanization is a vulcanization or curing process of a rubber (here a fluorocarbon elastomer) contained in a thermoplastic composition, where the curable rubber has a sufficiently high shear force at temperatures above the melting point of the thermoplastic component. Vulcanize under conditions. In this manner, the rubber is simultaneously crosslinked and dispersed within the thermoplastic matrix. Dynamic vulcanization is carried out in conventional mixing equipment such as roll mills, Moriyama mixers, Banbury mixers, Brabender mixers, continuous mixers, mixing extruders such as single and twin screw extruders, in the presence of curing agents, This can be achieved by adding mechanical energy and mixing the elastomer and thermoplastic components. An advantageous feature of dynamically cured compositions is that they do not resist the full cure of the elastomer component, but the compositions are conventional plastic processing techniques such as extrusion, injection molding, and compression molding. It can be processed and reprocessed. Scrap or flushing can also be used and reprocessed with thermoplastic technology.

  The vulcanized elastomeric material resulting from the dynamic vulcanization process is usually present as small particles in a continuous thermoplastic polymer matrix. Co-continuous forms are also possible depending on the amount of elastomeric material relative to the thermoplastic material, the curing system, the curing mechanism and the amount and degree of mixing.

  After dynamic vulcanization, a homogeneous mixture is obtained in which the cured fluoroelastomer is in the form of dispersed particles having an average particle size of less than about 50 μm, preferably an average particle size of less than about 25 μm. Typically, the particles have an average size of 10 μm or less, more preferably 5 μm or less. In some embodiments, the particles have an average size of 1 μm or less. In other embodiments, a significant number of hardened elastomer particles having a diameter of less than 1 micron are dispersed within the thermoplastic matrix even when the average particle size is larger.

  A peroxide masterbatch is prepared by mixing a peroxide cure initiator, a fluorocarbon elastomer, and optionally a crosslinker. The masterbatch can contain about 5-50% by weight of peroxide. The master batch can be easily prepared by mixing the compounding agent in a normal mixer such as a Banbury mixer. You may compound with a screw mixer like a twin screw extruder. The masterbatch containing the fluorocarbon elastomer and peroxide can be added to the molten mixture during dynamic vulcanization processing the batch mixture or in a continuous mixer such as a twin screw extruder.

  A fluorocarbon elastomer of the peroxide masterbatch can be selected to match the mixing in the fluorocarbon elastomer during the dynamic vulcanization process. In a typical dynamic vulcanization process, fluorocarbon elastomers are mixed together in a molten thermoplastic material. The temperature is usually 10-20 ° C. higher than the melting point of the thermoplastic material. Addition of a peroxide curative, optionally in the form of a masterbatch, along with a cross-linker containing multi-site olefinic unsaturation can speed up the incorporation of the peroxide curative into the elastomeric phase of the dynamic vulcanizate. it can. It is believed that the fluorocarbon elastomer component of the masterbatch protects the peroxide from bumping and volatilizing when added to the molten mixture.

  In one embodiment, the peroxide masterbatch fluorocarbon elastomer and the molten mixture fluorocarbon elastomer are selected to be identical. In this manner, the masterbatch containing the peroxide is readily compatible with the dynamically vulcanized rubber fluorocarbon elastomer. By using the masterbatch method, a portion of the fluorocarbon elastomer that is cured in the dynamic vulcanization process is added along with the peroxide. A dynamic vulcanization recipe with fluorocarbon elastomer loading at different stages of the dynamic vulcanization process can be designed and calculated by the concentration of the fluorocarbon elastomer in the masterbatch.

Although the masterbatch can contain a wide range of peroxide concentrations, it is usually preferred to prepare a masterbatch having a peroxide of about 5% to about 50% by weight. In some embodiments, it is desirable to add the peroxide in a masterbatch batch process to as little fluorocarbon elastomer as possible to achieve the desired properties of a fully cured dynamic vulcanizate. In other embodiments, it may be desirable to add additional fluorocarbon elastomer during the dynamic vulcanization process after the initial melt blending of the fluorocarbon elastomer and thermoplastic material. In this case, a masterbatch with a peroxide concentration towards the lower limit of the preferred range can be used.

  The masterbatch is blended under conditions such that the blending temperature does not exceed the temperature at which the peroxide will act to cure the fluorocarbon elastomer. Typically, the masterbatch can be blended at temperatures up to 100 ° C. to provide a low viscosity mixture sufficient for efficient blending. A preferred temperature range for blending the masterbatch is 80-100 ° C. For reactive elastomers, it may be desirable to blend below 80 ° C.

  The cured dynamic vulcanizate of the present invention can be prepared in a batch, semi-batch, or continuous process. For example, blending a thermoplastic material and a fluorocarbon elastomer at a temperature above that at which the thermoplastic material will flow sufficiently to form a dispersion of the fluorocarbon elastomer in the thermoplastic material to form a first mixture. Can prepare a melt processable fluoroelastomer composition. Such a temperature can be referred to as the melt flow temperature. Next, a second mixture (masterbatch) containing a fluorocarbon elastomer and preferably greater than about 5% by weight of organic peroxide is fed. This masterbatch is fed at a temperature below the temperature at which the peroxide will activate and initiate crosslinking of the fluorocarbon elastomer. The first mixture and the second mixture are then mixed and blended together while heating at a temperature sufficient for a sufficient time to achieve curing of the fluorocarbon elastomer in the first and second mixtures.

  This process can also be carried out continuously, for example in an extrusion mixer such as a twin screw extruder. In one embodiment, a solid blend of uncured fluorocarbon elastomer and thermoplastic material is fed to a first feeder of a first twin screw extruder. The solid blend is injected into the barrel of the extruder, heated above the temperature at which the thermoplastic material will melt and flow, to produce a dispersion of fluorocarbon elastomer in the thermoplastic material. For example, the barrel can be heated above the crystalline melting point of the thermoplastic material. In preferred embodiments, this temperature is 10 ° C, 20 ° C or 30 ° C above the melting point of the thermoplastic material. For example, the barrel may be heated above 180 ° C, 210 ° C, or 240 ° C. The solid blend is then mixed in a twin screw extruder to form a homogeneous melt blend. A peroxide masterbatch containing 5% by weight or more of organic peroxide is fed to the second feeder and injected into the barrel of the twin screw extruder at a point downstream of the first feeder. The peroxide masterbatch in the barrel and the homogeneous melt blend are further mixed while continuing to heat for a sufficient time and at a sufficient temperature to achieve curing of the fluorocarbon elastomer. The cured dynamic vulcanized rubber can then be extruded from a twin screw extruder.

  In an alternative embodiment, the peroxide masterbatch is run in a twin screw extruder that blends the organic peroxide, fluorocarbon elastomer, and optional crosslinker at a temperature below the temperature that will activate the peroxide and cure the elastomer. Can be fed to 2 feeders. In this manner, the fluorocarbon elastomer and thermoplastic material can be fed continuously at the first feeder port and the curing agent and fluorocarbon elastomer can be fed at the second port downstream from the first port.

  After extrusion from the mixing device, the dynamically vulcanized strand is cooled in a water bath and cut into pellets for later use.

  Use of the peroxide masterbatch process to produce dynamic vulcanizates is advantageous when compared to the physical properties of articles made with the addition of peroxide and crosslinking aids as separate components, rather than as part of the masterbatch This results in the formation of molded articles having a combination of physical properties. The masterbatch process also allows the use of high melting thermoplastics and fluororesins to produce dynamic vulcanizates while retaining acceptable elastomeric properties. Articles having a tensile strength of greater than about 10 MPa, or even 15 MPa or even 20 MPa at 150 ° C. can be produced. Even at 250 ° C., articles having a tensile strength of greater than 10 MPa, preferably greater than 12 MPa, and more preferably greater than 15 MPa can be produced. Articles made by methods other than the masterbatch method at these temperatures tend to exhibit lower or less advantageous values of tensile strength and other properties.

  The invention has been described with reference to preferred embodiments. In addition, the following examples provide non-limiting examples of the compositions and methods of the present invention.

Example 1-Preparation of Peroxide Masterbatch The procedure for making a masterbatch containing a curable fluorocarbon elastomer is as follows: 1) In a batch mixer such as a Brabender with an internal mixer attachment, at 80-100 ° C. At temperature, the fluorocarbon elastomer (eg, Technoflon P757, a peroxide curable fluorocarbon elastomer containing cure sites commercially available from Solvay) is melted. 2) Add a hardener package consisting of Luperco 101 XL and TAIC. Luperco 101 XL contains 2,5, -dimethyl-2,5-di (tert-butylperoxy) hexyne-3 as an active ingredient. TAIC is triallyl isocyanurate. Continue mixing until a homogeneous mixture is obtained. 3) Discharge the mixture from the internal mixer, cool and crush into powder or small pellets. This composition can be used as a masterbatch material during dynamic compounding of a fluorocarbon elastomer and a thermoplastic material.

Masterbatches are made with three different concentrations of peroxide and TAIC given in Examples 1a, 1b and 1c in the table below.

Examples 2-4 Continuous and Batch Methods Examples 2-4 show formulations for producing the molding compositions of the present invention. These can be produced in a batch or continuous process.

  In the batch method, a peroxide curable elastomer (Tecnoflon P757) and a thermoplastic (here fluoropolymer, Kynar Flex 2500-04) are mixed and melted in a Brabender or Banbury type batch mixer at 150 ° C. for 5 minutes. The zinc oxide is then stirred therein. Finely chopped masterbatch material (1-3 mm size, Example 1) is added to the mixer and stirred for a further 3-5 minutes at 150 ° C. to form a fully cured thermoplastic vulcanizate. Alternatively, a partially cured vulcanized rubber can be prepared by mixing in a short time such as 30 seconds. The composition is then discharged from a batch mixer and granulated to a small size for subsequent secondary processing processes such as injection molding, compression molding, blow molding, single layer extrusion, multilayer extrusion, insert molding, etc. A pellet is prepared.

The continuous process is carried out in a twin screw extruder. Mix Tecnoflon P757 and Kynar Flex 2500-04 pellets and add to hopper. Pellets are fed into a barrel heated to 150 ° C. The screw speed is 100-200 rpm. In the downstream hopper, the peroxide masterbatch pellets are fed into the barrel. The downstream port is about 1/3 of the total barrel length from the end of the extruder exit. The masterbatch is melted and blended with the molten elastomer and (fluoro) plastic mixture for a time determined by screw speed and barrel length. For example, the residence time is about 4-5 minutes at 100 rpm and about 2-2.5 minutes at 200 rpm. The cured material is extruded through a 1-3 mm diameter strand die, cooled in a water bath, quenched, and then passed through a strand pelletizer. The pellets can be processed into molded articles using a wide variety of thermoplastic techniques. This material can also be formed into plaques for measuring physical properties.

  Molded articles made from the cured compositions of Examples 2-4 are prepared by conventional plastic processing techniques. The cross section of the molded product is examined with a microscope or a scanning electron microscope. The dynamic vulcanized rubber made from the masterbatch of Examples 2 to 4 has a smooth surface and a structure without pores as compared with a molded product prepared in the same manner without using the masterbatch method.

Example 5
The physical properties of the composition of Example 2 are measured. A peroxide masterbatch is added to the melt blend of elastomer and thermoplastic material at 250 ° C. Use the batch method.

Example 6
Physical properties are measured as in Example 5, except that the composition is obtained by adding a peroxide masterbatch to the melt blend of elastomer and thermoplastic material at 150 ° C. Use the batch method.

Example 7-Comparative Example The formulation given in Example 2 except that peroxide and TAIC are added as separate components to the melt blend of elastomer and thermoplastic material, rather than as part of a masterbatch containing a fluorocarbon elastomer portion. A molding composition is prepared according to (batch method). The temperature of the melt blend is 250 ° C.

Claims (49)

A method for producing a molding polymer composition comprising the following steps:
(A) forming a mixture of a thermoplastic material and a curable fluorocarbon elastomer at a temperature above the melting point of the thermoplastic material;
(B) adding a curing composition comprising an initiator having a half-life of 0.1 hour or more at a temperature of about 180 ° C. or more and a crosslinking agent to the mixture; and (c) mixing the mixture and the curing composition Heating while continuing;
Including methods.   The method of claim 1, wherein the initiator has a half-life of 0.1 hours or more at a temperature of about 190 ° C. or more.   The method of claim 2, wherein the initiator has a half-life of 0.1 hours or more at a temperature of about 200 ° C. or more.   The method of claim 1, wherein the thermoplastic material comprises a fluorine-containing thermoplastic polymer.   The method of claim 1, wherein the curable fluorocarbon elastomer comprises a copolymer of VDF, HFP, and cure site monomer.   The method of claim 5, wherein the curable fluorocarbon elastomer comprises a copolymer of VDF, HFP, TFE, and cure site monomer.   The method of claim 1, wherein the fluorocarbon elastomer comprises a copolymer of VDF, fluorinated vinyl ether, TFE, and cure site monomer.   The method of claim 1, wherein the fluorocarbon elastomer comprises a copolymer of VDF, propylene, TFE, and cure site monomer.   The method of claim 1, wherein the fluorocarbon elastomer comprises a copolymer of VDF, TFE, HFP, ethylene, fluorinated vinyl ether, and cure site monomer.   The method of claim 1, wherein the fluorocarbon elastomer comprises perfluororubber.   The method of claim 1, wherein the fluorocarbon elastomer comprises a copolymer of TFE and propylene.   The method of claim 1, comprising heating the mixture at a temperature greater than about 180 ° C.   The method of claim 12, comprising heating the mixture at a temperature greater than about 190 ° C.   The method of claim 13, comprising heating the mixture at a temperature greater than about 200 degrees Celsius. A process for producing a melt-processable fluorocarbon rubber composition comprising the following steps:
(A) adding to the melt blend of the fluorocarbon elastomer of the first part and the thermoplastic material a peroxide masterbatch comprising about 5% by weight or more of an organic peroxide and further a fluorocarbon elastomer of the second part; and (b) ) Mixing the peroxide masterbatch, the first portion of the fluorocarbon elastomer, and the thermoplastic material with heating for a time and at a temperature sufficient to effect curing of the first and second fluorocarbon elastomers. Process;
Including methods. The method according to claim 15, wherein a twin screw extruder having a first feeder and a second feeder downstream from the first feeder is used, wherein the adding step includes the following steps:
(I) injecting a composition comprising the fluorocarbon elastomer of the first portion and the thermoplastic material into the first feeder of the extruder; and (ii) adding the masterbatch to the first of the extruder. Adding to 2 feeders;
Including methods.   The method of claim 15, wherein the fluorocarbon elastomer of the first portion and the second portion is the same.   The method of claim 15, wherein the fluorocarbon elastomer comprises a copolymer of vinylidene fluoride and a cure site monomer containing iodine.   The method of claim 15, wherein the peroxide masterbatch comprises greater than about 10% by weight peroxide.   The method of claim 15, wherein the peroxide masterbatch comprises greater than about 20% by weight peroxide.   The method of claim 19, wherein the thermoplastic material comprises a fluororesin.   The method of claim 21, wherein the fluororesin comprises a vinylidene fluoride homopolymer.   The method of claim 21, wherein the fluororesin comprises a vinylidene fluoride copolymer.   A molded article comprising a peroxide-cured dynamic vulcanized rubber of a fluorocarbon elastomer and a fluorine-containing thermoplastic resin having a tensile modulus greater than about 10 MPa.   25. The molded article of claim 24, having a tensile modulus greater than about 12 MPa.   26. The molded article of claim 25, having a tensile modulus greater than about 15 MPa.   The molded article according to claim 24, comprising a discontinuous phase of a cured fluorocarbon elastomer and a continuous phase of a fluororesin material.   27. A molded article according to claim 26, wherein the fluorocarbon elastomer comprises a copolymer of VDF and HFP.   30. The molded article of claim 28, wherein the fluorocarbon elastomer comprises a copolymer of VDF, HFP, and TFE.   27. The molded article of claim 26, wherein the fluorocarbon elastomer comprises a copolymer of VDF, fluorinated vinyl ether, and TFE.   27. The molded article of claim 26, wherein the fluorocarbon elastomer comprises a copolymer of VDF, TFE, and propylene.   27. The molded article of claim 26, wherein the fluorocarbon elastomer comprises a copolymer of VDF, HFP, TFE, fluorinated vinyl ether, and ethylene.   27. A molded article according to claim 26, wherein the fluorocarbon elastomer comprises perfluoro rubber. A process for producing a melt processable fluoroelastomer composition comprising the following steps:
(A) blending the thermoplastic polymer material and the first fluorocarbon elastomer at a temperature above the melt flow temperature of the thermoplastic material to form a first mixture;
(B) the first mixture comprising a second mixture comprising a second fluorocarbon elastomer and about 5% by weight or more of an organic peroxide; and the peroxide is activated to initiate crosslinking of the second fluorocarbon elastomer. Mixing at a temperature below the brazing temperature; and (c) heating the first and second mixtures together at a temperature sufficient to cure the fluorocarbon elastomer in the first and second mixtures. Blending while;
Including methods.   35. The method of claim 34, wherein the second mixture further comprises a crosslinker containing at least two sites of olefinic unsaturation.   36. The method of claim 35, wherein the cross-linking agent comprises triallyl isocyanurate.   36. The method of claim 35, wherein the first mixture further comprises a crosslinking agent containing at least two sites of olefinic unsaturation.   38. The method of claim 37, wherein the cross-linking agent comprises triallyl isocyanurate. Preparing a peroxide cured dynamic vulcanizate of fluorocarbon elastomer in a thermoplastic using a twin screw extruder having a barrel, a first feeder and a second feeder downstream of the first feeder A continuous process comprising the following steps:
(A) supplying a solid blend of uncured fluorocarbon elastomer and thermoplastic to the first feeder;
(B) pouring the solid blend into the barrel of the extruder heated to a temperature higher than the melt flow temperature of the thermoplastic;
(C) mixing the solid blend in the extruder to form a homogeneous melt blend;
(D) Injecting a peroxide masterbatch containing an uncured fluorocarbon elastomer and 5% by mass or more of an organic peroxide into the second feeder;
(E) mixing the peroxide masterbatch and the homogeneous melt blend in the barrel while continuing to heat for a sufficient time at a temperature sufficient to achieve curing of the fluorocarbon elastomer; and (f) the mixture. Extruding from the twin screw extruder;
Including methods.   40. The method of claim 39, wherein the peroxide masterbatch is fed to the second feeder in a twin screw apparatus that blends the organic peroxide and fluorocarbon elastomer at a temperature below that which would activate the peroxide.   40. The method of claim 39, wherein the fluorocarbon elastomer comprises a copolymer of vinylidene fluoride and cure site monomer, and the thermoplastic comprises a fluororesin.   42. The method of claim 41, wherein the fluororesin comprises a vinylidene fluoride polymer.   40. The method of claim 39, wherein the barrel is heated above about 180 ° C.   44. The method of claim 43, wherein the barrel is heated above about 210 degrees Celsius.   45. The method of claim 44, wherein the barrel is heated above about 240 ° C.   40. The method of claim 39, wherein the peroxide masterbatch further comprises a crosslinker containing two or more sites of olefinic unsaturation.   48. The method of claim 46, wherein the cross-linking agent comprises triallyl isocyanurate.   40. The method of claim 39, wherein the solid blend of uncured fluorocarbon elastomer and thermoplastic further comprises a crosslinker containing two or more sites of olefinic unsaturation. 49. The method of claim 48, wherein the cross-linking agent comprises triallyl isocyanurate.