WO2009086068A2

WO2009086068A2 - Low temperature curable amorphous fluoropolymers

Info

Publication number: WO2009086068A2
Application number: PCT/US2008/087620
Authority: WO
Inventors: Tatsuo Fukushi; Dennis E. Hull; Yeng Moua
Original assignee: 3M Innovative Properties Company
Priority date: 2007-12-21
Filing date: 2008-12-19
Publication date: 2009-07-09
Also published as: WO2009086068A3

Abstract

There is provided a composition having an amorphous peroxide curable fluoropolymer with an iodine, bromine or chlorine containing cure site; an organic peroxide; and a coagent, where the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07 is less than 30 minutes at 130°C. There is also provided a fluoroelastomer preparable by curing such composition. There is further provided a cure in place process using such composition to create a cure in place article and cure in place articles from such process. The disclosed cure in place article has a press-cure compression set in the range 10% to 50% after curing for 30 minutes at 130°C.

Description

LOW TEMPERATURE CURABLE AMORPHOUS FLUOROPOLYMERS

[0001] The present disclosure relates to curable compositions of amorphous fluoropolymers and a process for creating cured in place articles derived from such compositions. The present disclosure also relates to peroxide curable amorphous fluoropolymer compositions exhibiting fast cure times at low temperatures.

SUMMARY

[0002] In one aspect, the present disclosure provides a composition having an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site; an organic peroxide selected from one of Formula (I) or Formula (II)

O R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (H)

where Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms; and a coagent, where the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07 is less than 30 minutes at 130⁰C.

[0003] In another aspect, the present disclosure provides a fluoroelastomer preparable by providing a composition having an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site; an organic peroxide selected from one of Formula (I) or Formula (II) shown above, where Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms; providing a coagent; and curing the composition at 130⁰C for less than 30 minutes, where the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07. [0004] In yet another aspect, the present disclosure provides a cure in place process including the steps of: providing a substrate; positioning on the substrate a composition having an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site; an organic peroxide selected from one of Formula (I) or Formula (II) shown above, where Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms; and providing a coagent; and curing the composition at 130⁰C for less than 30 minutes, wherein the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07.

[0005] In still another aspect, the present disclosure provides a cure in place article derived from a composition including an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site; an organic peroxide selected from one of Formula (I) or Formula (II) shown above where Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms; and a coagent, where the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07 is less than 30 minutes at 130⁰C, and where the article has a compression set of 10% to 50% after curing for 30 minutes at 130⁰C with no post cure.

[0006] The above summary of the present disclosure is not intended to describe each embodiment of the present invention. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a plot showing 90% cure time (t'90) as the function of MDR curing temperature (⁰C) for peroxides including 2,5-dimethyl-2,5-di(t-butylperoxy)-hexane (DBPH), tert-butyl peroxy 2-ethylhexyl carbonate (TBEC), and tert-butyl peroxy isopropylcarbonate (TBIC).

[0008] FIGS. 2(a)-2(c) are compilation of plots showing Moving Disk Rheometer (MDR) cure charts with TBEC peroxide (Example 2) and TBIC peroxide (Example 4) at 130⁰C and Comparative Example 1 with DBPH peroxide. DETAILED DESCRIPTION

[0009] Curing temperatures for amorphous fluoropolymers or fluoroelastomers is generally higher than curing temperatures for non-fluorocarbon elastomers, such as silicone elastomers. Curing temperatures for amorphous fluoropolymers or fluoroelastomers generally range from about 160⁰C to about 180⁰C. Because of the high temperatures required to cure amorphous fluoropolymers, compounds containing amorphous fluoropolymers are difficult to mold or process with other plastics or other types of elastomers.

[0010] Peroxide curable fluoroelastomers having iodine cure sites or iodine end groups are generally known. The cure speed of a fluoroelastomer with an iodine cure site or iodine end groups is faster than that of fluoroelastomer with a bromine cure site or bromine end groups. Those skilled in the art appreciate that 2,5-dimethyl-2,5-di(t- butylperoxy)-hexane (DBPH) peroxide has been widely used as the standard peroxide for peroxide curable fluoroelastomer with an iodine cure site since the 1970's. Still other known peroxides used to prepare peroxide curable fluoroelastomers include peroxide including 2,5-dimethyl-2,5-di(t-butylperoxy)-hexane (DBPH), di(2-t- butylperoxyisopropyl)benzene and dicumyl peroxide. However, the presently known peroxide cure systems do not provide rapid curing at low temperatures.

[0011] The present disclosure provides compositions of amorphous fluoropolymers that can be quickly cured at low temperatures without compromising physical properties of articles derived from these compositions. These amorphous fluoropolymers may also exhibit low viscosities, which can be useful in milling and molding applications and cure in place applications. The presently disclosed compositions may also include one or more conventional adjuvants, such as, for example, fillers, acid acceptors, process aids, or colorants.

[0012] The fluoropolymers presently disclosed may include one or more interpolymerized units derived from at least two principal monomers. Examples of suitable candidates for the principal monomer(s) include perfluoroolefms (e.g., tetrafluoroethylene (TFE) and hexafluoropropylene (HFP)), perfluorovinyl ethers (e.g., perfluoroalkyl vinyl ethers (PAVE) and perfluoroalkoxy vinyl ethers (PAOVE)) and hydrogen-containing monomers such as olefins (e.g., ethylene, propylene, and the like) and vinylidene fluoride (VDF). Such fluoropolymers include, for example, fluoroelastomer gums and semi-crystalline fluoroplastics.

[0013] Those skilled in the art are capable of selecting specific interpolymerized units at appropriate amounts to form an elastomeric polymer Thus, the appropriate level of interpolymerized units are based on mole%, are selected to achieve an elastomeric, polymeric composition.

[0014] When the fluoropolymer is perhalogenated, preferably perfluorinated, it contains at least 50 mole percent (mol %) of its interpolymerized units derived from TFE and/or CTFE, optionally including HFP. The balance of the interpolymerized units of the fluoropolymer (10 to 50 mol %) is made up of one or more perfluoroalkyl vinyl ethers (PAVE) and/or perfluoroalkoxy vinyl ethers (PAOVE), and a suitable cure site monomer. An exemplary fluoropolymer is composed of principal monomer units of TFE and at least one perfluoroalkyl vinyl ether. In such copolymers, the copolymerized perfluorinated ether units constitute from about 10 to about 50 mol %, and preferably from about 15 to about 35 mol % of total monomer units present in the polymer.

[0015] When the fluoropolymer is not perfluorinated, it contains from about 5 mol % to about 90 mol % of its interpolymerized units derived from TFE, CTFE, and/or HFP, from about 5 mol % to about 90 mol % of its interpolymerized units derived from VDF, ethylene, and/or propylene, up to about 40 mol % of its interpolymerized units derived from a vinyl ether, and from about 0.1 mol % to about 5 mol %, and preferably from about 0.3 mol % to about 2 mol %, of a suitable cure site monomer.

[0016] Suitable perfluorinated ethers include those of the formula: CF2=CFO-(CF2)_m-(O(CF2)p)_n-OR_f (Formula 1) wherein R_f is a perfluorinated (Cl -C4) alkyl group, m=l-4, n=0-6, and p=l-2, or

CF2=CF(CF2)_m -O-Pv_f (Formula 2) wherein: m=l-4; R_f is a perfluorinated aliphatic group optionally containing O atoms. These perfluorinated ethers may be pre-emulsified with an emulsifier prior to its copolymerization with the other comonomers. Exemplary perfluoroalkoxy vinyl ethers include CF₂=CFOCF₂OCF_S, CF₂=CFOCF₂OCF₂CF₃, CF₂=CFOCF₂CF₂OCF₃, CF₂=CFOCF₂CF₂CF₂OCF₃, CF₂=CFOCF₂CF₂CF₂ CF₂OCF₃, CF₂=CFOCF₂OCF₂CF₃, CF₂=CFOCF₂ CF₂OCF₂CF₃, CF₂=CFOCF₂ CF₂CF₂OCF₂CF₃,

CF₂=CFOCF₂CF₂CF₂ CF₂OCF₂CF₃, CF₂=CFOCF₂CF₂OCF₂OCF_3, CF₂=CFOCF₂CF₂OCF₂CF₂OCF₃,

CF₂=CFOCF₂CF₂OCF₂CF₂CF₂OCF₃ CF₂=CFOCF₂CF₂OCF₂CF₂CF₂CF₂OCF_3, CF₂=CFOCF₂CF₂OCF₂CF₂CF₂CF₂CF₂OCF_3, CF₂=CFOCF₂CF₂(OCF₂)_SOCF₃, CF₂=CFOCF₂CF₂(OCF₂^OCF₃, CF₂=CFOCF₂CF₂OCF₂OCF₂OCF₃, CF₂=CFOCF₂CF₂OCF₂CF₂CF₃ and CF₂=CFOCF₂CF₂OCF₂CF₂OCF₂CF₂CF₃. Mixtures of perfluoroalkyl vinyl ethers (PAVE) and perfluoroalkoxy vinyl ethers (PAOVE) may also be employed. Perfluoroolefms useful in the present disclosure include those of the formula: CF₂=CF-Rf, where Rf is fluorine or a perfluoroalkyl of 1 to 8, preferably 1 to 3, carbon atoms.

[0017] Exemplary perfluoroalkoxy allyl ethers include CF₂=CFCF₂OCF₂CF₂OCF_3, CF₂=CFCF₂OCF₂CF₂ CF₂OCF₃and CF₂=CFCF₂OCF₂OCF₃.

[0018] In some embodiments, partially- fluorinated monomers or hydrogen-containing monomers such as olefins (e.g., ethylene, propylene, and the like), and vinylidene fluoride can be used in the fluoropolymer. An exemplary partially fluorinated polymer includes principal monomer units of TFE and propylene, such as the polymer available under the trade designation "AFLAS" (Asahi Glass Co. Ltd., Tokyo, Japan). Another exemplary partially fluorinated terpolymer having principal monomer units of tetrafluoroethylene, propylene and vinylidene fluoride, such as the polymer available under the trade designation "BRE 723 IX" (Dyneon LLC, Minnesota, USA).

[0019] The amorphous fluoropolymer presently disclosed is created by a sequence of steps, including polymerization, coagulation/drying, milling, compounding, pre-forming, and curing/molding. In one embodiment, an aqueous emulsion polymerization can be carried out continuously under steady-state conditions. In this embodiment, for example, an aqueous emulsion of the perfluoro ethers of Formulas (1) and (2) as previously disclosed, and the other monomers, water, emulsifϊers, buffers and catalysts are fed continuously to a stirred reactor under optimum pressure and temperature conditions while the resulting emulsion or suspension is continuously removed. In some embodiments, batch or semibatch polymerization is conducted by feeding the aforementioned ingredients into a stirred reactor and allowing them to react at a set temperature for a specified length of time or by charging ingredients into the reactor and feeding the monomers into the reactor to maintain a constant pressure until a desired amount of polymer is formed. After polymerization, unreacted monomers are removed from the reactor effluent latex by vaporization at reduced pressure. Polymer is recovered from the latex by coagulation.

[0020] The polymerization is generally conducted in the presence of a free radical initiator system, such as ammonium persulfate. The polymerization reaction may further include other components such as chain transfer agents and complexing agents. The polymerization is generally carried out at a temperature between 10⁰C and 100⁰C, and preferably between 30⁰C and 80⁰C. The polymerization pressure is usually in the range of 0.3 MPa to 30 MPa, and in some embodiments in the range of 2 MPa and 20 MPa.

[0021] When conducting emulsion polymerization, perfluorinated, partially fluorinated, APFO (ammonium perfluorooctanate) free emulsifϊers may be used, in addition to emulsifier-free polymerization. Generally these fluorinated emulsifϊers comprise from about 0.02% to about 3% by weight with respect to the polymer. Polymer particles produced with a fluorinated emulsifier typically have an average diameter, as determined by dynamic light scattering techniques, in range of about 10 nm to about 300 nm, and in some embodiments in range of about 50 nm to about 200 nm.

[0022] Such fluorinated and partially fluorinated emulsifϊers include those commonly used in emulsion polymerization of fluorine containing monomers. Examples of such emulsifier include fluoroalkyl, preferably perfluoroalkyl, carboxylic acids and salts thereof having 6-20 carbon atoms, preferably 6-12 carbon atoms, such as ammonium perfluorooctanoate (APFO) and ammonium perfluorononanoate. (See, e.g. U.S. Pat. No. 2,559,752 to Berry).

[0023] Additional examples of such emulsifϊers also include perfluorinated and partially fluorinated emulsifier having the formula [R_f-O-L-COO ]₁X¹⁺ wherein L represents a linear partially or fully fluorinated alkylene group or an aliphatic hydrocarbon group, Rf represents a linear partially or fully fluorinated aliphatic group or a linear partially or fully fluorinated aliphatic group interrupted with one or more oxygen atoms, X¹⁺ represents a cation having the valence i and i is 1, 2 or 3. (See, e.g. U.S. Pat. No. 2007/0015864 to Hinzter et al.).

[0024] Additional examples of such emulsifiers also include perfluorinated polyether emulsifiers having the formula (I) or (II), where CFs-(OCF₂)In-O-CF₂ -X (I) wherein m has a value of 1 to 6 and X represents a carboxylic acid group or salt thereof, CF₃-O-(CF₂)₃- (OCF(CF₃)-CF₂)_Z-O-L-Y (II) wherein z has a value of 0, 1, 2 or 3, L represents a divalent linking group selected from-CF(CF₃)-,-CF₂-and-CF ₂CF₂-and Y represents a carboxylic acid group or salt thereof. (See, e.g. U.S. Pat. Publ. No. 2007/0015865 to Hintzer et al.).

[0025] Further examples of such emulsifiers include perfluorinated polyether emulsifiers having the formula R_f-O(CF₂CF₂O)_mCF₂COOA wherein R_f is C_nF_(2n+i₎; where n = 1-4, A is a hydrogen atom, an alkali metal or NH₄, and m is an integer of from 1 to 3. (See, e.g. U.S. Pat. No. 2006/0199898 to Funaki; Hiroshi et al.). Additional examples of such emulsifiers also include perfluorinated emulsifiers having the formula F(CF₂)_nO(CF₂CF₂O)_mCF ₂ COOA wherein A is a hydrogen atom, an alkali metal or NH₄, n is an integer of from 3 to 10, and m is 0 or an integer of from 1 to 3. (See, e.g. U.S. Pat. Publ. No. 2007/0117915 to Funaki; Hiroshi et al.).

[0026] Additional examples of such emulsifiers include fluorinated polyether emulsifiers as described in U.S. Pat. No. 6,429,258 to Morgan et al. and perfluorinated or partially fluorinated alkoxy acids and salts thereof wherein the perfluoroalkyl component of the perfluoroalkoxy has 4-12 carbon atoms, preferably 7-12 carbon atoms. (See, e.g. U.S. Pat. No. 4,621,116 to Morgan).

[0027] Other exemplary emulsifiers include partially fluorinated polyether emulsifiers having the formula [R_f-(O)_t-CHF-(CF₂)_n-COO-]_!X¹⁺ wherein R_f represents a partially or fully fluorinated aliphatic group optionally interrupted with one or more oxygen atoms, t is 0 or 1 and n is 0 or 1, X¹⁺ represents a cation having a valence i and i is 1, 2 or 3. (See, e.g. U.S. Pat. Publ. No. 2007/0142541 to Hintzer et al.).

[0028] More exemplary emulsifiers include perfluorinated or partially fluorinated ether containing emulsifiers as described in U.S. Pat. Publ. Nos. 2006/0223924 to Tsuda; Nobuhiko et al., 2007/0060699 to Tsuda; Nobuhiko et al, 2007/0142513 to Tsuda; Nobuhiko et al and 2006/0281946 to Morita; Shigeru et al. [0029] The perfluorinated, partially fluorinated and/or APFO (ammonium perfluorooctanate) free emulsifϊers can be removed or recycled from the fluoropolymers latex as described in U.S. Pat. Nos. 5,442,097 to Obermeier et al, 6,613,941 to Felix et al, 6,794,550 to Hintzer et al., 6,706,193 to Burkard et al. and 7,018,541 Hintzer et al.

[0030] In some embodiments, the polymerization process may be conducted with no fluorinated emulsifϊers. Polymer particles produced without an emulsifϊer typically have an average diameter, as determined by dynamic light scattering techniques, in a range of about 40 nm to about 500 nm, typically in range of about 100 nm and about 400 nm, whereas suspension polymerization will typically produce particles sizes up to several millimeters.

[0031] In some embodiments, liquid perfluoro ethers of Formula 1 and/or Formula 2 as previously disclosed can be pre-emulsifϊed in water with the aid of a fluorinated emulsifϊer prior to copolymerization with gaseous fluorinated monomers. The pre-emulsification of the liquid fluorinated monomer preferably results in an emulsion having monomer droplets having a diameter of about 1 micrometer or more, with an expected range of about 1 micrometer to 20 micrometer as described in U.S. Pat. No. 6,677,414.

[0032] In some embodiments, a water soluble initiator can be used to start the polymerization process. Salts of peroxy sulfuric acid, such as ammonium persulfate, are typically applied either alone or sometimes in the presence of a reducing agent, such as bisulfϊtes or sulfϊnates (disclosed in U.S. Pat. Nos. 5,285,002 Grootaert and 5,378,782 to Grootaert) or the sodium salt of hydroxy methane sulfuric acid (sold under the trade designation "RONGALIT", BASF Chemical Company, New Jersey, USA). Most of these initiators and the emulsifϊers have an optimum pH-range where they show most efficiency. For this reason, sometimes buffers are used in some embodiments. Buffers include phosphate, acetate or carbonate buffers or any other acid or base, such as ammonia or alkali metal hydroxides. The concentration range for the initiators and buffers can vary from 0.01% to 5% by weight based on the aqueous polymerization medium.

[0033] At least one of the presently disclosed fluoropolymers has an effective amount of cure sites, such that it has a Mooney viscosity of 10 or less (ML 1+10) at 121⁰C according to ASTM D 1646-06 TYPE A. The end groups are iodine, bromine or chlorine end groups chemically bonded to chain ends of at least one of the fluoropolymers. The weight percent of iodine, bromine or chlorine may range from about 0.2 wt.% to about 2 wt.%, and preferably from about 0.3 wt.% to about 1 wt.%.

[0034] In the present disclosure, any one of an iodo-chain transfer agent, a bromo-chain transfer agent or a chloro-chain transfer agent can be used in the polymerization process. For example, suitable iodo-chain transfer agent in the polymerization include the formula OfRI_x, where (i) R is a perfluoroalkyl or chloroperfluoroalkyl group having 3 to 12 carbon atoms; and (ii) x = 1 or 2. The iodo-chain transfer agent may be a perfluorinated iodo- compound. Exemplary iodo-perfluoro-compounds include 1,3-diiodoperfluoropropane, 1 ,4-diiodoperfluorobutane, 1, 6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,10- diiodoperfluorodecane, 1 , 12-diiodoperfluorododecane, 2-iodo- 1 ,2-dichloro-l, 1,2- trifluoroethane, 4-iodo-l,2,4-trichloroperfluorobutan and mixtures thereof. In some embodiments, the bromine is derived from a brominated chain transfer agent of the formula: RBr_x, where (i) R is a perfluoroalkyl or chloroperfluoroalkyl group having 3 to 12 carbon atoms; and (ii) x = 1 or 2. The chain transfer agent may be a perfluorinated bromo-compound.

[0035] The cure site monomers are derived from one or more compounds of the formula: a) CX₂=CX(Z), wherein: (i) X each is independently H or F ; and (ii) Z is I, Br, R/ -U wherein U=I or Br and R/=a perfluorinated or partially perfluorinated alkylene group optionally containing O atoms. In addition, non-fluorinated bromo-or iodo-olefms, e.g., vinyl iodide and allyl iodide, can be used. In some embodiments, the cure site monomers are derived from one or more compounds selected from the group consisting of CH₂=CHI, CF₂=CHI, CF₂=CFI, CH₂=CHCH₂I, CF₂=CFCF₂I, CH₂=CHCF₂CF₂I, CF₂=CFCH₂CH₂I, CF₂=CFCF₂CF₂I, CH₂=CH(CF₂^CH₂CH₂I, CF₂=CFOCF₂CF₂I, CF₂=CFOCF₂CF₂CF₂I, CF₂=CFOCF₂CF₂CH₂I, CF₂=CFCF₂OCH₂CH₂I, CF₂=CFO(CF₂)_S- OCF₂CF₂I, CH₂=CHBr, CF₂=CHBr, CF₂=CFBr, CH₂=CHCH₂Br, CF₂=CFCF₂Br, CH₂=CHCF₂CF₂Br, CF₂=CFOCF₂CF₂Br, CF₂=CFCl, CF₂=CFCF₂Cl and mixtures thereof.

[0036] The chain transfer agents and/or the cure site monomers can be fed into the reactor by batch charge or continuously feeding. Because feed amount of chain transfer agent and/or cure site monomer is relatively small compared to the monomer feeds, continuous feeding of small amounts of chain transfer agent and/or cure site monomer into the reactor is difficult to control. Continuous feeding can be achieved by a blend of the iodo-chain transfer agent in one or more monomers. Exemplary monomers for such a blend include but are not limited to hexafluoropropylene (HFP) and perfluoromethyl vinyl ether (PMVE).

[0037] To coagulate the obtained fluoropolymer latex, any coagulant which is commonly used for coagulation of a fluoropolymer latex may be used, and it may, for example, be a water soluble salt such as calcium chloride, magnesium chloride, aluminum chloride or aluminum nitrate, an acid such as nitric acid, hydrochloric acid or sulfuric acid, or a water soluble organic liquid such as an alcohol or acetone. The amount of the coagulant to be added is preferably in range of 0.001 to 20 parts by mass, particularly preferably in a range of 0.01 to 10 parts by mass per 100 parts by mass of the fluorinated elastomer latex. Further, the fluorinated elastomer latex may be frozen for coagulation.

[0038] The coagulated fluorinated elastomer is preferably collected by filtration and washed with washing water. The washing water may, for example, be ion exchanged water, pure water or ultrapure water. The amount of the washing water may be from 1 to 5 times by mass to the fluorinated elastomer, whereby the amount of the emulsifier attached to the fluorinated elastomer can be sufficiently reduced by one washing.

[0039] Peroxide cure fluoroelastomers require a compounding process to add co-agents, peroxides and fillers such as carbon black. The typical compounding process is to use a two-roll mill. If the viscosity of raw or compounded gum is too low, raw or compounded gum will stick to the mill and it will be difficult to process. Surprisingly, fluoroelastomers of this invention don't stick to a roll mill significantly during compounding.

[0040] In some embodiments, the crosslinkable fluoropolymer composition can be compounded with the curable component or mixed in one or several steps, using any of the usual rubber mixing devices such as internal mixers (e.g., Banbury mixers), roll mills, etc. For best results, the temperature of the mixture should not rise above about 120⁰C. During mixing it is necessary to distribute the components and additives uniformly throughout for effective cure.

[0041] The fluoroelastomer compositions can be used to form articles. The term "article" as used herein means a final article, such as an O-ring, and/or preforms from which a final shape is made, e.g. an extruded tube from which a ring is cut. To form an article, the fluoroelastomer composition can be extruded using a screw type extruder or a piston extruder. Alternatively, the fluoroelastomer composition can be shaped into an article using injection molding, transfer molding or compression molding. Surprisingly, the presently disclosed fluoroelastomer composition can also be cured in place.

[0042] Uncured elastomers can be molded using any one of a number of techniques. In some embodiments, uncured elastomers are compression molded by placing a quantity of cold uncured elastomer mixture into a heated mold cavity and subsequently closing the mold using adequate pressure to shape the article. After retaining the elastomer at sufficient temperature during sufficient time to allow vulcanization to proceed it can then be demolded.

[0043] In some embodiments, uncured elastomers are injection molded by first heating and masticating elastomer mixtures in an extruder screw and then collecting the elastomer mixtures in a heated chamber from which they are injected into a hollow mold cavity by means of a hydraulic piston. After vulcanization the article can then be demolded.

[0044] Advantages of injection molding process include short molding cycles, little or no preform preparation, little or no flash to remove, and low scrap rate. If the compound viscosity is low, the cylinder, barrel and screw temperature can be low and there is less risk to scorch during the flow into the mold. Also low compound viscosity can improve fill or injection time. Typical mold temperature is 170⁰C to 220⁰C and heating or molding time is 20 seconds to 3 minutes depending on parts thickness.

[0045] In some embodiments, the elastomer mixtures are transfer molded. Transfer molding is similar to injection molding with the difference being that the elastomer mixture is not preheated and masticated by an extruder screw but introduced as a cold mass in the heated injection chamber. Typical curing conditions for fluoroelastomer mixtures are elevated temperatures e.g. about 160⁰C to about 210⁰C, pressures above 7 bar and maintaining these conditions for 30 seconds, in fast injection molding processes to 5 minutes or longer for larger compression molded articles.

[0046] Pressing of the compounded mixture (i.e., press cure) is typically conducted at a temperature of about 120 to 220⁰C, preferably about 130 to 200⁰C, for a period of about 0.5 minutes to about 2 hours, usually for about 1 to 15 minutes. A pressure of about 700 to 20,000 kPa, preferably about 3400 to about 6800 kPa, is typically used in molding the composition. The molded vulcanizate can be used as an article without additional cure (no post cure). The molds first may be coated with a release agent and prebaked.

[0047] The molded vulcanizate can be post cured in an oven at a temperature of about 120-300⁰C, preferably at a temperature of about 150-250⁰C, for a period of about 30 minutes to about 24 hours or more, depending on the type of polymer used and the cross- sectional thickness of the sample.

[0048] The amorphous fluoropolymer compound also includes a curing agent that enables vulcanization of the fluoropolymer. The presently disclosed curing agent includes curable materials, such as, for example, peroxide and one or more co-agents. Presently disclosed peroxide curatives include organic peroxides. Exemplary organic peroxides include those having the Formula (I) or (II) as shown below:

O R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (H)

[0049] where Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms. Further examples of non-limiting carbonate peroxides include tert-butyl peroxy isopropylcarbonate (TBIC) (Chemical Abstract Service (CAS) Registration No. (RN) 2372-21-6), tert-butyl peroxy 2-ethylhexyl carbonate (TBEC) (CAS RN 34443-12- 4), tert-amyl peroxy 2-ethylhexyl carbonate (CAS RN 70833-40-8), tert-hexylperoxy isopropyl carbonate (CAS RN132929-84-1), carbonoperoxoic acid, O,O'-l,3-propanediyl OO,OO'-bis(l,l-dimethylethyl) ester (CAS RN 403477-29-2). These carbonate peroxides have a ten-hour half-life temperature of from 90 to 110⁰C. The ten-hour half-life temperature is a temperature at which a half amount of the organic peroxide is decomposed within ten hours. Table 1 shows a typical 10-hour half life temperature of peroxides with CAS (chemical abstracts service) registry numbers (RN). Table 1 Peroxides CAS RN 10-hour half life temperature (⁰C) t-hexyl peroxy isopropyl carbonate 132929-84-1 95 t-butyl peroxy isopropyl carbonate (TBEC) 34443-12-4 99 t-butylperoxy 2-ethylhexyl carbonate (TBIC) 2372-21-6 99

2,5-dimethyl-2,5~di(t-butylperoxy)hexane (DBPH) 78-63-7 118 dicumyl peroxide 80-43-3 116 di(2-t-butylperoxyisopropyl)benzene 25155-25-3 119 di[ 1 ,3-dimethyl-3-(t-butylperoxy)butyl] carbonate 26826-59-5 123

The amount of peroxide curing agent used generally will be in a range of 0.1 to 5, preferably in a range of 1 to 3 parts by weight per 100 parts of fluoropolymer.

[0050] In peroxide cure systems, it is often desirable to include a co-agent. Those skilled in the art are capable of selecting conventional co-agents based on desired physical properties. Non-limiting examples of such agents include tri(methyl)allyl isocyanurate (TMAIC), triallyl isocyanurate (TAIC), tri(methyl)allyl cyanurate, poly-triallyl isocyanurate (poly- TAIC), xylylene-bis(diallyl isocyanurate) (XBD), N,N'-m-phenylene bismaleimide, diallyl phthalate, tris(diallylamine)-s-triazine, triallyl phosphite, 1,2- polybutadiene, ethyleneglycol diacrylate, diethyleneglycol diacrylate, etc. Another useful co-agent may be represented by the formula CH2=CH-R_fi-CH=CH2 wherein R_f1 may be a perfluoroalkylene of 1 to 8 carbon atoms. Such co-agents provide enhanced mechanical strength to the final cured elastomer. They generally are used in amount of 1 to 10 parts by weight, or preferably 1 to 5 parts by weight, per 100 parts of the fluorocarbon polymer.

[0051] Fluoropolymers, in particular VDF containing fluoroelastomers, may be cured using a polyhydroxy curing system. In such instance, it will not be required that the fluoropolymer includes cure site components. The polyhydroxy curing system generally comprises one or more polyhydroxy compounds and one or more organo-onium accelerators. The useful organo-onium compounds typically contain at least one heteroatom, i.e., a non-carbon atom such as N, P, S, O, bonded to organic or inorganic moieties. One useful class of quaternary organo-onium compounds broadly comprises relatively positive and relatively negative ions wherein a phosphorus, arsenic, antimony or nitrogen generally comprises the central atom of the positive ion. The negative ion may be an organic or inorganic anion (e.g., halide, sulfate, acetate, phosphate, phosphonate, hydroxide, alkoxide, phenoxide, bisphenoxide, etc.). [0052] Many of the organo-onium compounds are disclosed. See, for example, U.S. Pat. Nos. 4,233,421 to Worm, 4,912,171 to Grootaert et al, 5,086,123 to Guenthner et al, 5,262,490 to KoIb et al., and 5,929,169 to Jing et al. A class of useful organo-onium compounds includes those having one or more pendent fluorinated alkyl groups. Generally, a most useful class of fluorinated onium compounds id disclosed in U.S. Pat. No. 5,591,804 to Coggio et al.

[0053] The polyhydroxy compound may be used in its free or non-salt form or as the anionic portion of a chosen organo-onium accelerator. The crosslinking agent may be any polyhydroxy compounds that function as a crosslinking agent or co-curative for fluoroelastomers, such as those polyhydroxy compounds disclosed in U.S. Pat. Nos. 3,876,654 to Pattison, and 4,233,421 to Worm. One of the most useful polyhydroxy compounds includes aromatic polyphenols such as 4,4'-hexafluoroisopropylidenyl bisphenol, known more commonly as bisphenol AF. The compounds 4,4'- dihydroxydiphenyl sulfone (also known as bisphenol S) and 4,4'-isopropylidenyl bisphenol (also known as bisphenol A) are also widely used in practice.

[0054] Fluoropolymers, in particular VDF containing fluoroelastomers, may also be cured using a polyamine curing system. Examples of useful polyamines include N₅N'- dicinnamylidene- 1 ,6-hexanediamine, trimethylenediamine, cinnamylidene trimethylenediamine, cinnamylidene ethylenediamine, and cinnamylidene hexamethylenediamine. Examples of useful carbamates are hexamethylenediamine carbamate, bis(4-aminocyclohexyl)methane carbamate, 1,3-diaminopropane monocarbamate, ethylenediamine carbamate and trimethylenediamine carbamate. Usually about 0.1-5 phr of the diamine is used.

[0055] Additives such as carbon black, stabilizers, plasticizers, lubricants, fillers, and processing aids typically utilized in fluoropolymer compounding can be incorporated into the compositions, provided they have adequate stability for the intended service conditions. In particular, low temperature performance can be enhanced by incorporation of perfluoropolyethers. See, for example, U.S. Pat. No. 5,268,405 to Ojakaar et al. Carbon black fillers are typically also employed in fluoropolymers as a means to balance modulus, tensile strength, elongation, hardness, abrasion resistance, conductivity, and processability of the compositions. Suitable examples include MT blacks (medium thermal black) designated N-991, N-990, N-908, and N-907; FEF N-550; and large particle size furnace blacks. When used, 1 to 100 parts filler per hundred parts fluoropolymer (phr) of large size particle black is generally sufficient.

[0056] Fluoropolymer fillers may also be present in the compositions. Generally, from 1 to 100 phr of fluoropolymer filler is used. The fluoropolymer filler can be finely divided and easily dispersed as a solid at the highest temperature used in fabrication and curing of the inventive composition. By solid, it is meant that the filler material, if partially crystalline, will have a crystalline melting temperature above the processing temperature(s) of the curable composition(s). A preferred way to incorporate fluoropolymer filler is by blending latices. This procedure, including various kinds of fluoropolymer filler, is described in U.S. Pat. No. 6,720,360 to Grootaert et al.

[0057] Conventional adjuvants may also be incorporated into the compound of the present invention to enhance the properties of the compound. For example, acid acceptors may be employed to facilitate the cure and thermal stability of the compound. Suitable acid acceptors may include magnesium oxide, lead oxide, calcium oxide, calcium hydroxide, dibasic lead phosphite, zinc oxide, barium carbonate, strontium hydroxide, calcium carbonate, hydrotalcite, alkali stearates, magnesium oxalate, or combinations thereof. The acid acceptors are preferably used in amounts ranging from about 1 to about 20 parts per 100 parts by weight of the polymer.

[0058] The following specific, but non-limiting, examples will serve to illustrate the invention. In these examples, all amounts are expressed in parts by weight, or parts by weight per one hundred parts by weight of rubber (phr). The monomer composition ratio was measured by ¹H/ ¹⁹F cross-integration NMR analysis.

Examples

Example 1

[0059] A 4 liter reactor was charged with 2,250 grams of water, 33.3 grams of 30% aqueous solution Of CFsOCF₂CF₂CF₂OCF₂COONH₄, 1.1 grams of ammonium persulfate (APS, (NFLi)₂S₂Og), 8 grams of 50% aqueous solution of potassium phosphate dibasic (K₂HPO₄) and 2.7 grams of 1 ,4-diiodooctafluorobutane (obtained from SynQuest Lab, Florida, USA). The fluorinated emulsifϊer CF₃OCF₂CF₂CF₂OCF₂COONH₄WaS prepared as described in US Pat. No. 2007/0015864 to Hintzer et al. The reactor was evacuated, the vacuum was broken and it was pressurized with nitrogen to 25 psi (0.17 MPa). This vacuum and pressurization was repeated three times.

[0060] After removing oxygen, the reactor was heated to 80⁰C and pressurized to 62 psi (0.43 MPa) with hexafluoropropylene. The reactor was then charged with vinylidene fluoride (VDF) and hexafluoropropylene (HFP), bringing reactor pressure to 228 psi (1.57 MPa). The ratio of HFP and VDF was 0.621 by weight. The reactor was agitated at 650 rpm.

[0061] As reactor pressure dropped due to monomer consumption in the polymerization reaction, a blend of hexafluoropropylene (HFP) and 1 ,4-diiodooctafluorobutane, and VDF was continuously fed to the reactor to maintain the pressure at 228 psi (1.57 MPa).

[0062] To prepare the blend of hexafluoropropylene (HFP) and 1,4- diiodooctafluorobutane, a 1 -liter, stainless steel cylinder was evacuated and purged 3 times with N₂. After adding 1 ,4-diiodooctafluorobutane to the cylinder, HFP was added based on the amount of 1 ,4-diiodooctafluorobutane added. The blend was then attached to the reactor and was fed using a blanket of N₂. The blend contained 98.33 wt% of HFP and 1.67 wt% of 1,4-diiodooctafluorobutane. The ratio of the blend and VDF was 0.621 by weight.

[0063] After 4.7 hours the monomer and blend feeds were discontinued and the reactor was cooled. The resulting dispersion had a solid content of 30 wt% and a pH of 3.9. The dispersion particle size was 157 nm. For the coagulation, the same amount of a MgCl₂/DI water solution was added to the latex. The solution contained 1.25 wt% MgCl₂ ^»6H₂O. The latex was agitated and coagulated. About 4000 ml of deionized water (DI) water was added and agitated for 15 minutes to wash the crumb then the wash water was drained off. The crumb was washed four times, using a total of 16,000 ml of warm DI water and dried at 130⁰C for 16 hours.

[0064] The resulting fluoroelastomer raw gum had a Mooney viscosity of 4.8 with ML (l+10) at l21° C. The fluoroelastomer contained 82.1 mol% copolymerized units of VDF and 17.1 mol% HFP. The iodine end groups -CF₂CH₂I was 0.3 mol%. The iodine content by neutron activation analysis (NAA) was 0.45 wt%. [0065] In Table 2 glass transition temperature (T _g) was determined in accordance with ASTM D 793-01 and ASTM E 1356-98 by a Perkin-Elmer differential scanning calorimetry DSC Pyris 1 under a nitrogen flow. A DSC scan was obtained from -50⁰C to 200⁰C at 10°C/min. scan rate.

[0066] Mooney viscosity was determined in accordance with ASTM D 1646-06 TYPE A by a MV 2000 instrument (obtained from Alpha Technologies, Ohio, USA) using a large rotor (ML 1+10) at 121°C. Results are reported in Mooney units (Table 2).

Table 2

Example 2

[0067] A fluoroelastomer compound was prepared using a 6" two roll mill by compounding the fluoroelastomer prepared in Example 1 with 30 parts of carbon black (obtained under the trade designation "THERMAX MT", ASTM N990 from Cancarb, Medicine Hat, Alberta, Canada), 3 parts of zinc oxide (obtained under the trade designation "UPS-I" from Zinc Corporation of America), 1.7 parts of t-butyl peroxy ethylhexyl carbonate (TBEC) (CAS RN 34443-12-4), (obtained under the trade designation "TBEC" from Aldrich, Milwaukee, WI) ,and 3 parts of triallylisocyanurate (TAIC) co-agent (98%, obtained under the trade designation "TAIC" from Nippon Kasei, Japan). The compound Compound (Compound I) is shown in Table 3. Table 3 Compound formulation (phr*)

*phr; parts by weight per one hundred parts by weight of rubber

[0068] The cure characteristics were measured using an Alpha Technologies Rubber

Process Analyzer with Moving Disk Rheometer (MDR, a sealed torsion shear rotorless curemeter) mode under conditions corresponding to ASTM D5289-07. The following parameters were recorded:

ML: minimum torque level in unit of inch-lb

MH: maximum torque level in unit of inch-lb

Δ torque: difference between maximum torque (MH) and minimum torque (ML) ts2: minutes to 2 inch-lb rise t'50: minutes to 50% of Δ torque (50% cure time) t'90: minutes to 90% of Δ torque (90% cure time)

The cure characteristics were summarized in Table 4 and Fig. 1 shows 90% cure time (t'90) as the function of MDR curing temperature (⁰C). Fig. 2(a) is the MDR chart at 130⁰C for 120 minutes. Figs. 2(b) and 2(c) are the MDR chart at 130⁰C for 60 minutes.

[0069] The compound was press-cured using a 15 X 15 cm, 2 mm thick mold at 177°C for 5 minutes. Then the press-cured sheet was post cured at 230⁰C for 4 hours. The dumbbells for physical properties were cut from the cured sheets with ASTM Die D. The press-cured and post-cured samples were tested for physical properties in accordance with ASTM D 412-06a. The test results are summarized in Table 4. [0070] Mooney scorch was determined in accordance with ASTM D 1646-06 TYPE C by a MV 2000 instrument (obtained from Alpha Technologies, Ohio, USA) using a small rotor (MS 60min) at 121°C. The test results are summarized in Table 4.

Table 4 Compound Properties and Cured Compound Properties

[0071] The compound was press-cured using a 214 O-ring (AMS AS568) mold at 130, 140, 150, 160 or 177°C. Then the press-cured O-rings were post-cured at 230⁰C for 4 hours. The press-cured (no post cure) and post-cured O-rings were tested for compression set for 22 hours at 200⁰C in accordance with ASTM D 395-03 Method B and ASTM D 1414-94. Results are reported as percentages. The test results are summarized in Table 6.

Example 3

[0072] A compound sample was prepared and tested as in Example 2 except peroxide curable Fluoroelastomer B (Table 2) was used as the fluoroelastomer. The composition ratio of Fluoroelastomer B was TFE/ HFP/ VDF = 9.9/ 14.3/ 75.3 mole% and the polymer contained 0.5 mole% 4-bromotetrafluorobutene (BTFB) as the cure site monomer and 0.1 mole% iodine. The fluorine content was 65.7 wt%. Mooney viscosity of the raw gum was 35. The T_g of this polymer was -24⁰C. The test results are summarized in Tables 4 and 6.

Example 4

[0073] A compound sample was prepared as in Example 2 except 1.2 parts of 75% active t-butyl peroxy-isopropyl-carbonate (TBIC) (CAS RN 2372-21-6) in isododecane solution (obtained under the trade designation "TRIGONOX BPIC" from Acros Organics USA, Morris Plains, NJ) was used instead of 1.7 parts of TBEC (Compound II in Table 3). The amount of TBIC is the same molar equivalent to 1.7 parts of TBEC. The test results are summarized in Tables 4 and 6 and Figs. 2(b) and 2(c).

Examples 5 -7

|00"4| Compound samples were prepared as in Example 4 except Fluoroelastomer B, Fluoroelastomer C and Fluoroelastomer D (obtained under the trade designation "LTFE 6400" from Dyneon LLC, Oakdale, MN) were used instead of Fluoroelastomer A. The test results are summarized in Tables 4 and 6.

Comparative Example 1

[0075] A compound sample was prepared as in Example 2 except 2 parts of 50% active 2,5-dimethyl-2,5-di(t-butylperoxy)-hexane (CAS RN 78-63-7) (obtained under the trade designation "VAROX DBPH-50" from R.T.Vanderbilt, Norwalk, CT) was used instead of 1.7 parts of TBEC (Compound III in Table 3). The amount of DBPH is the same molar equivalent to 1.7 parts of TBEC. The test results are summarized in Tables 5 and 7 and Fig. 2(a) is the MDR chart at 130⁰C for 120 minutes.

Table 5 Compound Properties and Cured Compound Properties

Comparative Example 2

[0076] A compound sample was prepared and tested as in Example 3 except 2 parts of 50% active 2,5-dimethyl-2,5-di(t-butylperoxy)-hexane (obtained under the trade designation "VAROX DBPH-50" from R.T.Vanderbilt, Norwalk, CT) was used as the peroxide as in Table 3 (Compound III) The test results are summarized in Tables 5 and 7.

Comparative Examples 3 and 4

[0077] Compound samples were prepared and tested as in Comparative Example 2 except Fluoroelastomer C and Fluoroelastomer D (obtained under the trade designation "LTFE 6400" from Dyneon LLC, Oakdale, MN) were used instead of Fluoroelastomer A. The test results are summarized in Tables 5 and 7.

Comparative Example 5

[0078] A compound sample was prepared and tested as in Example 2 except 2.3 parts of 40% active dicumyl peroxide (CAS RN 80-43-3) (obtained under the trade designation "DI-CUP® 40KE" from GEO Specialty Chemicals, Gibbstown, NJ) was used as the peroxide as in Table 3 (Compound IV). The amount of the dicumyl peroxide is the same molar equivalent to 1.7 parts of TBEC. The test results are summarized in Tables 5 and 7.

Comparative Example 6

[0079] A compound sample was prepared and tested as in Comparative Example 5 except Fluoroelastomer C was used instead of Fluoroelastomer B. The test results are summarized in Tables 5 and 7. Comparative Example 7

[0080] A compound sample was prepared and tested as in Example 2 except 2.9 parts of 40% active 2,2-bis(tert-butylperoxy diisopropylbenzene) (CAS RN 25155-25-3) (obtained under the trade designation "VUL-CUP® 40KE" from GEO Specialty Chemicals, Gibbstown, NJ) was used as the peroxide as in Table 3 (Compound V) The test results are summarized in Tables 5 and 7.

Table 6 Compression set at various temperatures

Table 7 Compression set at various temperatures

Example 8

[0081] Compound VI in Table 8 was prepared as in Example 7 except N990 carbon black (filler) and zinc oxide (acid acceptor) were not used. The cure rheology was measured at 130⁰C for 60 minutes, 160⁰C for 12 minutes and 177°C for 12 minutes. The compound was press-cured using a 214 O-ring (AMS AS568) mold at 160⁰C for 5 minutes. After the press cure, the color of O-ring was clear or transparent because the compound did not contain any filler or acid acceptor. The press-cured O-rings were post- cured at 177°C, 200⁰C and 230⁰C for 4 hours. The press-cured (no post cure) and post- cured O-rings were tested for compression set for 22 hours at 200⁰C in accordance with ASTM D 395-03 Method B and ASTM D 1414-94. The test results are summarized in Tables 9 and 10. Comparative Example 8

[0082] Compound VII in Table 8 was prepared as in Comparative Example 4 except N990 carbon black (filler) and zinc oxide (acid acceptor) were not used and 2,5-dimethyl- 2,5-di(t-butylperoxy)-hexane (CAS RN 78-63-7) (obtained from Aldrich, Milwaukee, WI) was used instead of VAROX DBPH-50. The cure rheology was measured at 130⁰C for 120 minutes, 160⁰C for 12 minutes and 177°C for 12 minutes. The compound was press- cured using a 214 O-ring (AMS AS568) mold at 177°C for 5 minutes. After the press cure, the color of O-ring was clear or transparent because the compound does not contain any filler or acid acceptor. The press-cured O-rings were post-cured at 230⁰C for 4 hours. The press-cured (no post cure) and post-cured O-rings were tested for compression set for 22 hours at 200⁰C. The test results are summarized in Tables 9 and 10.

Table 8 Compound (phr*)

Table 9 Compound Cure Rheology

Table 10 Compression set at various post cure temperatures

[0083] As shown in FIG. 1, compounds with TBEC peroxide (Example 2) and TBIC peroxide (Example 4) can be cured at 130⁰C in 30 minutes while the DBPH peroxide compound of Comparative Example 1 can not.

[0084] The complete disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.

Claims

What is claimed is:

1. A composition comprising:

(a) an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site;

(b) an organic peroxide selected from one of Formula (I) or Formula (II)

O R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (^Π)

wherein Rl and R2, are the same or different hydrocarbon groups having 3 to 10 carbon atoms. R3 is divalent hydrocarbon groups of 2 to 8 carbon atoms which may contain O atoms; and

(c) a coagent, wherein the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07 is less than 30 minutes at 130⁰C.

2. The composition according to claim 1 wherein the 10-hour half life temperature of the peroxide ranges from 90⁰C to 110⁰C.

3. The composition according to claim 1 wherein the fluoropolymer comprises interpolymerized units derived from the group consisting of tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, ethylene, propylene, perfluoro(alkylvinylether), perfluoro(allylether), chlorotrifluoroethylene, vinylfluoride and trifluoroethylene.

4. The composition according to claim 1 wherein the organic peroxide is present at 0.1phr to 5 phr.

5. The composition according to claim 1 wherein the coagent is selected from tri(methyl)allyl isocyanurate (TMAIC), triallyl isocyanurate (TAIC), tri(methyl)allyl cyanurate, poly-triallyl isocyanurate (poly-TAIC), xylylene-bis(diallyl isocyanurate) (XBD), N,N'-m-phenylene bismaleimide, diallyl phthalate, tris(diallylamine)-s-triazine, triallyl phosphite, 1 ,2-polybutadiene, ethyleneglycol diacrylate, diethyleneglycol diacrylate, and compounds having the formula CH₂=CH-Rn-CH=CH₂, wherein Rn may be a perfluoroalkylene of 1 to 8 carbon atoms.

6. The composition according to claim 1 wherein composition comprises lwt% to 10wt% of the coagent.

7. The composition according to claim 1 wherein the organic peroxide is selected from tert-butyl peroxy isopropylcarbonate (TBIC), tert-butyl peroxy 2-ethylhexyl carbonate (TBEC), tert-amyl peroxy 2-ethylhexyl carbonate, tert-hexylperoxy isopropyl carbonate, carbonoperoxoic acid, O,O'-l,3-propanediyl OO,OO'-bis(l,l-dimethylethyl) ester and combinations thereof.

8. The composition according to claim 1 wherein the cure site is an end group.

9. The composition according to claim 1 wherein the weight percent of iodine, bromine or chlorine ranges from 0.2 to 2.

10. The composition of claim 1 wherein the iodine is derived from an iodinated chain transfer agent.

11. The composition of claim 1 wherein the bromine is derived from a brominated chain transfer agent.

12. The composition of claim 1 wherein the chlorine is derived from a chlorinated chain transfer agent.

13. The composition of claim 10 wherein the chain transfer agent is a perfluorinated iodo-compound.

14. The composition of claim 11 wherein the chain transfer agent is a perfluorinated bromo-compound.

15. The composition of claim 12 wherein the chain transfer agent is a perfluorinated chloro-compound.

16. The composition of claim 1 wherein the fluoropolymer has a Mooney viscosity of 10 or less (ML 1+10) at 12FC according to ASTM D 1646-06 TYPE A.

17. A fluoroelastomer preparable by

(a) providing a composition comprising:

(i) an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site;

(ii) an organic peroxide selected from one of Formula (I) or Formula (II)

O R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (^Π)

(iii) providing a coagent; and

(b) curing the composition at 130⁰C for less than 30 minutes, wherein the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07.

18. A cure in place process comprising the steps of:

(a) providing a substrate;

(b) positioning on the substrate a composition comprising:

(i) an amorphous peroxide curable fluoropolymer comprising an iodine, bromine or chlorine containing cure site; (ii) an organic peroxide selected from one of Formula (I) or Formula (II)

O R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (H)

(iii) providing a coagent; and

(c) curing the composition at 130⁰C for less than 30 minutes, wherein the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07.

19. A cure in place article derived from a composition comprising:

(b) an organic peroxide selected from one of Formula (I) or Formula (II) O

R¹OOCOR² ®

O O R¹OOCOR³OCOOR² (H)

(c) a coagent, wherein the fluoropolymer 90% cure time as measured by sealed torsion shear rotorless curemeter in ASTM D5289-07 is less than 30 minutes at 130⁰C, and wherein the article has a press-cure compression set of 10% to 50% after curing for 30 minutes at 130⁰C.