阅读说明：本技术 溴化的异丁烯对甲基-苯乙烯弹性体硫化胶囊 (Brominated isobutylene para-methyl-styrene elastomer curing capsules ) 是由 S·K·曼堵特 M·比索伊 C·沙纳瓦斯 田中良行 于 2019-05-22 设计创作，主要内容包括：组合物可包含：成形为硫化胶囊的弹性体组合物,该弹性体组合物包含：100份/百份橡胶(phr)的弹性体,所述弹性体包含C_4-C_7异烯烃、非卤化烷基苯乙烯和卤化的烷基苯乙烯；1phr至7.5phr烷基苯酚甲醛树脂；和0.5phr至5phr二硫化巯基苯并噻唑。制造轮胎硫化胶囊的相关方法包括：混合100phr的弹性体组合物,1phr至7.5phr烷基苯酚甲醛树脂,和0.5phr至5phr二硫化巯基苯并噻唑,所述弹性体组合物包含C_4-C_7异烯烃、非卤化烷基苯乙烯和卤化的烷基苯乙烯；和将混合物模塑和硫化为轮胎硫化胶囊的形状。(The composition may comprise: an elastomeric composition shaped as a curing bladder, the elastomeric composition comprising: 100 parts per hundred rubber (phr) of an elastomer comprising C 4 ‑C 7 Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; 1 to 7.5phr of an alkylphenol-formaldehyde resin; and 0.5 to 5phr of mercaptobenzothiazole disulfide. A related method of manufacturing a tire curing bladder comprises: mixing 100phr of an elastomeric composition comprising C, 1phr to 7.5phr of an alkylphenol formaldehyde resin, and 0.5phr to 5phr of a mercaptobenzothiazole disulfide 4 ‑C 7 Isoolefins, non-halogenated alkylstyrenes and halogenated alkylbenzenesEthylene; and molding and curing the mixture into the shape of a tire curing bladder.)

1. A composition comprising:

an elastomeric composition formed into a curing bladder, the elastomeric composition comprising:

100 parts per hundred rubber (phr) of an elastomer comprising C₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes;

1 to 7.5phr of an alkylphenol-formaldehyde resin; and

0.5 to 5phr of mercaptobenzothiazole disulfide.

2. The composition of claim 1, wherein the alkylphenol-formaldehyde resin comprises an octylphenol-formaldehyde resin and/or a brominated octylphenol-formaldehyde resin.

3. The composition of any preceding claim, wherein alkylphenol formaldehyde resin is present from about 3phr to about 5 phr.

4. The composition of any preceding claim, wherein mercaptobenzothiazole disulfide is present from 1.4phr to about 2.0 phr.

5. The composition of any preceding claim, wherein C₄-C₇The isoolefin comprises isobutylene.

6. The composition of any preceding claim, wherein the non-halogenated alkylstyrene comprises p-methylstyrene.

7. The curing bladder of any preceding claim, wherein the halogenated alkylstyrene comprises brominated p-methylstyrene.

8. The composition of any preceding claim, wherein the non-halogenated alkylstyrene and the halogenated alkylstyrene cumulatively are present in the elastomer composition in an amount of greater than or equal to about 10 weight percent based on the elastomer composition.

9. The composition of any preceding claim, wherein the halogenated alkylstyrene is present from 0.1 mol% to 7.5 mol% relative to the non-halogenated alkylstyrene.

10. The composition of any preceding claim, wherein C₄-C₇The isoolefin is present in the elastomeric composition in an amount of less than or equal to about 90 wt%, based on the elastomeric composition.

11. The composition of any preceding claim, further comprising a processing aid and a filler.

12. The composition of claim 11, wherein the filler comprises carbon black.

13. The composition of claim 11 or 12, wherein the filler comprises clay.

14. The composition of any preceding claim, wherein the elastomeric composition further comprises from 0.5phr to 30phr of butyl rubber.

15. A method of manufacturing a tire curing bladder comprising:

100 parts per hundred rubber are mixed (phr)) 1phr to 7.5phr of an alkylphenol formaldehyde resin, and 0.5phr to 5phr of a mercaptobenzothiazole disulfide, said elastomeric composition comprising C₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; and

the mixture is molded and cured into the shape of a tire curing bladder.

16. The method of claim 14, wherein vulcanizing lasts less than 30 minutes at about 170 ℃ to about 200 ℃.

17. The method of claim 14, wherein vulcanizing lasts from less than about 45 minutes to about 90 minutes at about 120 ℃ to about 150 ℃.

18. The method of claims 14-16, wherein the alkylphenol-formaldehyde resin comprises an octylphenol-formaldehyde resin and/or a brominated octylphenol-formaldehyde resin.

19. The method of claims 14-17, wherein the alkylphenol-formaldehyde resin is present from about 3phr to about 5 phr.

20. The method of claims 14-18, wherein mercaptobenzothiazole disulfide is present from 1.4phr to about 2.0 phr.

21. The method of claims 14-19, wherein C₄-C₇The isoolefin comprises isobutylene.

22. The method of claims 14-20, wherein the non-halogenated alkylstyrene comprises p-methylstyrene.

23. The method of claims 14-21, wherein the halogenated alkylstyrene comprises brominated p-methylstyrene.

24. The method of claims 14-22, further comprising a processing aid and a filler.

25. The composition of any preceding claim, wherein the elastomeric composition further comprises from 0.5phr to 30phr of butyl rubber.

Technical Field

The present invention relates to tire curing bladders, their manufacture and their use.

Background

Pneumatic rubber vehicle tires are typically produced by forming, molding and vulcanizing a green or uncured tire in a molding press. With this method, the green tire construction is pressed outwardly against the mold surface by means of an internal fluid-expandable bladder (commonly referred to as a curing bladder). In this way, the green tire is shaped against the outer mold surface, which defines the configuration of the tire tread pattern and sidewalls. The tire is molded and cured at elevated temperatures by applying heat and pressure through the curing bladder.

In short, proper selection of the elastomer and compounding materials of the bladder formulation is necessary to ensure durability, required service life, and efficient curing bladder operation in the tire plant. Butyl rubber (e.g., isobutylene-isoprene copolymer) is the elastomer of choice in curing bladder formulations due to its excellent heat aging resistance, good flex and tear resistance, and impermeability to air, inert gases, and water vapor. Fundamentally, this is due to the excellent heat and steam resistance of vulcanized butyl rubber, and this has led to its widespread use in high heat resistance applications.

Recently, there has been a global shortage of butyl rubber, creating a need to use less butyl rubber in the manufacture of curing bladders. There is also a continuing need to improve the durability and service life of curing bladders, which are often referred to as pull points. When a pull point occurs, it can result in the loss of up to six tires in a typical tire manufacturing process. There is a continuing need to improve the heat transfer through the bladder to improve the efficiency of the vulcanization process and to increase the production rate of the vulcanization press.

SUMMARY

The present invention relates to tire curing bladders, their manufacture and their use.

In one embodiment of the disclosure, a composition comprises: an elastomeric composition shaped as a curing bladder, the elastomeric composition comprising: 100 parts per hundred rubber (phr) of an elastomer comprising C₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; 1 to 7.5phr of an alkylphenol-formaldehyde resin; and 0.5 to 5phr of mercaptobenzothiazole disulfide.

In another embodiment of the disclosure, a method of manufacturing a tire curing bladder comprises: mixing 100 parts per hundred rubber (phr) of an elastomeric composition comprising C, 1phr to 7.5phr of an alkylphenol-formaldehyde resin, and 0.5phr to 5phr of mercaptobenzothiazole disulfide₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; and molding and curing the mixture into the shape of a tire curing bladder.

Detailed description of the invention

The curing capsules of the present invention are formed by curing brominated isobutylene para-methyl-styrene elastomer using a curative system comprising, consisting essentially of, or consisting of an alkylphenol formaldehyde resin and mercaptobenzothiazole disulfide. Brominated isobutylene para-methyl-styrene elastomers comprise C₄-C₇Isoolefins (e.g., isobutylene), non-halogenated alkylstyrenes (e.g., p-methylstyrene), and halogenated alkylstyrenes (e.g., p-bromomethylstyrene).

Various specific embodiments, variations, and examples are described herein, including exemplary embodiments and definitions employed for purposes of understanding the claimed invention. While the following detailed description gives specific embodiments, those skilled in the art will appreciate that these embodiments are exemplary only, and that the invention can be practiced in other ways. For infringement purposes, the scope of the invention will refer to any one or more of the appended claims, including equivalents thereof and elements or limitations that are equivalent to those that are recited. Any reference to "the invention" may refer to one or more, but not necessarily all, of the inventions defined by the claims.

Definition of

A "curing bladder" is a flexible, inflatable bladder used or capable of being inflated to mold and/or cure an elastomeric article, such as a tire, in a tire press.

The term "elastomer" as used herein refers to any polymer or combination of polymers that conforms to the ASTM D1566-15 definition (which is incorporated herein by reference). As used herein, the term "elastomer" may be used interchangeably with the term "rubber".

As used herein, "polymer" may be used to refer to homopolymers, copolymers, terpolymers, etc. As used herein, the term "copolymer" is intended to include polymers having two or more monomers. In some embodiments, the polymer may be prepared (1) by mixing all of the various monomers simultaneously or (2) by sequentially introducing different comonomers. The mixing of the comonomers can be carried out in one, two or possibly three different reactors in series and/or in parallel. As used herein, when a polymer is referred to as "comprising" a monomer, the monomer is present in the polymer in polymerized form of the monomer or in the form of a derivative of the monomer. Likewise, when the catalyst component is described as comprising a neutral stable form of the component, it will be well understood by those skilled in the art that the ionic form of the component is the form that reacts with the monomer to produce a polymer.

As used herein, "diolefin" refers to an unsaturated hydrocarbon having at least two unsaturated bonds between carbon atoms. Although typically a diene will have two double bonds, for the purposes of the present invention, a molecule with additional double bonds or with one or more triple bonds may also serve as a diene. The addition of double or triple bonds only to dienes does not prevent the improvement of the present invention. At present, the vast majority of possible starting materials are compounds having only two double bonds. However, unsaturated hydrocarbons such as n-1,3, 5-hexatriene or n-1,4, 6-heptatriene or propyne also meet the requirement to act as "diolefins" in the context of the present invention.

The term "blend" as used herein refers to a mixture of two or more polymers. The blend may be prepared by, for example, solution blending, melt mixing, or compounding in a shear mixer. Solution blending is common for preparing adhesive formulations comprising baled butyl rubber, tackifier and oil. The solution blend is then coated on the fabric substrate and the solvent is evaporated to leave the binder.

The term "monomer" or "comonomer" as used herein may refer to the monomer used to form the polymer (i.e., unreacted compound in a form prior to polymerization), and may also refer to the monomer after it has been incorporated into the polymer (also referred to herein as "[ monomer(s)") [ monomer(s) ]]-a derivative unit "). Various monomers are discussed herein, including but not limited to C₄-C₇Isoolefin monomers, non-halogenated alkylstyrene monomers, halogenated styrene monomers, and diene monomers.

As used herein, "phr" means "parts per hundred rubber", where "rubber" is the total rubber content of the composition. Herein, both the elastomer composition of the present invention and the additional rubber (when present) are considered to contribute to the total rubber content. Thus, for example, a composition having 30 parts by weight of an elastomer of the present invention and 70 parts by weight of a second rubber (e.g., butyl rubber) may be referred to as having 30phr elastomer and 70phr second rubber. Other components added to the composition are calculated on a phr basis. That is, the addition of 50phr of oil means that there is 50g of oil in the composition for every 100g of total rubber, for example. Unless otherwise specified, phr shall be taken to be phr on a weight basis.

As used herein, "mooney viscosity" is the mooney viscosity of a polymer or polymer composition. The polymer composition analyzed for determining mooney viscosity should be substantially free of solvent. For example, the sample may be placed on a boiling water vapor stage in a hood to evaporate most of the solvent and unreacted monomers and then dried overnight (12 hours, 90 ℃) in a vacuum oven and then tested according to laboratory analytical techniques, or the sample for testing may be taken from the devolatilized polymer (i.e., post devolatilization of the polymer in an industrial scale process). Mooney viscosity was measured using a mooney viscometer according to ASTM D1646-17, except with the following modifications/descriptions of the procedure, unless otherwise noted. First, the sample polymer was pressed between two hot plates of a compression press prior to testing. The plate temperature was 125 deg.C +/-10 deg.C rather than 50+/-5 deg.C as suggested in ASTM D1646-17 because 50 deg.C did not cause sufficient aggregation. Further, while ASTM D1646-17 allows several options for die protection, if any two options provide conflicting results, PET 36 micrometers should be used as die protection. Further, ASTM D1646-17 does not indicate the weight of the sample in section 8; thus, the Mooney viscosity determined using the procedure of section 8 of D1646-17 using a sample weight of 21.5+/-2.7g is based on the sense that the results can vary based on the sample weight. Finally, the rest procedure before the test set forth in section 8 of D1646-17 was 23+/-3 ℃ in air for 30 min; mooney values reported herein were determined after standing in air at 24+/-3 ℃ for 30 min. Placing samples on either side of the rotor according to ASTM D1646-17 test method; the torque required to rotate the viscometer motor at 2rpm was measured by the sensor used to determine the Mooney viscosity. The results are reported as Mooney units (ML,1+4 at 125 ℃ or ML,1+8 at 125 ℃), where M is the Mooney viscosity value, L represents a large rotor (defined as ML in ASTM D1646-17), 1 is the preheat time in minutes, 4 or 8 is the sample run time in minutes after motor start-up, and 125 ℃ is the test temperature. Thus, a Mooney viscosity of 90 as determined by the foregoing method would be reported as 90MU (ML,1+8 at 125 ℃) or 90MU (ML,1+4 at 125 ℃). Alternatively, mooney viscosity may be reported as 90 MU; in such cases, it should be assumed that such viscosity is determined using the (ML,1+4 at 125 ℃) method just described, unless otherwise indicated. In some cases, a lower test temperature (e.g., 100 ℃) may be used, in which case mooney is reported as mooney viscosity (ML,1+8 at 100 ℃), or at T ℃, where T is the test temperature.

Numerical ranges used herein include the numbers recited within the ranges. For example, a numerical range of "1 wt% to 10 wt%" includes 1 wt% and 10 wt% within the recited range.

Elastic body

The brominated isobutylene para-methyl-styrene elastomer described herein comprises at least one C₄-C₇An isoolefin derived monomer. The elastomer may be halogenated. Can be used as C₄-C₇Examples of isoolefins of the compounds include, but are not limited to, isobutylene (isobutene), 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, and 4-methyl-1-pentene. The elastomer further includes at least one non-halogenated alkylstyrene monomer and at least one halogenated alkylstyrene monomer. Examples of non-halogenated alkylstyrene monomers include, but are not limited to, alpha-methylstyrene, tert-butylstyrene, and C at the ortho-, meta-, or para-positions₁-C₅Alkyl or branched alkyl substituted styrene units. In a desired embodiment, the non-halogenated alkylstyrene monomer is para-methylstyrene. Examples of halogenated alkylstyrene monomers include, but are not limited to, halomethylstyrene and C halogenated at the ortho, meta or para positions₁-C₅Alkyl or branched alkyl substituted styrene units, wherein the halogen may be chlorine or bromine. In a desired embodiment, the halogenated alkylstyrene monomer is a para-halomethylstyrene, preferably para-bromomethylstyrene or para-chloromethylstyrene.

The elastomer described herein can be C₄-C₇Random elastomeric copolymers of isoolefins (e.g., isobutylene), non-halogenated alkylstyrenes (e.g., p-methylstyrene), and halogenated alkylstyrenes (e.g., p-bromomethylstyrene). The non-halogenated alkylstyrene and halogenated alkylstyrene monomers may each contain at least 80%, more preferably at least 90%, by weight of the corresponding para-isomer. Preferred materials can be characterized as elastomers containing the following monomer units randomly spaced along the polymer chain:

wherein R is¹⁰And R¹¹Independently hydrogen, lower alkyl, preferably C₁-C₇Alkyl and primary or secondary alkyl halide (halide) and X is a functional group such as halogen.

Preferably, R¹⁰And R¹¹Is hydrogen. Up to 60 mole percent of the para-substituted styrene present in the elastomeric structure may be functionalized structure in one embodiment, and from 0.1 to 5 mole percent in another embodiment. In yet another embodiment, the amount of functionalized structures is from 0.4 to 1 mole percent.

The functional group X may be halogen or a combination of halogen and some other functional group that may be incorporated by nucleophilic substitution of a benzylic halogen with other groups, such as carboxylic acids; a carboxylate; a carboxy ester; amides and imides; a hydroxyl group; an alkoxide; a phenolate salt; a mercaptide; a thioether; a xanthate salt; a cyanide compound; a nitrile; amino groups and mixtures thereof. These functionalized isoolefin copolymers, their methods of preparation, functionalization and vulcanization processes are more specifically disclosed in U.S. Pat. No. 5,162,445, and in particular, functionalized amines as described below.

Most useful of such functionalized materials are elastomeric random copolymers of isobutylene, para-methylstyrene and para-bromomethylstyrene, wherein the para-methylstyrene and para-bromomethylstyrene are present in a total amount of from 0.5 to 20 weight percent (wt%), or from 0.5 to 30 wt%. These halogenated elastomers are useful as EXXPRO^TMElastomers (ExxonMobil Chemical Company, Houston TX) are commercially available and are abbreviated as "BIMSM". If desired, these elastomers can have a substantially uniform composition distribution such that at least 95 weight percent of the polymer has a total para-methylstyrene and para-bromomethylstyrene content that is within 15 percent of the total para-methylstyrene and para-bromomethylstyrene content of the polymer.

Preferably, the elastomer contains a non-halogenated sum relative to the sum in the polymer0.1 to 7.5 mole percent (mol%) of halogenated alkylstyrene derived units based on the total amount of halogenated alkylstyrene derived units. For example, the amount of bromomethyl groups is 0.2 to 3.0 mol%, 0.3 to 2.8 mol%, 0.3 to 2.0 mol%, or 0.4 to 1.0 mol%, where a desired range can be any combination of any upper limit with any lower limit. In other words, preferred copolymers contain 0.3 to 4.5 weight percent bromine, 0.4 to 4 weight percent bromine, and 0.6 to 1.5 weight percent bromine, based on the weight of the polymer. In one embodiment of the invention, the elastomer is C₄-C₇A copolymer of isoolefin derived units (or isomonoolefin), p-methylstyrene derived units, and p-halomethylstyrene derived units, wherein from 0.4 to 1.0 mole percent of p-halomethylstyrene units are present in the elastomer, based on the total number of p-methylstyrene and p-halomethylstyrene derived units, and wherein from 3 weight percent to 15 weight percent or from 10 weight percent to 12 weight percent of p-methylstyrene derived units are present, based on the total weight of the polymer. The p-halomethylstyrene may be, for example, p-bromomethylstyrene.

Optionally, the elastomer may further comprise one or more diene monomers, wherein C₄-C₇Isoolefins are distinct from diolefins. Examples of dienes include, but are not limited to, isoprene; cis-1, 3-pentadiene; trans-1, 3-pentadiene; cyclopentene; cyclopentadiene; beta-pinene; limonene, and combinations thereof.

The diene monomer may be present in the elastomer in an amount of from 0.5% to 10%, or from 1% to 8%, or from 2% to 5% by weight of the polymer.

Example elastomers may include at least one C₄-C₇An isoolefin derived monomer (e.g., isobutylene), at least one non-halogenated alkylstyrene derived monomer (e.g., p-methylstyrene), at least one halogenated alkylstyrene derived monomer (e.g., p-bromomethylstyrene), and at least one diene derived monomer (e.g., isoprene). For example, at least one C₄-C₇The isoolefin derived monomer may be present from about 60 wt% to about 99 wt%, at least one non-halogenated alkylstyrene derived monomer and at least one halogenated alkylstyrene derived monomerThe monomer accumulation can be present from about 0.5 wt% to about 30 wt% (where the at least one halogenated alkylstyrene derived monomer is from 0.1 mol% to 7.5 mol% of the total content of the at least one non-halogenated alkylstyrene derived monomer and the at least one halogenated alkylstyrene derived monomer), and the at least one diene derived monomer can be present from about 0.5 wt% to about 10 wt%.

According to the invention, the elastomer has a (ML,1+8 at 100 ℃) mooney viscosity of less than 65, for example from 20 to 60, from 25 to 50, from 30 to 45 or from 32 to 37.

The desired brominated isobutylene para-methyl-styrene elastomer can also pass through a narrow molecular weight distribution (M) of less than 5, more preferably less than 2.5_w/M_n) And (5) characterizing.

Elastomers may also be characterized by preferred viscosity average molecular weights in the range from 2,000 up to 2,000,000 and preferred number average molecular weights in the range from 2500 to 750,000 as determined by gel permeation chromatography. In particular embodiments, it may be preferred to use two or more elastomers having similar backbones, for example, a low molecular weight elastomer having a weight average molecular weight of less than 150,000 may be blended with a high molecular weight elastomer having a weight average molecular weight of greater than 250,000.

In embodiments, the polymer may be prepared as follows: the monomer mixture is slurry polymerized using a lewis acid catalyst, followed by halogenation, preferably bromination, in solution in the presence of halogen and a free radical initiator, such as heat and/or light and/or a chemical initiator, and optionally followed by electrophilic substitution of bromine with different functional moieties. In embodiments, the polymer may be prepared by direct functionalization with different functional moieties without a bromination step.

Vulcanization system

As used herein, the term "cure system" refers to a combination of curatives. Examples of vulcanizing agents include, but are not limited to, sulfur, metals, metal oxides such as zinc oxide, peroxides, organometallic compounds, free radical initiators, fatty acids, accelerators, and other agents common in the art.

The curing capsules of the present invention are formed from an elastomer composition produced by curing the elastomers described herein using a curative system comprising, consisting essentially of, or consisting of an alkylphenol formaldehyde resin and mercaptobenzothiazole disulfide (MBTS). Optionally, metal oxides and/or additional accelerators may also be included in the curative system.

The alkylphenol-formaldehyde resin (which is an accelerator) may be present from 1phr to 7.5phr, or from 2phr to 6phr, or from 3phr to 5 phr. Examples of alkylphenol formaldehyde resins include, but are not limited to, SP1045^TM(Octylphenol formaldehyde resin, available from SI Group), SP1055^TM(brominated octylphenol formaldehyde resins, available from SI Group) and combinations thereof.

MBTS can act as an accelerator in the vulcanization system. Other accelerators include, but are not limited to, stearic acid, diphenyl guanidine (DPG), tetramethylthiuram disulfide (TMTD), N-tert-butyl-2-benzothiazolesulfenamide (TBBS), N-cyclohexyl-2-benzothiazolesulfenamide (CBS), thiourea, and combinations thereof. The one or more accelerators may be individually present from 0.1phr to 5phr, or from 0.5phr to 4phr, or from 1phr to 3 phr. Specifically, the MBTS may be present from 0.5phr to 5phr, or from 0.75phr to 4phr, or from 1phr to 3phr, or from 1.4phr to 2 phr. In some preferred embodiments, MBTS is present from 0.5phr to 5phr and stearic acid is present from 0.5phr to 5 phr. More preferably, MBTS is present from 1phr to 2phr and stearic acid is present from 0.1phr to 1 phr.

The metal oxide may act as a vulcanizing agent in the vulcanization system. Examples of metal oxides include, but are not limited to, zinc oxide, calcium oxide, lead oxide, magnesium oxide, and combinations thereof. When included, the one or more metal oxides may be present individually from 0.01phr to 5.0phr, or from 0.1phr to 4phr, or from 1phr to 3phr, or from 0.01phr to 0.5phr, or from 2phr to 4 phr.

The metal oxide may be used alone or in combination with its corresponding metal fatty acid complex (e.g., zinc stearate, calcium stearate, etc.), or with separately added organic and fatty acids such as stearic acid and optionally other vulcanizing agents such as sulfur or sulfur compounds, alkyl peroxide compounds, diamines, or derivatives thereof.

Other additives

The elastomeric compositions and blends thereof described herein may also contain other conventional additives such as fillers, dyes, pigments, antioxidants, heat and light stabilizers, plasticizers, oils, and other ingredients known in the art.

Optionally, one or more fillers may be included in the elastomeric compositions and blends thereof described herein. Examples of fillers include, but are not limited to, calcium carbonate, clay, mica, silica, silicates, talc, titanium dioxide, alumina, starch, wood flour, carbon black (e.g., N110 to N990 according to ASTM D1765-17), or combinations thereof. The filler may be of any size and typically ranges, for example, from about 0.0001 μm to about 100 μm in the tire industry. When included, the filler may be present alone at 10phr to 100phr, or 25phr to 80phr, or 30phr to 70 phr.

For example, in tire bladder formulations, high structure carbon black ISAF (e.g., N220 per ASTM D1765-17) or HAF (e.g., N330 per ASTM D1765-17) can yield a good balance of properties and can be used in bladder compounds at levels of 40phr to 60 phr. An alternative carbon black type is the GPF grade, which shows improved air aging, but the ISAF grade has better steam aging properties. Acetylene black compounds, along with, for example, N330, have good thermal conductivity, which can reduce tire cure time. However, acetylene black can be difficult to disperse in butyl rubber compounds. In general, lower carbon black loadings (e.g., 35phr) result in better air aging, while higher carbon black loadings (e.g., 65phr) result in better steam aging.

As used herein, silica means any type or particle size of silica or another silicic acid derivative, or silicic acid, processed by solution, pyrolysis, or similar methods, including untreated, precipitated silica, crystalline silica, colloidal silica, aluminum or calcium silicates, fumed silica, and the like. The precipitated silica may be conventional silica, semi-highly dispersed silica or highly dispersed silica.

The elastomeric composition may also include clay as a filler. The clay may be, for example, montmorillonite, nontronite, beidellite, volkonskoite (vokoskoite), laponite (laponite), hectorite, saponite, sauconite, magadite (magadite), kenyaite, stevensite, vermiculite, halloysite, aluminate oxides, hydrotalcite, or mixtures thereof, optionally treated with a modifier. The clay may contain at least one silicate. Alternatively, the filler may be a layered clay, optionally treated or pre-treated with a modifier such as an organic molecule; the layered clay may comprise at least one silicate.

Depending on the equipment, resin curing bladder compounds can be difficult to mix and process. To promote good dispersion and flow properties, it may be beneficial to use processing aids such as organosilicon compounds. There are several commercially available processing aids such as silicones and calcium fatty acid soaps suitable for curing capsule compounds.

Blending of the fillers, additives and/or cure system components may be carried out in any suitable mixing device, such as BANBURY^TMMixer, BRABENDER^TMThe elastomer and desired components described herein are combined in a mixer or preferably a mixer/extruder and mixed at a temperature in the range of 120 ℃ up to 300 ℃ under shear conditions sufficient to allow the components to become uniformly dispersed within the elastomer to form the elastomer compositions described herein and blends thereof.

Blends with butyl rubber

The brominated isobutylene para-methyl-styrene elastomer compositions described herein can also optionally be blended with a butyl rubber (e.g., an isobutylene-isoprene copolymer). Preferably, the isobutylene-isoprene copolymer has 0.5 mol% to 3 mol% isoprene, with the balance being isobutylene. Examples of isobutylene-isoprene copolymers include, but are not limited to, EXXON^TMBUTYL 065、EXXON^TM BUTYL 065S、EXXON^TM BUTYL 365、EXXON^TM BUTYL 068、EXXON^TM BUTYL 068S、EXXON^TM BUTYL 268、EXXON^TMBUTYL 268S and itA combination of these.

When included, the butyl rubber may be included in a blend with the brominated isobutylene paramethylstyrene elastomer composition (and optional additional additives) from 0.5phr to 30phr, or from 1phr to 25phr, or from 5phr to 20phr, or from 10phr to 15 phr.

Method of producing a composite material

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can be compounded (mixed) by any conventional means known to those skilled in the art. The mixing can be carried out in a single step or in multiple stages. For example, the ingredients are typically mixed in at least two stages (i.e., at least one non-productive stage followed by a productive mixing stage). The final curatives are usually mixed in a final stage, which is conventionally referred to as the "productive" mixing stage. In the productive mixing stage, mixing is typically carried out at a temperature or final temperature that is lower than the mixing temperature(s) of the previous non-productive mixing stage(s). If used, the elastomer, butyl rubber, polymer additive, silica and silica coupling agent, and carbon black are typically mixed in one or more non-productive mixing stages. The terms "non-productive" and "productive" mixing stages are well known to those skilled in the art of rubber mixing.

In one embodiment, the carbon black is added at a different stage than the zinc oxide and other vulcanization activators and accelerators. In another embodiment, the antioxidants, antiozonants, and processing materials are added in a stage after the carbon black is processed with the elastomer, and zinc oxide is added in a final stage to maximize compound modulus. In further embodiments, the mixing with clay is performed by techniques known to those skilled in the art, wherein the clay is added to the polymer simultaneously with the carbon black. In other embodiments, additional stages may include incremental additions of one or more fillers.

In another embodiment, the mixing of the components may be carried out in any suitable mixing device, such as a two-roll mill, BRABENDER^TMInternal mixer with tangent rotorBANBURY of^TMThe elastomer component, filler and clay are combined in an internal mixer, Krupp internal mixer with intermeshing rotors, or preferably a mixer/extruder by techniques known in the art. Mixing may be carried out up to the melting point of the elastomer(s) used in the composition in one embodiment, or at a temperature of from 40 ℃ to 250 ℃, or from 100 ℃ to 200 ℃. The mixing should generally be conducted under shear conditions sufficient to allow any clay to exfoliate and become uniformly dispersed in the elastomer(s).

Typically, 70% -100% of one or more elastomers are first mixed for 20 to 90 seconds, or until the temperature reaches 40 ℃ -75 ℃. Then, typically about 75% of the filler and the remaining amount of elastomer (if any) are added to the mixer, and mixing continues until the temperature reaches 90-150 ℃. Next, the remaining filler and processing aid are added and mixing is continued until the temperature reaches 140-190 ℃. The masterbatch is then finished in sheets (sheeting) on a mill and, when the remaining components of the vulcanization system can be added to produce the final batch, it is cooled to, for example, 60 ℃ to 100 ℃.

The curing bladder is a cylindrical bag typically made from the final batch of the mixture. Typically, the final batch of mixture is molded into the shape of a tire curing bladder and cured. Advantageously, the brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein have reduced cure times and/or temperatures as compared to butyl rubber compositions currently used to make tire curing bladders. That is, a typical cure cycle for butyl rubber compositions is 45min to 1 hour at 185 ℃ to 200 ℃. In contrast, the elastomeric compositions and blends thereof described herein can be cured, for example, at 170 ℃ to 200 ℃ for less than 30min (e.g., 15min to 30min, or 20min to 25 min). In another example, the vulcanization time can be 45min to 90min (e.g., 50min to 80min, or 60min to 70min), and the vulcanization temperature can be 120 ℃ to 150 ℃ (e.g., 125 ℃ to 145 ℃ or 130 ℃ to 140 ℃).

Generally, the lower the temperature, the longer the vulcanization time is required. As described, the cure temperature may be about the same as compared to a butyl rubber composition, but the cure time may be reduced by at least half. Alternatively, the cure time may be the same or slightly longer and at a lower temperature. In either case, energy costs are reduced.

In use, such a collapsible bladder is mounted in a lower region of a tire curing press and forms part of a press and mold assembly. A "green uncured tire is placed over the bladder in the lower half of the mold. When the mold is closed, pressurized steam, air, hot water or inert gas (nitrogen) is systematically (pre-programmed) introduced into the bladder to provide internal heat and pressure for the tire building and curing process. Two common types of tire curing presses that require bladders are: (1) SLIDEBACK^TM(tire curing presses and loaders, available from NRM) type presses that require AUTOFORM^TM(mechanical tire press, available from Bagwell) bladder and (2) TILTBACK^TM(mechanical tire presses, available from Bag-O-Matic) type presses, which require Bag-O-Matic bladders. Examples of tire curing bladders include wall curing bladders for passenger vehicles, light trucks and commercial trucks, annular curing bladders, closed-end curing bladders, and the like.

Three types of tire cure cycles can be found: a steam-high pressure hot water sulfidation cycle, a steam-inert gas sulfidation process, and a steam-steam sulfidation cycle. The hood (dome) temperature can reach 190 ℃ (180 ℃ for the die sidewall plate) and the capsule temperature can reach up to 220 ℃. An exemplary simple steam-hot water cure cycle time for a truck tire may be (1) 12 minutes of steam, (2) 30 minutes of high pressure hot water, (3) 4 minutes of cold water flush, and (4) 30 seconds of drain for a total cure time of 46: 30. The elastomeric compositions and blends thereof described herein are useful in curing capsules because they typically meet the basic property requirements: (1) uniform, well-mixed compounds that facilitate processing (mixing, extrusion, and die flow); (2) excellent thermal aging resistance; (3) resistance to degradation by saturated steam or high pressure hot water or inert gas; (4) excellent resistance to flexing and hot tear; (5) low tensile and compression set to maintain high elongation properties; and (6) impermeability to air, inert gases, and water vapor. Achieving these properties enables the curing bladder to achieve a sufficient service life (i.e., number of tire curing cycles), which is often referred to as a pull point. The pull point is the location where the capsule is removed before failure; thereby preventing failure during the tire cure cycle, which can lead to loss of the tire during production. Tire bladders comprising the brominated isobutylene para-methyl-styrene elastomer compositions and blends thereof described herein can have an increased pull point compared to tire bladders composed of butyl rubber compositions.

Properties of the composition

The brominated isobutylene paramethyl-styrene elastomer compositions and blends thereof described herein may have improved air impermeability after vulcanization, e.g., having an oxygen transmission rate of 0.300(mm) · (cc)/[ m ] at 40 ℃²·day·mmHg]Or less, as measured on a composition or article described herein, or 0.250(mm) · (cc)/[ m ] at 40 ℃²·day·mmHg]Or less, or 0.220(mm) · (cc)/[ m ] at 40 deg.C²·day·mmHg]Or less, or 0.210(mm) · (cc)/[ m ] at 40 deg.C²·day·mmHg]Or less, or 0.200(mm) · (cc)/[ m ] at 40 deg.C²·day·mmHg]Or lower. For example, the elastomeric compositions described herein and blends thereof formed into articles such as tire bladders can have oxygen transmission rates of 0.150 to 0.300(mm) · (cc)/[ m ] at 40 ℃²·day·mmHg]Or 0.155 to 0.250(mm) · (cc)/[ m ] at 40 ℃²·day·mmHg]Or 0.160 to 0.200(mm) · (cc)/[ m ] at 40 ℃²·day·mmHg]As measured on a composition or article described herein. ASTM D3985-05 andthe 2/61MJ assembly (oxygen transmission rate testing system, available from Mocon, inc.) tests for oxygen transmission rate.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have an improved mooney viscosity (ML,1+4 at 100 ℃) which can range from 75-92, or 77 to 90, or 80 to 88. Mooney viscosity (ML,1+4 at 100 ℃) can be measured as described above.

The brominated isobutylene para-methyl-styrene elastomer compositions and blends thereof described herein can have improved shore a hardness as measured by ASTM D2240-15e 1. The improvement in shore a hardness is a reduction in hardness, which increases the life of the elastomeric composition and articles produced therefrom, such as tire bladders. The elastomeric compositions and blends thereof described herein may have a shore a hardness of 50 or less, 55 to 60, or 55 to 58 after curing at 190 ℃ for an amount of time to achieve 90% cure plus 2 minutes (using a moving die rheometer) (tc90+2 at 190 ℃ MDR). The elastomeric compositions and blends thereof described herein can have a shore a hardness of 80 or less, 70 to 80, or 72 to 76 after tc90+2 MDR vulcanization at 190 ℃ and aging in air at 177 ℃ for two days. The elastomeric compositions and blends thereof described herein can have a shore a hardness of 65 or less, 50 to 65, or 55 to 70 after tc90+2 MDR vulcanization at 190 ℃ and aging in steam at 170 ℃ for three days.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have improved tear retention, which also increases the life of the elastomer composition and articles produced therefrom, such as tire bladders. Tear resistance can be measured by die c tear test of ASTM D624-00 (2012). Comparison of these values (after vulcanization and aging divided by after vulcanization alone) provides tear retention as a percentage when measured at tc90+2 after MDR vulcanization at 190 ℃ and then after aging. The elastomeric compositions and blends thereof described herein can have a tear retention of 100% to 135% or 110% to 130% based on tear resistance after vulcanization and aging at 177 ℃ in air for two days divided by tear resistance after vulcanization.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have an improved modulus at 100% elongation (modulus at 100%). For example, the elastomeric compositions and blends thereof described herein can have a modulus at 100% of 1.2MPa to 2.5MPa, or 1.5MPa to 2.2MPa, or 1.8MPa to 2.0MPa after tc90+2 MDR cure at 190 ℃. In another example, the elastomeric compositions and blends thereof described herein can have a modulus at 100% of 2.5MPa to 4.0MPa, or 2.9MPa to 3.8MPa, or 3.2MPa to 3.6MPa after tc90+2 MDR cure at 190 ℃ and aging for 2 days at 177 ℃ in air. In yet another example, the elastomeric compositions and blends thereof described herein can have a modulus at 100% of from 1.5MPa to 2.5MPa, or from 1.7MPa to 2.3MPa, or from 1.9MPa to 2.1MPa after tc90+2 at 190 ℃ MDR vulcanization and aging in steam at 170 ℃ for 3 days. Modulus at 100% can be measured by ASTM D412-16.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have an improved modulus at 300% elongation (modulus at 300%). For example, the elastomeric compositions and blends thereof described herein can have a modulus at 300% of 4.5MPa to 11.5MPa, or 6.0MPa to 11.0MPa, or 8.0MPa to 10.5MPa after tc90+2 MDR cure at 190 ℃. In another example, the elastomeric compositions and blends thereof described herein can have a modulus at 300% of 8.0MPa to 13.5MPa, or 9.0MPa to 13.0MPa, or 9.5MPa to 12.5MPa after tc90+2 MDR cure at 190 ℃ and aging for 2 days at 177 ℃ in air. In yet another example, the elastomeric compositions and blends thereof described herein can have a modulus at 300% of 6.5MPa to 12.5MPa, or 8.0MPa to 12.0MPa, or 9.0MPa to 11.5MPa after tc90+2 MDR vulcanization at 190 ℃ and aging in steam at 170 ℃ for 3 days. Modulus at 300% can be measured by ASTM D412-16.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have improved tensile strength at break. For example, the elastomeric compositions and blends thereof described herein may have a tensile strength at break after tc90+2 MDR vulcanization at 190 ℃ of 11.0MPa to 17.0MPa, or 13.0MPa to 16.5MPa, or 14.7MPa to 16.0 MPa. In another example, the elastomeric compositions and blends thereof described herein may have a tensile strength at break of 12.0MPa to 17.0MPa, or 12.5MPa to 16.5MPa, or 13.0MPa to 16.0MPa after tc90+2 MDR vulcanization at 190 ℃ and aging for 2 days at 177 ℃ in air. In yet another example, the elastomeric compositions and blends thereof described herein may have a tensile strength at break of 9.0MPa to 17.0MPa, or 12.0MPa to 16.5MPa, or 14.0MPa to 16.0MPa after tc90+2 MDR vulcanization at 190 ℃ and aging in steam at 170 ℃ for 3 days. Tensile strength at break can be measured by ASTM D412-16.

The brominated isobutylene para-methylstyrene elastomer compositions and blends thereof described herein can have improved elongation at break. For example, the elastomeric compositions and blends thereof described herein may have an elongation at break of 400% to 800%, or 600% to 775%, or 700% to 750% after tc90+2 MDR vulcanization at 190 ℃. In another example, the elastomeric compositions and blends thereof described herein may have an elongation at break of 300% to 550%, or 350% to 525%, or 400% to 500% after tc90+2 at 190 ℃ MDR vulcanization and aging in air at 177 ℃ for 2 days. In yet another example, the elastomeric compositions and blends thereof described herein may have an elongation at break of 350% to 500%, or 375% to 475%, or 400% to 450% after tc90+2 MDR vulcanization at 190 ℃ and aging in steam at 170 ℃ for 3 days. Elongation at break can be measured by ASTM D412-16.

Example embodiments

Example 1. a composition comprising: an elastomeric composition shaped as a curing bladder, the elastomeric composition comprising: 100 parts per hundred rubber (phr) of an elastomer comprising C₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; 1 to 7.5phr of an alkylphenol-formaldehyde resin; and 0.5 to 5phr of mercaptobenzothiazole disulfide.

Example 2. the composition of example 1, wherein the alkylphenol formaldehyde resin comprises an octylphenol formaldehyde resin and/or a brominated octylphenol formaldehyde resin.

Example 3. the composition of any preceding example, wherein the alkylphenol-formaldehyde resin is present from about 3phr to about 5 phr.

Example 4. the composition of any preceding example, wherein the mercaptobenzothiazole disulfide is present from 1.4phr to about 2.0 phr.

Example 5. the composition of any of the preceding examples, wherein C₄-C₇The isoolefin comprises isobutylene.

Example 6 the composition of any preceding example, wherein the non-halogenated alkylstyrene comprises para-methylstyrene.

Example 7. the curing capsule of any preceding example, wherein the halogenated alkylstyrene comprises brominated p-methylstyrene.

Example 8. the composition of any preceding example, wherein the non-halogenated alkylstyrene and the halogenated alkylstyrene cumulatively are present in the elastomer composition in an amount of greater than or equal to about 10 weight percent based on the elastomer composition.

Example 9. the composition of any preceding example, wherein the halogenated alkylstyrene is present from 0.1 mol% to 7.5 mol% relative to the non-halogenated alkylstyrene.

The composition of any preceding claim, wherein C₄-C₇The isoolefin is present in the elastomeric composition in an amount of less than or equal to about 90 wt%, based on the elastomeric composition.

Example 11 the composition of any preceding example, further comprising a processing aid and a filler.

Example 12 the composition of example 11, wherein the filler comprises carbon black.

Example 13 the composition of examples 11 or 12, wherein the filler comprises clay.

Example 14. the composition of any preceding example, wherein the elastomeric composition further comprises 0.5phr to 30phr butyl rubber.

Example 15. a method of manufacturing a tire curing bladder comprises: mixing 100 parts per hundred rubber (phr) of an elastomeric composition comprising C, 1phr to 7.5phr of an alkylphenol-formaldehyde resin, and 0.5phr to 5phr of mercaptobenzothiazole disulfide₄-C₇Isoolefins, non-halogenated alkylstyrenes and halogenated alkylstyrenes; and molding and curing the mixture into the shape of a tire curing bladder.

Example 16 the method of example 15, wherein the vulcanizing lasts less than 30 minutes at about 170 ℃ to about 200 ℃.

Example 17 the method of example 15, wherein the vulcanizing lasts for less than about 45 minutes to about 90 minutes at about 120 ℃ to about 150 ℃.

Example 18 the method of one of examples 15-17, wherein the alkylphenol formaldehyde resin comprises an octylphenol formaldehyde resin and/or a brominated octylphenol formaldehyde resin.

Example 19 the method of one of examples 15-18, wherein the alkylphenol-formaldehyde resin is present from about 3phr to about 5 phr.

Example 20 the method of one of examples 15-19, wherein the mercaptobenzothiazole disulfide is present from 1.4phr to about 2.0 phr.

Example 21 the method of one of examples 15-20, wherein C₄-C₇The isoolefin comprises isobutylene.

Example 22 the method of one of examples 15-21, wherein the non-halogenated alkylstyrene comprises para-methylstyrene.

Example 23 the method of one of examples 15-22, wherein the halogenated alkylstyrene comprises brominated p-methylstyrene.

Example 24 the method of one of examples 15-23, further comprising a processing aid and a filler.

Example 25 the method of one of examples 15-24, wherein the elastomeric composition further comprises 0.5phr to 30phr butyl rubber.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

One or more illustrative embodiments containing embodiments of the inventions disclosed herein are set forth herein. In the interest of clarity, not all features of a physical implementation are described or shown in this application. It will be appreciated that in the development of a physical embodiment that comprises an embodiment of the present invention, numerous implementation-specific decisions must be made in order to achieve the developer's goals, such as compliance with system-related, business-related, government-related, and other constraints, which will vary from one implementation to another. While a developer's efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in this art having the benefit of this disclosure.

Although compositions and methods are described herein in terms of "comprising" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components and steps.

In order to facilitate a better understanding of embodiments of the present invention, the following examples of preferred or representative embodiments are given. The following examples should in no way be construed as limiting or restricting the scope of the invention.

Examples

Ten samples were prepared according to the formulation in table 1 and the mixing parameters in table 2 below. Sample 1 is a control sample using butyl rubber, specifically 100phr EXXON^TMButyl 268S rubber (Butyl rubber, available from ExxonMobil Chemical Company, Houston TX) and 5phr chloroprene rubber (available from Skyprene B30) (available from Tosoh Corporation). Samples 2-10 are elastomeric compositions of the present disclosure using 100phr EXXPRO^TM3035 (available from ExxonMobil Chemical Company, Houston TX). In samples 2-10, the cure system was varied by varying the concentration of octylphenol formaldehyde resin and MBTS.

As illustrated in table 1, less zinc oxide and less octylphenol formaldehyde resin was used and no chloroprene rubber was used with the elastomer compositions described herein (samples 2-10). Chloroprene rubber is a specialty chemical and octylphenol-formaldehyde resin is a chemical with a short shelf life that requires special handling procedures. Reducing or eliminating these chemicals reduces the cost of the formulation and makes the formulation easier to produce.

TABLE 1 sample formulation

TABLE 1 sample recipe (continue)

TABLE 2 mixing parameters

TABLE 2 blending parameters (continuation)

Various properties of the ten samples were measured, see tables 3-7. Table 3 provides the Mooney viscosities and Mooney scorch properties for the ten samples. This data illustrates that the elastomeric compositions of the present disclosure (samples 2-10) have increased ML (1+4) and decreased t5 while maintaining consistent density compared to the control (sample 1).

TABLE 3 Mooney viscosity and Mooney scorch Properties

TABLE 3 Mooney viscosity and Mooney scorch Properties (continuation)

Table 4 provides the rheological properties of ten samples at three different temperatures. This data illustrates that the cure time (t90) for the control sample is two to three times the cure time for the elastomer compositions of the present disclosure (samples 2-10).

TABLE 4 rheological Properties at three different temperatures

TABLE 4 rheological Properties at three different temperatures

Table 5 provides the hardness, tensile and tear properties of the ten samples. This data illustrates that samples of the elastomeric composition after cure have a lower hardness than the control and an increase in tear force, which translates into a more stable tire curing bladder that will likely have a longer life than butyl rubber tire curing bladders.

TABLE 5 hardness, tensile and tear Properties

TABLE 5 hardness, tensile and tear Properties (continuations)

Table 6 provides tensile set, DeMattia crack initiation, permeability and fatigue to failure life test (FTFT) properties for ten samples. The data show that the tensile set can be adjusted by adjusting the cure system composition. Furthermore, the fatigue to failure life test gives a relative indication of the life of the tire curing bladder produced from the various samples. Many of the elastomer compositions described herein outperformed butyl rubber (sample 1).

TABLE 6 tensile set, DeMattia crack initiation, Permeability, and FTFT

TABLE 6 tensile set, DeMattia crack initiation, Permeability, and FTFT

K-cycles are 1000 cycles, so 69.5 are 69,500 cycles. 300.0 k-cycle means that the specimen did not break after 24 hours from complete removal of the ring.

Table 7 provides the hardness, tensile and tensile set properties of the ten samples at different cure times. This data demonstrates that the elastomer compositions described herein fully vulcanize (to a hardness of about 60 shore a) much faster than butyl rubber (sample 1). In addition, at those vulcanization times, other mechanical properties are comparable to or better than butyl rubber.

TABLE 7 hardness, tensile and tensile set at different vulcanization times

TABLE 7 hardness, tensile and permanent tensile set at different vulcanization times

TABLE 7 hardness, tensile and permanent tensile set at different vulcanization times

One of the two samples broke

The present invention is therefore well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components and steps. All numbers and ranges disclosed above may be varied by a certain amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, each numerical range disclosed herein (having the form "from about a to about b," or, equivalently, "from about a to b," or, equivalently, "from about a-b") should be understood to recite each number and range subsumed within the broader numerical range. Furthermore, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. In addition, the indefinite articles "a" or "an" as used in the claims are defined herein to mean one or more than one of the element it leads.