Rubber composition comprising disulfide silane, fatty acid, and trimethylolpropane
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-04
- Publication Date
- 2026-08-13
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Abstract
Description
Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366RUBBER COMPOSITION COMPRISING DISULFIDE SILANE, FATTY ACID,AND TRIMETHYLOLPROPANEFIELD OF THE INVENTION
[0001] The subject matter of the present invention relates to an improved rubber formulation with excellent green rubber properties and suitable for use in tires. In particular, the rubber formulation has particularly consistent industrial handling characteristics over time while retaining good performance of the cured rubber.BACKGROUND OF THE INVENTION
[0002] Rubber compositions have long been used to build tires for vehicles. Rubber has good flexibility, traction and durability making rubber compositions ideal for the road interface component of a vehicle and particularly suitable for the tread component of tires. Fillers substances, such as carbon black, titanium dioxide and talc, added to the rubber composition provide additional reinforcement, coloring and protection to the rubber composition. Silica fillers particularly provide superior wear resistance and traction in both dry and wet conditions. Silica elastomer mixes, defined herein as having at least 30 parts per hundred (“phr”) silica by weight of the elastomer, are particularly useful in tread rubber applications. Most of silica mixes tend to have significant variability in properties during their aging in the uncured rubber state, also known as “green rubber” state. These green rubber properties include varying viscosity and elasticity. Such variability of green rubber properties can cause variation in dimensions in the final intermediate uncured product leading to further difficulties in obtaining a consistent final product. Controlling the intermediate uncured product quality improves the final cured product quality leading to better finished cured tire products.
[0003] Silane is a well-known coupling agent used to increase the bonding of the silica filler to the rubber compound. The silane coupling agent has two fundamental functions in silica mixes: cover the silica and hide the highly polar silanol groups from the hydrophobic elastomer, and to provide a chemical link between the silica and the elastomer. The use of silane has made high silica mixes useful for tires, providing excellent traction and wear properties that could not have been obtained before with carbon black reinforced rubber compositions.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0004] Trimethylolpropane is a known processing aid, such as found in EP 0761734 in that it is known to reduce the viscosity of the mixture and improve rebound resilience of the vulcanized mixture at 70C. Mixtures of trimethylolpropane and fatty acid mixtures have been shown in DE 102004039545 to be used in rubber production as processing aids to lower viscosity of the mixture without significantly impairing the mechanical properties. Use of functionalized diene rubbers with trimethylolpropane and fatty acid has been shown in US 201202700974 to reduce viscosity and lower rolling resistance and increase grip under wet conditions. None, however, showed a reduction of the degradation of green rubber handling characteristics over time while retaining good performance of the cured rubber.
[0005] Mixing processes utilizing multiple mixers, such as those described in US Patent No. 10,328,608 are used to create rubber mixtures for industrial processes. These mixing methods enable efficient rubber mixing processes where multiple rubber mixes are made on the same equipment and formed into a sheet product and stored until needed later. The use of the green rubber sheet product is limited, however, by the quality and properties of the green rubber which change with time. Often the rubber extruded after being stored for a period becomes stiffer and less viscous as measured by Mooney viscosity, requiring more energy for shaping into an intermediate product and requiring variation in intermediate steps making subsequent stages more difficult or affect tire uniformity or finished weight variations in the finished product. Adaptations and subsequent machine adjustment to accommodate the increasing Mooney viscosity affects the cost of manufacturing by slowing down production, and addition of process aids to compensate can affect the final product’s physical properties. What is needed is a rubber composition having good intermediate product time stability and specifically a rubber composition having stable or decreasing Mooney viscosity after storage.SUMMARY OF THE INVENTION
[0006] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
[0007] In one exemplary embodiment, a rubber composition having improved uncured material property stability, comprising a diene elastomer, a silica filler comprising 30 to 50 phr of a silica having a BET surface area between 150 and 180 m2 / g, a silane present in the amount of 5 to 15.2% of the weight of the total loading of the silica filler, the majority ofInventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366the silane comprised of a disulfide silane composition, 1 to 4 phr of a mixture comprising trimethylolpropane and fatty acid amide, and a vulcanizing system.
[0008] Another exemplary embodiment as described in the paragraph above wherein over half by weight of the diene elastomer is natural rubber.
[0009] An embodiment as described in either of the embodiments above wherein the silica is present an amount of between 34-41 phr.
[0010] An embodiment as described in any one of the previous embodiments wherein the rubber composition further comprises 5 to 12 phr of carbon black, or alternatively 8 to 10 phr.
[0011] An embodiment as described in any one of the previous embodiments wherein the silane is present in the amount of 8 to 12 of the weight of the total loading of the silica filler.
[0012] An embodiment as described in any one of the previous embodiments wherein it contains less than 5 phr of a fatty acid processing aid, or alternatively no additional fatty acid processing aid other than the mixture.
[0013] An alternative embodiment of the rubber composition described in the paragraph above wherein the fatty acid processing aid consists of steric acid.
[0014] Another alternative embodiment in accordance with any of the embodiments described above wherein the vulcanizing system is comprised of sulfur, alternatively wherein such a rubber composition is comprised of 1.6 to 2.4 phr of sulfur or alternatively 1.8 to 2.2 phr of sulfur.
[0015] Another alternative embodiment in accordance with any of the embodiments described above further comprising a protection system.
[0016] Another alternative embodiment in accordance with any of the embodiments described above further comprising a vulcanizing activator.
[0017] Another alternative embodiment in accordance with any of the embodiments described above further comprising a vulcanizing accelerator.
[0018] Another alternative embodiment in accordance with any of the embodiments described above further comprising a vulcanizing retarder.
[0019] Another alternative embodiment in accordance with any of the embodiments described above wherein the mixture of trimethylolpropane and fatty acid amides also comprises polyethylene glycol, such as, by way of example, Aflux 37.
[0020] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.BRIEF DESCRIPTION OF THE DRAWINGS
[0021] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
[0022] FIG. 1 provides a chart showing the plasticity over time for a rubber composition having a non-disulfide silane and no trimethylolpropane and a rubber composition comprising disulfide silane, trimethylolpropane and fatty acid.DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides an improved rubber composition comprising a disulfide silane, trimethylolpropane and fatty acid having better improved uncured processability and stability such as improved Mooney viscosity over time. For purposes of describing the invention, reference now will be made in detail to embodiments and / or methods of the invention, one or more examples of which are illustrated in or with the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features or steps illustrated or described as part of one embodiment, can be used with another embodiment or steps to yield a still further embodiments or methods. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
[0024] As used herein, "phr" is “parts per hundred parts of rubber by weight” and is a common measurement in the art wherein components of a rubber composition are measured relative to the total weight of rubber in the composition, z.e., parts by weight of the component per 100 parts by weight of the total rubber(s) in the composition.
[0025] As used herein, “elastomer” and “rubber” are synonymous terms.
[0026] As used herein, “based upon” is a term recognizing that embodiments of the present invention are made at least in part of vulcanized or cured rubber compositions that were, at the time of their assembly, uncured. The cured rubber composition is thereforeInventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366“based upon” the uncured rubber composition. In other words, the cross-linked rubber composition is based upon or comprises the constituents of the cross-linkable rubber composition.
[0027] Reference will now be made in detail to embodiments of the invention. Each example is provided by way of explanation of the invention. For example, features described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.
[0028] In addition to the rubber components disclosed herein, particular embodiments of the rubber compositions further include a silica reinforcing filler. Reinforcing fillers are added to rubber compositions to, inter alia, improve their tensile strength and wear resistance.
[0029] Useful silica reinforcing fillers known in the art include fumed, precipitated and / or highly dispersible silica (known as “HD” silica). For example, precipitated SIL 160 such as Hi-Sil 160G from PPG, or SIL 165 such as Zeosil 165 from Solvay may be used in embodiments of the invention. In particular embodiments, the silica may have a BET surface area, for example, of between 100 m2 / g and 250 m2 / g or alternatively between 100 m2 / g and 230 m2 / g, between 100 m2 / g and 200 m2 / g or between 150 m2 / g and 190 m2 / g. Particular embodiments may have a CTAB as determined according to ISO 5794 of between 110 m2 / g and 200 m2 / g or alternatively between 130 m2 / g and 190 m2 / g, between 140 m2 / g and 180 m2 / g or between 155 m2 / g and 170 m2 / g.
[0030] Particular embodiment of the rubber compositions may include between 30 phr and 50 phr of the silica filler or alternatively between 36 phr and 46 phr or between 34 phr and 41 phr. Amounts that are less than this range do not provide the desired rigidity of the cured composition and amounts greater than this range provide unacceptable hysteresis of the uncured rubber composition, which has an unfavorable impact on rolling resistance. Larger amounts also impact the processability of the uncured rubber composition with a higher Mooney viscosity.
[0031] In addition to the rubber components and the silica reinforcing filler described above, particular embodiments of the rubber compositions may include a small amount of carbon black. Carbon black is also a reinforcing filler but may be added to rubber compositions to give the expected black color to the elastomers used in tires. Suitable carbon blacks of the type HAF, ISAF and SAF, for example, are conventionally used in tire treads. Non-limitative examples of carbon blacks include, for example, the N115, N134,Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366N234, N299, N326, N330, N339, N343, N347, N375 and the 600 series of carbon blacks, including, but not limited to N630, N650 and N660 carbon blacks.
[0032] The amount of carbon black included in the rubber compositions disclosed herein may range between 0 phr and 15 phr or alternatively between 5 phr and 12 phr, between 8 phr and 12 phr, between 8 phr and 10 phr or between 3 phr and 8 phr of carbon black. Some embodiments may include no carbon black.
[0033] In addition to the rubber components and the silica reinforcing fillers described above, a coupling agent is used in the embodiments herein. Silane is a well-known coupling agent used to increase the bonding of the silica filler to the rubber compound. As described herein, two types of silanes may be used in rubber compositions, a non-disulfide silane or “polysulfide silane” such as SI-69 may be used as a coupling agent, or disulfide silane, such as SI-75 or SI-266, a bis(triethoxysilylpropyl)disulfide, from Evonik. The disulfide silane is used in the embodiments of the present invention. The silane coupling agent has two fundamental functions in silica mixes: cover the silica and hide the highly polar silanol groups from the hydrophobic elastomer, provide a chemical link between the silica and the elastomer. The use of silane has made high silica mixes useful for tires, providing excellent traction and wear properties that could not have been obtained before with carbon black reinforced rubber compositions.
[0034] The amount of silane coupling agent can vary over a suitable range as known to one having ordinary skill in the art, generally depending upon the amount of silica present. Typically the amount added is between 7 wt. % and 15 wt. % or alternatively between 8 wt. % and 12 wt. % or between 9 wt. % and 11 wt. % of the total weight of silica added to the rubber composition.
[0035] The embodiments of the invention herein contain a mixture comprising trimethylolpropane and a fatty acid amide, such as Aflux-37. It was found that 1 to 4 phr of the mixture, combined with the use of a disulfide silane was particularly useful. The mixture may be comprised of other components, such as polyethylene glycol in addition to trimethylolpropane and fatty acid amides.
[0036] Particular embodiments of the rubber composition disclosed herein include no processing oil or liquid plasticizers. Oils and other liquid plasticizers are useful for improving the processability of rubber compositions but do so typically with a compromise of reducing wear. Surprisingly particular embodiments of the rubber compositions disclosed herein do not require such a processing aid.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0037] Oils and liquid plasticizers are well known to those having ordinary skill in the art. Examples include oils extracted from petroleum, vegetable oils, and low molecular weight polymers. Those extracted from petroleum may be classified as being paraffinic, aromatic or naphthenic type processing oil and including MES and TDAE oils. Those that are vegetable oils include, for example, rapeseed oil, and sunflower oil.
[0038] Some embodiments of the rubber compositions may include an elastomer, such as a synthetic polyisoprene, that has been extended with one or more such processing oils, but such oil is limited in the rubber compositions as being no more than 10 phr of the total elastomer content of the rubber compositions or alternatively, no more than 8 phr, no more than 6 phr or no more than 4 phr. Other embodiments include no such extended elastomers.
[0039] While particular embodiments of the rubber compositions disclosed herein include no liquid plasticizers, other embodiments may include no more than 10 phr of a liquid plasticizer or alternatively no more than 5 phr or no more than 2 phr of a liquid plasticizer.
[0040] Particular embodiments of the rubber composition disclosed herein include no plasticizing resins. Plasticizing resins are useful for, inter alia, improving processability of the rubber compositions but do so typically with a compromise of reducing wear.Surprisingly particular embodiments of the rubber compositions disclosed herein do not require such a processing aid.
[0041] Plasticizing resins are well known to those having ordinary skill in the art and are generally hydrocarbon based, often being petroleum based or plant based. Useful plasticizing resins typically are high Tg (glass transition temperature greater than 25 °C) though other resins are useful with lower Tg’s. Examples of useful resins include C5 / C9 aliphatic resins and C9 / dicyclopentadiene resins marketed by ExxonMobil, with softening points < 130 °C , and number-average molecular masses (Mn) < 1000.
[0042] Examples of other resins include the Escorez resins available from ExxonMobil, these resins being modified aliphatic hydrocarbon resins,
[0043] It may be noted that the glass transition temperatures of plasticizing resins may be measured by Differential Scanning Calorimetry (DCS) in accordance with ASTM D3418 (1999).
[0044] While particular embodiments of the rubber compositions disclosed herein include no such plasticizing resins, other embodiments may include no more than 5 phr of a resin or alternatively no more than 3 phr or no more than 1 phr of a plasticizing resin.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0045] The rubber compositions disclosed herein may be cured with any suitable sulfur curing system. Particular embodiments are cured with a sulfur curing system that includes free sulfur and may further include, for example, one or more of accelerators, stearic acid and zinc oxide. Stearic acid and zinc oxides are well known vulcanization activators in sulfur curing systems. Suitable free sulfur includes, for example, pulverized sulfur, rubber maker’s sulfur, commercial sulfur, and insoluble sulfur. The amount of free sulfur included in the rubber composition is not limited and may range, for example, between 0.5 phr and 10 phr or alternatively between 0.5 phr and 5 phr or between 0.5 phr and 3 phr. Particular embodiments contained between 1.6 to 2.4 phr of sulfur and alternatively between 1.8 and 2.2 phr or sulfur. Particular embodiments may include no free sulfur added in the curing system but instead include sulfur donors.
[0046] Accelerators are used to control the time and / or temperature required for vulcanization and to improve the properties of the cured rubber composition. Particular embodiments of the present invention include one or more accelerators. One example of a suitable primary accelerator useful in the present invention is a sulfenamide. Examples of suitable sulfenamide accelerators include n-cyclohexyl -2 -benzothiazole sulfenamide (CBS), N-tert-butyl-2 -benzothiazole Sulfenamide (TBBS), N-Oxydiethyl-2-benzthiazolsulfenamid (MBS) and N'-dicyclohexyl-2-benzothiazolesulfenamide (DCBS). Combinations of accelerators are often useful to improve the properties of the cured rubber composition and the particular embodiments include the addition of secondary accelerators.
[0047] Particular embodiments may include as a secondary accelerant the use of a moderately fast accelerator such as, for example, diphenylguanidine (DPG), triphenyl guanidine (TPG), diorthotolyl guanidine (DOTG), o-tolylbigaunide (OTBG) or hexamethylene tetramine (HMTA). Such accelerators may be added in an amount of up to 4 phr, between 0.2 and 3 phr, between 0.2 and 2 phr, between 0.2 to 0.5 phr, or between 0.5 and 2.5 phr. Particular embodiments may exclude the use of fast accelerators and / or ultrafast accelerators such as, for example, the fast accelerators: disulfides and benzothiazoles; and the ultra-accelerators: thiurams, xanthates, dithiocarbamates and dithiophosphates.
[0048] Other additives can be added to the rubber compositions disclosed herein as known in the art. Such additives may include, for example, some or all of the following: antidegradants, antioxidants, fatty acids, waxes. Examples of anti degradants and antioxidants include 6PPD, 77PD, IPPD and TMQ and may be added to rubber compositions in an amount, for example, of from 0.5 phr and 5 phr. Zinc oxide may be added in an amount, for example, of between 0.5 phr and 6 phr or alternatively, of betweenInventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT003661.0 phr and 4 phr. Waxes may be added in an amount, for example, of between 1 phr and 5 phr. Stearic acid may be added in an amount, for example, of between 1 phr and 6 phr or alternatively, of between 1.5 phr and 4 phr.
[0049] Particular embodiments of the rubber compositions disclosed herein provide good processability as demonstrated by their Mooney viscosities. The Mooney viscosity for particular embodiments is no greater than 130 MU or alternatively no greater than 125 MU or between 70 MU and 130 MU, between 70 MU and 125 MU or between 80 MU and 110MU or between 80 MU and 100 MU. The Mooney viscosity is measured at 100 °C in accordance with ASTM D 1646-1999 as described below.
[0050] The rubber compositions that are embodiments of the present invention may be produced in suitable mixers, such as in internal mixer, in a manner known to those having ordinary skill in the art. There are typically two successive preparation phases, a first phase of thermo-mechanical working at high temperature, followed by a second phase of mechanical working at lower temperature.
[0051] The first phase of thermo-mechanical working (sometimes referred to as "nonproductive" phase) is intended to mix thoroughly, by kneading, the various ingredients of the composition, with the exception of the vulcanization system. It is carried out in a suitable kneading device, such as an internal mixer or an extruder, until, under the action of the mechanical working and the high shearing imposed on the mixture, a maximum temperature generally between 120° C and 190° C, more narrowly between 130° C and 170° C, is reached. Typically DPG is mixed in the first stage to provide a covering for the silica as well as the disulfide silane and mixture of trimethylolpropane and fatty acid amide.
[0052] After cooling of the mixture, a second phase of mechanical working is implemented at a lower temperature. Sometimes referred to as "productive" phase, this finishing phase consists of incorporating by mixing the vulcanization (or cross-linking) system (sulfur, accelerators, activators), in a suitable device, for example an open mill although some or all of the accelerators and activators may be mixed in the non-productive phase. It is performed for an appropriate time (typically between 1 and 30 minutes, for example between 2 and 10 minutes) and at a sufficiently low temperature that is lower than the vulcanization temperature of the mixture, so as to protect against premature vulcanization.
[0053] The rubber composition can be formed into useful articles, including treads for use on vehicle tires. The treads may be formed as tread bands and then later made a part ofInventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366a tire or they be formed directly onto a tire carcass by, for example, extrusion and then cured in a mold. As such, tread bands may be cured before being disposed on a tire carcass or they may be cured after being disposed on the tire carcass. Typically a tire tread is cured in a known manner in a mold under an appropriate heat and pressure for a predetermined time, the mold configured to form tread elements into the tread, including, e.g., the sipes molded into the tread blocks or ribs.
[0054] The invention is further illustrated by the following examples, which are to be regarded only as illustrations and not delimitative of the invention in any way. The properties of the compositions disclosed in the examples were evaluated as described below and these utilized methods are suitable for measurement of the claimed properties of the claimed invention.
[0055] The Mooney viscosity ML(l+4) at 100 °C was measured in accordance with Standard ASTM D 1646 of 1999.
[0056] Hysteresis loss HL60 is measured in percent by rebound at 60°C at the sixth impact in accordance with the following equation:HL60(%) = 100(VF0 - VF1) / W1 (Eq-1)where W0 is the energy supplied and W1 is the energy restored.
[0057] The “modulus”, or moduli of elongation (MPa) were measured at 10% (MAIO), 100% (MA100) and 300% (MA300) elongation at a temperature of 23°C based on ASTM Standard D412-2006a on dumb bell test pieces. The measurements were taken in the second elongation; i.e., after an accommodation cycle. These measurements are secant moduli in MPa, based on the original cross section of the test piece. Generally, a material having a higher MAIO is a harder material and a material having a lower MAIO is a softer material. For rubber goods, for example, tire components, some reasonably high rigidity is required for the application performances.
[0058] Particular embodiments of the rubber compositions disclosed herein provide good processability as demonstrated by their Mooney viscosities. The Mooney viscosity for particular embodiments is no greater than 130 MU or alternatively no greater than 125 MU or between 70 MU and 130 MU, between 70 MU and 125 MU or between 80 MU and 110MU or between 80 MU and 100 MU. The Mooney viscosity is measured at 100 °C in accordance with ASTM D 1646-1999 as described below.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0059] Embodiments of the rubber compositions disclosed herein may additionally be described as having at one of the defined measurements provided above of at least two of the three characteristics of tan delta, G*(50% strain) and Mooney viscosity. Other embodiments may additionally have all three of the characteristics. For example, particular embodiments may have a tan delta max of between 0.045 and 0.013 and a G*(50% strain) of at least 1.0 MPa. Other embodiments have at least the measurements provided above in max tan delta and G*(50% strain).Example
[0060] Table 1 below lists the components of the sample tread rubber compositions that were made to determine the composition properties with and without the addition of a disulfide silane, such as SI-75, and a mixture of surface-active substances and fatty acids, such as Aflux 37, added to the rubber composition prior to or during mixing. Composition W1 represents a rubber composition made with a non-disulfide silane, particularly SI-69, and without a processing aid having a mixture of surface-active substances and fatty acids. The composition Fl represents an analogous rubber composition made with a disulfide silane and a processing aid comprised of a mixture of surface-active substances and fatty acids, specifically Aflux 37 from Rhein Chemie Corporation.Table 1Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0061] Rubber compositions were prepared using the components shown in Table 1.The amount of each component making up the rubber compositions are provided in parts per hundred parts of rubber by weight (phr). The rubber components, except the sulfur and non-DPG accelerator, were mixed in a Banbury mixer until a temperature of between 150 °C and 170 °C was reached. The sulfur and accelerator was added during the second phase on a mill. The green rubber compositions were then tested to measure their properties, the results of which are shown in FIG 1. The rubber formulations were cured at between 140 °C and 150 °C.
[0062] FIG. 1 provides comparison between the witness mix W1 (above) and embodiment mix Fl (lower) in terms of initial plasticity over the final plasticity for the (ML 4+10) Mooney measurement at 100C. The relationship of these values is expressed as a ratio (OS / M =Initial Mooney / Final Mooney). The closer the value is to 1.0, the less variable the rheology of the mix is after extrusion. The more stable this ratio is with time (across the x-axis), the less evolution is expected in green properties with age in the factory.
[0063] The results show that all the test mixes resulted in an OS / M closer to 1.0 than the witness mix. All of the embodiments mixes showed less variability between the mesasurement sets than the witness mix. All the embodiment mixes showed more stability with green rubber age as demonstrated by the lower slope of the trend lines. The embodiment mixes (Fl) performed much better than the witness mixes as it had the lowest OS / M and values that remained stable over time, compared with the increasing OS / M values of the witness mix (Wl). Rigidity and hysteresis are not significantly impacted by the change in silane grade or the introduction of the processing aid.Table 2Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366
[0064] Table 2 shows the rigidity and hysteresis values for the witness mix W1 and embodiment mix Fl. The results shows the embodiment having a lower Mooney value and only a slightly higher 10% Modulus value while the 100% and 300% modulus values are only slightly higher or the same. Hysteretic loss (HL60) is only negligibly higher in the embodiment mix.
[0065] Selected combinations of aspects of the disclosed technology correspond to a plurality of different embodiments of the present invention. It should be noted that each of the exemplary embodiments presented and discussed herein should not insinuate limitations of the present subject matter. Features or steps illustrated or described as part of one embodiment may be used in combination with aspects of another embodiment to yield yet further embodiments.
[0066] The terms “substantially” or “substantial” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. It is also noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement or other representation. These terms are also utilized herein to represent the degree by which quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
[0067] The terms "a," "an," and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The terms "at least one" and "one or more" are used interchangeably. Ranges that are described as being "between a and b" are inclusive of the values for "a" and "b."
[0068] The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
Claims
Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT00366WHAT IS CLAIMED IS:
1. A rubber composition comprising:a diene elastomer;a silica filler comprising 30 to 50 phr of a silica having a BET surface area between 150 and 180 m2 / g;a silane present in the amount of 5 to 15.2% of the weight of the total loading of the silica filler, the majority of the silane comprised of a disulfide silane composition;1 to 4 phr of a mixture comprising trimethylolpropane and fatty acid amide; and a vulcanizing system.
2. The rubber composition of claim 1 wherein the majority of the diene elastomer is natural rubber.
3. The rubber composition of claim 1 or claim 2 wherein the silica is present an amount of between 34-41 phr.
4. The rubber composition of any one of the above claims further comprising 5 to 12 phr of carbon black.
5. The rubber composition of claim 4 wherein the carbon black is present in an amount of between 8 to 10 phr.
6. The rubber composition of any one of the above claims wherein the silane is present in the amount of 8 to 12 of the weight of the total loading of the silica filler.
7. The rubber composition of any one of the above claims further comprising less than 5 phr of a fatty acid processing aid.
8. The rubber composition of claim 7 wherein the fatty acid processing aid consists of steric acid.
9. The rubber composition of any one of the above claims where the vulcanizing system is comprised of sulfur.
10. The rubber composition of claim 9 comprising 1.6 to 2.4 phr of sulfur.
11. The rubber composition of claim 9 comprising 1.8 to 2.2 phr of sulfur.
12. The rubber composition of any one of the above claims further comprising a protection system.
13. The rubber composition of any one of the above claims further comprising a vulcanizing activator.
14. The rubber composition of any one of the above claims further comprising a vulcanizing accelerator.Inventor: Alex Snyder, et al.Attorney Docket No.: 2024PAT0036615. The rubber composition of any one of the above claims further comprising a vulcanizing retarder.
16. The rubber composition of any one of the above claims wherein the mixture of trimethylolpropane and fatty acid amides also comprises polyethylene glycol.