Method of obtaining and composition of process oil for elastomeric compositions

Abstract

The invention relates to a method of obtaining and the contents of a process oil for elastomeric compositions that will find application in the manufacture of tyre treads and technical rubber products. According to the invention, the method for obtaining the process oil proceeds in two stages, the first step being a preparatory stage in which the graft is succinimide of the formula (CH2)2(CO)2NH dissolved in the process oil which is a mixture of hydrotreated heavy paraffinic petroleum distillates, by treatment in an ultrasonic bath at 37 kHz, at a temperature of 60 °C for a time period of 60 minutes., in the second stage, the carbon nanotubes are mixed with the mixture obtained from the first stage, the mixture is then homogenized in an ultrasonic bath at 37 kHz for 120 min. The composition of the process oil includes carbon nanotubes in an amount of 1 to 5 wt.%. of the total mixture from the process oil and the graft. The elastomeric compositions according to the invention comprise a process oil in amounts of 10 to 35 wt.% per 100 wt.% of elastomers. The elastomeric compositions comprising the process oil obtained according to the invention have improved heat generation performance, abrasion resistance and frictional rolling resistance.

Description

[0001] METHOD OF OBTAINING AND COMPOSITION OF PROCESS OIL FOR ELASTOMERIC COMPOSITIONS

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a process oil method and composition for elastomeric compositions, which will find particular use for the manufacture of tyre treads and conveyor belts, as well as for sealants and O-rings.

[0004] PRIOR ART

[0005] Elastomer compositions reinforced with carbon nanotubes are known which are dispersed in process / mineral oil for their reinforcing effect with respect to modulus and tensile strength.

[0006] Known as US11441006B2 - a rubber composition for tires comprising carbon nanotubes, and a method for producing the same published on 13 September 2022. The invention relates to a rubber tyre compound and a method of manufacturing of the latter, wherein the rubber tyre compound comprises: carbon nanotubes incorporating structural defects on at least part of the surface and having a thermal decomposition temperature equal to or less than 600 °C; and a rubber matrix. The rubber matrix may include a group consisting of acrylonitrile butadiene rubber, ethylene propylene diene rubber, styrene butadiene rubber, butadiene rubber, natural rubber, isoprene rubber, butyl rubber, and a combination of two or more thereof. A process oil is used in which the carbon nanotubes are mixed.

[0007] In patent document JP2022097273A RUBBER COMPOSITION FOR TIRE, AND TIRE, published on 30 June 2022 - a rubber composition for tires comprising a blend of diene rubber, silica and granular carbon nanotubes coated with a binder. Mineral oil is used as a binder.

[0008] Patent document CN 113929989A Composition, rubber compound, preparation method of rubber compound and tire, published on 14 January 2022, discloses a rubber compound composition, a method for preparing a rubber compound and a rubber tyre. The composition includes the following components by weight: 100 parts of rubber, 60-150 parts of white carbon black, 0-35 parts of carbon black and 1-35 parts of carbon nanotubes. The rubber consists of 0-50 parts of natural rubber by weight, 0-50 parts of butadiene rubber by weight and 0-100 parts by weight of butadiene-styrene rubber. The average tube diameter of carbon nanotubes is 5-25 nm. The average length of carbon nanotubes is 40-65 pm. The specific surface area of carbon nanotube is 100-360 m2 / g. According to the composition disclosed by the invention, some or all of the carbon black is replaced by carbon nanotubes, and the rubber made from the carbon nanotubes has a specific average tube diameter, a specific average length, and a specific surface area, has a relatively high static conductivity and relatively high wear resistance, so that driving safety is improved and the service life of the tyre is extended.

[0009] In order to avoid agglomeration of carbon nanotubes and to improve their dispersion rate in elastomeric compositions, the use of ultrasonic treatment has been developed in recent years. Patent document CN110818977A Rubber composite material using composite nanocarbon, and preparation method thereof, published on 21 February 2020, discloses a known mixture of graphene and nanotubes and dispersant in a weight ratio from 0.5 to 5:0.5 to 2:100, which is subjected to ultrasonic treatment to prevent agglomeration, by stirring at a rotational speed of 3,000 to 5,000 revolutions per second and a linear speed of 10 to 20 meters per second. The dispersant is polyvinylpyrrolidone.

[0010] Patent document CN109485929A - Tread rubber for all-steel truck radial tire and preparation method thereof, published on 19 March 2019, reveals the composition of a truck radial tire and method for its preparation. The tread rubber is prepared from the following components by weight: 0 to 80 parts matrix rubber, 30 to 153 parts wet blended rubber, 2 to 8 parts of active agent, 0 to 50 parts of carbon black, 0 to 20 parts of white carbon, 0 to 4 parts of silane coupling agent, 1 to 3 parts of accelerator, 3 to 6 parts of anti-aging agent and 1 to 2 parts of vulcanizing agent, whereas the wet-blended rubber is prepared from 0.1 to 3 parts of carbon nanotubes, 0.1 to 1 parts of graph ene, 10 to 50 parts of cracked carbon black, and 20 to 100 parts of natural rubber, it is produced by wet blending; and the total number of parts of natural rubber in the wet blended rubber and matrix rubber is 100. The material of the tread rubber has excellent mechanical properties, good treatment, low production costs and is beneficial to promoting the recycling of used tires. The method involves mixing carbon nanotubes, graphene and carbon black into an emulsion followed by ultrasonic treatment.

[0011] TECHNICAL NATURE OF THE INVENTION

[0012] The objective of the invention is to provide a method of preparation and composition of process oil for elastomer compositions, thereby replacing a portion of the carbon black and silica with carbon nanotubes dispersed in the process oil, thus providing improved mechanical properties of the vulcanizates. In this invention such objective is solved by a method which proceeds in two stages, the first stage is preparatory, the graft is succinimide (CHiXCOjiNH / IPAC 2310K7 is dissolved in process oil, which is a mixture of hydrotreated heavy paraffinic petroleum distillates / SN150 / by treating them in an ultrasonic bath at 37 kHz, at a temperature of 60 °C for a time period of 60 minutes. In the second stage, the carbon nanotubes are mixed with the mixture obtained from the first stage and the mixture is then homogenized in an ultrasonic bath at 37 kHz for 120 minutes.

[0013] The process oil composition according to the invention further comprises from 1 to 5 wt. % of carbon nanotubes from the total mixture of process oil and the graft. The elastomer compositions according to the invention contain process oil in an amount of from 10 to 35 wt.% per 100 wt.%. elastomer, the elastomers being isoprene rubber and butadiene rubber or butadiene rubber and butadiene styrene rubber or butadiene styrene rubber only or ethylene propylene rubber depending on the application, and the remaining ingredients are carbon black and / or silica filler, zinc oxide activator, stearin dispersant, N-isopropyl-N'-phenyl-l,4- phenylenediamine antioxidant, or microcrystalline wax and N-isopropyl-N'-phenyl-l,4- phenylenediamine antioxidant2,2,4-trimethyl-l, 2-dihydroquinoIine, plasticizer 2,2,4- trimethyl-l,2-dihydroquinoline, adhesion promoter Colophon, anti -premature vulcanization agent N-cyclohexyl-thiophthalimide, vulcanization accelerator N -cyclohexylbenzothiazole- 2-sulfenamide, vulcanizing agent sulphur , secondary vulcanizing accelerator diphenyl guanidine, coupling agent bis-(3-ethoxy-silylpropyl) disulphide, vulcanizing agent for ethylene propylene rubber mixes is di-(tert-butylperoxyisopropyl) benzene - organic peroxide.

[0014] Elastomer compositions incorporating the process oil obtained according to the invention have unexpectedly improved heat generation performance, abrasion resistance, and frictional rolling resistance

[0015] The unexpected effect is due to the preparatory stage of the reversal under the ultra sound of the process oil and the graft. This process, and its use as a pre-treatment step prior to the introduction of the carbon nanotubes to disperse them more uniformly, is not known to date. Pursuant to the studies carried out, the process oil according to the invention is included in the elastomer compositions of items such as: heavy-duty tyre treads, light radial tyre treads, “green” tyre treads, conveyor belt treads, sealants and O-rings. The following features have been studied upon the influence of carbon nanotubes: vulcanization, rheological, physical and mechanical, dynamic, resistance to thermal ageing, resistance to ozone ageing, resistance to fatigue under repeated sign-change deformations, resistance to static fatigue, heat formation, abrasion resistance, etc.

[0016] It is confirmed that small amounts of well-dispersed carbon nanotubes improve the mechanical properties of vulcanizates.

[0017] The advantages provided by the invention are seen in elastomeric compositions made for: Heavy-duty tyre treads have physical and mechanical performance, improved by 7% up to 20%. The 7% increase in relative elongation is associated with a 20% decrease in residual elongation, i.e. there is a significant improvement in the elasticity of the sample unit.

[0018] The treads for light radial tires have all of their physical and mechanical properties of vulcanizates improved. Their elasticity improved by about 30% due to the fact that their relative elongation improved by 7%, however their residual elongation decreased by about 25%;

[0019] The treads for green tires have the highest physical and mechanical performance indicators of vulcanizates. They contain 0.4 phr of carbon nanotubes, with an improvement of between 3% and 20%. The modules demonstrated improved tensile strength by 15-16% and improved relative elongation by 3-4%, yet the residual elongation was improved by 20%, meaning that the elasticity of the vulcanizates was also improved;

[0020] Conveyor belt treads, as well as the formulations of sealants and O-rings have all of their monitored indicators improved by 5-6%.

[0021] An extremely important feature according to the invention is the decrease in the rolling friction coefficient of the tyre, resulting in reduced fuel consumption and less pollution of the environment.

[0022] EXAMPLE EMBODIMENTS OF THE INVENTION

[0023] The enclosed examples do not limit the scope of protection of the invention.

[0024] Example 1.

[0025] Obtaining the process oil according to the invention:

[0026] The method proceeds in two stages: In the first step, the graft IP AC 231 OK ( succinimide of the formula (CHzXCO^NH) was dissolved in process oil SN150 (mixture of hydrotreated heavy paraffinic petroleum distillates) by treatment in an ultrasonic bath at 37 kHz and 60 °C for 60 minutes.

[0027] In the second step we have mixing of the carbon nanotubes with the resulting ultrasonically treated oil-graft mixture from the first step, the mixture is homogenized in a 37 kHz ultrasonic bath for 120 minutes.

[0028] The process oil composition of the invention further comprises 1% up to 5% of carbon nanotubes from the total mixture of the process oil and the graft.

[0029] Example 2. Elastomeric compound for heavy-duty tyre treads.

[0030] The technology of making the elastomeric compositions according to the invention is carried out in an open laboratory rubber mixer in the following sequence of operations and process mode:

[0031] Initially, the rubber is plasticized. At the fourth minute of plasticizing, zinc oxide and Stearin are added. After a three-minute homogenization, i.e. on the seventh minute, half the amount of filler is added. After another homogenization of 3 minutes, at the 10thminute, the second half of the filler is added. After a new homogenization, at the 16thminute, the vulcanization accelerator and the sulphur are added. After a new homogenization for 4 minutes, i.e. at the 20thminute the rubber mixture is ready.

[0032] The above process applies to all of the said examples from Example 2 up to and including Example 6.

[0033] Table 1. Treads for heavy-duty tyres

[0034] A-0 - control sample with base oil SN 150 without nanotubes

[0035] A-2 - oil with 2% nanotubes, i.e. 0.4 phr

[0036] A-3 - oil with 3% nanotubes, i.e. 0.6 phr

[0037] A-4 - oil with 4% nanotubes, i.e. 0.8 phr

[0038] A-5 - oil with 3% nanotubes, i.e. 0.6 phr, but derived from paste

[0039] Vulcanization characteristics

[0040] Vulcanization features are summarized in Table 2 .

[0041] Table 2. Vulcanization characteristics

[0042] As we can see from Table 1 the presence of carbon nanotubes (CNTs) in the composition of the rubber compound does not change the mechanism of the vulcanization process, yet it has an impact on the vulcanization features. As the CNT concentration increases from 0.4 to 0.8 phr, the relative viscosity of the mixes increases, the density of the vulcanization net and the hardness of the mixes also increases, there is a slight delay in the vulcanization process (up to 20 seconds), yet the effect on the vulcanization process of these rubber mixes is not explicitly pronounced.

[0043] Physical and mechanical indicators

[0044] The physical and mechanical indicators are summarized in Table 3.

[0045] Table 3. Physical and mechanical indicators

[0046] As we can see from Table 3, with carbon nano tube concentration of 0.8 phr (sample A-4) we observed the greatest impact, where the physical and mechanical performance indicators improved between 7% and 20%. We have the impression that the 7% increase in relative elongation is associated with a 20% decrease in residual elongation, i.e. there is this significant improvement in the elasticity of the sample unit. When using paste to obtain the dispersion, the results are lower than the case in which it is obtained directly.

[0047] Example 3. Elastomeric tread compound for light radial tyres.

[0048]

[0049] Table 4.

[0050] C-0 - control sample with oil without nanotubes

[0051] C-2 - oil with 2% nanotubes, i.e. 0.4 phr

[0052] C-3 - oil with 3% nanotubes, i.e. 0.6 phr

[0053] C-4 - oil with 4% nanotubes, i.e. 0.8 phr

[0054] Vulcanization characteristics

[0055] The vulcanization features of the studied mixes are systematized in Table 5.

[0056] Table 5. Vulcanization features of light radial tyre compounds containing carbon nano tubes

[0057] As we can see from Table 5, as the concentration of carbon nanotubes increases from 0.4 to 0.8 phr, the relative viscosity of the mixes increases, their hardness also increases, the induction period of vulcanization and the time for optimal vulcanization decrease by approximately 1 minute, i.e. the vulcanization process accelerates as the nanotube concentration increases.

[0058] Physical and mechanical indicators

[0059] The physical and mechanical indicators of light radial tyre tread compounds containing carbon nanotubes are indicated in Table 6.

[0060] Table 6. Physical and mechanical performance indicators of light radial tyre compounds

[0061] As we can see from the table, the effect of the introduction of carbon nanotubes is pronounced best with concentrations of 0.8 phr (sample C-4), where all the physical and mechanical features of the vulcanizates are improved, also improving their elasticity by about 30%, due to the fact that their relative elongation is improved by 7%, however their residual elongation is reduced by about 25%.

[0062] Example 4. Elastomeric tread composition for green tyres Table 7

[0063] G-0 - control sample with oil without nanotubes

[0064] G-2 - oil with 2% nanotubes, i.e. 0.2 phr

[0065] G-3 - oil with 3% nanotubes, i.e. 0.3 phr

[0066] G-4 - oil with 4% nanotubes, i.e. 0.4 phr According to current terminology in rubber technology, "green” tyres are those in which the classic carbon black used as a filler is replaced by silica. As well as being considered more environmentally friendly, green tyres reduce fuel consumption by approx. 8% and improve the grip on wet and snowy roads. They were first marketed in the mid-1990s by Michelin. Currently about 30% of all passenger car tyres produced in the world are green.

[0067] Vulcanization characteristics

[0068] The vulcanization features of the formulations developed for the production of green tyre treads are summarized in Table 8.

[0069] Table 8. Vulcanisation features of green tyre tread compositions

[0070] The presented results demonstrate that up to a concentration of 0.3 phr of carbon nanotubes, the viscosity of the mixes, their hardness and the density of the vulcanization net increase, the time to the start of the vulcanization process (the so-called induction period of vulcanization) also increases, as well as the time to complete 90% of the vulcanization process. The increase is by approx. 25 seconds. However, at nanotube concentrations above 0.3 phr, a decrease in the observed indicators starts.

[0071] Physical and mechanical indicators Physical and mechanical indicators of studied vulcanizates are summarized in Table 9.

[0072] Table 9. Physical and mechanical indicators of vulcanizates for the manufacturing of green tyre treads

[0073] The table shows that the vulcanizate containing 0.2 phr carbon nanotubes has the highest physical and mechanical indicators, with an improvement between 3% and 20%. The modules demonstrate improved tensile strength by 15-16%, and improved relative elongation by 3-4%, yet the residual elongation is improved by 20%, i.e. the elasticity of the vulcanizates is also improved. We should point out that the vulcanizates demonstrate significantly higher modules, especially M300, in the samples containing carbon nanotubes.

[0074] Example 5. Elastomer composition for conveyor belt treads

[0075] Table 10

[0076] H-0 - control sample with oil without nanotubes

[0077] H-2 - oil with 2% nanotubes, i.e. 0.4 phr

[0078] H-3 - oil with 3% nanotubes, i.e. 0.6 phr

[0079] H-4 - oil with 4% nanotubes, i.e. 0.8 phr Vulcanization characteristics

[0080] The vulcanization features of the mixes for the manufacturing of conveyor belt treads are indicated in Table 1 1 .

[0081] Table 11. Vulcanization features of mixes for the production of conveyor belt treads

[0082] The results in the table demonstrate a regular increase in the relative viscosity, hardness and density of the vulcanization net with the increase of nanotube concentration. The time to the onset of the vulcanization process and the optimum vulcanization time decrease gradually with the increase of nanotube concentration, i.e. vulcanization accelerates, yet such acceleration happens in the limits of 15-20 seconds.

[0083] Physical and mechanical features

[0084] The physical and mechanical indicators of vulcanizates for the production of conveyor belt treads are shown in Table 12.

[0085] Table 12. Physical and mechanical indicators of vulcanizates for the production of conveyor belt treads

[0086] The samples containing 0.6 phr carbon nanotubes (H-3) showed the best physical and mechanical indicators. An improvement in all monitored indicators is in place, yet in the range of 5-6%.

[0087] Example 6. Elastomeric composition for sealants and O-rings

[0088] Table 13.

[0089] 0-0 - control sample with oil without nanotubes

[0090] 0-2 - oil with 2% nanotubes, i.e. 0.7 phr

[0091] 0-3 - oil with 3% nanotubes, i.e. 1,05 phr

[0092] 0-4 - oil with 4% nanotubes, i.e. 1,4 phr

[0093] Vulcanization characteristics

[0094] The vulcanization features of the developed mixes are shown in Table 14.

[0095] Table 14. Vulcanization features of compounds for the production of sealants and O-rings

[0096] Presented results demonstrate that up to a carbon nanotube concentration of 0.7 phr, the relative viscosity, hardness and density of the vulcanization net increase, and then begin to gradually decrease. At the same time, the induction period of vulcanization and the optimum time for its progress decrease continuously, yet this decrease is in the order of only a few seconds.

[0097] Physical and mechanical indicators

[0098] The physical and mechanical indicators of vulcanizates for the production of sealants and O-rings are shown in Table 15.

[0099] Table 15. Physical and mechanical indicators for the production of sealants and O-rings

[0100] As we can see from Table 15 - the samples containing 0.7 phr carbon nano tubes have the best physical and mechanical indicators. Modules improve most significantly at 100% and 300% elongation

Claims

PATENT CLAIMS1. A method of preparing and composing a process oil for elastomeric compositions, whereas the process oil comprises the carbon nanotubes and is treated with ultrasound, characterized in that the method of preparing the process oil proceeds in two steps, the first step being a preparatory stage in which the graft is succinimide of the formula (CHJXCCOZNH dissolved in process oil, which is a mixture of hydrotreated heavy paraffinic petroleum distillates, by treatment in an ultrasonic bath at 37 kHz, at temperature of 60 °C for a time of 60 minutes. , in the second stage, the carbon nanotubes are mixed with the mixture obtained from the first stage, the mixture is then homogenized in an ultrasonic bath at 37 kHz for 120 min.

2. Process oil composition according to claim 1, characterized in that the process oil comprises carbon nanotubes in the amount of 1 to 5 wt.%. of the total mixture from the process oil and the graft.

3. The elastomeric compositions according to claim 1 , characterized in that process oil in the amount of 10 to 35 wt.% per 100 wt.% of elastomer, whereas the elastomer is isoprene rubber and butadiene rubber or butadiene rubber and butadiene styrene rubber or butadiene styrene rubber only or ethylene propylene rubber, depending on their application, and the remaining ingredients are carbon black and / or silica filler, zinc oxide activator, stearin dispersant, N-isopropyl-N' -phenyl- 1 ,4-phenylenediamine antioxidant, or microcrystalline wax and N-isopropyl-N'-phenyl-l ,4-phenylenediamine antioxidant 2,2,4 - trimethyl-1, 2 - dihydroquinoline, plasticizer 2,2,4-trimethyl-l,2-dihydroquinoline, adhesion promoter Rosin (Colophone), anti-premature vulcanization agent N-cyclohexyl-thiophthalimide, vulcanization accelerator N -cyclohexylbenzothiazole-2-sulfenamide, vulcanizing agent - Sulphur, secondary vulcanizing accelerator diphenyl guanidine, coupling agent bis-(3- ethoxy-silylpropyl) disulphide, vulcanizing agent for ethylene propylene rubber mixes - di- (tert-butylperoxyisopropyl) benzene - organic peroxide.

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