Rubber processing oil and rubber composition containing the same

Abstract

The present invention relates to a rubber processing oil and a rubber composition containing the same. The present invention provides a rubber processing oil comprising: a base oil; a liquid olefin copolymer prepared by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms; polyisobutylene; and one or more additives selected from an alkylated phosphoric acid compound and a butylhydroxybenzene-based compound. The present invention also provides a rubber composition containing the rubber processing oil.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from Korean Patent Application No. 10-2022-0055162, filed on May 4, 2022, which is hereby incorporated by reference in its entirety for all purposes. Technical Field

[0003] The present invention relates to a rubber processing oil and a rubber composition containing the same. Background Art

[0004] Ethylene-propylene diene monomer (EPDM) and styrene-ethylene / butylene-styrene (SEBS) are common types of rubber used in industrial applications. EPDM, in particular, is produced by copolymerizing ethylene, propylene, and ethylene norbornene (ENB), creating crosslinkable double bonds. Due to its excellent weather and ozone resistance, it is widely used in vehicle weather stripping and rubber components for household appliances and machinery.

[0005] In order to use EPDM / SEBS to manufacture rubber products, it is necessary to design the rubber combination that can obtain the mechanical properties of expectation, then need to manufacture semi-finished rubber products (intermediate product) by rubber mixing.Usually, in order to prepare rubber mix, use additives such as reinforcing agent, oil, antioxidant, activator, cross-linking agent, accelerator, adhesive and processing aid. Rubber mix can be formed into predetermined shape by such as extruding or calendering process, and the object of shaping can experience crosslinking to become rubber products when applying heat and pressure.

[0006] Rubber products have the unique property of deforming and returning to their original shape, which has led to their use in supporting bridges and buildings and absorbing their vibrations. In addition, rubber products are installed between moving mechanical devices to prevent noise and vibration.

[0007] A large amount of fillers are used to meet the desired mechanical properties of the rubber products used in various applications. When reinforcing agents such as carbon black or silicon dioxide are used in excess, the viscosity becomes too high, thereby hindering rubber mixing. In addition, the rubber wettability deteriorates, which causes the obtained rubber products to break. In this case, it is difficult to meet the desired mechanical properties of the rubber products.

[0008] In this case, to facilitate rubber mixing, oil can be used in appropriate amounts. However, there are limits to the amount of oil used. When excessive oil is added, rubber mixing is promoted, but the mechanical properties of the resulting rubber product deteriorate and become different from the designed properties. This affects product performance.

[0009] Furthermore, since oil has a lower molecular weight than rubber, it can be released into the air or diffused into the surrounding mix, which has a relatively low oil content, causing the remaining oil to decrease over time. This is one of the causes of changes in the mechanical properties of rubber and is a type of rubber aging.

[0010] Therefore, there is a need to develop a technology that can promote rubber kneading processability and extrusion and calendering processability while using a smaller amount of oil and can enhance the mechanical properties of rubber without causing loss of the added oil.

[0011] Korean Patent No. 10-1363718 discloses a related art.

[0012] [Related technical literature]

[0013] [Patent Document]

[0014] Korean Patent No. 10-1363718 (February 10, 2014) Summary of the Invention

[0015] An object of the present invention is to provide a rubber processing oil that facilitates rubber kneading without increasing the amount of processing oil used compared to conventional processing oils, improves the mechanical properties of rubber, and suppresses the phenomenon of a decrease in the amount of processing oil remaining during rubber production. Another object of the present invention is to provide a rubber composition containing the same rubber processing oil.

[0016] In a first aspect of the present invention, there is provided a rubber processing oil comprising: a base oil; a liquid olefin copolymer prepared by copolymerization of ethylene with an α-olefin having 3 to 20 carbon atoms; polyisobutylene; and one or more additives selected from alkylated phosphoric acid. Compounds and butylhydroxybenzene-based compounds.

[0017] In a first aspect, the rubber processing oil may include 1 to 80 wt % of a base oil, 1 to 80 wt % of a liquid olefin copolymer, 10 to 50 wt % of polyisobutylene, and 0.01 to 3 wt % of one or more additives.

[0018] In the first aspect, the liquid olefin copolymer may include 40 mol% to 60 mol% of ethylene units and 60 mol% to 40 mol% of α-olefin units having 3 to 20 carbon atoms.

[0019] In the first aspect, the polyisobutylene may have a number average molecular weight of 500 g / mol to 6,000 g / mol.

[0020] In a first aspect, alkylated phosphoric acid The compound may satisfy Formula 1 shown below.

[0021] [Formula 1]

[0022]

[0023] In Formula 1, R1 to R6 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms.

[0024] In a first aspect, alkylated phosphoric acid The compound may be selected from tetraoctyl bis(2-ethylhexyl)phosphate Tributyltetradecyl bis(2-ethylhexyl)phosphate Tetraethyl bis(2-ethylhexyl)phosphate and tributyl tetradecyl bis(2-ethylhexyl) phosphate One or more of .

[0025] In the first aspect, the butylhydroxybenzene-based compound may be one or more selected from N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), alkyl-tert-butyl hydroxyhydrocinnamate, alkyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and tert-butylhydroanisole.

[0026] In a second aspect of the present invention, there is provided a rubber comprising the above-mentioned rubber processing oil.

[0027] In the second aspect, the rubber composition may include 80 to 200 parts by weight of rubber processing oil per 100 parts by weight of rubber.

[0028] In a second aspect, the rubber composition may further comprise a diene-based rubber, wherein the diene-based rubber may be one or more selected from ethylene propylene diene (EPDM) rubber, butadiene rubber, natural rubber (NR), isoprene rubber, styrene butadiene rubber (SBR), nitrile rubber (NBR), isobutylene-isoprene rubber (IIR) and chloroprene rubber (CR).

[0029] Since the rubber processing oil according to the present invention contains not only base oil, but also liquid olefin copolymer, polyisobutylene and alkylated phosphoric acid Compounds and one or more additives of butylhydroxybenzene-based compounds, therefore, the rubber processing oil according to the present invention is advantageous in promoting rubber mixing and improving the mechanical properties of rubber without increasing the amount of rubber processing oil used compared with the case of using conventional processing oil. DETAILED DESCRIPTION

[0030] The advantages and features of the embodiments of the present invention will be clearly understood from the following description of the preferred embodiments. However, the present invention can be embodied in many different forms and should not be construed as being limited to the embodiments or examples set forth herein. On the contrary, these embodiments or examples are provided so that the present invention will be thorough and complete and will fully convey the viewpoints of the present invention to those skilled in the art. Therefore, the present invention will be limited only by the scope of the appended claims. Throughout the following description herein, like numbers refer to like elements.

[0031] In addition, when describing the embodiments or examples of the present invention, well-known functions or structures will not be described in detail because they may unnecessarily obscure the main purpose of the present invention. The following terms are defined with respect to their functions in the embodiments or examples of the present invention and may therefore vary depending on the intention of the user, operator, etc. Therefore, the definitions of each term should be interpreted based on the content throughout this specification.

[0032] A first aspect of the present invention relates to a rubber processing oil comprising: a base oil; a liquid olefin copolymer prepared by copolymerization of ethylene and an α-olefin having 3 to 20 carbon atoms; polyisobutylene; and one or more additives selected from alkylated phosphoric acid Compounds and butylhydroxybenzene-based compounds.

[0033] Since the rubber processing oil according to the present invention contains not only base oil, but also liquid olefin copolymer, polyisobutylene and alkylated phosphoric acid Compounds and one or more additives of butylhydroxybenzene-based compounds, therefore, the rubber processing oil according to the present invention is advantageous in promoting rubber mixing and improving the mechanical properties of rubber without increasing the amount thereof compared with the case of using conventional processing oils.

[0034] For this reason, the content of each component of process oil needs to be appropriately controlled.For example, rubber process oil comprises 1 wt % to 80 wt % of base oil, 1 wt % to 80 wt % of liquid olefin copolymer, 10 wt % to 50 wt % of polyisobutylene copolymer and 0.01 wt % to 3 wt % of one or more additives.More preferably, rubber process oil comprises 5 wt % to 60 wt % of base oil, 20 wt % to 80 wt % of liquid olefin copolymer, 12 wt % to 40 wt % of polyisobutylene copolymer and 0.05 wt % to 2 wt % of one or more additives.Most preferably, rubber process oil comprises 20 wt % to 45 wt % of base oil, 35 wt % to 45 wt % of liquid olefin copolymer, 15 wt % to 35 wt % of polyisobutylene copolymer and 0.1 wt % to 1.5 wt % of one or more additives.When the content of each component is within the above range, it is excellent to promote the effect of rubber mixing, and the mechanical properties of rubber can be improved. In the case where the content of each component is outside the range, the effect of promoting rubber kneading may not be significant, or the mechanical properties of the rubber may be reduced.

[0035] Hereinafter, a processing oil according to one embodiment of the present invention will be described.

[0036] First, in one embodiment, as the base oil, although the base oil varies in viscosity, heat resistance, oxidation stability, etc. according to the manufacturing method and refining method, any base oil can be used without limitation as long as it is commonly used in the field to which the present invention belongs. Generally, base oils are classified by the American Petroleum Institute (API) into Group I, Group II, Group III, Group IV, and Group V. These API categories are detailed in Appendix E of API Publication 1509, 15th Edition, April 2002, as shown in Table 1 below.

[0037] [Table 1]

[0038]

[0039] The base oil used in this embodiment can be any one of the Class I to Class V base oils classified by the American Petroleum Institute (API). The base oil suitable for use in the present invention belongs to any one of the Class I to Class III of the above-mentioned API classification, and "saturated hydrocarbons" can refer to paraffin compounds and cycloparaffin compounds. Paraffin compounds can be branched or linear, and cycloparaffin compounds can be cyclic saturated hydrocarbons such as cycloparaffins. Cyclic saturated hydrocarbons are generally derivatives of cyclopentane or cyclohexane. Cycloparaffin compounds are single ring structures (monocycloparaffins) or two isolated ring structures (isolated dicycloparaffins), or two fused ring structures (fused dicycloparaffins), or three or more fused ring structures (polycyclic cycloparaffins or polycycloparaffins).

[0040] According to one embodiment of the present invention, liquid olefin copolymer is used to promote the wetting of reinforcing agent during rubber mixing. The shearing force of mixing drum is transmitted to rubber, so that rubber and reinforcing agent can be mixed well. The liquid olefin copolymer produced by the copolymerization of ethylene and alpha-olefin with 3 to 20 carbon atoms shows the characteristic different from the mineral oil of such as naphthenic oil and paraffin oil. Liquid olefin copolymer is similar to EPDM / SEBS rubber in composition, is miscible better with mineral oil than rubber, and can reduce the viscosity of compounded rubber. These advantages help to reduce the power consumption during extrusion or calendering process, and help to produce the rubber product with desired size. The dimensional stability of rubber product is better, and manufacturing cost is lower, because reason is that defective rate reduces.

[0041] The liquid olefin copolymer can be prepared by copolymerizing ethylene and α-olefin monomers in the presence of a single-site catalyst system to uniformly distribute the α-olefin units in the copolymer chain. Preferably, the liquid olefin copolymer can be prepared by reacting ethylene and α-olefin monomers in the presence of a single-site catalyst system comprising a cross-linked metallocene compound, an organometallic compound, and an ionic compound that reacts with the cross-linked metallocene compound to form an ion pair.

[0042] The alpha-olefin monomer used together with ethene in the preparation of liquid olefin copolymer comprises the aliphatic olefin with 3 to 20 carbon atoms.Specifically, can use be selected from propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene and its isomer one or more aliphatic olefin, but be not limited to this for alpha-olefin monomer of the present invention.Preferably, alpha-olefin monomer can be one or more alpha-olefin with 3 to 6 carbon atoms.Most preferably, alpha-olefin monomer can be propylene.

[0043] Preferably, liquid olefin copolymer that is applicable to the present invention can be made up of 40 mol % to 60 mol % ethylene units and 60 mol % to 40 mol % alpha-olefin units with 3 to 20 carbon atoms.Using the liquid olefin copolymer with this composition range is good for improving processability and improving mechanical properties.On the other hand, when comprising ethylene units with an amount less than 40 mol % or greater than 60 mol %, the effect of improving processability may not be significant, or the mechanical properties of the rubber compound may reduce.

[0044] The liquid olefin copolymer may have a number average molecular weight (Mn) of 500 to 10,000 g / mol, a molecular weight distribution (Mw / Mn, where Mw is a weight average molecular weight) of 3 or less, and a kinematic viscosity at 100° C. of 30 to 5,000 cSt.

[0045] In one embodiment of the invention, polyisobutylene is a polymer whose main chain is isobutylene. When liquid olefin copolymer and polyisobutylene are added to base oil, the breaking strength and elongation at break of rubber can be improved. In the case of EPDM / SEBS rubber, the wear phenomenon of fine tearing may occur due to the repeated stress on the soft metal surface. According to the present invention, when the rubber processing oil comprising liquid olefin copolymer and polyisobutylene is added to the base rubber for rubber mixing, the breaking strength and elongation at break of rubber are improved, which helps to improve wear resistance. In addition, oil can be suppressed from escaping into the air or being diffused into the surrounding rubber, thereby suppressing the reduction of oil in the mixed rubber. This prevents the rubber aging phenomenon caused by the loss of oil and suppresses permanent deformation, which means that rubber cannot return to its original shape after experiencing repeated deformation.

[0046] The polyisobutylene suitable for the present invention has a number average molecular weight of 500 g / mol to 6,000 g / mol, preferably 1,000 g / mol to 4,000 g / mol, most preferably 1,500 g / mol to 3,000 g / mol; and a molecular weight distribution (PI) of 1 to 5, preferably 1 to 3. In addition, the kinematic viscosity at 100° C. may preferably be in the range of 2 cSt to 10,000 cSt, more preferably 100 cSt to 5,000 cSt, most preferably 1,000 cSt to 3,000 cSt.

[0047] For friction reduction and anti-oxidation effects, the addition of

[0048] Additives. As mentioned above, the additives can be selected from alkylated phosphoric acid One or more compounds of compounds and butylhydroxybenzene-based compounds.

[0049] Alkylated phosphoric acid The compound may be a compound satisfying Formula 1 shown below, and may be selected from tetraoctyl bis(2-ethylhexyl)phosphate Tributyltetradecyl bis(2-ethylhexyl)phosphate Tetraethyl bis(2-ethylhexyl)phosphate and tributyl tetradecyl bis(2-ethylhexyl) phosphate One or more of .

[0050] [Formula 1]

[0051]

[0052] In Formula 1, R1 to R6 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms.

[0053] The compound based on butylhydroxybenzene can be a compound containing a butylhydroxyphenyl group. Specifically, the compound based on butylhydroxybenzene can be one or more compounds selected from N, N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), alkyl-tert-butyl hydroxyhydrocinnamate, alkyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate and tert-butylhydroanisole. In this case, the alkyl group is an alkyl group with 1 to 20 carbon atoms, and the alkyl group can be linear or branched.

[0054] Furthermore, a second aspect of the present invention relates to a rubber composition comprising the rubber processing oil according to the first aspect. More specifically, the rubber composition comprises rubber, rubber processing oil, and a filler.

[0055] Since the rubber processing oil used herein is the same as described above, redundant description about the rubber processing oil will be omitted. The rubber composition preferably comprises 80 to 200 parts by weight of rubber processing oil per 100 parts by weight of rubber. More preferably, the rubber composition comprises 100 to 180 parts by weight of rubber processing oil per 100 parts by weight of rubber. When the rubber processing oil is used in an amount within the above range, the processability improvement effect is good, and the mechanical properties of the compounded rubber can be improved.

[0056] On the other hand, the rubber that can be used for an embodiment of the present invention is not particularly limited, as long as it is any one commonly used in the field to which the present invention belongs. Specifically, the rubber can be a diene-based rubber. Specifically, the diene-based rubber can be one or more selected from ethylene propylene diene (EPDM) rubber, butadiene rubber, natural rubber, isoprene rubber, styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), isobutylene-isoprene rubber (IIR) and chloroprene rubber (CR). Derivatives of such rubber can also be used. For example, polybutadiene rubber modified with tin compounds can be used. Alternatively, epoxy modified rubber, silane modified rubber or maleic acid modified rubber can be used alone or in combination.

[0057] The filler according to one embodiment of the present invention may be silica, carbon black, white carbon black, carbon nanotubes, clay, talc, or any mixture thereof. Preferably, the filler may be carbon black. The filler content may be in the range of 10 to 150 parts by weight, more preferably in the range of 30 to 120 parts by weight, and most preferably in the range of 50 to 100 parts by weight, per 100 parts by weight of rubber.

[0058] In addition, according to the application and needs, the rubber composition may further comprise one or more blending components selected from vulcanizing agents, vulcanization accelerators, zinc oxide and stearic acid commonly used in the rubber industry. For example, the vulcanizing agent may be one or more selected from sulfur (free sulfur), amine disulfide, polymeric polysulfide and sulfur-olefin adducts. The vulcanization accelerator may be one or more selected from the following: a benzothiazole-based accelerator, such as 2-mercaptobenzothiazole, dibenzothiazole disulfide, sodium 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc salt, 2-mercaptobenzothiazole cyclohexylamine salt, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, or N-oxydiethylene-2-benzothiazole sulfenamide; and a thiuram-based accelerator, such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, or dipentamethylenethiuram disulfide. Each of the blending components may be added in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the rubber, but is not limited thereto.

[0059] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The following examples are merely provided to help understand the present invention. The scope of the present invention is not limited by the following examples. In this article, unless otherwise indicated, "%" means "% by weight."

[0060] [Examples 1-15 and Comparative Examples 1 to 16]

[0061] Process oils were prepared by mixing paraffin oil, naphthenic oil, a liquid olefin copolymer (number average molecular weight (Mn) of 7,800 g / mol, ethylene content of 50 mol%), polyisobutylene (PIB) (manufactured by Daelim Co., Ltd., PB2000, Mn: 2,180 g / mol, kinematic viscosity at 100° C.: 2,200 to 2,400 cSt), and additives in the amounts (weight %) described in Table 2 below.

[0062] In this case, the abbreviations in Table 2 respectively refer to the additives.

[0063] TPEP: Tetraoctyl bis(2-ethylhexyl)phosphate

[0064] TBPEHP: tributyltetradecyl bis(2-ethylhexyl) phosphate

[0065] TEPEHP: Tetraethyl bis(2-ethylhexyl) phosphate

[0066] BHC: Octyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate

[0067] BHPPA: N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]

[0068] [Table 2]

[0069]

[0070]

[0071] [Examples 1-15 and Comparative Examples 1 to 16]

[0072] A compounded rubber was prepared by mixing rubber processing oil, EPDM (manufactured by Geumho Polychem Co., Ltd., KEP980N, ethylene content: 71% by weight, ENB content: 4.5% by weight, Mooney viscosity (ML (1+8) at 125° C.: 58)), carbon black (CB), zinc oxide (ZnO), stearic acid (SA), sulfur, tetramethylthiuram disulfide (TMTD), and 2,2′-dibenzothiazolyl disulfide (MBTS) according to the amounts (weight %) described in Table 3 below.

[0073] [Table 3]

[0074]

[0075]

[0076] [Characteristics evaluation]

[0077] The properties were evaluated according to the following methods. The rheological test results, Mooney viscosity, and tensile properties were expressed as indices. The higher the index, the better the physical properties.

[0078] 1) Rheological test at 160°C: measured according to ASTM D5289.

[0079] 2) Mooney viscosity (ML (1+4) at 100°C): Measured according to ASTM D1646. Mooney viscosity is an indicator of rubber viscosity. The higher the level, the lower the viscosity and the better the processability.

[0080] 3) Permanent compression set (CSET) (%): Measured according to ASTM D395. Permanent compression set indicates the mechanical strength of rubber. The lower the level, the smaller the deformation caused by compression.

[0081] 4) Tensile Properties: Tensile strength and elongation at break are measured according to ASTM D412. The tensile properties indicate the mechanical strength of the rubber. The higher the index, the better the mechanical strength.

[0082] [Table 4]

[0083]

[0084]

[0085] Referring to Tables 2 to 4, liquid olefin copolymer, polyisobutylene and alkylated phosphoric acid selected from In the case of the examples in which one or more additives of the compound and the butylhydroxybenzene-based compound were mixed with the base oil to prepare the rubber processing oil according to the present invention, it was found that the processability and mechanical properties of the rubber were generally improved compared with the comparative examples in which one or more of the liquid olefin copolymer and the polyisobutylene were not added.

[0086] However, in the case of Examples 10, 11, and 15 in which the amount of the liquid olefin copolymer or polyisobutylene was relatively small, the effect of improving the processability was not significant, or the mechanical properties of the rubber were degraded.

[0087] [Preparation Example 16]

[0088] A process oil was prepared by mixing 36.68 wt% of paraffin oil, 21.51 wt% of naphthenic oil, 26.00 wt% of a liquid olefin copolymer (number average molecular weight (Mn) of 7,800 g / mol, ethylene content of 35 mol%), 15.7 wt% of polyisobutylene (PIB) (manufactured by Daelim Co., Ltd., PB2000, Mn: 2,180 g / mol, kinematic viscosity at 100° C.: 2,200 to 2,400 cSt), and 0.11 wt% of BHC.

[0089] [Preparation Example 17]

[0090] A process oil was prepared by mixing 37.76 wt% of paraffin oil, 16.52 wt% of naphthenic oil, 25.50 wt% of a liquid olefin copolymer (number average molecular weight (Mn) of 7800 g / mol, ethylene content of 75 mol%), 20.1 wt% of polyisobutylene (PIB) (manufactured by Daelim Co., Ltd., PB2000, Mn: 2180 g / mol, kinematic viscosity at 100° C.: 2200 cSt to 2400 cSt), and 0.12 wt% of BHC.

[0091] [Preparation Example 18]

[0092] A process oil was prepared by mixing 67.63 wt% of paraffin oil, 25.00 wt% of a liquid olefin copolymer (number average molecular weight (Mn) of 7800 g / mol, ethylene content of 70 mol%), 7.25 wt% of polyisobutylene (PIB) (manufactured by Daelim Co., Ltd., PB2000, Mn: 2180 g / mol, kinematic viscosity at 100°C: 2200 cSt to 2400 cSt), and 0.12 wt% of BHC.

[0093] [Preparation Example 19]

[0094] A process oil was prepared by mixing 42.68 wt% of paraffin oil, 23.35 wt% of naphthenic oil, 26.54 wt% of a liquid olefin copolymer (number average molecular weight (Mn) of 7,800 g / mol, ethylene content of 30 mol%), 7.32 wt% of polyisobutylene (PIB) (manufactured by Daelim Co., Ltd., PB2000, Mn: 2,180 g / mol, kinematic viscosity at 100° C.: 2,200 to 2,400 cSt), and 0.11 wt% of BHC.

[0095] [Table 5]

[0096]

[0097] [Examples 16 to 19]

[0098] A compounded rubber was prepared by mixing process oil, EPDM (manufactured by Geumho Polychem Co., Ltd., KEP980N, ethylene content: 71% by weight, ENB content: 4.5% by weight, Mooney viscosity (ML (1+8) at 125° C.: 58)), carbon black (CB), zinc oxide (ZnO), stearic acid (SA), sulfur, tetramethylthiuram disulfide (TMTD), and 2,2′-dibenzothiazolyl disulfide (MBTS) according to the amounts (weight %) described in Table 6 below.

[0099] [Table 6]

[0100]

[0101] [Characteristics evaluation]

[0102] Rheological tests, Mooney viscosity, permanent compression set, and tensile properties were evaluated according to the above methods, and the results are shown in Table 7.

[0103] [Table 7]

[0104]

[0105] Examples 8 and 16 to 19 are experimental examples in which liquid olefin copolymers having different ethylene contents were added.

[0106] Among them, in the case of Example 8 in which a liquid olefin copolymer having an ethylene content in the range of 40 mol% to 60 mol% was used, processability was excellent, permanent compression set was 10.22%, and tensile strength index was 157. That is, mechanical properties were excellent.

[0107] On the other hand, in the case of Examples 16 to 19 in which the liquid olefin copolymer having an ethylene content outside the range of 40 mol% to 60 mol% was used, the effect of improving processability and mechanical properties was not significant, or the processability and mechanical properties were degraded.

Claims

1. A rubber processing oil comprising: 1 to 80 wt. % base oil; 1 to 80 weight percent of a liquid olefin copolymer soluble in the base oil and prepared by copolymerization of ethylene and an α-olefin having 3 to 20 carbon atoms, the liquid olefin copolymer comprising 40 to 60 mol percent of ethylene units and 60 to 40 mol percent of α-olefin units having 3 to 20 carbon atoms; 10 to 50 wt% polyisobutylene; as well as 0.01 to 3 wt% of one or more additives selected from alkylated phosphoric acids Compounds and butylhydroxybenzene-based compounds. 2 . The rubber processing oil according to claim 1 , wherein the polyisobutylene has a number average molecular weight of 500 to 6,000 g / mol.

3. The rubber processing oil according to claim 1, wherein the alkylated phosphoric acid The compound satisfies formula 1, [Formula 1] In Formula 1, R1 to R6 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms.

4. The rubber processing oil according to claim 3, wherein the alkylated phosphoric acid Compounds include tetraoctyl bis(2-ethylhexyl)phosphate , tributyl tetradecyl bis(2-ethylhexyl) phosphate 、Tetraethyl bis(2-ethylhexyl) phosphate and tributyl tetradecyl bis(2-ethylhexyl) phosphate One or more of .

5. The rubber processing oil according to claim 1, wherein the butylhydroxybenzene-based compound comprises one or more selected from the group consisting of N,N′-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), alkyl-tert-butyl hydroxyhydrocinnamate, alkyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and tert-butylhydroanisole. A rubber composition comprising the rubber processing oil according to claim 1 . 7 . The rubber composition according to claim 6 , comprising 80 to 200 parts by weight of the rubber processing oil per 100 parts by weight of rubber.

8. The rubber composition according to claim 6, further comprising a diene-based rubber.

9. The rubber composition according to claim 8, wherein the diene-based rubber is one or more selected from ethylene propylene diene (EPDM) rubber, butadiene rubber, natural rubber, isoprene rubber, styrene butadiene rubber (SBR), nitrile rubber (NBR), isobutylene-isoprene rubber (IIR) and chloroprene rubber (CR).

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