Process oil for rubber

Abstract

Provided is a process oil for rubber, said process oil containing a terpene compound (A) and at least one oil component (B) selected from the group consisting of ester compounds (B1) and olefins (B2), wherein the oil component (B) has a dynamic viscosity of 4.0 mm2 / s or higher at 100°C and the terpene compound (A) content is 20 mass% or more. The terpene compound (A) content is preferably 60 mass% or less based on the total amount of the process oil for rubber. Furthermore, the total content of the terpene compound (A) and the oil component (B) is preferably 50 mass% or more based on the total amount of the process oil for rubber.

Description

Rubber processing oil

[0001] This invention relates to a process oil for rubber.

[0002] Rubber compositions undergo various processing steps to become molded articles, depending on the intended use and required properties of the final product. Process oils are added to improve the processability of the rubber composition. Various process oils using mineral oil have been proposed (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2009-013421

[0004] In recent years, from the perspective of moving away from fossil fuels, there has been a desire for the creation of process oils that can replace or partially replace petroleum-derived mineral oils. However, sufficient research has not yet been conducted on process oils that can suppress the bleeding and stickiness of rubber compositions.

[0005] Therefore, the object of the present invention is to provide a process oil for rubber that can impart excellent viscoelastic properties to a rubber composition while suppressing bleeding and stickiness of the rubber composition.

[0006] The present invention provides the following [1] to [4]: ​​[1] A mixture containing a terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil component (B) at 100°C is 4.0 mm ２ [2] A rubber process oil having a viscosity of 1 / s or more and containing 20% ​​by mass or more of the terpene compound (A). [3] A rubber composition containing the rubber process oil described in [1] above and rubber. [4] A method for producing a rubber process oil, comprising the step of mixing a terpene compound (A) with one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil components (B) at 100°C is 4.0 mm. ２A method for producing a rubber process oil, wherein the ratio is 1 / s or more, and the amount of the terpene compound (A) blended is 20% by mass or more based on the total amount of the rubber process oil. [4] A method for producing a rubber composition, comprising the step of mixing the rubber process oil described in [1] above with rubber.

[0007] According to the present invention, it is possible to provide a process oil for rubber that can impart excellent viscoelastic properties to a rubber composition while suppressing bleeding and stickiness of the rubber composition.

[0008] The upper and lower limits of the numerical ranges described herein can be combined in any way. For example, if the numerical ranges "A to B" and "C to D" are described, the numerical ranges "A to D" and "C to B" are also included within the scope of the present invention. Furthermore, unless otherwise specified, the numerical ranges "lower limit to upper limit" described herein mean greater than or equal to the lower limit and less than or equal to the upper limit.

[0009] [Description of the rubber process oil] The rubber process oil of this embodiment contains a terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2). The kinematic viscosity of the oil component (B) at 100°C is 4.0 mm. ２ The viscosity is 20% by mass or more, and the content of terpene compound (A) is 20% by mass or more. As a result of diligent research by the present inventors, the present inventors have found a substance containing terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of oil component (B) at 100°C is 4.0 mm. ２ We discovered that using a process oil with a viscosity of 1 / s or higher and a terpene compound (A) content of 20% by mass or more can suppress bleeding and tackiness of rubber compositions. After further investigations, we completed the present invention.

[0010] The rubber process oil of this embodiment may consist only of a terpene compound (A) and an oil component (B), but may also further contain other components other than the terpene compound (A) and the oil component (B). In the rubber process oil of this embodiment, the total content of the terpene compound (A) and the oil component (B) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the rubber process oil.

[0011] The components constituting the rubber process oil of this embodiment, the physical properties of the rubber process oil, the method for producing the rubber process oil, the uses of the rubber process oil, and the method for producing the rubber composition will be described in detail below. In this specification, "ester compound (ester compound (B1))" means an ester which is a dehydration condensate product of an alcohol and a carboxylic acid. Here, in this embodiment, it is preferable that the ester compound (ester compound (B1)) is a non-aromatic ester. By using a non-aromatic ester as the ester compound, it is possible to prevent the scattering of aromatic components into the work environment and provide a rubber process oil with excellent work environment properties.

[0012] <Terpene Compound (A)> The rubber process oil of this embodiment contains terpene compound (A). By containing terpene compound (A), the rubber process oil of this embodiment can effectively suppress bleeding of the rubber composition. Terpene compound (A) is a compound having a constituent unit derived from isoprene, and is preferably a terpene resin. Examples of terpene resins include terpene resins, aromatically modified terpene resins, hydrogenated terpene resins, terpene phenol resins, etc., and among these, terpene resins are preferred. Preferred terpene resins include pinene-dipentene copolymers mainly composed of α-pinene, β-pinene, and dipentene, longifolene polymers, limonene polymers, and potassium olefin polymers. Commercially available terpene compound (A) can also be used. Examples of commercially available products include Daimaron (manufactured by Yasuhara Chemical Co., Ltd., pinene-dipentene copolymer). Terpene compound (A) may be used alone or in combination of two or more types.

[0013] (Content of terpene compound (A)) In this embodiment, the content of terpene compound (A) must be 20% by mass or more based on the total amount of rubber process oil. A content of 20% by mass or more of terpene compound (A) suppresses bleeding of the rubber composition. Here, from the viewpoint of improving the bleeding suppression of the rubber composition, the content of terpene compound (A) is preferably 30% by mass or more, more preferably 34% by mass or more, and even more preferably 36% by mass or more, based on the total amount of rubber process oil. Also, in this embodiment, from the viewpoint of improving the adhesion suppression of the rubber composition, the content of terpene compound (A) is preferably 60% by mass or less, more preferably 56% by mass or less, and even more preferably 52% by mass or less, based on the total amount of rubber process oil. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, preferably 30% by mass to 60% by mass, more preferably 34% by mass to 56% by mass, and even more preferably 36% by mass to 52% by mass.

[0014] <Oil component (B)> The process oil for rubber of the present embodiment contains, together with the terpene compound (A), one or more oil components (B) selected from the group consisting of an ester compound (B1) and a polyolefin (B2). And the oil component (B) is required to have a kinematic viscosity at 100 ° C of 4.0 mm ２ / s or more. By the process oil for rubber of the present embodiment containing, together with the terpene compound (A), an oil component (B), it is possible to achieve both bleed suppression and adhesion suppression of the rubber composition. In addition, in the kneading process when producing the rubber composition, the friction suppression effect is favorably exhibited, and the suppression effects such as heat generation suppression effect and adverse effects on the kneading apparatus are also exhibited. Here, from the viewpoint of more easily improving the effects of the present invention and from the viewpoint of improving the friction suppression effect in the kneading process during the production of the rubber composition, the kinematic viscosity at 100 ° C of the oil component (B) is preferably 10 mm ２ / s or more, more preferably 20 mm ２ / s or more, still more preferably 40 mm ２ / s or more, even more preferably 60 mm ２ / s or more. Also, from the viewpoint of more easily improving the effects of the present invention, the kinematic viscosity at 100 ° C of the oil component (B) is preferably 200 mm ２ / s or less, more preferably 160 mm ２ / s or less, still more preferably 120 mm ２ / s or less, even more preferably 100 mm ２ / s or less. The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, preferably 10 mm ２ / s to 200 mm ２ / s, more preferably 20 mm ２ / s to 160 mm ２ / s, still more preferably 40 mm ２ / s to 120 mm ２ / s, even more preferably 60 mm ２ / s to 100 mm ２The kinematic viscosity is 4.0 mm² / s. If the oil component (B) is an ester compound (B1) alone, the kinematic viscosity of the ester compound (B1) at 100°C should be within the above range. If the oil component (B) is a polyolefin (B2) alone, the kinematic viscosity of the polyolefin (B2) at 100°C should be within the above range. However, from the viewpoint of improving the effects of the present invention, the kinematic viscosity of the polyolefin (B2) at 100°C is preferably 4.0 mm². ２ / s ~ 8.0 mm ２ The kinematic viscosity is / s. Furthermore, if the oil component (B) is an ester compound (B1) and a polyolefin (B2), the kinematic viscosity at 100°C of the mixture of the ester compound (B1) and the polyolefin (B2) should be within the above range, but it is preferable that the kinematic viscosity at 100°C of at least the ester compound (B1) is within the above range. In this specification, kinematic viscosity at 100°C means the value measured in accordance with JIS K2283:2000.

[0015] In this embodiment, the oil component (B) is one or more selected from the group consisting of ester compounds (B1) and polyolefins (B2), and has a kinematic viscosity of 4.0 mm at 100°C. ２ Any oil with a viscosity of / s or higher can be used without particular restriction, but from the viewpoint of improving the effects of the present invention, it is preferable that the oil component (B) has biomass-derived carbon.

[0016] Furthermore, the oil component (B) may contain both an ester compound (B1) and a polyolefin (B2), or only one of them, but from the viewpoint of improving the effects of the present invention, it is preferable that the oil component (B) is an ester compound (B1). Furthermore, it is preferable that the oil component (B) is an ester compound (B1) and a polyolefin (B2). More preferable embodiments of the oil component (B) include the following embodiments: - A combination of an ester compound (B1) having biomass-derived carbon and a polyolefin (B2) having biomass-derived carbon - An ester compound (B1) having biomass-derived carbon alone However, "ester compound (B1) alone" here means that it does not contain polyolefin (B2) and contains an ester compound (B1), and there is no restriction on using multiple types of ester compound (B1) itself.

[0017] (Ester compound (B1)) In this embodiment, as the ester compound (B1), any compound that can adjust the kinematic viscosity of the oil component (B) at 100°C to the above range can be used as appropriate. For example, an ester of a polyhydric alcohol (e.g., an aliphatic polyhydric alcohol) and a carboxylic acid (preferably a fatty acid, more preferably a fatty acid having 12 to 24 carbon atoms) can be used. Here, it is preferable to use an ester compound (B1) having biomass-derived carbon. By using an ester compound (B1) having biomass-derived carbon, a rubber process oil with a high biomass content can be obtained. An ester compound (B1) having biomass-derived carbon is, for example, a plant-derived ester compound. Specifically, examples include ester oils synthesized from vegetable oils such as palm oil, coconut oil, soybean oil, rapeseed oil, and mixtures thereof. Examples of commercially available ester compounds (B1) containing biomass-derived carbon include Synative ES 3100 (BASF), Synative ES 3101 (BASF), Cosmoll 44V (Nisshin Oillio), and Priolubé 2088 (Cargill). Ester compounds (B1) may be used individually or in combination of two or more.

[0018] In this embodiment, from the viewpoint of facilitating the production of a rubber composition that has both bleed suppression and tackiness suppression while also having an excellent balance of viscoelastic properties, it is preferable that the ester compound (B1) has a (poly)glycerin skeleton. In other words, it is preferable that the ester compound (B1) is an ester of (poly)glycerin, which is a polyhydric alcohol, and a carboxylic acid. Having a (poly)glycerin skeleton in the ester compound (B1) makes it easier to further improve the effects of the present invention. In this specification, "(poly)glycerin" means glycerin or polyglycerin. Polyglycerin means a polymer of glycerin, preferably a 2 to 10-mer of glycerin, more preferably a 2 to 6-mer of glycerin, even more preferably a 2 to 4-mer of glycerin, and even more preferably a dimer of glycerin (i.e., diglycerin). Furthermore, it is preferable that the carboxylic acid constituting the ester compound (B1) is a fatty acid having 12 to 24 carbon atoms. The carboxylic acid constituting the ester compound (B1) is a fatty acid having 12 to 24 carbon atoms, which makes it easier to improve the effects of the present invention. The fatty acid may be a straight-chain fatty acid or a branched fatty acid, and may be a saturated fatty acid or an unsaturated fatty acid, but from the viewpoint of further improving the effects of the present invention, it is preferable that it be a saturated branched fatty acid. Furthermore, from the viewpoint of further improving the effects of the present invention, the number of carbon atoms in the fatty acid is more preferably 14 to 22, even more preferably 16 to 20, and even more preferably 18. In this embodiment, a preferred ester compound (B1) is an ester of diglycerin and isostearic acid (an ester of diglycerin and isostearic acid containing polyglyceryl-2 tetraisostearate, which is a full ester). A commercially available ester compound (B1) having a (poly)glycerin skeleton and biomass-derived carbon is Cosmol 44V (manufactured by Nisshin Oillio Co., Ltd.).

[0019] (Polyolefin (B2)) In this embodiment, as polyolefin (B2), any polyolefin (B2) that can adjust the kinematic viscosity of the oil component (B) at 100°C to the above range can be used as appropriate. Examples include olefin homopolymers consisting of olefins having 2 to 20 carbon atoms, or copolymers consisting of two or more of these olefins. Here, it is preferable to use polyolefin (B2) having biomass-derived carbon. By using polyolefin (B2) having biomass-derived carbon, a process oil for rubber with a high biomass content can be obtained. Polyolefin (B2) having biomass-derived carbon is, for example, a plant-derived polyolefin. Specifically, examples include polyolefins synthesized from vegetable oils such as palm oil, coconut oil, soybean oil, rapeseed oil, and mixtures thereof. A commercially available polyolefin (B2) having biomass-derived carbon is SynNova 4 Base Oil (manufactured by Novvi). Polyolefin (B2) may be used alone or in combination of two or more types.

[0020] (Content of oil component (B)) In this embodiment, from the viewpoint of improving the adhesion suppression of the rubber composition, the content of oil component (B) is preferably 40% by mass or more, more preferably 44% by mass or more, and even more preferably 48% by mass or more, based on the total amount of rubber process oil. Furthermore, from the viewpoint of ensuring the content of terpene compound (A) and making it easier to suppress bleeding of the rubber composition, the content of oil component (B) is preferably 65% ​​by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less, based on the total amount of rubber process oil. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, preferably 40% by mass to 65% by mass, more preferably 44% by mass to 60% by mass, and even more preferably 48% by mass to 55% by mass.

[0021] (Content ratio of terpene compound (A) and oil component (B)) In the present embodiment, the content ratio [(A) / (B)] of the terpene compound (A) and the oil component (B) is preferably 2 / 10 to 30 / 10, more preferably 4 / 10 to 20 / 10, still more preferably 6 / 10 to 15 / 10 in terms of mass ratio from the viewpoint of making it easier to further improve the effects of the present invention (particularly, from the viewpoint of imparting good viscoelastic properties to the rubber composition).

[0022] (Content of ester compound (B1)) When the rubber process oil of the present embodiment contains an ester compound (B1) as the oil component (B), the content of the ester compound (B1) is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and even more preferably 40% by mass or more based on the total amount of the rubber process oil from the viewpoint of improving the adhesion suppression property of the rubber composition. Also, from the viewpoint of ensuring the content of the terpene compound (A) and making it easier to suppress bleeding of the rubber composition, the content of the ester compound (B1) is preferably 65% by mass or less, more preferably 60% by mass or less, still more preferably 55% by mass or less based on the total amount of the rubber process oil. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 10% by mass to 65% by mass, more preferably 20% by mass to 65% by mass, still more preferably 30% by mass to 60% by mass, and even more preferably 40% by mass to 55% by mass.

[0023] (Polyolefin (B2) content) When the rubber process oil of this embodiment contains polyolefin (B2) as the oil component (B), the polyolefin (B2) content is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total amount of the rubber process oil, from the viewpoint of improving the adhesion suppression of the rubber composition. Furthermore, from the viewpoint of ensuring the content of terpene compound (A) and making it easier to suppress bleeding of the rubber composition, the polyolefin (B2) content is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, based on the total amount of the rubber process oil. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, they are preferably 10% by mass to 50% by mass, more preferably 20% by mass to 45% by mass, and even more preferably 30% by mass to 40% by mass.

[0024] <Other Components> The process oil for rubber of the present embodiment may contain other components other than the terpene compound (A) and the oil component (B) as long as the effects of the present invention are not significantly inhibited. Examples of the other components include other base oil components other than the terpene compound (A) and the oil component (B). Here, examples of the other base oil components include mineral oils and ester compounds (C) other than the ester compound (B1). However, from the viewpoint of improving the effects of the present invention, it is preferable that the content of the mineral oil is low. Specifically, the content of the mineral oil is preferably less than 50% by mass, more preferably less than 30% by mass, still more preferably less than 20% by mass, and even more preferably less than 10% by mass based on the total amount of the process oil for rubber. Further, from the viewpoint of improving the effects of the present invention, it is preferable that the content of the ester compound (C) is low. Specifically, the content of the ester compound (C) is preferably less than 50% by mass, more preferably less than 30% by mass, still more preferably less than 10% by mass, even more preferably less than 1% by mass, and still more preferably does not contain the ester compound (C) based on the total amount of the process oil for rubber. The ester compound (C) is preferably a non-aromatic ester. When the ester compound (C) is an aromatic ester, the content of the ester compound (C) is preferably less than 3% by mass, more preferably less than 1% by mass, and still more preferably does not contain the ester compound (C) based on the total amount of the process oil for rubber from the viewpoint of improving the working environment.

[0025] <Physical Properties of Process Oil for Rubber> The process oil for rubber of the present embodiment preferably satisfies the following physical properties from the viewpoint of improving the effects of the present invention.

[0026] (Kinematic Viscosity at 100°C) The process oil for rubber of the present embodiment preferably has a kinematic viscosity at 100°C of preferably 5.0 mm ２ / s to 70.0 mm ２ / s, more preferably 7.0 mm ２ / s to 60.0 mm ２ / s, still more preferably 9.0 mm ２ / s to 55.0 mm ２The value is / s. Furthermore, by having a kinematic viscosity at 100°C that is above the above lower limit, a good friction suppression effect is exhibited during the kneading process when manufacturing the rubber composition, and effects such as suppression of heat generation and adverse effects on the kneading equipment are also exhibited.

[0027] (Acid Value) The rubber process oil of this embodiment has an acid value of preferably 0.01 mg KOH / g to 0.60 mg KOH / g, more preferably 0.02 mg KOH / g to 0.50 mg KOH / g, and even more preferably 0.03 mg KOH / g to 0.40 mg KOH / g. In this specification, the acid value is a value measured in accordance with JIS K2501-7:2003.

[0028] (Base Number) The rubber process oil of this embodiment has a base number of preferably less than 0.1 mg KOH / g, more preferably less than 0.05 mg KOH / g, and even more preferably less than 0.01 mg KOH / g. In this specification, the base number is a value measured by the hydrochloric acid method in accordance with JIS K2501-8:2003.

[0029] (Saponification Value) The rubber process oil of this embodiment has a saponification value of preferably 20 mg KOH / g to 200 mg KOH / g, more preferably 25 mg KOH / g to 170 mg KOH / g, and even more preferably 30 mg KOH / g to 150 mg KOH / g. In this specification, the saponification value is a value measured in accordance with JIS K 2503:2010.

[0030] (Hydroxyl value) The rubber process oil of this embodiment has a hydroxyl value of 3.0 mg KOH / g to 30.0 mg KOH / g, more preferably 4.0 mg KOH / g to 25.0 mg KOH / g, and even more preferably 5.0 mg KOH / g to 22.0 mg KOH / g.

[0031] (Iodine value) The rubber process oil of this embodiment preferably has an iodine value of 5.0 gI ２ / 100g~80.0g ２ / 100g, more preferably 10.0g ２ / 100g~70.0g ２ / 100g, more preferably 12.0g ２ / 100g to 65.0g ２ This is per 100g. In this specification, the iodine value is the value measured in accordance with JIS K 0070:1992.

[0032] (Density at 15°C) The rubber process oil of this embodiment preferably has a density of 0.890 g / cm³ at 15°C. ３ ~0.960g / cm ３ More preferably 0.895 g / cm³ ３ ~0.957g / cm ３ More preferably 0.897 g / cm³ ３ ~0.955g / cm ３ In this specification, the density at 15°C is the value measured in accordance with JIS K 2249-1:2011 (Crude oil and petroleum products - Method for determining density - Part 1: Vibration method).

[0033] (Flash point by Cleveland Open Method) The rubber process oil of this embodiment has a flash point by the Cleveland Open Method preferably between 180°C and 220°C, more preferably between 185°C and 215°C, and even more preferably between 190°C and 210°C. In this specification, the flash point is a value measured by the Cleveland Open Method (COC) in accordance with JIS K 2265-4:2007.

[0034] [Method for Manufacturing Rubber Process Oil] The method for manufacturing the rubber process oil of this embodiment is not particularly limited. For example, the method for manufacturing the rubber process oil of this embodiment includes a step of mixing a terpene compound (A) with one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2). The kinematic viscosity of the oil component (B) at 100°C is 4.0 mm. ２The amount is 20% by mass or more based on the total amount of rubber process oil. The process may also include a step of blending other components as needed. Preferred embodiments of terpene compound (A), oil component (B), and other components are as previously described. The amounts and blending ratios of terpene compound (A), oil component (B), and other components are preferably the amounts corresponding to the preferred content and content ratio of terpene compound (A), oil component (B), and other components as described above.

[0035] [Applications of the rubber process oil] The rubber process oil of this embodiment can suppress bleeding and stickiness of rubber compositions. Therefore, the rubber process oil of this embodiment can be suitably used as a process oil for various products containing rubber compositions, such as in the molding of tires.

[0036] [Rubber Composition] The rubber composition of this embodiment contains the rubber process oil of this embodiment, and therefore bleed and stickiness are suppressed, and it has excellent viscoelastic properties. Here, it is preferable that the rubber composition of this embodiment satisfies the following physical properties.

[0037] <Bleed suppression> In the evaluation of bleed suppression of the rubber composition containing the rubber process oil of this embodiment, it is preferable that no oil stains are observed on the release paper according to the method described in the examples below.

[0038] <Adhesion Suppression> In the rubber composition containing the rubber process oil of this embodiment, it is preferable that, in the evaluation of adhesiveness by the method described in the examples below, no elongation due to adhesive force is observed when the rubber composition is peeled off.

[0039] <Viscoelastic properties 1: Breaking stress> The rubber composition containing the rubber process oil of this embodiment has a breaking stress, as measured by the method described in the examples below, preferably 6.0 MPa or higher, more preferably 7.0 MPa or higher, even more preferably 7.5 MPa, and even more preferably 8.0 MPa or higher. Having a breaking stress within the above range provides the rubber composition with good tensile strength.

[0040] <Viscoelastic properties 2: Fracture strain> The rubber composition containing the rubber process oil of this embodiment has a fracture strain, as measured by the method described in the examples below, preferably 600% or more, more preferably 650% or more, and even more preferably 700% or more. Having a fracture strain within the above range gives the rubber composition good flexibility.

[0041] [Method for Manufacturing the Rubber Composition] The method for manufacturing the rubber composition of this embodiment is not particularly limited as long as it is a manufacturing method using the rubber process oil of this embodiment, but for example, it includes a step of mixing the rubber process oil of this embodiment with rubber.

[0042] <Rubber> In the method for producing the rubber composition of this embodiment, examples of rubber include styrene-butadiene rubber (hereinafter also referred to as "SBR"), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber, and natural rubber. Among these, SBR is preferred.

[0043] <Additives> In the method for producing the rubber composition of this embodiment, additives may be further added to the rubber composition. Examples of additives to be added to the rubber composition include one or more general-purpose additives for rubber compositions, such as antioxidants, ultraviolet absorbers, lubricants, flame retardants, antistatic agents, fillers, and foaming agents.

[0044] <Manufacturing Conditions> In the method for manufacturing the rubber composition of this embodiment, the mixing conditions of the rubber process oil and the rubber are not particularly limited, and the usual conditions for compounding and mixing (kneading) rubber with process oil can be used. In addition, in the method for manufacturing the rubber composition of this embodiment, the amount of process oil compounded with the rubber is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 30 to 60 parts by mass, per 100 parts by mass of rubber.

[0045] <Molding Process> The method for producing the rubber composition of this embodiment may further include a molding process for obtaining a molded product. The molding method for obtaining the molded product is not particularly limited and includes, for example, extrusion molding, injection molding, blow molding, and calendering.

[0046] [One aspect of the present invention provided] According to one aspect of the present invention, the following [1] to

[11] are provided: [1] A terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil component (B) at 100°C is 4.0 mm ２[1] A rubber process oil having a concentration of 20% by mass or more of the terpene compound (A). [2] The rubber process oil according to [1], wherein the content of the terpene compound (A) is 60% by mass or less on a total basis of the rubber process oil. [3] The rubber process oil according to [1] or [2], wherein the total content of the terpene compound (A) and the oil component (B) is 50% by mass or more on a total basis of the rubber process oil. [4] The rubber process oil according to any one of [1] to [3], wherein the oil component (B) contains biomass-derived carbon. [5] The rubber process oil according to any one of [1] to [4], wherein the total content of the terpene compound (A) and the oil component (B) is 80% by mass or more on a total basis of the rubber process oil. [6] The rubber process oil according to any one of [1] to [5] above, wherein the content of the terpene compound (A) is 30% by mass or more based on the total amount of the rubber process oil. [7] The rubber process oil according to any one of [1] to [6] above, wherein the oil component (B) is the ester compound (B1). [8] The rubber process oil according to any one of [1] to [6] above, wherein the oil component (B) is the ester compound (B1) and the polyolefin (B2). [9] A rubber composition containing the rubber process oil according to any one of [1] to [8] above and rubber.

[10] A method for producing a rubber process oil, comprising the step of mixing a terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil component (B) at 100°C is 4.0 mm. ２ A method for producing a rubber process oil, wherein the ratio is 1 / s or more, and the amount of the terpene compound (A) blended is 20% by mass or more based on the total amount of the rubber process oil.

[11] A method for producing a rubber composition, comprising the step of mixing the rubber process oil described in any one of [1] to [8] above with rubber.

[0047] The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

[0048] [Preparation of Process Oil] The raw materials for process oil are as follows. <Ingredients> ・"Terpene A1": Daimaron (manufactured by Yasuhara Chemical Co., Ltd., pinene-dipentene copolymer) ・"Ester B1-1": Synative ES 3100 (manufactured by BASF, a synthetic high-performance ester with a basic skeleton of trimethylolpropane and esters of C16 saturated carboxylic acid and C18 unsaturated carboxylic acid) ・"Ester B1-2": Cosmol 44V (manufactured by Nisshin Oillio Co., Ltd., an ester of diglycerin and isostearic acid (an ester of glycerin containing polyglyceryl-2 tetraisostearate, which is a full ester, and isostearic acid)) ・"Ester B1-3": Priolube 2088 (manufactured by Cargill, an ester of trimethylolpropane (TMP) polymer and saturated fatty acid (mainly composed of saturated fatty acid with 10 carbon atoms)) ・"Ester B1-4": Synative ES 3101 (BASF, complex ester) • "Polyolefin B2-1": SynNova4 (NOVVI, plant-derived synthetic base oil hydrocarbon) • "Mineral oil": Diana Process NH-70S (Idemitsu Kosan, mineral oil)

[0049] <Measurement of various physical properties of process oil> Process oil was prepared according to the formulation shown in Table 1 (unit: mass%), and various physical properties of the process oil were measured by the following methods. (1) Kinematic viscosity at 100°C Measured in accordance with JIS K2283:2000. (2) Acid value Measured in accordance with JIS K2501-7:2003. (3) Base number Measured by hydrochloric acid method in accordance with JIS K2501-8:2003. (4) Saponification value Measured in accordance with JIS K 2503:2010. (5) Hydroxyl value Measured in accordance with JIS K 0070:1992. (6) Iodine value Measured in accordance with JIS K 0070:1992. (7) Density (15°C) was measured in accordance with JIS K 2249-1:2011 (Crude oil and petroleum products - Method for determining density - Part 1: Vibration method). (8) Flash point was measured in accordance with JIS K 2265-4:2007 using the Cleveland Open-Cold (COC) method.

[0050] Table 1 shows each process oil and its physical properties. The kinematic viscosity at 100°C, iodine value, and hydroxyl value of process oils 1a to 4a and 3b were calculated based on the blending amounts of each oil component in process oils 1a to 4a and 3b, using the kinematic viscosity at 100°C, iodine value, and hydroxyl value of process oil 1b (Dymaron), process oil 2b (SynNova 4), process oil 4b (Synative ES 3100), process oil 5b (Synative ES 3101), process oil 6b (Priolubé 2088), and process oil 7b (Cosmall 44V). The above calculations were performed assuming that the hydroxyl value of process oil 1a (Cosmall 44V) is 0 mgKOH / g.

[0051]

[0052] [Examples 1-4, Comparative Examples 1-7, and Reference Examples] Rubber compositions were produced using the methods described in Examples 1-4, Comparative Examples 1-7, and Reference Examples, and the evaluations described below were carried out.

[0053] <Raw Materials> Details of the raw materials used in Examples 1-4, Comparative Examples 1-7, and the Reference Example are shown below. In Examples 1-4, Comparative Examples 1-7, and the Reference Example, the blending ratio (unit: mass%) of each raw material was as shown in Table 2 below. ・"SBR": SBR1500 (ENEOS Material Co., Ltd.) ・"Carbon Black": Asahi #60U (Asahi Carbon Co., Ltd.) ・"Zinc Oxide": Zinc Oxide Type 2 (Seido Chemical Industry Co., Ltd.) ・"Stearic Acid": Lunac S-70V (Kao Corporation) ・"Sulfur": Fine Sulfur Powder (Hosoi Chemical Industry Co., Ltd.) ・"Vulcanization Accelerator": Noxellar CZ (Ouchi Shinko Chemical Industry Co., Ltd.)

[0054] <Example 1> A mixture of carbon black, zinc oxide, zinc stearate, and process oil 1a was prepared. Then, SBR was placed in a Banbury mixer and kneaded for 1 minute, after which the mixture was placed in the Banbury mixer and kneaded for 4 minutes to obtain a first knead. Sulfur and a vulcanization accelerator were added to the obtained first knead, and rubber kneading was performed at 50°C using two rolls to prevent vulcanization from progressing, to obtain a second knead in which sulfur and vulcanization accelerator were uniformly mixed in the first knead. Then, the second knead was placed in a mold measuring 250 mm × 150 mm × 2 mmt and pressed at a pressure of 20 MPa and a temperature of 145°C for 60 minutes to obtain rubber composition 1a.

[0055] <Examples 2-4> Process oil 1a was changed as follows, and rubber compositions 2a-4a were obtained in the same manner as in Example 1. • Example 2 (rubber composition 2a): Changed to process oil 2a • Example 3 (rubber composition 3a): Changed to process oil 3a • Example 4 (rubber composition 4a): Changed to process oil 4a

[0056] <Comparative Examples 1-7> Process oil 1a was changed as follows, and rubber compositions 1b-7b were obtained in the same manner as in Example 1. • Comparative Example 1 (rubber composition 1b): Changed to process oil 1b • Comparative Example 2 (rubber composition 2b): Changed to process oil 2b • Comparative Example 3 (rubber composition 3b): Changed to process oil 3b • Comparative Example 4 (rubber composition 4b): Changed to process oil 4b • Comparative Example 5 (rubber composition 5b): Changed to process oil 5b • Comparative Example 6 (rubber composition 6b): Changed to process oil 6b • Comparative Example 7 (rubber composition 7b): Changed to process oil 7b

[0057] <Reference Example> Process oil 1a was changed to process oil c, and rubber composition c was obtained in the same manner as in Example 1. • Reference Example (Rubber Composition c): Changed to process oil c

[0058] [Evaluation] The rubber compositions 1a to 4a obtained in Examples 1 to 4, rubber compositions 1b to 7b obtained in Comparative Examples 1 to 7, and rubber composition c obtained in the Reference Example were evaluated as follows (1 to 4).

[0059] <Evaluation 1: Evaluation of Bleed Inhibition> The rubber composition was sandwiched between two sheets of release paper (manufactured by Maru Adhesive Co., Ltd., model number "G73AN44") and left to stand at room temperature (23°C) for one week, and the appearance was visually evaluated. The evaluation criteria were as follows, and in this example, evaluation A was considered acceptable. - Evaluation A: No oil stains on the release paper. - Evaluation B: Oil stains covering less than 50% of the area of ​​the release paper. - Evaluation C: Oil stains covering 50% or more of the area of ​​the release paper.

[0060] <Evaluation 2: Evaluation of Adhesion Inhibition> The rubber composition was cut into JIS-3 dumbbell shapes, stacked in three layers, and stored in a submerged environment at room temperature (23°C) for 17 days. Subsequently, when the three stacked rubber compositions were peeled apart, if the rubber compositions could be peeled apart without stretching due to adhesive force, it was evaluated as evaluation A (no adhesiveness). If adhesive force acted between the stacked rubber compositions when peeling them apart, requiring enough force to stretch the rubber compositions, it was evaluated as evaluation B (adhesion present). In this example, evaluation A was considered acceptable.

[0061] <Evaluation 3: Evaluation of Viscoelastic Properties 1 (Breaking Stress)> The rubber composition was cut into a JIS-3 dumbbell shape, and the breaking stress was measured using an INSTRON 68TMR (manufactured by INSTRON) under the following measurement conditions. (Measurement conditions) ・Temperature: Room temperature (23℃) ・Tensile speed: 500 mm / min ・Chuck distance: 70 mm The higher the breaking stress, the less likely the rubber composition is to break. In this example, a breaking stress of 8.00 MPa or higher was considered acceptable.

[0062] <Evaluation 4: Evaluation of Viscoelastic Properties 2 (Fracture Strain)> The rubber composition was cut into a JIS-3 dumbbell shape, and the fracture strain was measured using an INSTRON 68TMR (manufactured by INSTRON). Specifically, while the rubber composition was stretched, the distance between the chucks was detected, and the difference from the initial value of the distance between the chucks was defined as ΔL (mm). The tensile nominal strain ε was then calculated as ε = ΔL / 20 × 100 (%), and the tensile nominal strain at the time of fracture was defined as the fracture strain. The greater the fracture stress, the more flexible the rubber composition. In this example, a fracture strain of 600% or more was considered acceptable.

[0063] The results are shown in Table 2.

[0064]

[0065] From Table 2, the following can be seen: The rubber compositions 1a to 4a of Examples 1 to 4, which used process oils 1a to 4a, are excellent in terms of bleed suppression, adhesion suppression, and viscoelastic properties. In contrast, the rubber compositions 1b to 7b of Comparative Examples 1 to 7, which used process oils 1b to 7b, are inferior in either bleed suppression, adhesion suppression, or viscoelastic properties.

Claims

1. Contains a terpene compound (A) and one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil component (B) at 100°C is 4.0 mm. ２ A rubber process oil having a coefficient of 1 / s or higher and containing 20% ​​by mass or more of the terpene compound (A).

2. The rubber process oil according to claim 1, wherein the content of the terpene compound (A) is 60% by mass or less based on the total amount of the rubber process oil.

3. The rubber process oil according to claim 1 or 2, wherein the total content of the terpene compound (A) and the oil component (B) is 50% by mass or more based on the total amount of the rubber process oil.

4. The rubber process oil according to any one of claims 1 to 3, wherein the oil component (B) contains biomass-derived carbon.

5. The rubber process oil according to any one of claims 1 to 4, wherein the total content of the terpene compound (A) and the oil component (B) is 80% by mass or more based on the total amount of the rubber process oil.

6. The rubber process oil according to any one of claims 1 to 5, wherein the content of the terpene compound (A) is 30% by mass or more based on the total amount of the rubber process oil.

7. The rubber process oil according to any one of claims 1 to 6, wherein the oil component (B) is the ester compound (B1).

8. The rubber process oil according to any one of claims 1 to 6, wherein the oil component (B) is the ester compound (B1) and the polyolefin (B2).

9. A rubber composition containing the rubber process oil and rubber described in any one of claims 1 to 8.

10. A method for producing a process oil for rubber, comprising the step of mixing a terpene compound (A) with one or more oil components (B) selected from the group consisting of ester compounds (B1) and polyolefins (B2), wherein the kinematic viscosity of the oil components (B) at 100°C is 4.0 mm. ２ A method for producing rubber process oil, wherein the ratio is 1 / s or higher, and the amount of the terpene compound (A) blended is 20% by mass or more based on the total amount of the rubber process oil.

11. A method for producing a rubber composition, comprising the step of mixing rubber process oil according to any one of claims 1 to 8 with rubber.

Images