Emulsion composition and method for producing same

Abstract

The preset invention provides: an emulsion composition which is able to be produced by an easy method in comparison to conventional ones, while exhibiting excellent stability of an emulsion; and a method for producing this emulsion composition.　An emulsion composition which contains: a conjugated diene rubber in a liquid state; a diluent that has a vapor pressure of 10 Pa or less at 20°C; a surfactant; and water.

Description

[Technical Field]

[0001] The present invention relates to an emulsion composition having excellent emulsion stability, and a method for producing the same. [Background technology]

[0002] Liquid rubber is widely used as a tackifier, adhesive, cold resistance improver for rubbers, processing oil, and reactive plasticizer. When used for these purposes, liquid rubber is generally used as is, but it may also be emulsified before use. Liquid rubbers with molecular weights of several thousand have low viscosity and can be easily emulsified using a common emulsifier. However, liquid rubbers with molecular weights of several tens of thousands have high viscosity and are therefore difficult to emulsify. In this case, emulsification can be achieved by applying extremely large mechanical shear forces, but this poses problems such as the need for specialized equipment and a complicated manufacturing process. Even if emulsions are successfully formed, they are prone to poor stability, resulting in phase separation during storage.

[0003] To solve these problems, Patent Document 1 proposes a method for preparing an oil-in-water emulsion by mixing an organic solvent solution (A) of a polymer with an aqueous medium (B) in the presence of an emulsifier, in which (A) and (B) are mixed at a specific volume ratio with low-speed stirring to prepare a water-in-oil emulsion, and then further stirred at high speed to invert the phases to form an oil-in-water emulsion. Patent Document 2 also proposes an emulsification method for emulsifying a liquid cis-1,4-polyisoprene rubber having a molecular weight of 10,000 to 60,000, in which the cis-1,4-polyisoprene rubber is not dissolved in an organic solvent and water is used in an amount of at most 80 parts by mass per 100 parts by mass of the liquid cis-1,4-polyisoprene rubber. Furthermore, Patent Document 3 proposes an emulsification method using a dialkyl sulfosuccinate as an emulsifier for liquid polyisoprene having a molecular weight of 10,000 to 60,000, and Patent Document 4 proposes a method for producing an emulsion using polyoxyethylene alkyl (allyl) ether phosphate as an emulsifier when emulsifying liquid polyisoprene having a molecular weight of 10,000 to 60,000. Furthermore, Non-Patent Document 1 describes a method for emulsifying liquid rubber in which the liquid rubber is diluted with an organic solvent, mixed with an emulsifier and water, and then the organic solvent is distilled off to emulsify the mixture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 49-332 [Patent Document 2] Japanese Patent Application Publication No. 54-124043 [Patent Document 3] Japanese Patent Application Laid-Open No. 62-141033 [Patent Document 4] Japanese Unexamined Patent Publication No. 54-124040 [Non-patent literature]

[0005] [Non-Patent Document 1] Journal of the Society of Rubber Science and Technology of Japan, Vol. 57, No. 10, pp. 78-89 Summary of the Invention [Problem to be solved by the invention]

[0006] Although emulsion compositions can be obtained using conventional methods, the emulsions are not sufficiently stable. Furthermore, the method of Patent Document 1 in particular requires high-speed stirring of a highly viscous composition, which requires specialized equipment and makes the emulsion difficult to produce. Furthermore, Non-Patent Document 1 uses an organic solvent, which requires a step of distilling off the solvent, making the production method complicated.

[0007] The present invention has been made in view of the above problems, and aims to provide an emulsion composition that can be produced more simply than conventional methods and has excellent emulsion stability, and a method for producing the same. [Means for solving the problem]

[0008] The present inventors have conducted extensive research into the emulsification of liquid conjugated diene rubbers and have found that the use of a diluent having a vapor pressure of 10 Pa or less at 20°C results in a very stable emulsion composition that is less susceptible to phase separation, and further that the emulsion composition can be obtained by a simpler method than conventional methods, thereby completing the present invention.

[0009] That is, the present invention provides the following [1] to [7]. [1] An emulsion composition containing a liquid conjugated diene rubber, a diluent having a vapor pressure of 10 Pa or less at 20°C, a surfactant, and water. [2] The emulsion composition according to [1], wherein the liquid conjugated diene rubber contains monomer units derived from one or more selected from butadiene, isoprene, and β-farnesene. [3] The emulsion composition according to [1] or [2], wherein the liquid conjugated diene rubber is a modified conjugated diene rubber having a hydrogen-bonding functional group in a portion of the conjugated diene rubber. [4] The emulsion composition according to [3] above, wherein the hydrogen-bonding functional group is at least one selected from a hydroxy group, an epoxy group, an aldehyde group, an acetalized aldehyde group, a carboxy group, a salt of a carboxy group, an esterified carboxy group, an acid anhydride of a carboxy group, a boronyl group, a salt of a boronyl group, an esterified boronyl group, a silanol group, and an esterified silanol group. [5] The emulsion composition according to any one of the above [1] to [4], wherein the surfactant is a nonionic surfactant. [6] The emulsion composition according to any one of [1] to [5], wherein the content of the surfactant in the emulsion composition is 1 to 15 parts by mass per 100 parts by mass of the total of the liquid conjugated diene rubber and the diluent. [7] A method for producing the emulsion composition according to any one of [1] to [6] above, characterized in that after the liquid conjugated diene rubber, the diluent, the surfactant, and water are mixed to produce an oil-in-water emulsion, the diluent is not removed. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an emulsion composition that can be produced more easily than conventional methods and has excellent emulsion stability, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Emulsion composition] The emulsion composition of the present invention is an emulsion composition containing a liquid conjugated diene rubber, a diluent having a vapor pressure of 10 Pa or less at 20° C., a surfactant, and water. According to the present invention, a liquid conjugated diene rubber is used in combination with a diluent having a vapor pressure of 10 Pa or less at 20°C, making it possible to obtain an emulsion composition that is highly stable and resistant to phase separation. If the vapor pressure of the diluent at 20°C exceeds 10 Pa, the diluent may evaporate during storage, resulting in the collapse of emulsion particles. In contrast, if the vapor pressure of the diluent at 20°C is 10 Pa or less, the collapse of the emulsion particles can be suppressed. Furthermore, the emulsion composition of the present invention is easy to produce and has excellent handleability because its viscosity does not increase easily during production. Furthermore, it can suppress contamination of production equipment, and at the same time, it can eliminate the need for a diluent removal step compared to production methods that use organic solvents for dilution, resulting in excellent production efficiency. Furthermore, since the emulsion composition of the present invention is a stable emulsion, when it is used as an adhesive it can be adhered more uniformly and efficiently to an object to be adhered, resulting in improved adhesive strength.

[0012] The present invention will be described in detail below. <Liquid conjugated diene rubber> The liquid conjugated diene rubber used in the present invention contains at least a monomer unit derived from a conjugated diene (hereinafter also referred to as a "conjugated diene unit") in the molecule, and for example, it is preferable that the conjugated diene rubber contains 50 mol % or more of a monomer unit derived from a conjugated diene among all the monomer units of the conjugated diene rubber. In this specification, a liquid conjugated diene rubber refers to one having a melt viscosity measured at 38°C of 30 Pa·s or more and 4,000 Pa·s or less. From the viewpoint of improving adhesiveness, the melt viscosity is preferably 35 Pa·s or more, and more preferably 40 Pa·s or more. From the viewpoint of improving emulsion stability and ease of handling, the melt viscosity is preferably 2,500 Pa·s or less, more preferably 1,500 Pa·s or less, even more preferably 1,000 Pa·s or less, and even more preferably 500 Pa·s or less. When the melt viscosity is within the above range, the dispersibility of the emulsion composition is improved and an increase in viscosity is suppressed, resulting in good handleability. The melt viscosity of the liquid conjugated diene rubber means the viscosity measured at 38°C using a Brookfield viscometer (B-type viscometer).

[0013] Examples of conjugated diene monomers include butadiene, 2-methyl-1,3-butadiene (hereinafter also referred to as "isoprene"), 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, β-farnesene (hereinafter also referred to as "farnesene"), myrcene, and chloroprene. These conjugated dienes may be used alone or in combination of two or more. From the viewpoint of adhesiveness when the emulsion composition is used as an adhesive, the liquid conjugated diene rubber more preferably contains monomer units derived from one or more selected from butadiene, isoprene, and farnesene.

[0014] The liquid conjugated diene rubber used in the present invention may contain units derived from other monomers than the conjugated diene monomer, within the range that does not impair the effects of the present invention. Examples of other monomers include copolymerizable ethylenically unsaturated monomers and aromatic vinyl compounds. Examples of the ethylenically unsaturated monomer include olefins such as ethylene, 1-butene, and isobutylene. Examples of the aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene. These compounds may be used alone or in combination of two or more. When the liquid conjugated diene rubber contains monomer units derived from monomers other than the conjugated diene monomer, the content thereof is preferably 30 mol % or less, more preferably 10 mol % or less, and even more preferably 5 mol % or less.

[0015] The liquid conjugated diene rubber used in the present invention is preferably a modified conjugated diene rubber having a hydrogen-bonding functional group in a portion of the conjugated diene rubber, and more preferably a modified conjugated diene rubber containing a conjugated diene unit in at least a portion of the polymer chain and having a hydrogen-bonding functional group in a side chain or at the end of the polymer chain. When the conjugated diene rubber is the modified conjugated diene rubber, when the emulsion composition of the present invention is used as an adhesive, the modified conjugated diene rubber interacts with the adherend, thereby improving adhesive strength.

[0016] In this specification, the term "hydrogen bond" refers to a bonding interaction formed between a hydrogen atom (donor) that is bonded to an atom with high electronegativity (such as O, N, or S) and is electrically positively polarized, and an electronegative atom (acceptor) that has a lone pair of electrons.

[0017] In the present invention, a "hydrogen-bonding functional group" refers to a functional group that can function as a donor and acceptor in the hydrogen bond. Specific examples include a hydroxy group, an epoxy group, an ether group, a mercapto group, a carboxy group, a carbonyl group, an aldehyde group, an amino group, an imino group, an imidazole group, a urethane group, an amide group, a urea group, an isocyanate group, a nitrile group, a boronyl group, a silanol group, and derivatives thereof. Derivatives of aldehyde groups include acetalized derivatives thereof. Derivatives of carboxy groups include salts thereof, esterified derivatives thereof, amidated derivatives thereof, and acid anhydrides thereof. Derivatives of boronyl groups include salts thereof and esterified derivatives thereof. Derivatives of silanol groups include esterified derivatives thereof. Furthermore, examples of carboxy groups include groups derived from monocarboxylic acids and groups derived from dicarboxylic acids. Among these, from the viewpoint of improving adhesion and ease of production of the liquid conjugated diene rubber, one or more selected from a hydroxy group, an epoxy group, an aldehyde group, an acetalized aldehyde group, a carboxy group, a salt of a carboxy group, an esterified carboxy group, an acid anhydride of a carboxy group, a boronyl group, a salt of a boronyl group, an esterified carboxy group, a silanol group, and an esterified silanol group are preferred, one or more selected from a hydroxy group, an epoxy group, a carboxy group, a salt of a carboxy group, an esterified carboxy group, an acid anhydride of a carboxy group, a boronyl group, a salt of a boronyl group, and an esterified carboxy group are more preferred, and one or more selected from a carboxy group, an esterified carboxy group, a boronyl group, and an esterified carboxy group are even more preferred.

[0018] From the viewpoint of improving adhesiveness when the emulsion composition is used as an adhesive, the number of hydrogen-bonding functional groups in the modified conjugated diene rubber is preferably 0.5 or more, more preferably 2 or more, and even more preferably 3 or more on average per molecule. Furthermore, from the viewpoint of controlling the viscosity of the modified conjugated diene rubber within an appropriate range and improving handleability, the number of hydrogen-bonding functional groups is preferably 80 or less, more preferably 40 or less, more preferably 20 or less, and even more preferably 10 or less on average per molecule.

[0019] The average number of hydrogen-bonding functional groups per molecule of the modified conjugated diene rubber is calculated from the equivalent weight (g / eq) of the hydrogen-bonding functional groups of the modified conjugated diene rubber and the number-average molecular weight Mn in terms of styrene, based on the following formula: The equivalent weight of the hydrogen-bonding functional groups of the modified conjugated diene rubber means the mass of the conjugated diene bonded to each hydrogen-bonding functional group and the mass of other monomers other than the conjugated diene that are contained as necessary. Average number of hydrogen-bonding functional groups per molecule = [(number average molecular weight (Mn)) / (molecular weight of styrene unit) × (average molecular weight of conjugated diene and other monomer units other than conjugated diene contained as needed)] / (equivalent weight of hydrogen-bonding functional group) The method for calculating the equivalent weight of the hydrogen-bonding functional group can be appropriately selected depending on the type of the hydrogen-bonding functional group.

[0020] Examples of methods for obtaining modified conjugated diene rubber include a method of adding a modifying compound to a polymer of a conjugated diene monomer (hereinafter also referred to as "production method (1)"), a method of oxidizing a conjugated diene polymer (hereinafter also referred to as "production method (2)"), a method of copolymerizing a conjugated diene monomer with a radically polymerizable compound having a hydrogen-bonding functional group (hereinafter also referred to as "production method (3)"), and a method of adding a modifying compound capable of reacting with an active polymerization terminal to a polymer of an unmodified conjugated diene monomer having an active polymerization terminal before adding a polymerization terminator (hereinafter also referred to as "production method (4)").

[0021] [Method for producing modified conjugated diene rubber (1)] The production method (1) is a method in which a modifying compound is added to a polymer of a conjugated diene monomer, that is, an unmodified conjugated diene rubber (hereinafter also referred to as "unmodified conjugated diene rubber"). The unmodified conjugated diene rubber can be obtained by polymerizing a conjugated diene and, if necessary, a monomer other than the conjugated diene, for example, by emulsion polymerization or solution polymerization.

[0022] As the solution polymerization method, a known method or a method equivalent to a known method can be applied, for example, a method in which a predetermined amount of a monomer containing a conjugated diene is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, or an anionically polymerizable active metal or active metal compound, optionally in the presence of a polar compound. Examples of the solvent include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene, toluene, and xylene.

[0023] Examples of anionically polymerizable active metals include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; and lanthanoid rare earth metals such as lanthanum and neodymium. Among these anionically polymerizable active metals, alkali metals and alkaline earth metals are preferred, and alkali metals are more preferred. As the anionically polymerizable active metal compound, organic alkali metal compounds are preferred. Examples of organic alkali metal compounds include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; polyfunctional organic lithium compounds such as dilithiomethane, dilithionaphthalene, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene, and the like. Among these organic alkali metal compounds, organic lithium compounds are preferred, and organic monolithium compounds are more preferred.

[0024] The amount of the organic alkali metal compound used can be appropriately set depending on the melt viscosity, molecular weight, etc. of the target unmodified conjugated diene rubber and modified conjugated diene rubber, but it is usually used in an amount of 0.01 to 3 parts by mass per 100 parts by mass of all monomers including conjugated dienes. The organic alkali metal compounds can also be reacted with secondary amines such as dibutylamine, dihexylamine, and dibenzylamine to form organic alkali metal amides.

[0025] In anionic polymerization, polar compounds are usually used to adjust the microstructure of the conjugated diene moiety without deactivating the reaction. Examples of polar compounds include ether compounds such as dibutyl ether, tetrahydrofuran, ethylene glycol diethyl ether, and 2,2-di(2-tetrahydrofuryl)propane; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides; and phosphine compounds. The polar compound is usually used in an amount of 0.01 to 1,000 moles relative to the organic alkali metal compound. The temperature for solution polymerization is usually in the range of −80 to 150° C., preferably in the range of 0 to 100° C., and more preferably in the range of 10 to 90° C. The polymerization may be carried out in a batch or continuous manner. The polymerization reaction can be terminated by adding a polymerization terminator. Examples of the polymerization terminator include alcohols such as methanol and isopropanol. The unmodified conjugated diene rubber can be isolated by pouring the resulting polymerization reaction solution into a poor solvent such as methanol to precipitate the polymer, or by washing the polymerization reaction solution with water, separating it, and then drying it. Of the above methods, the solution polymerization method is preferred as the method for producing the unmodified conjugated diene rubber.

[0026] The emulsion polymerization may be carried out by a known method or a method similar to a known method, for example, by emulsifying and dispersing a predetermined amount of a monomer containing a conjugated diene in the presence of an emulsifier, and then emulsion-polymerizing the resulting mixture with a radical polymerization initiator. Examples of emulsifiers include salts of long-chain fatty acids having 10 or more carbon atoms, rosinate salts, etc. Examples of long-chain fatty acid salts include potassium salts or sodium salts of fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, and stearic acid. As the dispersion solvent, water is usually used, and it may contain a water-soluble organic solvent such as methanol or ethanol to the extent that stability during polymerization is not impaired. Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, organic peroxides, and hydrogen peroxide. A chain transfer agent may be used to adjust the molecular weight of the resulting unmodified conjugated diene rubber. Examples of the chain transfer agent include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; carbon tetrachloride, thioglycolic acid, diterpenes, terpinolene, γ-terpinene, and α-methylstyrene dimer.

[0027] The temperature of the emulsion polymerization can be appropriately set depending on the type of radical polymerization initiator used, etc., but is usually in the range of 0 to 100° C., preferably 0 to 60° C. The polymerization method may be either continuous polymerization or batch polymerization.

[0028] The polymerization reaction can be terminated by adding a polymerization terminator, such as an amine compound such as isopropylhydroxylamine, diethylhydroxylamine, or hydroxylamine, a quinone compound such as hydroquinone or benzoquinone, or sodium nitrite.

[0029] After the polymerization reaction is terminated, an antioxidant may be added as needed. After the polymerization reaction is terminated, unreacted monomers are removed from the obtained latex as needed. Next, the polymer is coagulated using a salt such as sodium chloride, calcium chloride, or potassium chloride as a coagulant, and an acid such as nitric acid or sulfuric acid is added as needed to adjust the pH of the coagulation system to a predetermined value. The polymer is then recovered by separating the dispersion solvent. The polymer is then washed with water, dehydrated, and dried to obtain an unmodified conjugated diene rubber. During the coagulation, the latex may be mixed with an extender oil previously prepared as an emulsified dispersion, if needed, and the oil-extended unmodified conjugated diene rubber may be recovered.

[0030] (Modifying compound used in production method (1)) The modifying compound used in the production method (1) is not particularly limited, but from the viewpoint of improving the adhesiveness when the emulsion composition is used as an adhesive, those having a hydrogen-bonding functional group are preferred. Examples of the hydrogen-bonding functional group include those similar to those described above. Among them, from the viewpoint of the strength of the hydrogen bonding force, a hydroxy group, an epoxy group, an aldehyde group, an acetalized product of an aldehyde group, a carboxy group, a salt of a carboxy group, an esterified product of a carboxy group, an acid anhydride of a carboxy group, a boronyl group, a salt of a boronyl group, an esterified product of a boronyl group, a silanol group, and an esterified product of a silanol group are preferred.

[0031] Examples of the modifying compound include unsaturated carboxylic acids such as maleic acid, fumaric acid, citraconic acid, and itaconic acid; unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, and itaconic anhydride; unsaturated carboxylic esters such as maleic esters, fumaric esters, citraconic esters, and itaconic esters; unsaturated carboxylic amides such as maleic amides, fumaric amides, citraconic amides, and itaconic amides; unsaturated carboxylic imides such as maleic imide, fumaric imide, citraconic imide, and itaconic imide; vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, mercaptomethylmethyldiethoxysilane, and mercaptomethyltriethoxysilane. Examples of the modified compounds include silane compounds such as 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethoxydimethylsilane, 2-mercaptoethylethoxydimethylsilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyldiethoxymethylsilane, 3-mercaptopropyldimethoxyethylsilane, 3-mercaptopropyldiethoxyethylsilane, 3-mercaptopropylmethoxydimethylsilane, and 3-mercaptopropylethoxydimethylsilane; and boronate esters such as triethyl borate, tripropyl borate, triisopropyl borate, and tributyl borate. These modified compounds having a hydrogen-bonding functional group may be used alone or in combination of two or more.

[0032] The amount of the modifying compound used is preferably 0.1 to 100 parts by mass, more preferably 0.5 to 50 parts by mass, and even more preferably 1 to 30 parts by mass, based on 100 parts by mass of the unmodified conjugated diene rubber. The reaction temperature is usually preferably in the range of 0 to 200°C, more preferably in the range of 50 to 200°C. Alternatively, the modifying compound may be grafted onto an unmodified conjugated diene rubber to introduce a hydrogen-bonding functional group, and then a modifying compound capable of reacting with the functional group may be added to introduce another hydrogen-bonding functional group into the polymer. Specific examples of such methods include grafting maleic anhydride onto an unmodified conjugated diene rubber obtained by living anionic polymerization, followed by reaction with a compound having a hydroxyl group, such as 2-hydroxyethyl methacrylate or methanol, or a compound such as water.

[0033] The amount of the modifying compound added to the modified conjugated diene rubber is preferably 0.5 to 40 parts by mass, more preferably 1 to 30 parts by mass, and even more preferably 1.5 to 20 parts by mass, per 100 parts by mass of the unmodified conjugated diene rubber. The amount of the modifying compound added to the modified conjugated diene rubber can be calculated based on the acid value of the modifying compound, or can be determined using various analytical instruments such as infrared spectroscopy and nuclear magnetic resonance spectroscopy.

[0034] The method for adding the modifying compound to the unmodified conjugated diene rubber is not particularly limited, and examples thereof include a method in which a liquid unmodified conjugated diene rubber, one or more modifying compounds selected from unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, boronic acid derivatives, silane compounds, etc., and a radical generator are further added as needed, and the resulting mixture is heated in the presence or absence of an organic solvent. There are no particular limitations on the radical generator used, and commercially available organic peroxides, azo compounds, hydrogen peroxide, etc. can be used. The organic solvent used in the method generally includes hydrocarbon solvents and halogenated hydrocarbon solvents, and among these, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene, and xylene are preferred.

[0035] Furthermore, when the reaction of adding the modified compound is carried out by the above method, an antioxidant may be added from the viewpoint of suppressing side reactions, etc. Such antioxidants can be generally commercially available ones, and examples thereof include butylated hydroxytoluene (BHT), N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (Nocrac 6C), etc.

[0036] The amount of antioxidant added is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the unmodified conjugated diene rubber. When the amount of antioxidant added is within the above range, side reactions can be suppressed, and the modified conjugated diene rubber can be obtained in good yield.

[0037] [Method for producing modified conjugated diene rubber (2)] The production method (2) includes a method of oxidizing a raw material conjugated diene rubber to obtain an oxidized conjugated diene rubber having oxygen-containing functional groups or bonds in the molecule generated by the oxidation reaction, such as hydroxyl groups, aldehyde groups, carbonyl groups, carboxyl groups, and ether bonds. Methods for oxidizing the raw material conjugated diene rubber include a method of heat treating the raw material conjugated diene rubber at a temperature equal to or higher than the oxidation temperature (hereinafter also referred to as "production method (2-1)"), a method of activating the raw material conjugated diene rubber by irradiating it with light of an absorption wavelength of the raw material conjugated diene rubber and reacting it with oxygen (hereinafter also referred to as "production method (2-2)"), etc. Among these, the method of heat treating the raw material conjugated diene rubber at a temperature equal to or higher than the oxidation temperature (production method (2-1)) is preferred.

[0038] [Method for producing oxidized conjugated diene rubber (2-1)] The production method (2-1) is a method in which a raw material conjugated diene rubber is heat-treated at a temperature equal to or higher than the oxidation temperature in an oxygen-containing atmosphere, preferably in an air atmosphere. The heat treatment temperature is not particularly limited as long as it is a temperature at which the raw material conjugated diene rubber is oxidized. From the viewpoint of increasing the reaction rate of the oxidation and improving productivity, the heat treatment temperature is preferably 150°C or higher, more preferably 170°C or higher, and even more preferably 190°C or higher. The heat treatment time is not particularly limited as long as it is within a range that does not cause deterioration of the raw material conjugated diene rubber, but is preferably 30 minutes or less, more preferably 20 minutes or less. Furthermore, the temperature required for the oxidation reaction can be lowered by adding a thermal radical generator to the raw material conjugated diene rubber.

[0039] Examples of the thermal radical generator include peroxides, azo compounds, redox initiators, etc. Among them, peroxides are preferred from the viewpoint that the thermal radical generator bonds with the conjugated diene rubber and an oxygen-containing structure is added to the conjugated diene rubber. Examples of the peroxides include t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctanoate, t-butyl peroxyneodecanoate, t-butyl peroxyisobutyrate, lauroyl peroxide, t-amyl peroxypivalate, t-butyl peroxypivalate, dicumyl peroxide, benzoyl peroxide, potassium persulfate, and ammonium persulfate.

[0040] Examples of the azo compound include azobisisobutyronitrile (AIBN), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-butanenitrile), 4,4'-azobis(4-pentanoic acid), 1,1'-azobis(cyclohexanecarbonitrile), 2-(t-butylazo)-2-cyanopropane, and 2,2'-azobis[2-methyl-N-(1,1)-bis(hydroxymethyl)-2-hydroxyethyl]propane. Examples of the thermal radical generator include 2,2'-azobis(2-methyl-N-hydroxyethyl)propionamide, 2,2'-azobis(N,N'-dimethyleneisobutylamidine) dichloride, 2,2'-azobis(N,N-dimethyleneisobutylamide), 2,2'-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide), 2,2'-azobis(isobutylamide) dihydrate, etc. The thermal radical generators can be used alone or in combination of two or more.

[0041] Alternatively, a redox initiator may be used as the thermal radical generator, such as a combination of persulfate, acidic sodium sulfite, and ferrous sulfate, a combination of t-butyl hydroperoxide, acidic sodium sulfite, and ferrous sulfate, or a combination of p-menthane hydroperoxide, ferrous sulfate, sodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate.

[0042] [Method for producing oxidized conjugated diene rubber (2-2)] The production method (2-2) is a method in which the starting material conjugated diene rubber is activated by being irradiated with light having an absorption wavelength thereof, and is then reacted with oxygen. The production method (2-2) is carried out in an oxygen-containing atmosphere, preferably in an air atmosphere. The wavelength of the light used is not particularly limited as long as it is absorbed by the raw material conjugated diene rubber to cause a radical reaction, but ultraviolet light, which is strongly absorbed by the raw material conjugated diene rubber, is preferred. Furthermore, by adding a photoradical generator to the raw material conjugated diene rubber, it is possible to reduce the amount of light irradiation required for the oxidation reaction.

[0043] Examples of the photoradical generator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4,4′-dimethoxybenzophenone, benzoin propyl ether, benzil dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy- Examples of photoradical generators include bis-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, etc. The photoradical generators can be used alone or in combination of two or more.

[0044] [Method for producing modified conjugated diene rubber (3)] The production method (3) includes a method in which a conjugated diene monomer and a radically polymerizable compound having a hydrogen-bonding functional group are randomly copolymerized, block copolymerized, or graft copolymerized by a known method.

[0045] (Radically polymerizable compound having a hydrogen-bonding functional group used in production method (3)) The radical polymerizable compound having a hydrogen-bonding functional group used in production method (3) is not particularly limited as long as it is a compound having both a hydrogen-bonding functional group and a reactive multiple bond in the molecule. Specific examples include aldehydes having a reactive multiple bond, acetalized products of the aldehydes, monocarboxylic acids having a reactive multiple bond, salts of the monocarboxylic acids, esterified products of the monocarboxylic acids, acid anhydrides of the monocarboxylic acids, dicarboxylic acids having a reactive multiple bond, salts of the dicarboxylic acids, esterified products of the dicarboxylic acids, acid anhydrides of the dicarboxylic acids, and amine compounds having a reactive multiple bond.

[0046] Among the aldehydes having a multiple bond, examples of aldehydes having a reactive carbon-carbon double bond include acrolein, methacrolein, crotonaldehyde, 3-butenal, 2-methyl-2-butenal, 2-methyl-3-butenal, 2,2-dimethyl-3-butenal, 3-methyl-2-butenal, 3-methyl-3-butenal, 2-pentenal, 2-methyl-2-pentenal, 3-pentenal, and 3-methyl -4-Pentenal, 4-pentenal, 4-methyl-4-pentenal, 2-hexenal, 3-hexenal, 4-hexenal, 5-hexenal, 7-octenal, 10-undecenal, 2-ethylcrotonaldehyde, 3-(dimethylamino)acrolein, myristoleinaldehyde, palmitoleinaldehyde, oleinaldehyde, elaidinaldehyde, vaccenaldehyde, gadoleinaldehyde, el Alkenals having 3 to 30 carbon atoms, preferably alkenals having 3 to 25 carbon atoms, such as cinnamaldehyde, nervonaldehyde, linolealdehyde, citronellal, cinnamaldehyde, and vanillin; alkadienals having 5 to 30 carbon atoms, preferably alkadienals having 5 to 25 carbon atoms, such as 2,4-pentadienal, 2,4-hexadienal, 2,6-nonadienal, and citral; linolenic aldehyde, eleostearic aldehyde, Examples of suitable aldehydes include unsaturated aldehydes such as alkatrienals having 7 to 30 carbon atoms, preferably alkatrienals having 7 to 25 carbon atoms, such as aldehyde; alkatetraenals having 9 to 30 carbon atoms, such as stearidone aldehyde and arachidone aldehyde, preferably alkatetraenals having 9 to 25 carbon atoms; and alkapentaenals having 11 to 30 carbon atoms, such as eicosapentaene aldehyde, preferably alkapentaenals having 11 to 25 carbon atoms. Note that, when the aldehydes have cis-trans isomers, they include both the cis and trans isomers. These aldehydes may be used alone or in combination of two or more.

[0047] Among the acetalized products of aldehydes having a multiple bond, examples of acetalized products of aldehydes having a reactive carbon-carbon double bond include acetalized products of the aldehydes, specifically 3-(1,3-dioxalan-2-yl)-3-methyl-1-propene, which is an acetalized product of 2-methyl-3-butenal, and 3-(1,3-dioxalan-2-yl)-2-methyl-1-propene, which is an acetalized product of 3-methyl-3-butenal.

[0048] Among the aldehydes having a multiple bond and acetalized products of the aldehydes, examples of the aldehydes having a reactive carbon-carbon triple bond and acetalized products thereof include aldehydes having a carbon-carbon triple bond such as propioaldehyde, 2-butyn-1-al, and 2-pentyn-1-al, and acetalized products of the aldehydes.

[0049] Among the aldehydes having a multiple bond and the acetalized products of the aldehydes, aldehydes having a reactive carbon-carbon double bond are preferred, such as acrolein, methacrolein, crotonaldehyde, 3-butenal, 2-methyl-2-butenal, 2-methyl-3-butenal, 2,2-dimethyl-3-butenal, 3-methyl-2-butenal, 3-methyl-3-butenal, 2-pentenal, and the like. Among them, one or more selected from acrolein, methacrolein, crotonaldehyde, and 3-butenal are more preferred because of their good reactivity during copolymerization.

[0050] Examples of the monocarboxylic acid having a multiple bond, the salt of the monocarboxylic acid, the ester of the monocarboxylic acid, and the acid anhydride of the monocarboxylic acid include (meth)acrylic acid, sodium salt of (meth)acrylic acid, potassium salt of (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2 ... butyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, vinyl (meth)acrylate, 2-(trifluoromethyl)acrylic acid, methyl 2-trifluoromethylacrylate, ethyl 2-trifluoromethylacrylate, propyl 2-trifluoromethylacrylate, 2-butyl 2-trifluoromethylacrylate, 2-hydroxyethyl 2-trifluoromethylacrylate, vinyl 2-trifluoromethylacrylate, methyl cinnamate, vinyl cinnamate, methyl crotonate, vinyl crotonate, 3 Methyl 3-methylbutenoate, vinyl 3-methylbutenoate, methyl 4-pentenoate, vinyl 4-pentenoate, methyl 2-methyl-4-pentenoate, vinyl 2-methyl-4-pentenoate, methyl 5-hexenoate, vinyl 5-hexenoate, methyl 3,3-dimethyl-4-pentenoate, vinyl 3,3-dimethyl-4-pentenoate, methyl 7-octenoate, vinyl 7-octenoate, methyl trans-3-pentenoate, vinyl trans-3-pentenoate, methyl trans-4-decenoate, vinyl trans-4-decenoate, 3-methyl-3- Ethyl butenoate, ethyl 4-pentenoate, ethyl 2-methyl-4-pentenoate, ethyl 5-hexenoate, ethyl 3,3-dimethyl-4-pentenoate, ethyl 7-octenoate, ethyl trans-3-pentenoate, ethyl trans-4-decenoate, methyl 10-undecenoate, vinyl 10-undecenoate, (meth)acrylic anhydride, 2-(trifluoromethyl)acrylic anhydride, cinnamic anhydride, crotonic anhydride, 3-methyl-3-butenoic anhydride, 4-pentenoic anhydride, 2-methyl-4-pentenoic anhydride, 5-hexenoic anhydride, 3,3-dimethyl-4-pentenoic anhydride, 7-octenoic anhydride, trans-3-pentenoic anhydride, trans-4-decenoic anhydride, things, and 10-undecenoic anhydride, etc.; carboxylic acids having a reactive carbon-carbon double bond, salts of the carboxylic acid, esterified products of the carboxylic acid, and acid anhydrides of the carboxylic acid; and carboxylic acids having a reactive carbon-carbon triple bond and esterified products of the carboxylic acid, such as propiolic acid, methyl propiolate, ethyl propiolate, vinyl propiolate, tetrolic acid, methyl tetrolate, ethyl tetrolate, and vinyl tetrolate. In this specification, the term "(meth)acrylic acid" refers collectively to "acrylic acid" and "methacrylic acid."

[0051] Examples of the dicarboxylic acids having a multiple bond, salts of the dicarboxylic acids, esterified products of the dicarboxylic acids, and acid anhydrides of the dicarboxylic acids include dicarboxylic acids having a reactive carbon-carbon double bond, salts of the dicarboxylic acids, esterified products of the dicarboxylic acids, and acid anhydrides of the dicarboxylic acids, such as maleic acid, sodium maleate, potassium maleate, methyl maleate, dimethyl maleate, maleic anhydride, itaconic acid, methyl itaconate, dimethyl itaconate, itaconic anhydride, himic acid, methyl himic acid, dimethyl himic acid, and himic acid anhydride.

[0052] As the monocarboxylic acid having a multiple bond, the salt of the monocarboxylic acid, the esterified product of the monocarboxylic acid, the monocarboxylic acid anhydride, the dicarboxylic acid having a multiple bond, the salt of the dicarboxylic acid, the esterified product of the dicarboxylic acid, and the acid anhydride of the dicarboxylic acid, a compound having a reactive carbon-carbon double bond is preferred, and among these, one or more selected from methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, vinyl (meth)acrylate, (meth)acrylic anhydride, 2-(trifluoromethyl)acrylic anhydride, cinnamic anhydride, crotonic anhydride, methyl maleate, dimethyl maleate, maleic anhydride, methyl itaconate, dimethyl itaconate, and itaconic anhydride are more preferred because of their good reactivity during copolymerization.

[0053] Among the amine compounds having a multiple bond, examples of amine compounds having a reactive carbon-carbon double bond include allylamine, 3-butenylamine, 4-pentenylamine, 5-hexenylamine, 6-heptenylamine, 7-octenylamine, oleylamine, 2-methylallylamine, 4-aminostyrene, 4-vinylbenzylamine, 2-allylglycine, S-allylcysteine, α-allylalanine, 2-allylaniline, geranylamine, vigabatrin, 4-vinylaniline, and 4-vinyloxyaniline. Among these, one or more selected from allylamine, 3-butenylamine, and 4-pentenylamine are preferred because of their good reactivity during copolymerization.

[0054] [Method for producing modified conjugated diene rubber (4)] The production method (4) is a method in which a modifying compound capable of reacting with an active polymerization end is added to a polymer of an unmodified conjugated diene monomer having an active polymerization end (unmodified conjugated diene rubber) before adding a polymerization terminator. The unmodified conjugated diene rubber having an active polymerization end can be obtained by polymerizing a conjugated diene monomer and, if necessary, a monomer other than the conjugated diene, by, for example, emulsion polymerization or solution polymerization, as in the production method (1). Examples of modifying compounds that can be used in production method (4) include dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolylenediisocyanate, carbon dioxide, ethylene oxide, succinic anhydride, boronate esters such as triethyl borate, tripropyl borate, triisopropyl borate, and tributyl borate, boronic acid anhydride groups, boronic acid anhydrides such as phenylboronic acid anhydride, 4,4'-bis(diethylamino)benzophenone, N-vinylpyrrolidone, N-methylpyrrolidone, 4-dimethylaminobenzylideneaniline, and dimethylimidazolidinone, as well as other modifying agents described in JP 2011-132298 A.

[0055] In the production method (4), the amount of the modifying compound used is preferably 0.01 to 100 molar equivalents relative to the organic alkali metal compound when the polymerization is carried out using the organic alkali metal compound. The reaction temperature is usually −80 to 150° C., preferably 0 to 100° C., and more preferably 10 to 90° C. Alternatively, the modifying compound may be added before the addition of the polymerization terminator to introduce a hydrogen-bonding functional group into the unmodified conjugated diene rubber, and then a modifying compound capable of reacting with the functional group may be added to introduce another hydrogen-bonding functional group into the polymer.

[0056] The modified conjugated diene rubber may contain units derived from other monomers than the conjugated diene monomer and the radically polymerizable compound having a hydrogen-bonding functional group, as long as the effects of the present invention are not impaired. Examples of other monomers include copolymerizable ethylenically unsaturated monomers and aromatic vinyl compounds, and the specific compounds and contents thereof are the same as those described above.

[0057] There are no particular limitations on the method for producing the modified conjugated diene rubber, but from the viewpoint of productivity, it is preferable to produce it by production method (1), (2) or (3), more preferably by production method (1) or (3), and even more preferably by production method (1).

[0058] [Physical Properties of Liquid Conjugated Diene Rubber] The weight-average molecular weight (Mw) of the liquid conjugated diene rubber is preferably 2,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 15,000 or more, even more preferably 20,000 or more, and particularly preferably 25,000 or more, from the viewpoint of improving adhesiveness when the emulsion composition is used as an adhesive. Furthermore, from the viewpoint of maintaining adhesive strength for a long period of time, it is more preferably 35,000 or more. From the viewpoint of improving the handleability of the liquid conjugated diene rubber, it is preferably 150,000 or less, more preferably 120,000 or less, even more preferably 100,000 or less, and even more preferably 75,000 or less. The Mw and Mn of the liquid conjugated diene rubber are the weight average molecular weight and number average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC).

[0059] The molecular weight distribution (Mw / Mn) of the liquid conjugated diene rubber is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, even more preferably 1.0 to 2.0, and even more preferably 1.0 to 1.3. When Mw / Mn is within the above range, the liquid conjugated diene rubber has little variation in viscosity and is easy to handle. The molecular weight distribution (Mw / Mn) means the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of standard polystyrene, determined by GPC measurement.

[0060] The glass transition temperature (Tg) of the liquid conjugated diene rubber may vary depending on the vinyl content of the conjugated diene units, the type of conjugated diene, the content of units derived from monomers other than the conjugated diene, etc., but is preferably −100 to 10° C., more preferably −100 to −10° C., and even more preferably −100 to −20° C. If the Tg is within the above range, an increase in viscosity can be suppressed, making the rubber easier to handle. The glass transition temperature (Tg) of the liquid conjugated diene rubber means a value measured by differential scanning calorimetry (DSC), and specifically, it can be measured by the method described in the examples.

[0061] <Diluents with a vapor pressure of 10 Pa or less at 20°C> In the present invention, the diluent used has a vapor pressure of 10 Pa or less at 20° C. There are no particular restrictions on the specific diluent, but examples include oil and low-viscosity liquid rubber. In the present invention, the low-viscosity liquid rubber refers to a rubber having a melt viscosity of less than 30 Pa·s measured at 38° C., and differs from the liquid conjugated diene rubber in terms of melt viscosity. In addition, in this specification, a "diluent having a vapor pressure of 10 Pa or less at 20° C." may be simply referred to as a "diluent."

[0062] If the vapor pressure of the diluent at 20°C exceeds 10 Pa, it becomes difficult to stabilize the emulsion. Furthermore, when the emulsion composition of the present invention is used as an adhesive, coating unevenness is likely to occur, which may result in reduced adhesiveness. Furthermore, there is a possibility that production equipment may be contaminated during production. From these viewpoints, the vapor pressure of the diluent at 20°C is preferably 5.0 Pa or less, more preferably 1.0 Pa or less, and more preferably 1.0 x 10 -1 Pa or less, more preferably 1.0 × 10 -2 It is even more preferable that the temperature is 1.0×10 Pa or less. -3 The vapor pressure of the diluent at 20°C is preferably 1.0 x 10 Pa or less. -8 It is preferable that the viscosity is 0.05 Pa or more. In the present invention, the vapor pressure at 20°C is 10 3 The vapor pressure of a diluent at 20°C, which is less than Pa, is the value calculated from the best-fit curve obtained by applying the Antoine equation to the measured values ​​measured by the gas flow method. In addition, the vapor pressure at 20°C is 10 3 The vapor pressure of the diluent at 20°C exceeding Pa refers to the value measured directly using the static method.

[0063] 〔oil〕 The diluent is preferably, for example, a non-volatile oil. The oil is not particularly limited as long as it has a vapor pressure of 10 Pa or less at 20°C and is compatible with the liquid conjugated diene rubber, and examples of the oil include natural oils and synthetic oils. Examples of natural oils include mineral oils and vegetable oils. Examples of mineral oils include paraffinic mineral oils, aromatic mineral oils, and naphthenic mineral oils obtained by conventional refining methods such as solvent refining and hydrogenation refining, as well as waxes produced by the Fischer-Tropsch process (gas-to-liquid wax) and mineral oils produced by isomerizing wax. Commercially available paraffinic mineral oils include the "Diana Process Oil" series manufactured by Idemitsu Kosan Co., Ltd., the "Super Oil" series manufactured by JX Energy Corporation, and "SUNPAR150" manufactured by Nippon Sun Oil Co., Ltd. Furthermore, examples of commercially available naphthenic mineral oils include "SUNTHENE250J" manufactured by Nippon Sun Oil Co., Ltd.

[0064] Examples of vegetable oils include linseed oil, camellia oil, macadamia nut oil, corn oil, mink oil, olive oil, avocado oil, camellia oil, castor oil, safflower oil, jojoba oil, sunflower oil, almond oil, rapeseed oil, sesame oil, soybean oil, peanut oil, cottonseed oil, coconut oil, palm kernel oil, and rice bran oil. Examples of synthetic oils include hydrocarbon synthetic oils, ester synthetic oils, and ether synthetic oils. Examples of hydrocarbon synthetic oils include α-olefin oligomers such as polybutene, polyisobutylene, 1-octene oligomer, 1-decene oligomer, and ethylene-propylene copolymer, or hydrogenated products thereof, alkylbenzene, and alkylnaphthalene. Examples of ester synthetic oils include triglycerin fats. acidExamples of synthetic oils include esters, diglycerin fatty acid esters, monoglycerin fatty acid esters, monoalcohol fatty acid esters, and polyhydric alcohol fatty acid esters. Examples of ether-based synthetic oils include polyoxyalkylene glycols and polyphenyl ethers. Examples of commercially available synthetic oils include the "Linearene" series manufactured by Idemitsu Kosan Co., Ltd., and "FGC32," "FGC46," and "FGC68" manufactured by ANDEROL.

[0065] The oil may be one selected from the natural oils and synthetic oils, or a mixture of two or more natural oils, two or more synthetic oils, or one or more natural oils and one or more synthetic oils.

[0066] From the viewpoint of safety, the flash point of the oil used in the present invention is preferably 70° C. or higher, more preferably 100° C. or higher, even more preferably 130° C. or higher, and even more preferably 140° C. or higher. There is no particular upper limit to the flash point of the oil, but it is preferably 320° C. or lower.

[0067] [Low viscosity liquid rubber] It is also preferable to use a low-viscosity liquid rubber as the diluent. There are no particular restrictions on the low-viscosity liquid rubber, as long as it has a melt viscosity of less than 30 Pa·s measured at 38°C and a vapor pressure of 10 Pa or less at 20°C. More specific examples include liquid butadiene rubber, liquid isoprene rubber, and liquid farnesene rubber, which may be either a homopolymer (single polymer) or a copolymer. In particular, low viscosity is preferred for dilution, and low-molecular-weight liquid rubber is preferred, with liquid butadiene rubber and liquid farnesene rubber being particularly preferred.

[0068] When the low-viscosity liquid rubber is a liquid butadiene rubber, the weight-average molecular weight is preferably 500 to 10,000, more preferably 700 to 7,000, and even more preferably 800 to 6,000. On the other hand, when the low-viscosity liquid rubber is a liquid farnesene rubber, the weight-average molecular weight is preferably 1,000 to 80,000, preferably 1,000 to 50,000, more preferably 1,000 to 30,000, and even more preferably 1,000 to 10,000. When the weight average molecular weight of the low-viscosity liquid rubber is within the above range, the stability of the emulsion is further improved, and the handleability of the emulsion composition is also improved. The weight average molecular weight of the low viscosity liquid rubber is a weight average molecular weight calculated in terms of polystyrene and determined by gel permeation chromatography (GPC).

[0069] In the present invention, the diluent is preferably a naphthenic mineral oil or a low-viscosity liquid rubber, more preferably a naphthenic mineral oil or a liquid butadiene rubber, from the viewpoint of improving the stability of the emulsion and the adhesive properties of an adhesive using the emulsion composition.

[0070] <Surfactant> The surfactant used in the present invention is not particularly limited, and examples thereof include cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants. Among these, nonionic surfactants are preferred from the viewpoint of improving the stability of the emulsion. These surfactants may be used alone or in combination of two or more.

[0071] Examples of cationic surfactants include alkylammonium acetate salts, alkyldimethylbenzylammonium salts, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylpyridinium salts, oxyalkylene alkylamines, polyoxyalkylene alkylamines, etc. These cationic surfactants may be used alone, or, if necessary, two or more types may be used in combination.

[0072] Examples of anionic surfactants include carboxylates of fatty acid soaps and the like, higher alcohol sulfates, higher alkyl polyalkylene glycol ether sulfates, sulfates of styrenated phenol alkylene oxide adducts, sulfates of alkylphenol alkylene oxide adducts, sulfated oils, sulfated fatty acid esters, sulfated fatty acids, sulfated olefins, and the like, alkylbenzene sulfonates, alkylnaphthalene sulfonates, naphthalene sulfonates, formalin condensates of naphthalene sulfonic acid, and the like, sulfonates such as α-olefin sulfonates, paraffin sulfonates, and sulfosuccinic acid diester salts, and higher alcohol phosphate salts. These anionic surfactants may be used alone, or, if necessary, two or more may be used in combination. Commercially available anionic surfactants include "Plysurf A210B" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and "Phosphanol RD-720N" manufactured by Toho Chemical Industry Co., Ltd.

[0073] Examples of nonionic surfactants include polyoxyalkylene-type nonionic surfactants such as higher alcohol alkylene oxide adducts, alkylphenol alkylene oxide adducts, styrenated phenol alkylene oxide adducts, fatty acid alkylene oxide adducts, polyhydric alcohol aliphatic ester alkylene oxide adducts, higher alkylamine alkylene oxide adducts, and fatty acid amide alkylene oxide adducts, as well as polyhydric alcohol-type nonionic surfactants such as alkylglycoxides and sucrose fatty acid esters. These nonionic surfactants may be used alone or, if necessary, in combination of two or more. Commercially available nonionic surfactants include "Adekatar PC-6," "Adekatar PC-8," "Adekatar PC-10," and "Adekatar TN-100" manufactured by ADEKA CORPORATION, and polyoxyethylene alkyl ethers (trade names "Pegnol TE-10A," "Pegnol L-9A," and "Pegnol TH-8") manufactured by Toho Chemical Industry Co., Ltd.

[0074] The HLB (Hydrophilic-Lipophilic Balance) value of a nonionic surfactant is an index showing the balance of hydrophilicity and lipophilicity, and is expressed as a value ranging from 0 to 20. In the present invention, the value calculated by the following formula (I) based on the Griffin method is used. HLB value = 20 × total formula weight of hydrophilic moieties / molecular weight (I)

[0075] Nonionic surfactants are identified by detecting and measuring their molecular weight and structural units using mass spectrometry. 1 H and 13 The structure can be detected and measured using C-NMR, and the structure can be identified based on this, so the HLB value can be calculated using formula (I) based on the identified information. A method for separating a nonionic surfactant from an emulsion composition includes, for example, fractionation and isolation by reverse phase liquid chromatography.

[0076] <Composition of emulsion composition> From the viewpoint of improving emulsion stability and improving adhesive strength when the emulsion composition is used as an adhesive, the content of the liquid conjugated diene rubber in the emulsion composition of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 4% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the emulsion composition. When the content of the liquid conjugated diene rubber in the emulsion composition is within the above range, the stability of the emulsion can be improved while preventing the viscosity of the emulsion composition from becoming extremely high.

[0077] The content of the diluent in the emulsion composition is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 4% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the emulsion composition. When the content of the diluent in the emulsion composition is within the above range, the viscosity of the emulsion composition can be prevented from becoming extremely high, improving production efficiency. Furthermore, since the stability of the emulsion is improved, problems such as phase separation are less likely to occur over a long period of time after production.

[0078] The content of the surfactant in the emulsion composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more, per 100 parts by mass of the total of the liquid conjugated diene rubber and the diluent. When the content of the surfactant is 1 part by mass or more, the stability of the emulsion can be improved. On the other hand, from the viewpoint of production costs, the amount of the surfactant is preferably 15 parts by mass or less, more preferably 10 parts by mass or less.

[0079] The liquid conjugated diene rubber may be used alone or in combination of two or more kinds. The diluent may be used alone or in combination of two or more kinds. The surfactant may be used alone or in combination of two or more kinds.

[0080] Furthermore, the emulsion composition of the present invention may contain other components other than the liquid conjugated diene rubber, the diluent having a vapor pressure of 10 Pa or less at 20°C, the surfactant, and water, within the range that does not impair the stability of the emulsion. Examples of the other components include other polymers, acids, basic compounds such as sodium hydroxide, antioxidants, curing agents, dispersants, pigments, dyes, adhesion aids, and carbon black.

[0081] Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, etc. Among these, sodium hydroxide and ammonia are preferred from the viewpoint of stability and adhesiveness, and ammonia is preferred from the viewpoint of worker safety.

[0082] When the emulsion composition contains other components, the content thereof is preferably 1,000 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 10 parts by mass or less, and still more preferably 1 part by mass or less, relative to 100 parts by mass of the liquid conjugated diene rubber. For example, when the emulsion composition contains a basic compound such as sodium hydroxide in the above range, the stability of the emulsion is further improved.

[0083] [Method for producing emulsion composition] The method for producing an emulsion composition of the present invention is characterized in that after the liquid conjugated diene rubber, the diluent, the surfactant, and water are mixed to produce an oil-in-water emulsion, the diluent is not removed. According to the production method of the present invention, a diluent having a vapor pressure of 10 Pa or less at 20°C is used, and therefore, an emulsion composition with excellent stability can be obtained more easily than with conventional methods while suppressing an increase in the viscosity of the emulsion composition. Furthermore, while conventional methods using highly volatile solvents require a solvent removal step, the method of the present invention makes it possible to produce an emulsion composition without the need for such a solvent removal step. In other words, the production method of the present invention makes it possible to efficiently use the emulsion composition in applications such as adhesives without the need for a post-treatment step. In the production method of the present invention, "without removing the diluent" means that there is no need to provide a step for removing the diluent.

[0084] The order of mixing the liquid conjugated diene rubber, the diluent, the surfactant, and water may be such that the liquid conjugated diene rubber, the diluent, and the surfactant are mixed first, followed by the addition of water. A more preferred mixing order is to mix the liquid conjugated diene rubber and the diluent to prepare a diluted solution, then mix the surfactant into the diluted solution, and then gradually add water and, if necessary, a basic compound such as sodium hydroxide. A method for producing an emulsion composition using this order is generally called a phase inversion emulsification method, in which an emulsifier is dissolved in an oil phase, and water is added thereto while stirring to invert the continuous phase from the oil phase to the aqueous phase, thereby producing an O / W emulsion. When mixing water and, if necessary, a basic compound such as sodium hydroxide, by gradually adding the water and the basic compound, if necessary, while mixing, the phase inversion can be promoted slowly, resulting in an emulsion composition with finer particles and a narrower particle size distribution. Furthermore, when adding a basic compound such as sodium hydroxide, it is preferable to complete the addition of the basic compound before the completion of the above-mentioned phase inversion, since this can improve the storage stability of the resulting emulsion composition.

[0085] When mixing the liquid conjugated diene rubber, diluent, and surfactant in this order, followed by adding water, the components are preferably mixed by a mechanical method. Examples of the mechanical method include a method using a kneader, a super mixer, or a twin-screw extruder, which can be used alone or in combination. By using the above-mentioned devices, an emulsion composition with fine particle size can be obtained by applying strong shear.

[0086] When adopting the following order of mixing: preparing a diluted solution by mixing the liquid conjugated diene rubber and the diluent, mixing the diluted solution with the surfactant, and then adding water and, if necessary, a basic compound such as sodium hydroxide little by little while mixing, it is preferable to perform the mixing in each step by the method shown below. That is, in the step of mixing the liquid conjugated diene rubber and the diluent to prepare a diluted solution, and the step of mixing the surfactant into the obtained diluted solution, it is preferable to mix using a kneader, a super mixer, or a twin-screw extruder. By using these devices, a uniformly mixed mixed solution can be obtained relatively easily with high productivity. In the subsequent step of gradually mixing water and, if necessary, a basic compound such as sodium hydroxide, preferred mixing methods include mixing using a homogenizer, homomixer, disper mixer, colloid mill, kneader, planetary mixer, super mixer, high-pressure homogenizer, twin-screw extruder, ultrasonic emulsifier, etc., which can be used alone or in combination. By using such devices, an emulsion composition with fine particle size can be obtained by applying strong shear.

[0087] When water is added in the method for producing the emulsion composition, water may be added in a single emulsion composition production step so that the contents of the liquid conjugated diene rubber and the diluent in the emulsion composition fall within the above-mentioned preferred ranges. In a more preferred embodiment, the emulsion composition production step is divided into two or more steps, and in the first production step, the amount of water added is limited so that the liquid conjugated diene rubber and the diluent are contained at high concentrations, and in the subsequent emulsion composition production steps, further water is added so that the contents of the liquid conjugated diene rubber and the diluent are appropriate for the final product. By adopting such a production step, the product quality of the emulsion composition obtained is more likely to be stable. Furthermore, when this production process is adopted, it is not necessarily necessary to carry out the first production process and the second and subsequent production processes at the same location, and it is also preferable to transport the high-concentration emulsion composition obtained in the first production process to a location where the emulsion composition will actually be used or nearby, and then, in the second and subsequent production processes of the emulsion composition, further add water so that the contents of the liquid conjugated diene rubber and the diluent are appropriate for the final product. In this case, a high-concentration emulsion composition is preferable from an economical point of view because the transportation cost is relatively lower for the high-concentration emulsion composition.

[0088] The production method of the present invention can reduce the viscosity of the dilution, so that when emulsifying by the mechanical method, the rotation speed can be increased without placing an excessive load on the apparatus, and sufficient shear can be applied. From the above viewpoints, the viscosity of the dilution measured at 25°C is 1.0 × 10 3 Pa·s or less is preferable, and 5.0×10 2 Pa·s or less is more preferable, and 1.0×10 2 It is more preferable that the viscosity is 5.0×10 Pa·s or less, and most preferable that the viscosity is 5.0×10 Pa·s or less. When the viscosity is within the above range, the viscosity can be sufficiently low, which facilitates production. The viscosity of the diluent means the viscosity of a composition obtained by mixing only the conjugated diene rubber and the diluent, measured using a Brookfield viscometer (B-type viscometer) at 25° C. The rotor and rotation speed during measurement are appropriately set so as to be close to full scale.

[0089] <Uses of emulsion composition> As described above, the emulsion composition of the present invention has high emulsion stability, and therefore exhibits excellent adhesive properties when used, for example, as an adhesive component of an adhesive. When the emulsion composition of the present invention is used as an adhesive component, there are no particular limitations on its application, and examples thereof include the application of bonding fibers and rubber.

[0090] 〔fiber〕 Although there are no particular limitations on the fibers used as the adherend, hydrophilic fibers are preferred from the viewpoint of affinity with the adhesive using the emulsion composition. In the present invention, the term "fiber" includes not only monofilaments and filaments but also forms such as nonwoven fabrics, woven fabrics, knitted fabrics, felts, and sponges.

[0091] Examples of hydrophilic synthetic fibers include synthetic fibers made of a thermoplastic resin having hydrophilic functional groups such as hydroxyl groups, carboxyl groups, sulfonic acid groups, and amino groups, and / or hydrophilic bonds such as amide bonds. Specific examples of such thermoplastic resins include polyvinyl alcohol resins, polyamide resins (aliphatic polyamides such as polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, and polyamide 9C (a polyamide composed of nonanediamine and cyclohexanedicarboxylic acid); semi-aromatic polyamides synthesized from aromatic dicarboxylic acids and aliphatic diamines, such as polyamide 9T (a polyamide composed of nonanediamine and terephthalic acid); wholly aromatic polyamides synthesized from aromatic dicarboxylic acids and aromatic diamines, such as polyparaphenylene terephthalamide), and polyacrylamide resins). Among these, polyvinyl alcohol resins and polyamide resins are preferred. One type of hydrophilic synthetic fiber may be used alone, or two or more types may be used in combination. These hydrophilic synthetic fibers may be further subjected to a hydrophilization treatment described below to further enhance their hydrophilicity.

[0092] Examples of hydrophilic natural fibers include natural cellulose fibers such as wood pulp, e.g., kraft pulp, and non-wood pulp, e.g., cotton pulp and straw pulp. Hydrophilic regenerated fibers include regenerated cellulosic fibers such as rayon, lyocell, cupra, and polynosic. These natural fibers and regenerated fibers may be used alone or in combination of two or more. Furthermore, these hydrophilic natural fibers and regenerated fibers may be further subjected to a hydrophilization treatment described below to further enhance the hydrophilicity.

[0093] The hydrophilic fiber may have at least a hydrophilic surface, and may be, for example, a hydrophobic fiber whose surface has been hydrophilized, or a core-sheath composite fiber in which a hydrophobic resin is used as the core and a hydrophilic resin is used as the sheath. Examples of hydrophilic resins that constitute the sheath are described in the description of hydrophilic synthetic fibers. Examples of hydrophobic fibers made of hydrophobic resins include polyolefin fibers such as polyethylene and polypropylene, polyester fibers such as polyethylene terephthalate, and wholly aromatic polyester fibers. Among these, polyester fibers are preferred.

[0094] The hydrophilization treatment is not particularly limited as long as it is a treatment that chemically or physically imparts hydrophilic functional groups to the fiber surface. For example, the hydrophilization treatment can be carried out by a method in which hydrophobic fibers made of the hydrophobic resin are modified with a compound containing a hydrophilic functional group such as an isocyanate group, an epoxy group, a hydroxy group, an amino group, an ether group, an aldehyde group, a carbonyl group, a carboxy group, or a urethane group, or a derivative thereof, or by a method in which the surface is modified by electron beam irradiation.

[0095] The fibers used in the present invention are preferably synthetic fibers and regenerated fibers from the viewpoint of compatibility between the emulsion composition and the fibers, and more preferably one or more fibers selected from polyvinyl alcohol fibers made from polyvinyl alcohol resins, regenerated cellulose fibers, polyester fibers, and polyamide fibers. Of these, hydrophilically treated polyester fibers are most preferred.

[0096] [Method for applying emulsion composition to fibers] The method for applying the emulsion composition to the fibers is not particularly limited, and is preferably carried out by one or more methods selected from immersion, roll coater, oiling roller, oiling guide, nozzle (spray) application, brush application, and the like.

[0097] From the viewpoint of improving the adhesion between the fiber and the rubber, the amount of the emulsion composition applied is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 1 part by mass or more, per 100 parts by mass of the fiber, and from the viewpoint of balancing production costs and effects, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0098] After the emulsion composition of the present invention is applied to the fibers, it is preferably allowed to soak for about 3 to 10 days at room temperature of about 20° C. In some cases, after application to the fibers, the fibers may be subjected to a heat treatment. The heat treatment is preferably carried out at a temperature of 100 to 200°C for a treatment time of 0.1 seconds to 2 minutes. Because the liquid conjugated diene rubber contained in the emulsion composition has reactive multiple bonds, the heat treatment in the presence of oxygen is preferably carried out at 200°C or lower, and more preferably at 175°C or lower. When the heat treatment temperature is within the above range, the amount of reactive multiple bonds in the liquid conjugated diene rubber does not decrease, and adhesive strength can be improved, fiber degradation is suppressed, and quality such as coloring is also improved.

[0099] [Rubber] The rubber bonded to the fibers is not particularly limited, and examples thereof include NR (natural rubber), IR (polyisoprene rubber), BR (polybutadiene rubber), SBR (styrene-butadiene rubber), NBR (nitrile rubber), EPM (ethylene-propylene copolymer rubber), EPDM (ethylene-propylene-non-conjugated diene copolymer rubber), IIR (butyl rubber), halogenated butyl rubber, and CR (chloroprene rubber). Of these, it is more preferable to use NR, BR, or SBR. These rubbers may be used alone or in combination of two or more.

[0100] As a method for bonding the fibers and the rubber to produce a rubber molded article, for example, an emulsion composition is applied to the fibers, which are then embedded in the unvulcanized rubber component, and the rubber component is then vulcanized, thereby obtaining a molded article in which the fibers and the rubber are bonded via the emulsion composition. [Example]

[0101] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0102] <Production of liquid conjugated diene rubber> Production Example 1: Production of modified conjugated diene rubber (A-1) A thoroughly dried 5 L autoclave was purged with nitrogen, and 1260 g of hexane and 36.3 g of n-butyllithium (17% by mass hexane solution) were charged. The temperature was raised to 50°C, and then 1260 g of butadiene was gradually added while stirring to maintain the polymerization temperature at 50°C. Polymerization was carried out for 1 hour. Methanol was then added to terminate the polymerization reaction, yielding a polymer solution. Water was added to the resulting polymer solution, followed by stirring, and the polymer solution was washed with water. After stirring was stopped, separation of the polymer solution phase and the aqueous phase was confirmed, and the water was then separated. The washed polymer solution was vacuum dried at 70°C for 24 hours to yield unmodified liquid polybutadiene (A'-1). Next, 500 g of the resulting unmodified liquid polybutadiene (A'-1) was placed in a nitrogen-purged 1 L autoclave, and 25 g of maleic anhydride and 0.5 g of N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (trade name "Nocrac 6C", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) were added, followed by a reaction at 170°C for 24 hours to obtain maleic anhydride-modified liquid polybutadiene. 8.5 g of methanol was added to 525 g of the resulting maleic anhydride-modified liquid polybutadiene, and the mixture was reacted at 80°C for 6 hours to obtain monomethyl maleate-modified liquid polybutadiene (A-1).

[0103] Production Example 2: Production of modified conjugated diene rubber (A-2) A modified conjugated diene rubber (A-2) was produced in the same manner as in Production Example 1, except that 1260 g of hexane and 23.6 g of n-butyllithium (17 mass % hexane solution) were charged and heated to 50°C, and then 1260 g of butadiene was gradually added under stirring conditions while controlling the polymerization temperature to 50°C.

[0104] <Production of low-viscosity liquid rubber> Production Example 3: Production of low-viscosity liquid butadiene rubber (B-1) A thoroughly dried 5 L autoclave was purged with nitrogen, and 1260 g of hexane and 166 g of n-butyllithium (17% by mass hexane solution) were charged. The temperature was raised to 50°C, and then 1260 g of butadiene was gradually added while stirring to maintain the polymerization temperature at 50°C. Polymerization was carried out for 1 hour. Methanol was then added to terminate the polymerization reaction, yielding a polymer solution. Water was added to the resulting polymer solution, followed by stirring, and the polymer solution was washed with water. After stirring was stopped, separation of the polymer solution phase and the aqueous phase was confirmed, and the water was then separated. The washed polymer solution was vacuum dried at 70°C for 24 hours to yield a low-viscosity liquid butadiene rubber (B-1).

[0105] The methods for measuring and calculating the properties of the modified conjugated diene rubber and the like are as follows. The results are shown in Table 1. <Methods for measuring weight-average molecular weight, number-average molecular weight, and molecular weight distribution> The Mw, Mn and Mw / Mn of the modified conjugated diene rubber etc. were determined as values ​​converted into standard polystyrene by GPC (gel permeation chromatography) using the following measuring device and conditions. Equipment: GPC equipment "GPC8020" manufactured by Tosoh Corporation Separation column: Tosoh Corporation "TSKgel G4000HXL" Detector: Tosoh Corporation "RI-8020" Eluent: Tetrahydrofuran ·Eluent flow rate: 1.0ml / min Sample concentration: 5mg / 10ml Column temperature: 40℃

[0106] <Melt viscosity measurement method> The melt viscosity of the modified conjugated diene rubber etc. at 38° C. was measured using a Brookfield viscometer (manufactured by Brookfield Engineering Labs. Inc.).

[0107] <Method for measuring glass transition temperature> 10 mg of the modified conjugated diene rubber was placed in an aluminum pan, and a thermogram was measured by differential scanning calorimetry (DSC) at a heating rate of 10°C / min. The value at the peak top of the DSC was taken as the glass transition temperature.

[0108] <Average number of hydrogen-bonding functional groups per molecule> The average number of hydrogen-bonding functional groups per molecule of the modified conjugated diene rubber was calculated from the equivalent weight (g / eq) of the hydrogen-bonding functional groups of the modified conjugated diene rubber and the number-average molecular weight Mn in terms of styrene using the following formula: Average number of hydrogen-bonding functional groups per molecule = [(number average molecular weight (Mn)) / (molecular weight of styrene unit) × (average molecular weight of conjugated diene and other monomer units other than conjugated diene contained as needed)] / (equivalent weight of hydrogen-bonding functional group) The method for calculating the equivalent weight of the hydrogen-bonding functional group can be appropriately selected depending on the type of the hydrogen-bonding functional group.

[0109] The average number of hydrogen-bonding functional groups per molecule of the modified conjugated diene rubber was calculated by determining the acid value of the modified conjugated diene rubber and calculating the equivalent weight (g / eq) of the hydrogen-bonding functional groups from the acid value. After the modification reaction, the sample was washed four times with methanol (5 mL per 1 g of sample) to remove impurities such as antioxidants, and then dried under reduced pressure at 80°C for 12 hours. 3 g of the sample after the modification reaction was dissolved in 180 mL of toluene and 20 mL of ethanol, and then neutralized with a 0.1 N potassium hydroxide ethanol solution to determine the acid value using the following formula. Acid value (mgKOH / g)=(AB)×F×5.611 / S A: Amount of 0.1N potassium hydroxide ethanol solution added for neutralization (mL) B: Amount of 0.1N potassium hydroxide ethanol solution dropped into a blank containing no sample (mL) F: Potency of 0.1N potassium hydroxide in ethanol S: mass of weighed sample (g)

[0110] The mass of the hydrogen-bonding functional group contained in 1 g of the modified conjugated diene rubber was calculated from the acid value using the following formula, and the mass of the components other than the functional group (polymer main chain mass) contained in 1 g of the modified conjugated diene rubber was also calculated. The equivalent weight (g / eq) of the hydrogen-bonding functional group was then calculated using the following formula. [Hydrogen-bonding functional group mass per 1g] = [acid value] / [56.11] x [hydrogen-bonding functional group molecular weight] / 1000 [Mass of polymer main chain per 1g] = 1 - [Mass of hydrogen-bonding functional group per 1g] [Equivalent weight of hydrogen-bonding functional group] = [mass of polymer main chain per 1 g] / ([mass of hydrogen-bonding functional group per 1 g] / [molecular weight of hydrogen-bonding functional group])

[0111] [Table 1]

[0112] The components used in the examples and comparative examples are as shown in Tables 2 and 3. [Table 2]

[0113] [Table 3]

[0114] The vapor pressures of the diluents at 20°C in Table 2 and the HLB values ​​of the surfactants in Table 3 were measured according to the following method. [Vapor pressure of diluent at 20°C] The vapor pressure of synthetic oils and mineral oils at 20°C was calculated based on measurements taken using the gas flow method, after calculating constants A, B, and C in the Antoine equation: log10P=A-(B / (T+C)). The vapor pressure of toluene at 20°C was measured directly by the static method.

[0115] [HLB value of surfactants] Nonionic surfactants are identified by detecting and measuring their molecular weight and structural units using mass spectrometry. 1 H and 13 The structure was detected and measured using C-NMR, and the structure was identified based on this. Based on the identified information, the HLB value was calculated using the following formula (I) based on the Griffin method. HLB = 20 × total formula weight of hydrophilic moieties / molecular weight (I)

[0116] Example 1: Preparation of emulsion The liquid conjugated diene rubber was a modified conjugated diene rubber (A-1), and the diluent (oil) had a vapor pressure of 10 Pa or less at 20°C. The diluent was a naphthenic oil (trade name "SUNTHENE250J" manufactured by Nippon Sun Oil Co., Ltd., vapor pressure at 20°C: 1.0 x 10 -1 Pa) were mixed in the proportions shown in Table 4, and the mixture was stirred for 24 hours while heated to 50°C to prepare 300 g of an oil solution dilution of the modified conjugated diene rubber (A-1). Next, 18 g of a surfactant, polyoxyethylene alkyl ether (trade name "TE-10A", manufactured by Toho Chemical Industry Co., Ltd., HLB value: 14.1) and 0.6 g of a 50% by mass aqueous solution of sodium hydroxide were added to the diluted oil solution and stirred for 10 minutes. Subsequently, 210 g of water was gradually added while stirring, and the mixture was stirred for 60 minutes to obtain an emulsion composition (E-1) of a modified conjugated diene rubber (A-1).

[0117] <Examples 2 to 4, 7 to 8, Comparative Examples 1 to 3: Preparation of emulsion compositions> An emulsion composition was prepared in the same manner as in Example 1, except that the components were blended as shown in Table 4.

[0118] <Examples 5 and 6: Preparation of emulsion compositions> An emulsion composition was prepared in the same manner as in Example 1, except that the components were blended as shown in Table 4 and a primary alcohol ethoxylate (trade name "TN-100", manufactured by ADEKA Corporation, HLB: 13.8) was used as the surfactant.

[0119] [evaluation] <Ease of manufacturing (viscosity when diluted)> In the examples and comparative examples, the viscosity of the diluted solution immediately after mixing the liquid conjugated diene rubber and the diluent was measured using a rotary B-type viscometer (rotation speed: 100 rpm). The measurement was carried out at room temperature (25°C). The lower the viscosity, the easier the production. In the present invention, "ease of production" means that an emulsion composition with excellent stability can be easily produced, and specifically means that when the liquid conjugated diene rubber is mixed with a diluent, the viscosity does not become excessively high, resulting in excellent handleability and ease of production.

[0120] <Stability of emulsion composition> After preparing the emulsion compositions of the Examples and Comparative Examples, they were placed in sample bottles and allowed to stand at room temperature (25°C) for one day. The emulsion compositions in the sample bottles were visually observed, and the volume of the emulsion composition that was phase-separated out of the total volume was evaluated according to the following criteria. The results are shown in Table 4.

[0121] 〔standard〕 A: The phase separation ratio is less than 10% of the total volume, and the stability is excellent. B: The phase-separated ratio is 10% or more and less than 50% of the total volume, and the stability is somewhat poor. C: The phase-separated ratio is 50% or more of the total volume, and the stability is poor.

[0122] <Adhesion to polyester fibers> Regarding adhesion to polyester fiber, reinforcing fibers were prepared according to the following procedure, and then test specimens for evaluation were prepared. Note that the evaluation of adhesion to polyester fiber was conducted only for Examples 1, 3, and 5 and Comparative Examples 1 and 2, in which the sum of the amounts of liquid conjugated diene rubber, diluent, surfactant, and sodium hydroxide in the formulations in Table 4 was 10 mass% of the total (emulsion composition). The results are shown in Table 4. (1) Manufacturing of reinforcing fibers [Constituent materials of the surface modification layer (surface modification agent)] First, the following components were mixed to prepare a constituent material (C-1) for the surface modification layer. Blocked isocyanate compound: 2.29 parts by mass Epoxy compound: 0.8 parts by weight ·Water: 96.91 parts by mass

[0123] Details of the compound used in C-1 are as follows: Blocked isocyanate compounds Meikanate DM-3031 CONC (Meisei Chemical Industry Co., Ltd., purity 54% by mass) Epoxy compounds Denacol EX-614B (Nagase Chemtec Corporation, pure content 100% by mass)

[0124] [Method of processing twisted cords] Next, the following twisted cord was treated with the constituent material (C-1) of the surface modification layer. Specifically, two polyester-based PET fibers (total fineness 1100 dtex, single yarn fineness 6.10 dtex) were twisted 470 times / m and 470 times / m, to produce a twisted fiber cord. Next, the twisted cord was immersed in the constituent material (C-1) of the surface modification layer and then squeezed with a roller. The resulting fiber cord was dried at 140°C for 60 seconds and then heat-treated at 240°C for 60 seconds to produce a fiber cord.

[0125] Next, the obtained fiber cord was immersed in an emulsion containing the modified conjugated diene rubber (A-1) or the modified conjugated diene rubber (A-2), and then squeezed with a roller, dried at 140°C for 60 seconds, and then wound up to produce a reinforcing fiber.

[0126] (2) Preparation of evaluation specimens Three of the prepared reinforcing fibers were placed at regular intervals in an unvulcanized NR / SBR rubber composition prepared by the formulation described below. Then, the composition was subjected to a temperature of 150°C and a pressure of 20 kg / cm. 2 The test specimens were prepared by press-vulcanizing the mixture for 30 minutes under the conditions of

[0127] [NR / SBR unvulcanized rubber compounding composition] NR rubber: 70 parts by mass SBR rubber: 41.25 parts by mass Filler (carbon black): 45 parts by mass Vulcanizing agent (sulfur powder): 3.5 parts by mass Vulcanization aid (zinc oxide, stearic acid): 6 parts by mass Vulcanization accelerator (thiazole type): 1 part by mass

[0128] (3) Evaluation Finally, the force (N / 3) required to T-peel the obtained test specimen from the rubber was measured, and the adhesive strength to the rubber was used to evaluate the adhesiveness to the fiber. The results are shown in Table 4. In the evaluation results of rubber adhesive strength, a larger value indicates a stronger adhesive strength between the reinforcing fiber and rubber. 〔standard〕 A: When the adhesive strength to polyester fiber is 70N / 3 or more B: Adhesion to polyester fibers is 40N / 3 or more and less than 70N / 3 C: Adhesion to polyester fibers is less than 40N / 3 fibers The values ​​in parentheses in the table are the measured values ​​(N / 3 pieces).

[0129] [Table 4]

[0130] <Adhesion to polyamide fibers> Regarding the adhesiveness to polyamide-based fibers, reinforcing fibers were prepared according to the following procedure, and then test specimens for evaluation were prepared. The evaluation of adhesion to polyamide fibers was carried out only for Example 7, in which the sum of the amounts of the liquid conjugated diene rubber, diluent, surfactant, and sodium hydroxide in the formulation of Table 5 was 10 mass % of the total (emulsion composition). The results are shown in Table 5.

[0131] (1) Manufacturing of reinforcing fibers [Constituent materials of the surface modification layer (surface modification agent)] First, the following components were mixed to prepare a constituent material (D-1) of the surface modification layer. Polyethyleneimine compound: 0.01 parts by mass ·Water: 99.99 parts by mass

[0132] Details of the compound used in D-1 are as follows: Polyethyleneimine compound (SP-200 manufactured by Nippon Shokubai Co., Ltd.)

[0133] [Method of processing twisted cords] Next, the following twisted cord was treated with the constituent material (D-1) of the surface modification layer. Specifically, a twisted fiber cord was produced by twisting two nylon fibers (total fineness 1400 dtex, single filament fineness 6.86 dtex), which are polyamide-based fibers, 470 times / m in upper twist and 470 times / m in lower twist. Next, the twisted cord was immersed in the constituent material (D-1) of the surface modification layer and then squeezed with a roller. The resulting fiber cord was dried at 140°C for 60 seconds and further heat-treated at 210°C for 60 seconds to produce a fiber cord.

[0134] Next, the obtained fiber cord was immersed in an emulsion containing modified conjugated diene rubber (A-2), squeezed with a roller, dried at 140°C for 60 seconds, and then wound up to produce a reinforcing fiber.

[0135] [Table 5]

[0136] As is clear from the examples and comparative examples, the present invention provides an emulsion composition with excellent emulsion stability. Furthermore, it is clear that when the emulsion composition of the present invention is used for adhesion, excellent adhesiveness is exhibited.

Claims

1. An oil-in-water emulsion composition containing a liquid conjugated diene rubber, a diluent having a vapor pressure of 10 Pa or less at 20°C, a surfactant, at least one basic compound selected from the group consisting of sodium hydroxide and ammonia, and water.

2. 2. The oil-in-water emulsion composition according to claim 1, wherein the liquid conjugated diene rubber contains monomer units derived from one or more selected from the group consisting of butadiene, isoprene, and β-farnesene.

3. 3. The oil-in-water emulsion composition according to claim 1, wherein the liquid conjugated diene rubber is a modified conjugated diene rubber having a hydrogen-bonding functional group in a portion of the conjugated diene rubber.

4. 4. The oil-in-water emulsion composition according to claim 3, wherein the hydrogen-bonding functional group is at least one selected from the group consisting of a hydroxy group, an epoxy group, an aldehyde group, an acetalized aldehyde group, a carboxy group, a salt of a carboxy group, an esterified carboxy group, an acid anhydride of a carboxy group, a boronyl group, a salt of a boronyl group, an esterified boronyl group, a silanol group, and an esterified silanol group.

5. 5. The oil-in-water emulsion composition according to claim 1, wherein the surfactant is a nonionic surfactant.

6. 6. The oil-in-water emulsion composition according to claim 1, wherein the content of the surfactant in the emulsion composition is 1 to 15 parts by mass per 100 parts by mass of the total of the liquid conjugated diene rubber and the diluent.

7. 7. A method for producing the oil-in-water emulsion composition according to claim 1, wherein the liquid conjugated diene rubber, the diluent, the surfactant, and water are mixed to produce the oil-in-water emulsion, and then the diluent is not removed.

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