Lubricant composition and additive for lubricant

Abstract

To provide a novel lubricant agent additive and a novel lubricant agent composition that can reduce friction of a sliding part.SOLUTION: A lubricant agent additive comprises a polymer containing an olefin compound as a monomer unit or a modified polymer obtained by modifying a hydrogenated polymer with maleic acid or maleic anhydride. A lubricant agent composition comprises: a base oil; and a polymer containing an olefin compound as a monomer unit or a modified polymer obtained by modifying a hydrogenated polymer with maleic acid or maleic anhydride.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a lubricating oil composition and an additive for a lubricating oil.

Background Art

[0002] A lubricating oil composition for lubricating a sliding part of a mechanical system is used. The lubricating oil composition generally contains a base oil and an additive selected according to desired properties. For energy saving and power saving of a mechanical system, reduction of friction in the sliding part is essential. In order to reduce the friction in the sliding part, for example, a friction reducer is used as an additive. As the friction reducer, for example, Patent Document 1 discloses an alkanolamine having a specific chemical structure, and Patent Document 2 discloses glycerol monooleate. Such friction reducers are required to be able to cope with a wide range of lubrication conditions (speed range, load, temperature, sliding material).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An aspect of the present invention aims to provide a novel lubricating additive and a lubricating oil composition capable of reducing the friction in a sliding part.

Means for Solving the Problems

[0005] The present inventors have found that a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride can function as an additive for reducing the friction in a sliding part.

[0006] One aspect of the present invention is a lubricant composition containing a base oil and a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride.

[0007] The olefin compound may contain a conjugated diene compound. The polymer or its hydrogenated product may be a block copolymer containing a block containing a conjugated diene compound as a monomer unit and a block containing an aromatic vinyl compound as a monomer unit, or a hydrogenated product thereof. The polymer or its hydrogenated product may be a homopolymer containing only one kind of conjugated diene compound as a monomer unit or a hydrogenated product thereof. The content of the modified polymer may be 0.001% by mass or more and 50% by mass or less based on the total amount of the lubricant composition. The lubricant composition may further contain a crosslinking agent having active hydrogen.

[0008] Another aspect of the present invention is an additive for a lubricant containing a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride.

[0009] The olefin compound may contain a conjugated diene compound. The polymer or its hydrogenated product may be a block copolymer containing a block containing a conjugated diene compound as a monomer unit and a block containing an aromatic vinyl compound as a monomer unit, or a hydrogenated product thereof. The polymer or its hydrogenated product may be a homopolymer containing only one kind of conjugated diene compound as a monomer unit or a hydrogenated product thereof. The additive for a lubricant may further contain a crosslinking agent having active hydrogen.

Advantages of the Invention

[0010] According to one aspect of the present invention, it is possible to provide a novel lubricating additive and a lubricant composition capable of reducing the friction of a sliding part.

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail. One embodiment of the present invention is a lubricant composition containing a base oil and a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride.

[0012] Examples of the base oil include hydrocarbon oils and oxygen-containing oils. Examples of the hydrocarbon oil include mineral oil-based hydrocarbon oils and synthetic hydrocarbon oils. Examples of the oxygen-containing oil include esters, ethers, carbonates, ketones, silicones, and the like. The base oil may be used alone or in combination of two or more.

[0013] Examples of the mineral oil-based hydrocarbon oil include paraffinic mineral oils (normal paraffins, isoparaffins, etc.), naphthenic mineral oils, and aromatic mineral oils obtained by subjecting a lubricating oil fraction obtained by atmospheric distillation and / or vacuum distillation of crude oil to purification treatments such as solvent dewaxing, solvent extraction, hydrocracking, solvent deoiling, catalytic deoiling, hydrorefining, sulfuric acid washing, and clay treatment alone or in appropriate combination of two or more.

[0014] Examples of the synthetic hydrocarbon oil include alkylbenzenes, alkylnaphthalenes, polyalpha-olefins (PAO), polybutenes, ethylene-alpha-olefin copolymers, and the like.

[0015] Examples of the ester include polyol esters, complex esters, and the like. Examples of the ether include polyvinyl ethers, polyalkylene glycols, and the like.

[0016] The kinematic viscosity of the base oil at 40 °C is, for example, 1 mm 2 / s or more, 5 mm 2 / s or more, or 10 mm 2 / s or more, and may be 1000 mm 2 / s or less, 500 mm 2 / s or less, 200 mm 2 / s or less, 100 mm 2 / s or less, or 50 mm2 It may be 100 °C or lower. In this specification, the kinematic viscosity means the kinematic viscosity measured in accordance with JIS K 2283:2000.

[0017] The content of the base oil may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 97% by mass or more based on the total amount of the lubricant composition.

[0018] The polymer or its hydrogenated product contains one or more olefin compounds as monomer units. The polymer or its hydrogenated product may contain only one or more olefin compounds as monomer units, or may contain one or more olefin compounds and other compounds copolymerizable with the olefin compound. The other compound may be, for example, a vinyl compound having a vinyl group. The polymer may be a homopolymer or a copolymer.

[0019] The olefin compound is a hydrocarbon compound having at least one carbon-carbon double bond. The number of carbon atoms of the olefin compound may be, for example, 1 or more and 6 or less. The olefin compound may be, for example, an alkene compound having one carbon-carbon double bond, and specifically may be ethylene, propylene, butylene, etc.

[0020] The olefin compound may be, for example, a diene compound having two carbon-carbon double bonds, or may be a conjugated diene compound having a pair of conjugated double bonds (carbon-carbon double bonds). Examples of the conjugated diene compound include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. The conjugated diene compound is preferably at least one selected from the group consisting of 1,3-butadiene and isoprene.

[0021] The polymer may contain only an alkene compound as the olefin compound as a monomer unit. Examples of such polymers include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-acrylic copolymer, ethylene-butene copolymer, and chlorosulfonated polyethylene.

[0022] The polymer may contain only a conjugated diene compound as the olefin compound as a monomer unit. Such a polymer may be a homopolymer containing only one kind of conjugated diene compound as a monomer unit, and may be, for example, polybutadiene (poly-1,3-butadiene), polyisoprene, etc., preferably polyisoprene. Such a polymer may also be a copolymer containing a conjugated diene compound as a monomer unit, and may be, for example, a styrene-diene copolymer, an acrylonitrile-diene copolymer, etc.

[0023] The polymer may contain, for example, an alkene compound and a conjugated diene compound as the olefin compound as a monomer unit. Such a polymer may be, for example, an ethylene-propylene-diene copolymer.

[0024] In one embodiment, the polymer may be a block copolymer, preferably a block copolymer containing block A containing a conjugated diene compound as a monomer unit and block B containing an aromatic vinyl compound as a monomer unit. The aromatic vinyl compound has an aromatic ring and a vinyl group. Examples of the aromatic vinyl compound include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, and vinylanthracene. The aromatic vinyl compound is preferably styrene.

[0025] Block A is a polymer block containing, as monomer units, a conjugated diene compound in an amount exceeding 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of monomer units contained in Block A. Block A may be a homopolymer block containing only a conjugated diene compound as monomer units, or may be a copolymer block containing a conjugated diene compound and an aromatic vinyl compound as monomer units.

[0026] Block B is a polymer block containing, as monomer units, an aromatic vinyl compound in an amount exceeding 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of monomer units contained in Block B. Block B may be a homopolymer block containing only an aromatic vinyl compound as monomer units, or may be a copolymer block containing an aromatic vinyl compound and a conjugated diene compound as monomer units.

[0027] The block copolymer may have a structure represented by any of the following formulas (1) to (3), for example. B-(A-B) m …(1) B-(A-B) n -A …(2) A-(B-A) m …(3) In the formulas, A represents Block A, B represents Block B, m represents an integer of 1 to 5, and n represents an integer of 0 to 5. m may be 1.

[0028] The block copolymer is preferably a block copolymer having a structure represented by formula (1). In this case, Block A is preferably a block containing 1,3-butadiene or isoprene as monomer units, more preferably a homopolymer block containing only 1,3-butadiene or isoprene as monomer units, and Block B is preferably a block containing styrene as monomer units, more preferably a homopolymer block containing only styrene as monomer units.

[0029] The modified polymer may be a polymer containing one or more olefin compounds as monomer units or a hydrogenated product thereof modified with maleic acid or maleic anhydride. Preferably, it is a polymer containing a conjugated diene compound as an olefin compound or a modified polymer of its hydrogenated product. More preferably, it is a modified polymer of a block copolymer containing a block containing a conjugated diene compound as a monomer unit and a block containing an aromatic vinyl compound as a monomer unit or its hydrogenated product. The modified polymer is preferably a modified polymer obtained by modifying a homopolymer (polyisoprene) containing only isoprene as a monomer unit with maleic anhydride. More preferably, it is a modified polymer obtained by modifying a styrene-butadiene-styrene block copolymer (SBS), its hydrogenated product styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), or its hydrogenated product styrene-ethylene / propylene-styrene block copolymer (SEPS) with maleic acid or maleic anhydride.

[0030] The number average molecular weight Mn of the modified polymer may be 1,000 or more, 5,000 or more, 10,000 or more, 30,000 or more, or 50,000 or more, and may be 500,000 or less, 200,000 or less, 100,000 or less, or 80,000 or less. The weight average molecular weight Mw of the modified polymer may be 2,000 or more, 10,000 or more, 20,000 or more, 50,000 or more, or 70,000 or more, and may be 750,000 or less, 300,000 or less, 200,000 or less, or 150,000 or less. The z average molecular weight Mz of the modified polymer may be 50,000 or more, 70,000 or more, or 100,000 or more, and may be 400,000 or less, 350,000 or less, or 320,000 or less. The Mw / Mn of the modified polymer may be 1 or more, 1.1 or more, or 1.2 or more, and may be 2.5 or less, 2.2 or less, or 2 or less. These average molecular weights are measured by a conventionally known GPC (gel permeation chromatography) analysis method (polystyrene conversion value).

[0031] The maleation rate of the modified polymer may be 0.1% by mass or more, 0.5% by mass or more, 0.7% by mass or more, or 1% by mass or more, and may be 5% by mass or less, 4% by mass or less, or 3% by mass or less. The maleation rate is measured by the acid value measurement method, which is a conventionally known method.

[0032] The modified polymer as described above can be obtained by modifying the above polymer or its hydrogenated product with maleic acid or maleic anhydride by a known method. Alternatively, a commercially available product can also be purchased as the modified polymer.

[0033] The content of the modified polymer may be 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more based on the total amount of the lubricant composition, and may be 50% by mass or less, 20% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less.

[0034] From the viewpoint of further reducing the friction of the sliding part, the lubricant composition may further contain a crosslinking agent capable of crosslinking the above modified polymers. The crosslinking agent may be present in the lubricant composition in a state where the modified polymers are crosslinked, or may be present in the lubricant composition in a single state where the modified polymers are not crosslinked.

[0035] Examples of such crosslinking agents include crosslinking agents having active hydrogen. The crosslinking agent may have, as a functional group having active hydrogen, for example, a hydroxyl group, an amino group, or a thiol group. The crosslinking agent preferably may further have a nitrogen-containing heterocyclic ring in addition to the functional group having active hydrogen. Examples of the nitrogen-containing heterocyclic ring include a triazole ring, a pyridine ring, a thiadiazole ring, an imidazole ring, an isocyanurate ring, a triazine ring, and a hydantoin ring. The crosslinking agent preferably has a hydroxyl group or an amino group and a triazole ring, an isocyanurate ring, or a triazine ring, and more preferably has a hydroxyl group or an amino group and a triazole ring or an isocyanurate ring. Examples of such crosslinking agents include 4H-3-amino-1,2,4-triazole, 2-aminopyridine, aminoimidazole, 2-amino-1,3,5-triazine, aminoisocyanurate, hydroxypyridine, tris(2-hydroxyethyl)isocyanurate, and the like.

[0036] The content of the crosslinking agent may be 0.001 equivalent or more, 0.01 equivalent or more, 0.1 equivalent or more, or 0.5 equivalent or more, and may be 5 equivalents or less, 3 equivalents or less, or 2 equivalents or less, relative to the amount of the modified functional group in the modified polymer.

[0037] In addition to the base oil and the modified polymer, the lubricant composition may further contain other additives according to the desired properties and the use of the lubricant composition. Examples of the other additives include antiwear agents, antioxidants, oiliness agents, defoamers, metal deactivators, viscosity index improvers, pour point depressants, detergents, acid scavengers, rust inhibitors, thickeners (especially when the lubricant composition is used for grease applications), and the like. The content of the other additives may be, for example, 0.1% by mass or more and 20% by mass or less based on the total amount of the lubricant composition.

[0038] The lubricant composition described above, in addition to the base oil, contains a polymer containing a conjugated diene compound as a monomer unit or a hydrogenated product thereof modified with maleic acid or maleic anhydride. By doing so, compared with a lubricant composition that does not contain the modified polymer or a lubricant composition that contains a polymer containing a conjugated diene compound as a monomer unit (not modified with maleic acid or maleic anhydride) or a hydrogenated product thereof, the friction of the sliding part can be reduced. Further, in one embodiment, the lubricant composition containing the above-mentioned modified polymer can improve the wear resistance of the sliding part compared with a lubricant composition that does not contain the modified polymer.

[0039] In other words, the above-mentioned modified polymer is suitable as an additive for lubricants. Another embodiment of the present invention is an additive for lubricants containing the above-mentioned modified polymer. This additive for lubricants can also be referred to as a friction reducer (for lubricants), an anti-wear agent (for lubricants), a lubricity improver (for lubricants), etc. The additive for lubricants may further contain the cross-linking agent described above. Another embodiment of the present invention can also be a method for lubricating a sliding part using the above-mentioned modified polymer (a method for reducing the friction of a sliding part, a method for improving the wear resistance of a sliding part, a method for improving the lubricity of a sliding part).

[0040] Examples of the uses of lubricants include lubricating oils and thin film coating oils. Examples of lubricating oils include engine oils, two-stroke engine oils, automatic transmission oils, differential gear oils, tridal CVT oils, shock absorber oils, hydraulic oils, turbine oils, compressor oils, sliding surface oils, machine tool oils, bearing oils, sintered oil-impregnated bearing oils, metalworking oils, chain oils, chain saw oils, precision machine oils, robot joint sliding oils, drone bearing oils, refrigeration oils, automotive greases, EPS greases, high-speed shaft greases, industrial greases, industrial gear oils, centralized lubrication greases, propeller shaft greases, hub bearing greases, CVJ greases, wheel bearing greases, etc. Examples of thin film coating oils include household quick-drying lubricating oils, industrial assembly oils, industrial rust-preventive coating oils, etc.

Examples

[0041] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.

[0042] (Example 1-1) As test oil 1, a commercially available hydraulic oil (product name: Super High Land SE32 (manufactured by ENEOS Corporation)) and a modified polymer obtained by modifying a styrene-ethylene / butylene-styrene block copolymer (SEBS) with maleic anhydride (hereinafter also referred to as "maleic anhydride-modified SEBS". Product name: FG1924 (manufactured by Kraton Corporation), Mn: 68,500, Mw: 12,300, Mz: 215,700, Mw / Mn: 1.859, maleation rate: 1% by mass) were used to prepare a lubricant composition having the composition shown in Table 1 (mass% based on the total amount of the lubricant composition). Specifically, 99.9 g of test oil 1 and 0.1 g of maleic anhydride-modified SEBS were placed in an eggplant-shaped flask, and the gas phase part was replaced with nitrogen. Then, in an oil bath, the inside of the eggplant-shaped flask was stirred at 130 °C for 3 hours to completely dissolve the maleic anhydride-modified SEBS, thereby obtaining a lubricant composition.

[0043] (Example 1-2) In Example 1-1, after dissolving the maleic anhydride-modified SEBS, 1 equivalent of a crosslinking agent (4H-3-amino-1,2,4-triazole (ATA)) was further added with respect to the amount of the maleic acid-modified functional group in the maleic anhydride-modified SEBS, and the inside of the eggplant-shaped flask was stirred at 180 °C for 30 minutes in an oil bath. A lubricant composition was prepared in the same manner as in Example 1-1 except for this.

[0044] (Example 1-3) A lubricant composition was prepared in the same manner as in Example 1-2 except that tris(2-hydroxyethyl)isocyanurate (TIC) was used instead of ATA as the crosslinking agent.

[0045] (Example 1-4) Instead of maleic anhydride-modified SEBS, a modified polymer obtained by modifying polyisoprene with maleic anhydride (hereinafter also referred to as "maleic anhydride-modified isoprene"; trade name: LIR-403, molecular weight: 34,000, a modified polymer with 3 molecules of maleic anhydride added to one molecule of the modified polymer) was used, and a lubricant composition was prepared in the same manner as in Examples 1-2.

[0046] (Comparative Example 1-1) Test oil 1 was used as the lubricant composition as it was.

[0047] (Comparative Example 1-2) Instead of maleic anhydride-modified SEBS, unmodified SEBS was used, and a lubricant composition was prepared in the same manner as in Example 1-1.

[0048] (Measurement of Friction Coefficient) For each of the above lubricant compositions of Examples and Comparative Examples, the friction coefficient (μ) was measured under the following conditions using an MTM (Mini Traction Machine) tester (manufactured by PCS Instruments). Ball: 3 / 4-inch steel ball Disk: Steel Load: 20 N Slip ratio (SRR): 50% Average speed: 0 - 3000 mm / s Oil temperature: 40 °C The friction coefficients at average speeds of 5 mm / s and 10 mm / s are shown in Table 1.

[0049]

Table 1

[0050] (Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2) Instead of Test oil 1, mineral oil (kinematic viscosity at 40 °C: 20 mm 2Except for using test oil 2 which is a mixture of 99 parts by mass of / s)99 and 1 part by mass of tricresyl phosphate, a lubricant composition having the composition (mass% based on the total amount of the lubricant composition) shown in Table 2 was prepared in the same manner as in Example 1-1 or Example 1-2. In Comparative Example 2-2, glycerol monooleate known as a friction reducer was added. For each of the obtained lubricant compositions, the friction coefficient was measured in the same manner as in Example 1-1 and the like. Table 2 shows the friction coefficients at average speeds of 5 mm / s and 10 mm / s respectively.

[0051] [Table 2]

[0052] (Examples 3-1 to 3-2 and Comparative Example 3-1) A lubricant composition was prepared in the same manner as in Example 2-1 and the like, except that the composition of the lubricant composition (mass% based on the total amount of the lubricant composition) was changed as shown in Table 3.

[0053] (Measurement of Friction Coefficient and Wear Scar Width) For each of the obtained lubricant compositions, the friction coefficient and the wear scar width were measured under the following conditions using a ball-on-disk reciprocating sliding lubrication tester. Ball: 1 / 4 inch steel ball (SUJ-2) Disk: Steel plate (SUJ-2) or copper plate (pure copper: 99.9%) Oil amount: 0.5 mL Load: 2000 g (when the disk is a steel plate) 250 g (when the disk is a copper plate) Sliding amplitude: ±20 mm Sliding speed: 10 mm / s Sliding: 150 reciprocations, 10 minutes (when the disk is a steel plate) 15 reciprocations, 1 minute (when the disk is a copper plate) Temperature: Room temperature Table 3 shows the average friction coefficient in the last 5 reciprocations before the end of the friction test and the wear scar width of the disk after the test.

[0054] [Table 3]

[0055] (Example 4-1 and Comparative Example 4-1) A lubricant composition was prepared in the same manner as in Example 2-1 and the like, except that the composition of the lubricant composition (mass% based on the total amount of the lubricant composition) was changed as shown in Table 4.

[0056] (Measurement of coefficient of friction) For each of the obtained lubricant compositions, the coefficient of friction was measured in the same manner as in Example 1-1 and the like, except that a fluororubber plate was used as the disk and the load was changed to 10 N. The coefficients of friction at average speeds of 100 mm / s and 1000 mm / s are shown in Table 4. Also, for each of the obtained lubricant compositions, a test was carried out using a polyetheretherketone (PEEK) plate as the disk and a load of 10 N, and the coefficient of friction was measured in the same manner as in Example 1-1 and the like using an MTM tester. The coefficients of friction at average speeds of 10 mm / s and 100 mm / s are shown in Table 4.

[0057] [Table 4]

[0058] (Example 5-1 and Comparative Example 5-1) A lubricant composition having the composition (mass% based on the total amount of the lubricant composition) shown in Table 5 was prepared in the same manner as in Example 1-2, except that test oil 3, which is a polyol ester of pentaerythritol and a mixed acid of 2-hexanoic acid / 3,5,5-trimethylhexanoic acid (=1 / 1 (molar ratio)), was used instead of test oil 1. For each of the obtained lubricant compositions, the coefficient of friction was measured in the same manner as in Example 1-1 and the like. The coefficients of friction at average speeds of 2 mm / s and 5 mm / s are shown in Table 5.

[0059] [Table 5]

[0060] (Examples 6-1 to 6-2 and Comparative Example 6-1) Instead of Test Oil 1, Test Oil 4, which is a mixture of 99 parts by mass of paraffinic mineral oil (kinematic viscosity at 40°C: 2 mm 2 / s) and 1 part by mass of tricresyl phosphate, was used. A lubricant composition having the composition (mass% based on the total amount of the lubricant composition) shown in Table 6 was prepared in the same manner as in Example 1-1 or Example 1-2. For each of the obtained lubricant compositions, the coefficient of friction was measured in the same manner as in Example 1-1 etc., except that the load was changed to 10 N. Table 6 shows the coefficients of friction at average speeds of 10 mm / s and 100 mm / s, respectively.

[0061]

Table 6

Claims

1. a base oil, a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride, and containing, wherein the polymer or its hydrogenated product is a homopolymer containing only one kind of conjugated diene compound as the olefin compound as a monomer unit or a hydrogenated product thereof, a lubricant composition.

2. The lubricant composition according to claim 1, wherein the content of the modified polymer is 0.001% by mass or more and 50% by mass or less based on the total amount of the lubricant composition.

3. The lubricant composition according to claim 1 or 2, further containing a crosslinking agent having active hydrogen.

4. containing a modified polymer obtained by modifying a polymer containing an olefin compound as a monomer unit or a hydrogenated product thereof with maleic acid or maleic anhydride, wherein the polymer or its hydrogenated product is a homopolymer containing only one kind of conjugated diene compound as the olefin compound as a monomer unit or a hydrogenated product thereof, an additive for lubricant.

5. The additive for lubricant according to claim 4, further containing a crosslinking agent having active hydrogen.

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