LUBRICANT, METAL MATERIAL, METHOD FOR PLASTICALLY FORMING METAL MATERIAL, AND METHOD FOR PRODUCING FORMED METAL MATERIAL

Abstract

 Provided is a novel lubricant capable of suppressing seizure due to the friction between metal materials.
The above-mentioned object can be achieved by a lubricant including a smectite clay mineral, and an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine, the ammonium ion being intercalated between layers of the smectite clay mineral, the primary amine, the secondary amine or the tertiary amine containing one or more long-chain alkyl groups each having 8 or more carbon atoms in a main chain, the total number of carbon atoms in the main chains of the long-chain alkyl groups being 16 or more.

Description

Technical Field

[0001] The present invention relates to a lubricant which is useful for plastically processing a metal material, a metal material with a coating of the lubricant, a metal material with the lubricant attached thereon/thereover, and a method for plastically processing a metal material with the use of the lubricant, and a method for producing a formed metal material with the use of the lubricant.

Background Art

[0002] During plastic processing and frictional motions, frictions are caused between metal materials (for example, between machine parts, between metal molds and metal materials for forming processes), and the frictions adversely affects the metal material. Thus, various lubricants have been developed for decreasing the frictions. For example, Patent Literature 1 discloses a lubricant for plastically processing a metal material, containing an organically modified clay mineral with a cationic organic compound intercalated between layers of a layered clay mineral in the range of 5 to 95% by mass in solid content ratio.

Citation List

Patent Literature

[0003] Patent Literature 1: WO 2012/086564

Summary of Invention

Technical Problem

[0004] An object of the present invention is to provide a novel lubricant capable of suppressing seizure due to the friction between metal materials, a metal material with a coating of the lubricant, a metal material with the lubricant attached thereon, and a method for plastically processing a metal material with the use of the lubricant, and a method for producing a formed metal material with the use of the lubricant.

Solution to Problem

[0005] As a result of intensive studies carried out for achieving the object mentioned above, the inventors have found that, when plastic processing with the use of a mold is carried out after a lubricant including a smectite clay mineral in which a predetermined cationized primary amine, secondary amine or tertiary amine is intercalated between layers is brought into contact with a metal material before plastic processing (workpiece for plastic processing) to form a lubricating coating on/over the surface of the metal material, the inventors found that it is possible to suppress seizure due to the friction between the metal material and the mold, and then have achieved the present invention.

[0006] The present invention (1) provides a lubricant comprising: a smectite clay mineral, and an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine,
wherein the ammonium ion is intercalated between layers of the smectite clay mineral, the primary amine, the secondary amine or the tertiary amine has one or more long-chain alkyl groups, the long-chain alkyl groups have 8 or more carbon atoms in a main chain, and the total number of carbon atoms in the main chains of the long-chain alkyl groups is 16 or more,
provided that the lubricant excludes any lubricant comprising lithium borate.

[0007] The present invention (2) provides a lubricant including a smectite clay mineral, an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine, and one or more inorganic solid particles selected from graphite, graphene, graphene oxides, fullerene, carbon nanotubes, diamond-like carbon (DLC), onion-like carbon, molybdenum disulfide and tungsten disulfide, wherein at least the ammonium ion is intercalated between layers of the smectite clay mineral, the primary amine, the secondary amine or the tertiary amine has one or more long-chain alkyl groups, the long-chain alkyl groups have 8 or more carbon atoms in a main chain, and the total number of carbon atoms in the main chains of the long-chain alkyl groups is 16 or more.

[0008] The invention (3) provides the lubricant according to the invention (1) or (2), which is solid.

[0009] The present invention (4) provides a metal material having a coating of the lubricant according to the invention (1) or (2).

[0010] The present invention (5) provides a metal material on/over which the lubricant according to the invention (3) is attached.

[0011] The present invention (6) provides a method for plastically processing a metal material, including a step of forming a lubricating coating by bringing the lubricant according to the invention (1) or (2) into contact with a surface of at least one of two metal materials that cause friction.

[0012] The present invention (7) provides a method for plastically processing a metal material, including a step of attaching the lubricant according to the invention (3) on/over a surface of at least one of two metal materials that cause friction.

[0013] The present invention (8) provides a method for producing a formed metal material, including the steps of: forming a lubricating coating by bringing the lubricant according to the invention (1) or (2) into contact with a surface of at least one of two metal materials that cause friction; and carrying out plastic processing with the two metal materials brought into contact with each other.

[0014] The present invention (9) provides a method for producing a formed metal material, including the steps of: attaching the lubricant according to the invention (3) on/over a surface of at least one of two metal materials that cause friction; and carrying out plastic processing with the two metal materials while bringing into contact with each other.

Advantageous Effects of Invention

[0015] The present invention can provide a novel lubricant capable of suppressing seizure due to the friction between metal materials, a metal material with a coating of the lubricant, a metal material with the lubricant attached thereon, and a method for plastically processing a metal material with the use of the lubricant, and a method for producing a formed metal material with the use of the lubricant.

Brief Description of Drawings

[0016] Fig. 1 is a diagram showing evaluation criteria for the seizure degree of a test piece subjected to a workability performance evaluation test.

Description of Embodiments

[0017] Hereinafter, the contents of the present invention will be described in detail, but the present invention is not limited thereto in any way.

<<<Lubricant>>>

[0018] According to an embodiment of the present invention, a lubricant includes a smectite clay mineral, and an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine, the ammonium ion being intercalated between layers of the smectite clay mineral. It is to be noted that this lubricant contains no lithium borate. This lubricant may be composed only of a smectite clay mineral and the ammonium ion, or may include other components besides the smectite clay mineral and the ammonium ion.

[0019] Furthermore, according to an embodiment of the present invention, a lubricant includes a smectite clay mineral, ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine, and inorganic solid particles, at least the ammonium ion being intercalated between layers of the smectite clay mineral. It is to be noted that the lubricant may further contain a lithium borate, or may contain no lithium borate. This lubricant may be composed only of a smectite clay mineral, the ammonium ion and the inorganic solid particles, or may contain other components in addition to the smectite clay mineral, the ammonium ion and the inorganic solid particles.

[0020] These lubricants may be solid lubricants, or liquid lubricants further including a liquid medium.

[0021] Attaching such a lubricant to the surface of at least one of the two metal materials which cause a friction, or forming a coating of the lubricant on/over the surface makes it possible to suppress seizure due to the friction between the metal materials.

<<Components>>

<Smectite Clay Mineral>

[0022] The smectite clay mineral is not to be considered particularly limited.
Specifically, examples of the smectite clay mineral include natural products such as montmorillonite, beidellite, nontronite, saponite, iron saponite, hectorite, and sauconite, and synthetic products thereof. One of these smectite clay minerals may be used alone, or two or more thereof may be used in combination.

[0023]  Cations such as Li⁺, K⁺, Na⁺, NH₄⁺, H₃O⁺, Ca²⁺, Mg²⁺, Ba²⁺, Fe²⁺ and Al³⁺ are typically present between layers of the smectite clay mineral as a raw material, but cations other than the foregoing cations (excluding the ammonium ion described later) may be present.

<Ammonium Ion>

[0024] The ammonium ion can be obtained by cationization of a primary amine, a secondary amine or a tertiary amine. The primary amine, the secondary amine or the tertiary amine is not to be considered particularly limited as long as the amine has one or more alkyl groups each having 8 or more carbon atoms in the main chain (hereinafter, such alkyl groups may be referred to as long-chain alkyl groups), and the total number of carbon atoms contained in the main chains of all of the long-chain alkyl groups is 16 or more. More specifically, in a compound represented by the following formula (1) [hereinafter referred to as a compound (1)], at least R₁ represents a long-chain alkyl group, R₂ represents a hydrogen atom or an alkyl group, and R₃ represents a hydrogen atom or an alkyl group. It is to be noted that the alkyl groups of R₂ and R₃ may be independently an alkyl group having 1 to 22 carbon atoms in the main chain or an alkyl group having 8 to 22 carbon atoms in the main chain. In addition, in the compound (1), the total number of carbon atoms contained respectively in the main chains of all of the long-chain alkyl groups bonded to N is 16 or more.

[0025] Specifically, in the case of the primary amine, in the compound (1), R₁ represents a long-chain alkyl group having 16 or more carbon atoms in the main chain, and R₂ and R₃ represent hydrogen atoms. It is to be noted that in the case of the primary amine, the number of carbon atoms in the main chain of the long-chain alkyl group is not particularly limited as long as the number is 16 or more, but is preferably 22 or less.

[0026] Examples of the primary amine include, but not limited to, compounds such as n-palmitylamine and n-stearylamine.

[0027] In the case of the secondary amine, in compound (1), R₁ represents a long-chain alkyl group having 16 or more carbon atoms in the main chain, R₂ represents an alkyl group having 1 or more carbon atoms in the main chain, and R₃ represents hydrogen; or R₁ represents a long-chain alkyl group having 8 or more carbon atoms in the main chain, R₂ represents a long-chain alkyl group having 8 or more carbon atoms in the main chain, and R₃ represents a hydrogen atom. It is to be noted that in the case of the secondary amine, the total number of carbon atoms in the main chains of the long-chain alkyl groups is not particularly limited as long as the number is 16 or more, but is preferably 36 or less.

[0028] Examples of the secondary amine include, but not limited to, compounds such as N, N-di-n-stearylamine and N-n-stearyl-N-methylamine.

[0029] In the case of the tertiary amine, in compound (1), R₁ represents a long-chain alkyl group having 16 or more carbon atoms in the main chain, and R₂ and R₃ each represent an alkyl group having 1 or more carbon atoms in the main chain; or R₁ represents a long-chain alkyl group having 8 or more carbon atoms in the main chain, and R₂ and/or R₃ represent a long-chain alkyl group having 8 or more carbon atoms in the main chain. It is to be noted that in the case of the tertiary amine, the total number of carbon atoms in the main chain of the long-chain alkyl group is not particularly limited as long as the number is 16 or more, but is preferably 36 or less.

[0030] Examples of the tertiary amines include, but not limited to, compound such as N,N-di-n-octyl-N-methylamine, N,N-di-n-decyl-N-methylamine, N,N-di-n-lauryl-N-methylamine, N,N-di-n-myristyl-N-methylamine, N,N-di-n-stearyl-N-methylamine, N,N-dimethyl-N-n-palmitylamine, N,N-dimethyl-N-n-stearylamine, N,N-dimethyl-N-n-behenylamine, N,N,N-tri-n-octylamine, N,N,N-tri-n-decylamine and N,N,N-tri-n-dodecylamine.

[0031] In this regard, the long-chain alkyl group in the compound (1) is not limited to any straight chain as long as the main chain has 8 or more carbon atoms, and may be a branched chain. Examples of the compound having one or more branched long-chain alkyl groups and having 16 or more carbon atoms in total in the main chain of the long-chain alkyl group include, but not limited to, diisononylamine, tris(7-methyloctyl)amine, bis(2,4-diethyloctyl)amine and bis (10-methylundecyl)amine.

[0032] It is to be noted that one of the ammonium ion obtained by cationization of the various amines may be used alone, or two or more thereof may be used in combination.

<Inorganic Solid Particles>

[0033] Examples of the inorganic solid particles include graphite, graphene, graphene oxides, fullerene, carbon nanotubes, onion-like carbon, diamond-like carbon (DLC), molybdenum disulfide and tungsten disulfide. One type of these inorganic solid particles may be used alone, or two or more types thereof may be used in combination. Even if a metal material with the lubricant according to the present embodiment, including the inorganic solid particles, which is obtained by bringing the lubricant into contact with the surface of the metal material, or a metal material with a lubricating coating formed by bringing the lubricant into contact with the surface is subjected to plastic processing or frictional motion under a high-temperature (200°C or higher; the temperature of the metal material) condition, it is possible to further suppress seizure at the surface of the metal material.

<Liquid Medium>

[0034] Examples of the liquid medium include water or a mixed solvent of water and a water-miscible solvent (the proportion of water is, for example, 60% by mass or more with respect to the total mass of the mixed solvent). The water-miscible solvent is not to be considered particularly limited as long as the solvent undergoes no phase separation after mixing with water, and examples of the solvent include alcohols such as methanol and ethanol.

<Other Components>

[0035] Examples of the other components include coating-forming components such as organic polymers (for example, acrylic resins, amide resins, epoxy resins, phenol resins, urethane resins and polymaleic resins), water-soluble inorganic salts (for example, sulfates, silicates, borates, molybdates, vanadates, tungstates) and water-soluble organic salts (for example, malates, succinates, citrates, tartrates); anticorrosive additives such as phosphites, zirconium compounds, tungstates, vanadates, silicates, borates, carbonates, amines, benzotriazoles and chelate compounds; viscosity modifiers such as hydroxyethyl cellulose, carboxymethyl cellulose, polyacrylic acid amide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, clay minerals such as mica and talc, fine silica; dispersants such as nonionic surfactants, anionic surfactants, amphoteric surfactants, cationic surfactants and water-soluble polymers; lubricating components such as soaps (sodium stearate, potassium stearate, sodium oleate), metallic soaps (calcium stearate, magnesium stearate, aluminum stearate, barium stearate, lithium stearate, zinc stearate, calcium palmitate), waxes (polyethylene wax, polypropylene wax, Carnauba wax, beeswax, paraffin wax, microcrystalline wax), fatty acid amide (ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bisbehenic acid amide, N,N'-distearyl adipic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide) and the like; and oils such as vegetable oils, mineral oils, and synthetic oils. One of these components may be contained in the lubricant according to the present invention, or two or more thereof may be contained therein in combination.

[0036] It is to be noted that the term of water-soluble means the property of dissolving 1 g or more in 100 g of water at 25°C.

<<Content>>

[0037] The ratio (B_M/A_M) between the mass (A_M) of the smectite clay mineral contained in the lubricant and the amine equivalent mass of the ammonium ion (total mass of the compound (1) as a raw material for the ammonium ion: B_M) is not to be considered particularly limited, but preferably falls within the range of 0.1 to 1.0, more preferably within the range of 0.25 to 0.65. Further, in a case where the inorganic solid particles are included in the lubricant according to the present invention, the content of the inorganic solid particles is not particularly limited, but preferably falls within the range of 0.01 to 10% by mass, more preferably within the range of 0.05 to 5% by mass as the solid content ratio of the inorganic solid particles in the entire lubricant.

[0038] In addition, in a case where the lubricant according to the present invention is a liquid lubricant, the content of the liquid medium included in the liquid lubricant is not particularly limited, and set appropriately in consideration of the method for bringing the lubricant into contact with the surface of a metal material, the thickness of a lubricating coating formed, and the like.

<<Lubricant Production Method>>

[0039] The lubricant can be produced, for example, as follows. After dispersing the compound (1) in deionized water heated to a temperature equal to or higher than the melting point of the compound (1), an acid for cationization of the compound (1) is added to and then mixed with the dispersion to adjust the pH to a predetermined range, thereby preparing an aqueous solution of a cationized amine. Next, this aqueous solution and a dispersion in which a smectite clay mineral is dispersed in the liquid medium are mixed while maintaining the pH in the predetermined range. This mixing causes cations present between layers of the smectite clay mineral to be ion-exchanged with the cationized compound (1), thereby making it possible to produce a liquid lubricant including the smectite clay mineral with the cationized compound (1) intercalated between the layers of the smectite clay mineral. It is to be noted that in the case of using two or more types of amines in combination, a liquid lubricant can be produced used in the same manner as mentioned above, after dispersing the two or more types of amines in deionized water heated to a temperature equal to or higher than the melting point of the amine with a higher melting point. In addition, the pH is not to be considered particularly limited as long as the pH is 6.0 or less, and preferably 4.5 or less. The value of pH refers to the value measured at the above-mentioned temperature to which the deionized water is heated, with the use of an existing pH meter or pH test paper. The acid used for cationization of the compound (1) is not to be considered particularly limited, and examples of the acid include inorganic acids such as nitric acid and phosphoric acid; and organic acids such as maleic acid, succinic acid, malic acid, tartaric acid and citric acid; but non-halogen acids are preferred.

[0040] It is to be noted that the ion exchange between the cations present between the layers of the smectite clay mineral and the ammonium ion obtained by cationization of the compound (1) increases the distances between the layers of the smectite clay mineral. Accordingly, the fact that the ammonium ion are intercalated between the layers of the smectite clay mineral can be easily confirmed by measuring the distances between the layers of the smectite clay mineral before and after the intercalation of the ammonium ion. Further, the distance between the layers of the smectite clay mineral can be determined from the Bragg's formula (2d·sinθ = λ) by, for example, measuring a diffraction pattern through X-ray diffraction by a fixed orientation method with the use of a Cu tube, and determining the diffraction angle at a bottom reflection (d001) plane from the diffraction pattern. It is to be noted that in the Bragg equation, "d", "θ", and "λ" respectively means the distance between the layers of the smectite clay mineral, the determined diffraction angle, and the wavelength of a Kα ray.

[0041] In the case of producing a lubricant including inorganic solid particles and other components, the timing of adding the inorganic solid particles and other components is not particularly limited, and for example, the particles and the components may be added to an aqueous solution of the amine or a dispersion in which the smectite clay mineral is dispersed, or may be added to a mixture obtained by mixing the aqueous solution of the amine and the dispersion in which the smectite clay mineral is dispersed, but preferably added in advance to the aqueous solution of the amine.

[0042] Moreover, a solid lubricant can be produced by evaporating or distilling away the liquid medium included in the said liquid lubricant under reduced pressure. Further, the liquid lubricant and the solid lubricant may be subjected to grinding with the use of a grinding mill. Further, a liquid lubricant may be produced by adding a liquid medium to the produced solid lubricant.

<<Use of Lubricant>>

[0043] Since frictions between metal materials, caused by motions such as sliding motions, rotational motions or piston motion, or plastic processing for materials such as wire rods, pipe materials, rod materials or block materials results in seizure of the metal materials, the lubricant according to the present invention, which is capable of suppressing seizure of the metal materials, is useful for metal materials which cause frictions.

<<<Metal Material with Coating of the Lubricant, Metal Material with Lubricant Deposited>>>

[0044] A metal material with a coating of the lubricant (hereinafter, which may be referred to as a lubricating coating) can be produced by implementing a contact step of bringing a liquid lubricant into contact with the surface of the metal material, and a drying step of drying the liquid lubricant brought into contact. Examples of the method for bringing the liquid lubricant into contact can include known methods such as an immersion method, a flow coating method and a spray method. The contact conditions in the contact step, that is, the contact time and the contact temperature are not to be considered particularly limited as long as the coating of the lubricant can be produced. The liquid lubricant is dried by evaporating the liquid medium in the lubricant until reaching 15% by weight or less, preferably 3% by weight or less. Examples of the drying method can include known methods such as natural drying, drying by heating and air drying.

[0045] The attaching amount of the lubricating coating thus formed preferably falls within the range of 0.5 to 40 g/m², more preferably within the range of 0.5 to 30 g/m², particularly preferably within the range of 2 to 20 g/m². The attaching amount of the lubricating coating is adjusted to fall within the range of 0.5 to 40 g/m², thereby making it possible to not only provide excellent lubricity, but also improve performance such as seizure resistance and scum clogging resistance.

[0046] A metal material with a solid lubricant attached can be produced by implementing an attaching step of attaching the solid to the surface of the metal material. Examples of the method for attaching the solid lubricant can include known methods such as electrostatic coating, fluidized bed dipping process and spraying. The attaching conditions in the deposition step, that is, the attaching temperature is not to be considered particularly limited.

[0047] The attaching amount of the solid lubricant preferably falls within the range of 0.5 to 40 g/m², more preferably within the range of 0.5 to 30 g/m², particularly preferably within the range of 2 to 20 g/m². The attaching amount of the solid lubricant is adjusted to fall within the range of 0.5 to 40 g/m², thereby making it possible to not only provide excellent lubricity, but also improve performance such as seizure resistance and scum clogging resistance.

[0048] It is to be noted that in the method for producing a metal material with a lubricant coating or the method for producing a metal material with a solid lubricant attached, before the contact step or the attaching step, the metal material may be subjected to at least one type of cleaning treatment selected from the group consisting of shot blasting, sand blasting, wet blasting, peeling, alkaline degreasing and acid cleaning. In this regard, the cleaning is intended to remove oxide scale grown by annealing or the like, and various types of contamination (e.g., oil). In addition, before and/or after these treatments, water rinsing may be carried out.

[0049] Moreover, the metal material may be subjected to a chemical conversion treatment, a base treatment, and the like, if necessary, before the contact step or the attaching step. Examples of the chemical conversion treatment can include an iron phosphate chemical conversion treatment, a zinc phosphate chemical conversion treatment, a zinc calcium phosphate chemical conversion treatment, an iron oxalate chemical conversion treatment, an aluminum fluoride chemical conversion treatment and a zircon oxide chemical conversion treatment. Examples of the base treatment can include a method in which a base treatment agent containing an alkali metal salt of, for example, a boric acid, a silicic acid, a sulfuric acid, a phosphoric acid, a tungstic acid or the like is brought into contact with the surface of the metal material and dried; and a mechanically coating method with a known solid lubricant other than the lubricant according to the present invention (for example, zinc phosphate, zinc oxide, titanium dioxide, mica, molybdenum disulfide, tungsten disulfide, tin disulfide, graphite fluoride, graphite, boron nitride, calcium hydroxide, calcium carbonate, lime, calcium sulfate, barium sulfate, or the like) by a projection method such as blasting.

[0050] The metal material is not particularly limited, and examples thereof include iron, an iron alloy (for example, steel, stainless steel), copper, a copper alloy, aluminum, an aluminum alloy, titanium and a titanium alloy. The metal material is a sliding member, a member in contact with the sliding member, a rotational motion member, a cylinder, a piston, a workpiece for plastic processing, a mold member for plastic processing, or the like.

<<<Method for Plastically Processing Metal Material and Method for Producing Formed Metal Material>>>

[0051] The use of the lubricant allows plastic processing for the metal material to be performed efficiently. The method for plastically processing a metal material includes a step of forming a lubricating coating by bringing a liquid lubricant into contact with a surface of at least one of two metal materials (a workpiece for plastic processing and a mold member for plastic processing) which cause frictions. The formation of the lubricating coating can be performed by carrying out the contact step and the drying step described above. The formation of the lubricating coating may be performed on/over the surfaces where the two metal materials (the surface of the plastic processing material and the surface of the plastic processing mold member) are in contact with each other.

[0052] Further, the plastic processing method of the metal material includes a step of attaching a solid lubricant on/over the surface of at least one of the two metal materials (work material for plastic processing and mold member for plastic processing) that cause friction. The solid lubricant can be attached by implementing the attaching step described above. It is to be noted that the solid lubricant may be attached on each of the surfaces of the two metal materials (the workpiece for plastic processing and the mold member for plastic processing) in contact with each other.

[0053] Further, treatments such as the cleaning treatment, chemical conversion treatment and base treatment mentioned above may be carried out before the formation of the lubricating coating or the attaching of the solid lubricant.

[0054] As described above, the step of carrying out plastic processing with the two metal materials brought into contact with each other is implemented after the formation of the lubricating coating or the attaching of the solid lubricant, thereby allowing a metal material formed into a desired shape to be produced. The plastic processing method is not particularly limited, and examples thereof include known methods such as an extrusion process, a wire drawing process, a drawing process, a squeezing process, a bending process, a joining process, a shearing process and a sizing process.

[Examples]

[0055] Hereinafter, the present invention will be described more specifically together with advantageous effects thereof by providing examples of the present invention together with comparative examples. It is to be noted that the present invention is not to be considered limited by these examples.

I. Production of Lubricant

[0056] Production examples for lubricants will be provided below.

(Production Example 1)

[0057] To 950 g of deionized water, 50 g of montmorillonite (exchangeable cation = Na+, CEC (Cation Exchange Capacity) value = 115 meq/100 g) was added, and stirred for 1 hour with a homogenizer to prepare a dispersion. Next, 13.9 g (1.0 molar equivalent of CEC) of n-palmitylamine [the number of long-chain alkyl groups (hereinafter, referred to simply as "Num"): 1, the total number of carbon atoms of main chains of the long-chain alkyl groups (hereinafter, referred to simply as "Tot"): 16] was dispersed in 200 g of deionized water heated to a temperature equal to or higher than the melting point of the amine, and the pH was adjusted to 3.3 with the use of 10 wt% tartaric acid, thereby preparing an aqueous solution of a cationized amine. While maintaining the pH of the prepared aqueous solution at 3.3, the dispersion was added thereto, and further stirred for 1 hour. Subsequently, the stirred mixture was subjected to suction filtration with the use of 5C filter paper, and then, the solid content was collected. The collected product was dried at 60°C overnight, and then subjected to grinding in an agate mortar to produce a solid lubricant. It is to be noted that the CEC value was measured, based on the Schollenberger method.

(Production Example 2)

[0058] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with n-stearylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 18), and adjusting the pH to 4.1, a solid lubricant was produced.

(Production Example 3)

[0059] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-palmitylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 16), and adjusting the pH to 3.2, a solid lubricant was produced.

(Production Example 4)

[0060] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-stearylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 18), and adjusting the pH to 3.2, a solid lubricant was produced.

(Production Example 5)

[0061] In the same way as in Production Example 4 except for replacing 1.0 molar equivalent of CEC with 0.8 molar equivalent of CEC and adjusting the pH to 3.2, a solid lubricant was produced.

(Production Example 6)

[0062] In the same way as in Production Example 4 except for replacing 1.0 molar equivalent of CEC with 1.2 molar equivalent of CEC and adjusting the pH to 3.8, a solid lubricant was produced.

(Production Example 7)

[0063] In the same way as in Production Example 4 except for replacing 1.0 molar equivalent of CEC with 1.4 molar equivalent of CEC and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 8)

[0064] In the same way as in Production Example 4 except for replacing 1.0 molar equivalent of CEC with 1.6 molar equivalent of CEC and adjusting the pH to 3.6, a solid lubricant was produced.

(Production Example 9)

[0065] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-behenylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 22), and adjusting the pH to 3.7, a solid lubricant was produced.

(Production Example 10)

[0066] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-di-n-octyl-N-methylamine (1.0 molar equivalent of CEC, Num = 2, Tot = 16), and adjusting the pH to 3.7, a solid lubricant was produced.

(Production Example 11)

[0067] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-di-n-lauryl-N-methylamine (1.0 molar equivalent of CEC, Num = 2, Tot = 24), and adjusting the pH to 3.9, a solid lubricant was produced.

(Production Example 12)

[0068] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-di-n-stearyl-N-methylamine (1.0 molar equivalent of CEC, Num = 2, Tot = 36), and adjusting the pH to 3.5, a solid lubricant was produced.

(Production Example 13)

[0069] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N,N-tri-n-octylamine (1.0 molar equivalent of CEC, Num = 3, Tot = 24), and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 14)

[0070] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N,N-tri-n-decylamine (1.0 molar equivalent of CEC, Num = 3, Tot = 30), and adjusting the pH to 3.8, a solid lubricant was produced.

(Production Example 15)

[0071] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N,N-tri-n-dodecylamine (1.0 molar equivalent of CEC, Num = 3, Tot = 36), and adjusting the pH to 3.7, a solid lubricant was produced.

(Production Example 16)

[0072] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-di-n-stearylamine (1.0 molar equivalent of CEC, Num = 2, Tot = 36), and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 17)

[0073] To 950 g of deionized water, 50 g of montmorillonite (exchangeable cation = Na+, CEC value = 115 meq/100 g) was added, and stirred for 1 hour with a homogenizer to prepare a dispersion. Next, N,N-di-n-stearylamine (1.0 molar equivalent of CEC, Num = 2, Tot = 36) was dispersed in 200g of deionized water heated to a temperature equal to or higher than the melting point of the amine, and the pH was adjusted to 3.3 with the use of 10 wt% tartaric acid, thereby preparing an aqueous solution of a cationized amine. Then, this aqueous solution was mixed with 0.5 g of graphene (1 wt% of the montmorillonite) as inorganic solid particles over 30 minutes, thereby preparing a mixture. While maintaining the pH of the prepared mixture, the dispersion was added thereto, and further stirred for 1 hour. Subsequently, the stirred mixture was subjected to suction filtration with the use of 5C filter paper, and then, the solid content was collected. The collected product was dried at 60°C overnight, and then subjected to grinding in an agate mortar to produce a solid lubricant.

(Production Example 18)

[0074] In the same way as in Production Example 17 except that the pH was adjusted to 3.7, an aqueous solution of a cationized amine was prepared. While maintaining the pH of the prepared aqueous solution, the dispersion was added thereto, and further stirred for 1 hour, and then, 0.5 g of graphene was mixed as inorganic solid particles over 30 minutes to prepare a mixture. Subsequently, the mixture was subjected to suction filtration with the use of 5C filter paper, and then, the solid content was collected. The collected product was dried at 60°C overnight, and then subjected to grinding in an agate mortar to produce a solid lubricant.

(Production Example 19)

[0075] In the same way as in Production Example 17 except for replacing the graphene with carbon nanotubes and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 20)

[0076] In the same way as in Production Example 18 except for replacing the graphene with carbon nanotubes and adjusting the pH to 4.1, a solid lubricant was produced.

(Production Example 21)

[0077] In the same way as in Production Example 17 except for replacing the graphene with molybdenum disulfide and adjusting the pH to 3.7, a solid lubricant was produced.

(Production Example 22)

[0078] In the same way as in Production Example 18 except for replacing the graphene with molybdenum disulfide and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 23)

[0079] In the same way as in Production Example 1 except for replacing the montmorillonite and the n-palmitylamine respectively to natural hectorite (exchangeable cation = Na+, CEC value = 97 meq/100 g) and 24.1 g of N,N-di-n-stearylamine (1.0 molar equivalent of CEC), and adjusting the pH to 2.8, a solid lubricant was produced.

(Production Example 24)

[0080] In the same way as in Production Example 1 except for replacing the montmorillonite and the n-palmitylamine respectively to synthetic hectorite (exchangeable cation = Na+; CEC value = 79 meq/100 g) and 29.9 g of N,N-di-n-stearylamine (1.0 molar equivalent of CEC), and adjusting the pH to 2.9, a solid lubricant was produced.

(Production Example 25)

[0081] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with n-octylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 8), and adjusting the pH to 3.0, a solid lubricant was produced.

(Production Example 26)

[0082] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with n-laurylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 12), and adjusting the pH to 3.4, a solid lubricant was produced.

(Production Example 27)

[0083] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with n-myristylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 14), and adjusting the pH to 4.0, a solid lubricant was produced.

(Production Example 28)

[0084] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-octylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 8), and adjusting the pH to 3.6, a solid lubricant was produced.

(Production Example 29)

[0085] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-laurylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 12), and adjusting the pH to 3.8, a solid lubricant was produced.

(Production Example 30)

[0086] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-dimethyl-N-n-myristylamine (1.0 molar equivalent of CEC, Num = 1, Tot = 14), and adjusting the pH to 3.9, a solid lubricant was produced.

(Production Example 31)

[0087] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N-di-n-hexyl-N-methylamine (1.0 molar equivalent of CEC, Num = 0, Tot = 0), and adjusting the pH to 3.6, a solid lubricant was produced.

(Production Example 32)

[0088] In the same way as in Production Example 1 except for replacing n-palmitylamine (1.0 molar equivalent of CEC) with N,N,N-tri-n-hexylamine (1.0 molar equivalent of CEC, Num = 0, Tot = 0), and adjusting the pH to 3.7, a solid lubricant was produced.

(Production Example 33)

[0089] To 950 g of deionized water, 50 g of montmorillonite was added, and stirred for 1 hour with a homogenizer to prepare a dispersion. Next, N,N-di-n-stearylamine (1.0 molar equivalent of CEC) was dispersed in 200 g of deionized water heated to a temperature equal to or higher than the melting point of the amine, and the pH was adjusted to 4.0 with the use of 10 wt% tartaric acid, thereby preparing an aqueous solution of a cationized amine. While maintaining the pH of the prepared aqueous solution, the dispersion was added thereto, and further stirred for 1 hour, thereby producing a slurry. To 91.0 parts by weight of the slurry, 1.6 parts by weight of potassium tetraborate as a binder, 0.5 parts by weight of carboxymethyl cellulose as a dispersant, and 6.9 parts by weight of deionized water were each added, thereby producing a liquid lubricant.

II. Method for Preparing Liquid Lubricant

[0090] With the use of the respective solid lubricants according to Production Examples 1 to 32, respective liquid lubricants were prepared in accordance with the following composition.

(Composition)

[0091] 

Organically modified smectite clay mineral (powder) 7.5% by weight

Binder: Potassium tetraborate 2.0% by weight

Dispersant: Carboxymethyl cellulose 0.5% by weight

Deionized water 90.0% by weight

III. Workability Performance Evaluation

<Production of Test Piece with Lubricating Coating Formed>

[0092] With the use of a cylindrical steel material (S10C) of 14 mmϕ in diameter and of 32 mm in height as a test piece, the following treatment step was implemented.

(Treatment Step)

[0093] The test piece was immersed in an alkaline degreasing agent [an aqueous solution of Fine Cleaner E6400 (manufactured by Nihon Parkerizing Co., Ltd.) mixed with water to reach a concentration of 20 g/L] at 60°C for 10 minutes, thereby carrying out alkaline degreasing. Next, after immersing the test piece in tap water for 1 minute, the test piece was immersed in deionized water for 1 minute. Subsequently, the test piece was immersed at 60°C for 1 minute in the liquid lubricants prepared with the use of the solid lubricants according to Production Examples 1 to 32 or the liquid lubricant according to Production Example 33. After the immersion, the test pieces (Examples 1 to 18 and 20 to 28 and Comparative Examples 1 to 8) with lubricating coatings formed were prepared by drying at 100°C for 30 minutes. It is to be noted that as for the liquid lubricant prepared with the use of the solid lubricant according to Production Example 16, a test piece (Example 19) with a lubricating coating formed was prepared in the same way as mentioned above except that the drying temperature was changed to 25°C.

[0094] Table 1 shows the attaching amount of each lubricating coating on the test pieces according to Examples 1 to 28 and Comparative Examples 1 to 8. The attaching amount of the lubricating coating was determined from the weight difference between before and after the coating formation. It is to be noted that the attaching amount of the lubricating coating was adjusted by changing the solid content ratio in the liquid lubricant.

<Workability Performance Evaluation Test>

[0095] The workability performance evaluation was performed in accordance with the upsetting-ball ironing tribo-test disclosed in the reference (Akinori TAKAHASHI, Masatoshi HIROSE, Shinobu KOMIYAMA, WANG Zhigang: Proceedings of the 62th Japanese Joint Conference for the Technology of Plasticity, (2011), 89-90). It is to be noted that the upsetting process was implemented at an upsetting ratio of 45%, thereby processing the test pieces according to Examples 1 to 28 and Comparative Examples 1 to 8 into a barrel shape. Side surface bulges of the barrel-shaped test pieces were subjected to an ironing process (strengthening process) with the use of three ball-shaped molds (SUJ-2 bearing balls of 10 mm in diameter).

[0096] The workability performance evaluation of each test piece was performed in accordance with the evaluation criteria shown in FIG. 1 by checking the degree of seizure in the latter half of the ironing process in which the surface area was more expanded. The results are shown in Table 1. It is to be noted that, "Δ" or better was regarded as pass.

[Table 1]

[0097] 

[Table 1]

Example	Production Example	Coating Amount (g/m2)	Workability (Seizure Resistance)		Comparative Example	Production Example	Coating Amount (g/m2)	Workability (Seizure Resistance)
1	1	4.5	○		1	25	5.3	× ×
2	2	4.1	○		2	26	7.0	×
3	3	4.5	Δ		3	27	7.0	x
4	4	4.1	Δ		4	28	4.6	× ×
5	5	5.2	Δ		5	29	6.5	×
6	6	6.3	Δ		6	30	6.6	×
7	7	4.0	Δ		7	31	6.0	× ×
8	8	6.0	Δ		8	32	5.2	×
9	9	3.4	○
10	10	5.1	Δ
11	11	6.2	○
12	12	7.0	⊚
13	13	5.8	⊚
14	14	6.0	⊚
15	15	5.2	⊚
16	16	6.8	⊚
17		0.5	Δ
18		38.8	⊚
19		5.9	Δ
20	33	6.3	⊚
21	17	5.8	⊚
22	18	6.2	⊚
23	19	5.2	⊚
24	20	5.5	⊚
25	21	6.0	⊚
26	22	6.1	⊚
27	23	3.8	⊚
28	24	4.1	⊚

IV. Lubricity Performance Evaluation

<Production of Test Piece with Lubricating Coating Formed>

[0098] With the use of, instead of the cylindrical steel material (S10C) of 14 mmϕ in diameter and of 32 mm in height, cold-rolled steel (SPCC) of 70 mm × 150 mm (0.8 mm in thickness) as a test piece, the treatment step described in the section of the workability performance evaluation was implemented, thereby preparing test pieces with lubricating coatings formed (Examples 29 to 54 and Comparative Examples 9 to 16). It is to be noted that the test piece according to Example 44 was obtained by drying at 100°C, whereas the test piece according to Example 45 was obtained by drying at 25°C. In addition, the attaching amounts of the lubricating coatings were each 4 g/m².

<Lubricity Performance Evaluation Test>

[0099] The test pieces according to Examples 29 to 54 and Comparative Examples 9 to 16 were subjected to a sliding test with a Wear and Friction Test Machine. The sliding test was carried out by the Bowden test. More specifically, the test pieces were reciprocated at a speed of 10 mm/s with a load of 1 kg applied to a SUJ2 steel ball (10 mmϕ) on/over the surfaces with the lubricating coatings formed. It is to be noted that the reciprocation was performed at intervals of 1 cm. Further, this test was performed under the condition of 25°C. For the lubricity performance evaluation of each test piece, the dynamic friction coefficient value of the fifth reciprocation was measured, and evaluated in accordance with the following evaluation criteria. It is to be noted that, "Δ" or better was regarded as pass.

(Evaluation Criteria)

[0100] 

○: the dynamic friction coefficient is less than 0.15

Δ: the dynamic friction coefficient is 0.15 or more and less than 0.2

×: the dynamic friction coefficient is 0.2 or more

[Table 2]

[0101] 

[Table 2]

Example	Production Example	Lubricity		Comparative Example	Production Example	Lubricity
29	1	Δ		9	25	×
30	2	Δ		10	26	×
31	3	Δ		11	27	×
32	4	Δ		12	28	×
33	5	Δ		13	29	×
34	6	Δ		14	30	×
35	7	Δ		15	31	×
36	8	Δ		16	32	×
37	9	Δ
38	10	Δ
39	11	Δ
40	12	○
41	13	○
42	14	○
43	15	○
44		○
45	16	Δ
46	33	○
47	17	○
48	18	○
49	19	○
50	20	○
51	21	○
52	22	○
53	23	○
54	24	Δ

V. Corrosion Performance Evaluation

<Production of Test Piece with Lubricating Coating Formed>

[0102] With the use of, instead of the cylindrical steel material (S10C) of 14 mmϕ in diameter and of 32 mm in height, a cylindrical steel material (S45C) of 25 mmϕ in diameter and of 30 mm in height as a test piece, the treatment step described in the section of the workability performance evaluation was implemented, thereby preparing test pieces with lubricating coatings formed (Examples 55 to 80 and Comparative Examples 17 to 24). It is to be noted that the test piece according to Example 70 was obtained by drying at 100°C, whereas the test piece according to Example 71 was obtained by drying at 25°C. In addition, the attaching amounts of the lubricating coatings were each 4 g/m².

<Corrosion Performance Evaluation Test>

[0103] The test pieces according to Examples 55 to 80 and Comparative Examples 17 to 24 were subjected to an upsetting process. The upsetting process was implemented with the use of a 200-ton crank press, by sandwiching each test piece between mirror-finished flat molds (SKD11) and applying a pressure such that the compression ratio was about 50% (the processing speed was 30 strokes/min).

[0104] The corrosion performance evaluation of the test piece subjected to the upsetting process was performed by leaving the test piece subjected to the upsetting process in a room for 10 days, then observing the worked surface, and checking for the presence or absence of rusting. The test piece without any rusting recognized was evaluated as ○, and the test piece with rusting recognized was evaluated as ×. The results are shown in Table 3.

[Table 3]

[0105] 

[Table 3]

Example	Production Example	Corrosion Performance		Comparative Example	Production Example	Corrosion Performance
55	1	○		17	25	○
56	2	○		18	26	○
57	3	○		19	27	○
58	4	○		20	28	○
59	5	○		21	29	○
60	6	○		22	30	○
61	7	○		23	31	○
62	8	○		24	32	○
63	9	○
64	10	○
65	11	○
66	12	○
67	13	○
68	14	○
69	15	○
70	16	○
71		○
72	33	○
73	17	○
74	18	○
75	19	○
76	20	○
77	21	○
78	22	○
79	23	○
80	24	○

Claims

1. A lubricant comprising: a smectite clay mineral; and an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine,
wherein the ammonium ion is intercalated between layers of the smectite clay mineral, the primary amine, the secondary amine or the tertiary amine has one or more long-chain alkyl groups, the long-chain alkyl groups have 8 or more carbon atoms in a main chain, and the total number of carbon atoms in the main chains of the long-chain alkyl groups is 16 or more,
provided that the lubricant excludes any lubricant comprising lithium borate.

2. A lubricant comprising: a smectite clay mineral; an ammonium ion obtained by cationization of a primary amine, a secondary amine or a tertiary amine; and one or more inorganic solid particles selected from graphite, graphene, graphene oxides, fullerene, carbon nanotubes, diamond-like carbon (DLC), onion-like carbon, molybdenum disulfide and tungsten disulfide, wherein at least the ammonium ion is intercalated between layers of the smectite clay mineral, the primary amine, the secondary amine or the tertiary amine has one or more long-chain alkyl groups, the long-chain alkyl groups have 8 or more carbon atoms in a main chain, and the total number of carbon atoms in the main chains of the long-chain alkyl groups is 16 or more.

3. The lubricant according to claim 1 or 2, wherein the lubricant is solid.

4. A metal material having a coating of the lubricant according to claim 1 or 2.

5. A metal material on/over which the lubricant according to claim 3 is attached.

6. A method for plastically processing a metal material, comprising a step of forming a lubricating coating by bringing the lubricant according to claim 1 or 2 into contact with a surface of at least one of two metal materials that cause friction.

7. A method for plastically processing a metal material, comprising a step of attaching the lubricant according to claim 3 on/over a surface of at least one of two metal materials that cause friction.

8. A method for producing a formed metal material, comprising the steps of: forming a lubricating coating by bringing the lubricant according to claim 1 or 2 into contact with a surface of at least one of two metal materials that cause friction; and carrying out plastic processing with the two metal materials brought into contact with each other.

9. A method for producing a formed metal material, comprising the steps of:
attaching the lubricant according to claim 3 on/over a surface of at least one of two metal materials that cause friction; and carrying out plastic processing with the two metal materials brought into contact with each other.

Drawing