0001]The present invention relates to compositions, and a solid lubricating coating composition which are used in particular threaded joint for oil well pipes, and the pipe threaded joint having a solid lubricating coating formed from the composition, methods of making pipe thread fittings bet on.
Background technique
[0002]For mining oil and natural gas fields, oil well pipe is used. OCTG, depending on the depth of the well is formed by connecting a plurality of steel pipes. Coupling of the steel pipe is performed by screwing using a component called or end which is formed on the pipe threaded joint between the steel pipe (male thread and female thread) and box forming a threaded on the short tube inner surface. Oil country tubular goods, raised several times by such trouble in the middle of fucan, is back screw, after the screw fastening portion has been inspected or not damaged, is again screw fastening.
[0003]
　Common pipe thread joint comprises a pin and box. Pin includes a male screw portion formed on the outer peripheral surface and an unthreaded metal contact portion of the distal end portion of the steel pipe. Box includes a female threaded portion and an unthreaded metal contact portion formed on the inner peripheral surface of the distal end portion of the steel pipe. Threaded portion and the unthreaded metal contact portions of the pin and box, repeatedly subjected to strong friction sliding during the return screw tightening and screw of the steel pipe. These sites, if there is sufficient resistance to frictional sliding, galling (with irreparable baked) when repeated back screw tightening and screw is lowered tightness of a threaded joint for occurs tube. Therefore, the Pipe threaded joint, sufficient durability against friction sliding, i.e., is required to have excellent seizure resistance.
[0004]
　Conventionally, in order to improve the seizure resistance, heavy metal containing the compound grease called dope have been used. By applying a compound grease on the surface of the pipe thread joint, it can improve the seizure resistance of pipe thread fittings. However, heavy metals Pb, Zn and Cu or the like contained in the compound grease is likely to affect the environment. Therefore, development of a pipe thread joint not using compound grease is desired.
[0005]
　WO 2009/072486 (Patent Document 1) and JP 2011-12251 (Patent Document 2) proposes a pipe thread joint having excellent galling resistance without the compound grease. JP 2003-74763 (Patent Document 3), in the fitting for the oil country tubular goods, discloses placing the Cu-Sn alloy plating layer on the surface of the particular portion.
[0006]
　Pipe threaded joint described in Patent Document 1, the contact surface of the box has a solid lubricating coating having plastic or viscoplastic rheological behavior as an uppermost layer, the contact surface of the pin, an ultraviolet curable resin as an uppermost layer characterized in that it has a solid corrosion protective coating composed mainly of. Thus, without using a compound grease, suppressing the occurrence of rust, it showed excellent galling resistance and airtightness, and no stickiness on the surface, a threaded joint for pipes having excellent appearance and inspection can be obtained, It is described in Patent Document 1.
[0007]
　The photocurable compositions described in Patent Document 2 is characterized by containing the following components (A) ~ (G). (A) photocurable (meth) acrylate resin, (B) a monofunctional (meth) selected from acrylate monomers and bifunctional (meth) acrylate monomers (meth) acrylate monomer, (C) 3-functional or higher polyfunctional ( meth) acrylate monomers, (D) a photopolymerization initiator, (E) a benzotriazole corrosion inhibitor, (F) anticorrosive pigment selected from phosphate anticorrosive pigment and calcium ion exchange silica and (G) phosphorus acid ester. The photocurable composition, airtightness, adhesion to a substrate, lubricity, excellent galling resistance and corrosion resistance, and can form a high transparency photocured film on the surface of the pipe thread joint a thin film, and It is described in Patent Document 2.
[0008]
　On the other hand, OCTG, after being manufactured, transported by ship or the like, is stored a certain period until used. Transport and storage of oil country tubular goods, there is a case in which over a long period of time. Furthermore, storage of oil well pipes might be carried out outdoors. If long term stored outdoors, rust is generated in the pipe thread joint, galling resistance and airtightness of pipe thread joint may be lowered. Therefore, the Pipe threaded joint, in addition to the seizure of the above are excellent corrosion resistance is required.
CITATION
Patent Document
[0009]
Patent Document 1: International Patent Publication No. 2009/072486 Publication
Patent Document 2: JP 2011-12251 JP
Patent Document 3: JP 2003-74763 JP
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　Pipe threaded joint described in the above patent documents, the normal temperature of the use environment, having adhesion and lubrication performance superior solid lubricating coating. Therefore, with sufficient seizure resistance in a normal temperature. However, the environmental temperature used for oil country tubular goods, there is a case of hot or cold. And the base material of the pipe thread joint, the thermal expansion coefficient between the solid lubricant film is different. Therefore, use environmental temperatures of the oil well pipe if high temperature, adhesion of the solid lubricating coating decreases. Environment temperature of oil well pipes further if the high-temperature, solid lubricating coating is softened and oxidation. Thereby, adhesion of the solid lubricating coating is further reduced. On the other hand, the ambient temperature of the oil well pipe if cryogenic, solid lubricating coating is hardened and embrittled. Thereby, adhesion of the solid lubricating coating decreases. A decline in adhesion of a solid lubricating coating, peeling and some damage to the solid lubricating coating to occur, seizure resistance of pipe thread joint is reduced. In addition, OCTG, during transportation is exposed to high temperatures, which may in use be exposed to cryogenic temperatures. Therefore, the solid lubricating coating formed on the pipe threaded joint, even if repeatedly exposed to high temperatures and cryogenic temperatures is required to have high adhesion.
[0011]
　An object of the present invention, the composition for forming a solid lubricating film having a high temperature and repeated exposure is also high adhesion to a very low temperature, with a solid lubricating coating formed from the composition, excellent with seizure pipe threaded joint having a sex and corrosion resistance, and is to provide a method of manufacturing pipe thread fittings.
Means for Solving the Problems
[0012]
　The composition according to the present embodiment is a composition for forming a solid lubricating coating on the pipe thread joint, containing a binder, a lubricant additive, a rust-preventive agent, and a plasticizer.
[0013]
　Pipe thread joint according to the present embodiment is a tube for a threaded joint comprising a pin and box. Each pin and box has a contact surface having a threaded portion and an unthreaded metal contact portion. Pipe threaded joint, on at least one of the contact surfaces of the pin and box comprising a solid lubricating coating. Solid lubricating coating contains a binder, a lubricant additive, a rust-preventive agent, and a plasticizer.
[0014]
　Method for manufacturing a pipe thread joint according to the present embodiment, on at least one contact surface of the aforementioned pin and box, and solidifying the step of applying the above composition, the composition applied on the contact surface solid and forming a lubricating coating.
Effect of the invention
[0015]
　Solid lubricating coating formed using the composition according to the present embodiment contains a plasticizer. Therefore, having a high adhesion even if repeatedly exposed to high temperatures and cryogenic temperatures. As a threaded joint for pipes having a solid lubricant coating formed from the composition has a seizure resistance superior be repeatedly exposed to high temperatures and cryogenic temperatures. Further, the pipe threaded joint has excellent corrosion resistance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016]
[1] Figure 1 is a diagram showing a configuration of a pipe thread joint of the present embodiment.
FIG. 2 is a cross-sectional view of a pipe thread joint according to the present embodiment.
FIG. 3 is a cross-sectional view of the contact surface of the pipe thread joint according to the present embodiment.
[4] FIG. 4 is a diagram showing the protector mating tests.
DESCRIPTION OF THE INVENTION
[0017]
　Hereinafter, with reference to the accompanying drawings, the present embodiment will be described in detail. Its description will not be repeated the same reference numerals designate like or corresponding parts in FIG.
[0018]
　The composition according to the present embodiment is a composition for forming a solid lubricating coating on the pipe thread joint, containing a binder, a lubricant additive, a rust-preventive agent, and a plasticizer.
[0019]
　Solid lubricating coating formed using the composition according to the present embodiment contains a plasticizer. Therefore, having a high adhesion even if repeatedly exposed to high temperatures and cryogenic temperatures.
[0020]
　Plasticizers described above preferably contains at least one selected from the group consisting of bis (2-ethylhexyl) adipate and sebacic acid bis (2-ethylhexyl).
[0021]
　In this case, further increases the adhesion of the solid lubricating coating.
[0022]
　In the above-described composition, the content of the plasticizer is preferably from 0.2 to 5 mass%. In this case, further increases the adhesion of the solid lubricating coating.
[0023]
　As described later, the case of a composition containing a solvent, the content of the plasticizer, refers to mass% of a plasticizer in the case where the mass of the total of all components other than the solvent contained in the composition as 100%. For compositions that do not contain a solvent, the plasticizer content is the mass% of the plasticizer when the mass of the total composition as 100%.
[0024]
　In the above-described composition, the binder is ethylene vinyl acetate resin contains at least one selected from the group consisting of polyolefin resins and waxes, lubricating additives, earthy graphite, graphite fluoride, perfluoro polyether and contains at least one selected from the group consisting of polytetrafluoroethylene, rust-preventive agent preferably contains at least one selected from the group consisting of calcium ion exchange silica and phosphorous acid aluminum.
[0025]
　Pipe thread joint according to the present embodiment is a tube for a threaded joint comprising a pin and box. Pin and box has a contact surface having a threaded portion and an unthreaded metal contact portion. Pipe threaded joint, on at least one of the contact surfaces of the pin and box, provided with a solid lubricant film. Solid lubricating coating contains a binder, a lubricant additive, a rust-preventive agent, and a plasticizer.
[0026]
　Pipe thread joint according to the present embodiment has a solid lubricating coating contains a plasticizer. Therefore, it has excellent seizure resistance even if repeatedly exposed to high temperatures and cryogenic temperatures. Further, the pipe threaded joint has excellent corrosion resistance.
[0027]
　In pipe thread joint described above, the above-mentioned solid lubricating film, for example, 60 to 80% by weight of binder, and 10-25 wt% of the lubricating additives, and 2-10% by weight of the rust-preventive agent, 0. containing from 2 to 5% by weight of a plasticizer.
[0028]
　Pipe threaded joint described above, one of the contact surfaces of the pin and box is provided with the above-described solid lubricating coating, the pin and box the other contact surface may be provided with a solid corrosion protective coating containing an ultraviolet curable resin.
[0029]
　In this case, further increases the corrosion resistance of pipe thread fittings.
[0030]
　In pipe thread joint described above, the thickness of the above-mentioned solid corrosion protective coating, for example, a 5 ~ 50 [mu] m.
[0031]
　In pipe thread joint described above, the thickness of the above-mentioned solid lubricating film is, for example, 10 ~ 200 [mu] m.
[0032]
　Method for manufacturing a pipe thread joint according to the present embodiment, on at least one contact surface of the aforementioned pin and box, and solidifying the step of applying the above composition, the composition applied on the contact surface solid and forming a lubricating coating.
[0033]
　Manufacturing methods described above, on one of the contact surfaces of the above-described pin and box, the steps of applying the above-mentioned composition, and solidifying the applied composition on the contact surface and forming a solid lubricant film , and irradiation and applying a solid corrosion protective coating-forming composition containing an ultraviolet curable resin to the pin and box of the other contact on the surface, an ultraviolet ray to the contact surface coated with the composition for a solid corrosion protective coating formed it may comprise the steps of forming a solid corrosion protective coating Te. In other words, the above-described manufacturing method includes the steps of: (a) forming a solid lubricating film may include the step (b) to form a solid corrosion protective coating. Forming a solid lubricant film (a) is on one of the contact surfaces of the above-described pin and box, the step of applying the above-mentioned composition (a-1), the composition applied on the contact surface solidified by including a step (a-2) to form a solid lubricating coating. Forming a solid corrosion protective coating (b) includes the steps of applying to the pin and box of the other contact on the surface of the composition for a solid corrosion protective coating formed containing an ultraviolet curable resin (b-1), the solid corrosion protective the composition for film formation by irradiating ultraviolet rays to the coated contact surface and a step (b-2) forming a solid corrosion protective coating. Step (a-2) is performed after step (a-1), as long as the step (b-2) is performed after step (b-1), there is no limitation to the order of the steps.
[0034]
　Above manufacturing method further contact surface before the composition for forming the above-described solid lubricating coating is applied, selected from the group consisting of sand blasting, pickling, phosphate chemical conversion treatment and a zinc alloy plating process preferably comprises a step of at least one underlying processing.
[0035]
　In the manufacturing method described above, surface treatment of the above may include zinc alloy plating. In that case, the above-described manufacturing method, before the step of applying the composition for forming the above-described solid lubricating coating even after carrying out the zinc alloy plating described above, the pin and box at least one contact surface preferably further comprises a step of performing a trivalent chromate treatment.
[0036]
　In this case, further increases the corrosion resistance of pipe thread fittings.
[0037]
　Hereinafter, the composition according to the present embodiment, a method for manufacturing a pipe thread fittings and pipe thread joint will be described in detail.
[0038]
　[Pipe thread fittings]
　pipe thread joint comprises a pin and box. Figure 1 is a diagram showing a configuration of a pipe thread joint of the present embodiment. Pipe threaded joint 1 is provided with a pin 5 which is formed at both ends of a steel pipe 2, and a box 8 formed on both sides of the coupling 3. At both ends of the steel pipe 2 is pin 5 having a male screw portion 4 on the outer surface is formed. On both sides of the coupling 3, box 8 having an internally threaded portion 7 on the inner surface is formed. By screwing the pin 5 and the box 8, the end of the steel pipe 2, is mounted coupling 3. Although not shown, the pin 5 and box 8 of the coupling 3 of the steel pipe 2 that mating member is not attached, to protect the respective threaded portion, in some cases protector (not shown) is attached .
[0039]
　Typical pipe thread joint, as shown in FIG. 1, and a steel pipe 2 and the coupling 3, a coupling scheme. On the other hand, without using a coupling, one end of the steel pipe as a pin-shaped, also pipe thread joint of integral scheme in which the other end with the box-shaped. Pipe thread joint of the present embodiment is applicable to any of the coupling type and integral type.
[0040]
　Each pin and box has a contact surface having a threaded portion and an unthreaded metal contact portion. Figure 2 is a cross-sectional view of a pipe thread joint according to the present embodiment. Pin 5 is provided with a male screw portion 4 and an unthreaded metal contact portion. Unthreaded metal contact portion is formed at the tip of the pin 5, and a metal sealing portion 10 and the shoulder portion 11. Box 8 is provided with a female screw portion 7 and the unthreaded metal contact portion. Unthreaded metal contact portion of the box 8 is provided with a metal seal part 13 and the shoulder portion 12. A pin 5 and the box 8 the portion contacting when screwing referred contacting surface. Specifically, when the pin 5 and the box 8 screwing, shoulder portions (shoulder portions 11 and 12), the metal seal portions (metal seal part 10 and 13), and, threaded portions (male screw portion 4 and internal thread portion 7) are in contact with each other. In other words, the contact surface is a shoulder portion, a metal seal part, and a threaded portion.
[0041]
　Pipe threaded joint 1, on at least one contact surface of the pin 5 and box 8 comprises a solid lubricating coating. Figure 3 is a cross-sectional view of the contact surface of the pipe thread joint according to the present embodiment. Solid lubricating film 21, the composition for forming a solid lubricating film 21 is coated on at least one contact surface of the pin 5 and box 8 is formed by solidifying. Solid lubricating film 21 contains a binder, a lubricant additive, a rust-preventive agent, and a plasticizer. Thus, even a composition for forming a solid lubricating coating 21, containing a binder, a lubricant additive, a rust-preventive agent, and a plasticizer. Compositions, solvent-free composition (i.e., only contains the aforementioned components) even may be a composition of solvent-dissolved in a solvent. For solvent-based compositions, the weight percent of each component refers to the weight% in the case where the mass of the total of all components other than the solvent contained in the composition is 100%. That is, the content of each component in the composition, the content of each component in the solid lubricating coating 21 is the same. Hereinafter also referred to simply as "composition" a composition for forming a solid lubricating film 21.
[0042]
　Solid lubricating film 21, contains a plasticizer. Therefore, adhesion of the solid lubricating film 21 is high. It described in detail below each component.
[0043]
　[Binding agent]
　binders, ethylene vinyl acetate resins, containing at least one selected from the group consisting of polyolefin resins and waxes.
[0044]
　Ethylene vinyl acetate resin is a copolymer of ethylene and vinyl acetate. Ethylene vinyl acetate resins, for example, a HM224 manufactured by Cemedine (softening point 86 ° C.).
[0045]
　Polyolefin resin is a general term of the resulting polymer by polymerization of olefin (alkene). Polyolefin resins, because of crystalline polymers, the physical properties are changed by the degree of crystallinity. Polyolefin resin such as polyethylene, polypropylene. Specific examples of the polyolefin resins are, for example, HM712 manufactured by Cemedine (softening point 120 ° C.).
[0046]
　Waxes, the friction-reducing the solid lubricating film, suppress seizure. Wax further adjust the hardness of the solid lubricating coating, enhance the toughness of a solid lubricating coating. As a wax, animal, vegetable, none of mineral and synthetic waxes can be used. Available waxes are, for example, beeswax, spermaceti (or, animal), Japan wax, carnauba wax, candelilla wax, rice wax (or, vegetable), paraffin wax, microcrystalline wax, petrolatum, montan wax, ozocerite , ceresin (or, mineral), oxidized wax, polyethylene wax, Fischer-Tropsch wax, amide wax, hydrogenated castor oil (castor wax) (or, synthetic wax) is. Wax is preferably a solid at room temperature. A preferred lower limit of the melting point of the wax is 40 ° C.. By using a solid wax at room temperature, it can be the adhesion strength of the solid lubricant film in the vicinity of room temperature in an appropriate range.
[0047]
　When the melting temperature of the binder is too high, it is difficult to apply the composition in a hot melt process. On the other hand, when the melting temperature of the binder is too low, the solid lubricant film 21 in a high temperature environment is softened, the adhesion may decrease. Thus, the binder melting temperature (or softening temperature) is 80 ~ 320 ° C. of ethylene vinyl acetate resin, and at least one selected from the group melting temperature (or softening temperature) is composed of 80 ~ 320 ° C. of the polyolefin resin preferably contains a. At least more preferably, the binder, the melting temperature (or softening temperature) is 90 ~ 200 ° C. of ethylene vinyl acetate resin, and is selected from the group melting temperature (or softening temperature) is composed of 90 ~ 200 ° C. of the polyolefin resin preferably it contains one.
[0048]
　Ethylene vinyl acetate resins, in order to suppress an abrupt softening due to a temperature rise, is preferably a mixture of two or more ethylene-vinyl acetate resins having different melting temperatures. Similarly, polyolefin resins, is preferably a mixture of two or more polyolefin resins having different melting temperatures.
[0049]
　The content of the binder in the solid lubricating film 21 is preferably 60 to 80 mass%. When the content of the binder is 60 mass% or more, further enhance the adhesion of the solid lubricating coating 21. When the content of the binder is 80 mass% or less, lubricity of the solid lubricating coating 21 is better maintained.
[0050]
　Lubricating Additives]
　composition, in order to further enhance the lubricity of the solid lubricating coating 21, containing a lubricant additive. The lubricating additive is a general term for additive having lubricating properties. Lubricating additives, it is broadly classified into the following five types. Lubricant additive contains at least one selected from the group consisting of the following (1) to (5).
　(1) slippery specific crystal structure, for example, shows the lubricity by having a hexagonal layered crystal structure (e.g., graphite, zinc oxide, boron nitride),
　a reactive element in addition to
　(3)(2) shows the lubricity by a chemical reactivity (e.g., certain thiosulfate sulfate compounds),
　(4) shows the lubricity by plastic or viscoplastic behavior under frictional stresses (e.g., polytetrafluoroethylene (PTFE) and polyamide), and
　(5) a liquid or grease form, contact shows the lubricity by present in the boundary surface prevent direct contact between the surface and the surface (e.g., perfluoropolyether (PFPE)).
[0051]
　Any lubricant additive of (1) to (5) may also be used. Lubricating additives, (1) above may be used alone or to (5). For example, it may be used alone lubricating additive (1). Lubricating additives may be used in combination of a plurality of the above (1) to (5). For example, in addition to the above (1), may be used in combination (4) and (5).
[0052]
　Preferably, the lubricating additive is above (1), containing at least one selected from the group consisting of (4) and (5). The lubricant additive (1), preferably graphite from the viewpoint of adhesion and corrosion resistance of a solid lubricating film 21, earthy graphite is preferred from the viewpoint of film formability. Polytetrafluoroethylene as a lubricant additive (4) (PTFE) is preferred. The lubricant additive (5), fluorine-based additive is preferable. Fluorine-based additive improves the lubricity at the time of sliding. Fluorine-based additive further enhance the toughness of the solid lubricating film 21 in the cryogenic temperature. Fluorine-based additives are, for example, a fluorinated polymer such as perfluoropolyether (PFPE) or grease-like liquid system. Perfluoropolyether-modified material, such as a basic skeleton, such as fluorinated polyether having a molecular weight of 500-10,000 can also be used as lubricant additives.
[0053]
　The content of the lubricant additive in the solid lubricating coating 21 is preferably 10 to 25 mass%. When the content of the lubricity additive is 10 wt% or more, further enhanced seizure resistance. Therefore, the number of times that can return screw tightening and screw without causing seizure increases. On the other hand, if the content of the lubricity additive is less than 25 mass%, further increases the strength of the solid lubricating film 21. Therefore, wear of the solid lubricating coating 21 is suppressed.
[0054]
　[Rust Additives
　solid lubricating coating 21 is required to have a rust resistant over a long period until it is actually used. Therefore, the composition contains anti-rust additives. The rust-preventive agent, is a general term for additives having corrosion resistance. Antirust additives, for example, contains at least one selected from the group consisting of aluminum tripolyphosphate, phosphorous acid Aruminimu and calcium ion exchange silica. Preferably, rust-preventive agent contains at least one selected from the group consisting of calcium ion exchange silica and phosphorous acid aluminum. As rust-preventive agents, other commercial water repellent (e.g. reaction water repellent), or the like can be used.
[0055]
　The content of the rust-preventive agent in the solid lubricating coating 21 is preferably 2 to 10 mass%. When the content of the rust-preventive additive is 2 mass% or more, rust of the solid lubricating coating 21 is increased in a stable manner. On the other hand, if the content of the rust-preventive additive is 10 wt% or less, lubricity of the solid lubricating coating 21 is increased in a stable manner. The content of the rust-preventive additive, if it exceeds 10 wt%, antirust effect is saturated.
[0056]
　[Plasticizer]
　The solid lubricating coating 21 contains a plasticizer. Therefore, flexibility of the solid lubricating film 21 is high. As a result, in a high-temperature environment, even when the pipe thread joint 1 is thermally expanded, the peeling of the solid lubricating coating 21 is suppressed. Meanwhile, even under extremely low temperature environment, the flexibility of the solid lubricating film 21 is high. Therefore, even under the extremely low temperature environment, the peeling due to the shrinkage of the solid lubricating coating 21 is suppressed. That is, adhesion of the solid lubricating film 21, even if repeatedly exposed to high temperatures (70 ° C.) and cryogenic (-60 ° C.), which remain high. For example, even when subjected to friction during off fitting protectors, damage and peeling of the solid lubricating coating 21 is suppressed. Thus, the pipe threaded joint 1 comprising a solid lubricant film 21 formed by the composition may be repeatedly exposed to high temperatures (70 ° C.) and cryogenic (-60 ° C.), has excellent seizure resistance.
[0057]
　Plasticizers which may be used is not particularly limited as long as it is generally used as a plasticizer. Plasticizers such as phthalic acid esters, adipic acid esters, trimellitic acid esters, phosphoric acid esters, citric acid esters, epoxidized vegetable oils, sebacic acid esters, azelaic acid esters, maleic acid esters, benzoic acid esters and carboxylic acids and glycols reacting the bets containing at least one selected from the group consisting of low molecular weight polyester obtained. Phthalic acid esters, for example, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), Bis (2-ethylhexyl) (DOP or DEHP), phthalic acid di-n-octyl (DnOP), diisononyl phthalate (DINP), a dinonyl phthalate (DNP), diisodecyl phthalate (DIDP) and butylbenzyl phthalate (BBP). Adipic acid esters such as adipic acid bis (2-ethylhexyl) (DOA), diisononyl adipate (DINA), adipic acid di-n-alkyl (C 6 , C 8 , C 10 ) and adipic acid dialkyl (C 7 , C 9) It is. Trimellitic acid esters, for example, a trioctyl trimellitate (TOTM). Phosphoric acid esters, for example, a tricresyl phosphate (TCP). Citric acid esters are, for example, acetyl tributyl citrate (ATBC). Epoxidized vegetable oils are, for example, epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELSO). Sebacic acid esters, for example, dibutyl sebacate (DBS) and sebacic acid bis (2-ethylhexyl) (DOS). Azelaic acid esters are, for example, azelaic acid bis (2-ethylhexyl). Plasticizers, which may contain only one kind of these may contain two or more kinds.
[0058]
　Preferably, the plasticizer is selected bis (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, sebacic acid bis (2-ethylhexyl), from the group consisting of tricresyl phosphate and azelaic acid bis (2-ethylhexyl) It contains at least one. More preferably, the plasticizer comprises at least one selected from the group consisting of bis (2-ethylhexyl) adipate and sebacic acid bis (2-ethylhexyl). More preferably, the plasticizer is a sebacate Bis (2-ethylhexyl).
[0059]
　The content of plasticizer in the solid lubricating coating 21 is preferably 0.2 to 5 mass%. When the content of the plasticizer is more than 0.2 mass%, it is possible to enhance the adhesion of the solid lubricating film 21 in a stable manner. When the content of the plasticizer is 5% by mass or less, further it can suppress a decrease in lubricity of the solid lubricating film 21, increasing the strength of a solid lubricating coating 21. Even when the content of the plasticizer more than 5 wt%, the effect is saturated. A more preferred lower limit of the content of the plasticizer in the composition (or a solid lubricant film 21) is 0.3 wt%, more preferably 0.5% by mass. More preferable upper limit of the content of the plasticizer in the composition (or a solid lubricant film 21) is 3 mass%, more preferably 2 mass%.
[0060]
　Other Components
　The compositions of the present embodiment, in addition to the above components, surfactants, coloring agents, may also contain minor amounts additive component of the inorganic powder or the like for adjustment of the antioxidant and slidability . Inorganic powders are, for example, bismuth oxide and titanium dioxide. The content of the other components are, for example, 5 mass% or less in total. Composition further extreme pressure agent, if such be 2 wt% or less of a very small amount liquid oil may contain.
[0061]
　Binding agents described above, lubricating additives, anti-rust additives, by mixing the plasticizer and other ingredients can produce a composition of the present embodiment.
[0062]
　[Solid lubricating coating 21]
　solid lubricating coating 21, the above-mentioned composition to at least one contact surface of the pin 5 and box 8 is applied, is formed by solidifying. As described above, the solid lubricating coating 21 contains a plasticizer. For containing a plasticizer, even if repeatedly exposed to high temperatures (70 ° C.) and cryogenic (-60 ° C.), a solid lubricating coating 21 has excellent adhesion.
[0063]
　Referring to FIG. 1, the tube end for fastening the pin 5 and box 8 at the factory, only one of the contact surfaces of the pin 5 and box 8 to form a solid lubricant film 21, it may be subsequently fastened. In this case, than the steel pipe 2 having a long dimension, towards the coupling 3 short dimension, it is easy coating work of the composition. Therefore, it is preferable to form the solid lubricating film 21 on the contact surface of the coupling 3. The pins 5 and not fasten the box 8 tube end at the time of shipping, to form a solid lubricant film 21 on both the contact surface of the pin 5 and box 8, it is previously granted rust resistance at the same time as the lubricity good. Alternatively, only one of the contact surfaces of the pin 5 and box 8 to form a solid lubricating film 21, on the other contact surface may be formed solid corrosion protective coating to be described later. In either case, galling resistance to a threaded joint, the airtightness and corrosion resistance can be imparted.
[0064]
　Solid lubricating coating 21 to cover all of the at least one contact surface of the pin 5 and box 8 are preferred. Solid lubricating film 21, part of the contact surface only (e.g., a metal seal part 10 and 13 only) may be coated.
[0065]
　Solid lubricating film 21 may be a single layer or a multilayer. The multilayer, refers to a state in which the solid lubricant film 21 are stacked two or more layers from the contact surface side. By repeating the solidified coating composition, the solid lubricant film 21 can be formed of two or more layers. Solid lubricating film 21 may be formed directly on the contact surface may be formed after the surface treatment to be described later.
[0066]
　The preferred thickness of the solid lubricating coating 21 is 10 ~ 200 [mu] m, more preferably 25 ~ 100 [mu] m. If the 10μm or thickness of the solid lubricant film 21, increased more lubricity of pipe thread joint 1, the seizure resistance is enhanced. Solid lubricating film 21, in addition to lubricity, and a corrosion resistance. Therefore, further if the thickness of the solid lubricating coating 21 is 10μm or more, the corrosion resistance of the pipe thread joint 1 is enhanced. The solid lubricant film 21 when the multi-layer, the thickness of the solid lubricating coating 21, the total thickness of the laminated solid lubricating coating 21. When the solid lubricating coating 21 is less thin 25μm further on the upper layer or the lower layer of a solid lubricating coating 21, a thin film antirust coating of solid or liquid may be formed.
[0067]
　When carrying out the surface treatment to be described later, it is preferred solid lubricating coating 21 is thicker than the surface roughness of the base. If thicker solid lubricating coating 21 than the surface roughness of the underlying solid lubricating coating 21 may completely cover the base. The thickness of the solid lubricating coating 21 when the base is rough, the area of ​​the solid lubricating film 21, is calculated from the mass and density, the average value of the thickness of the entire solid lubricating film 21.
[0068]
　Specifically, the thickness of the solid lubricating coating 21 is measured by the following method. Under the same conditions as in the case of applying a solid lubricant film 21 on the pipe thread joints, applying a solid lubricant film on a flat plate. Among the coating conditions of the threaded joint and the flat plate for tube, the distance between the object to be coated and the nozzle tip, the injection pressure, to match the conditions such as the rotational speed of the viscosity and the coating object of the composition. To match the viscosity of the composition, the tank, the temperature of the piping and the nozzle outlet, to match with the threaded joint and the flat plate for tube. And weight before plating of applying the composition, the difference between the weight of the plate after application of the composition, and calculates the application amount of the composition per unit time. Solidifying the composition on plates to form a solid lubricating coating. The thickness of the solid lubricating coating 21 is measured using a film thickness meter. And weight before plating of applying the composition, the difference between the weight of the plate after forming the solid lubricating coating 21, which calculates the weight of the solid lubricant film 21. From the film thickness and the weight of the solid lubricating coating 21, which calculates the density of the solid lubricant film 21. Next, the screw shape and size from the (inner diameter and thickness, etc.), and calculates the application target area of ​​pipe thread fittings. The application target area corresponds to the area when expanding thread forming surface having irregularities in the plane. Application time of the composition to the pipe thread joint 1, the density of the coating target area and the solid lubricating coating 21, is calculated for the pipe thread joint 1, the average film thickness of the solid lubricating coating 21.
[0069]
　[Solid corrosion protective coating]
　above pipe thread joint, one of the contact surfaces of the pin 5 and box 8 is provided with a solid lubricant film 21, the other contact surface of the pin 5 and box 8, the solid corrosion protective coating containing an ultraviolet curable resin it may be provided. As described above with respect to FIG. 1, until use pipe thread joint 1 is actually, it may be stored for a long period of time. In this case, if the solid corrosion protective coating is formed, it increases the corrosion resistance of the pin 5 or box 8.
[0070]
　Solid corrosion protective coating contains an ultraviolet curable resin. Thus, an intensity which is not destroyed by the force the solid corrosion protective coating is applied during protector mounting. Moreover, during transport or storage, the solid corrosion protective coating is not dissolved even when exposed to condensed water from the relationship between the dew point. Furthermore, the solid corrosion protective coating even at high temperatures exceeding 40 ° C. is not easy to softening.
[0071]
　UV-curable resins are known resin compositions. UV-curable resin, a monomer, containing oligomer and a photopolymerization initiator, as long as it causes a photopolymerization reaction to form a cured coating film by being irradiated with ultraviolet rays is not particularly limited.
[0072]
　Monomers, for example, polyhydric alcohol (meth) polyvalent (di- or higher tri) acrylic acid other esters, various (meth) acrylate compounds, N- vinylpyrrolidone, from the group consisting of N- vinylcaprolactam, and styrene It contains at least one selected. Oligomers such as epoxy (meth) acrylate, containing urethane (meth) acrylate, polyester (meth) acrylates, polyether (meth) at least one selected from the group consisting of acrylate and silicone (meth) acrylate.
[0073]
　Preferred photoinitiators are compounds having absorption in the wavelength of 260 ~ 450 nm. Photopolymerization initiator, for example, contains benzoin and its derivatives, benzophenone and its derivatives, acetophenone and its derivatives, Michler's ketone, benzyl and at least one derivative thereof, selected from the group consisting of tetraalkyl thiuram monosulfide and thioxane acids. Preferred photoinitiators are thioxane class.

claims

[Claim 1]A composition for forming a solid lubricating coating on the pipe thread joint,
　a binder,
　a lubricant additive,
　a rust-preventive agent,
　containing a plasticizer composition.
[Claim 2]
　A composition according to claim 1,
　wherein the plasticizer contains at least one selected from the group consisting of bis (2-ethylhexyl) adipate and sebacic acid bis (2-ethylhexyl), composition.
[Claim 3]
　A composition according to claim 1 or claim 2,
　the content of the plasticizer is from 0.2 to 5 mass%, the composition.
[Claim 4]
　A composition according to any one of claims 1 to 3,
　wherein the binder is ethylene vinyl acetate resin contains at least one selected from the group consisting of polyolefin resins and waxes,
　the lubricant additives, earthy graphite, fluorinated graphite containing at least one selected from the group consisting of perfluoropolyether and polytetrafluoroethylene,
　wherein the anti-rust additive, a calcium ion exchange silica and phosphorous acid aluminum containing at least one selected from the group consisting, composition.
[Claim 5]
　A pipe thread joint comprising a pin and box,
　each of the pin and the box, provided with a contact surface having a threaded portion and the unthreaded metal contact portions,
　a threaded joint for the tube, at least one of the pin and the box wherein comprising a solid lubricating coating on the contact surface of
　the solid lubricant film,
　a binder,
　a lubricant additive,
　a rust-preventive agent,
　containing a plasticizer, pipe threaded joint.
[Claim 6]
　A pipe thread joint according to claim 5,
　wherein the binder is ethylene vinyl acetate resin contains at least one selected from the group consisting of polyolefin resins and waxes,
　the lubricant additive, earthy graphite, graphite fluoride contains at least one selected from the group consisting of perfluoropolyether and polytetrafluoroethylene,
　wherein the anti-rust additive is at least one selected from the group consisting of calcium ion exchange silica and phosphorous acid aluminum containing,
　the plasticizer contains at least one selected from the group consisting of bis (2-ethylhexyl) adipate and sebacic acid bis (2-ethylhexyl) pipe threaded joint.
[Claim 7]
　A pipe thread joint according to claim 5 or claim 6,
　wherein the solid lubricating coating is
　60 to 80 mass% of the binder,
　and 10 to 25 mass% said lubricant additive,
　2-10 mass % of said and antirust additives,
　contains a 0.2 to 5% by weight the plasticizer, pipe threaded joint.
[8.]
　A pipe thread joint according to any one of claims 5 to claim 7,
　wherein the pin and one said contact surface of said box comprises the solid lubricant film,
　the pin and the other of the said box contact surface is provided with a solid corrosion protective coating containing an ultraviolet curable resin, the pipe threaded joint.
[Claim 9]
　A pipe thread joint according to claim 8,
　wherein the thickness of the solid corrosion protective coating is 5 ~ 50 [mu] m, Pipe threaded joint.
[Claim 10]
　A pipe thread joint according to any one of claims 5 to claim 9,
　wherein the solid lubricant coating thickness is 10 - 200 [mu] m, Pipe threaded joint.
[Claim 11]
　A method of manufacturing a pipe thread joint comprising a pin and box with a contact surface having a threaded portion and the unthreaded metal contact portion,
　wherein the pin and at least one of the contact surface of the box, claims 1 to 4 and applying a composition according to any one of,
　and forming a solidified by solid lubricating coating said composition applied on the contact surface, the manufacturing method of the pipe thread fittings.
[Claim 12]
　A method of manufacturing a pipe thread joint according to claim 11,
　on the pin and one said contact surface of said box, applying a composition according to any one of claims 1 to 4 a step,
　a step of forming a solidified by solid lubricating coating the applied the composition onto the contact surface,
　on the pin and the other of the contact surface of the box, the solid corrosion protective containing an ultraviolet curable resin a step of applying the composition for film formation,
　and forming the solid corrosion protective coating forming composition for is irradiated with ultraviolet rays to the coated said contact surface solid corrosion protective coating, the manufacture of the pipe threaded joint Method.
[Claim 13]
　Claim 11 or claim 12 further method of manufacturing a pipe thread joint according to,
　to the contact surface before the composition for forming the solid lubricating coating is applied, sandblasted, pickled, comprising the step of at least one surface treatment selected from the group consisting of phosphate chemical conversion treatment and a zinc alloy plating, the manufacturing method of the pipe thread fittings.
[Claim 14]
　A method of manufacturing a pipe thread joint according to claim 13,
　wherein the surface treatment includes the zinc alloy plating,
　the composition for forming the solid lubricating coating to the zinc alloy plating even after having performed prior to the step of applying an object, further comprising, a manufacturing method of the pipe thread joint the step of implementing a trivalent chromate treatment on at least one of the contact surfaces of the pin and the box was subjected to the zinc alloy plating.