AN AGENT FOR FORMING A SOLID LUBRICANT COATING FILM ON A THREADED PORTION OF AN OIL WELL PIPE, AN OIL WELL PIPE, AND A THREADED UNION INCLUDING SAID SOLID LUBRICANT COATING FILM

Abstract

An agent is disclosed for forming a solid lubricant coating film on a threaded portion of an oil well pipe, capable of imparting excellent corrosion resistance, as well as lubricity, to an oil well pipe screw, even when a solid lubricant coating film is adopted for lubrication.An agent for forming a solid lubricant coating film on a threaded portion of an oil well pipe, wherein a binder resin contains a prepolymer and a curing agent, the prepolymer being formed from one or more epoxy resins, 70 parts by weight or more of the prepolymer being contained with respect to 100 parts by weight of the binder resin, the epoxy resin constituting the prepolymer having an epoxy equivalent of 100 or more and 500 or less, the solid lubricant containing boron nitride (BN) in an amount of 80% by weight or more, the BN having an average particle size of 10 µm or less, and the total weight of the solid lubricant being 0.1 times or more and two times or less the total weight of the binder resin. Also disclosed is an oil well pipe including the solid lubricant coating film, and a threaded oil well pipe joint having the lubricant coating film.

Description

Technical field This description relates to the technology concerning the lubrication and corrosion resistance of an oil well pipe and a threaded oil well pipe joint. This description relates to the technology concerning an oil well pipe and a threaded oil well pipe joint in each of which a solid lubricant coating film is formed on a surface (including a metal sealing surface) of a threaded portion instead of a wet lubricating compound. In this specification, a fitting surface of a threaded portion includes a metal sealing surface. In this context, the term "solid lubricant coating film" means a coating film comprising a binder resin as a matrix component, a solid lubricant dispersed and distributed within the binder resin, and an additive as required. Furthermore, this description aims to impart corrosion resistance while simultaneously improving lubrication through a solid lubricant coating film that lubricates a screw in an oil wellhead pipe. 1810668 of 128 Furthermore, in this descriptive report, a phenomenon described by the term lubricity and the expression "high lubricity" means a slippery phenomenon with low friction in a broad sense. Additionally, the expression "high lubricity" means that the number of times it can be tightened and loosened (also referred to as the M / B number) is a specific number of times or more in a strict sense. For example, the resistance to seizing of a threaded connection for oil well tubing is described in API 5C5. API 5C5 requires that the fitting be able to be tightened up to three times per casing diameter. Furthermore, it requires that the fitting be able to be tightened up to ten times per pipe diameter. Note that, in this descriptive report, a tube with a female screw may be collectively referred to as a female member. That is, a coupling is also described as a type of female member. Background In a threaded connection for oil well pipes, for the lubrication of a threaded portion, conventionally, a fitting surface (sealing surface) (hereafter also referred to simply as a fitting surface) which is a surface of a 2 1810668 of 128 threaded portion of at least one male and one female screw, is surface treated with a chemical conversion coating film of Mn phosphate or galvanized using Cu or similar to form a coating film. A lubricating compound containing Pb, Zn or similar is then applied over the coating film to achieve lubrication. Note that, in this descriptive report, when a coating film is formed on a fitting surface (sealing surface) of a threaded portion, the coating film is also referred to as the fitting surface. On the other hand, in recent years, dry / additive-free non-wet lubrication technology has attracted attention. The term "dry / additive-free" means that the film itself is not a viscous liquid of the API-modified compound type and that the film does not contain any harmful heavy metals. A technology exists for forming a solid lubricant coating film on a mating surface to achieve lubrication such as dry / additive-free lubrication. This description refers to one such dry / additive-free lubrication technology. The documents in the prior patent bibliography describe inventions related to various solid lubricating coating films. A solid lubricating coating film includes a lubricating component and a solid film as a matrix component that retains the lubricating component within the film. The term "solid film" means a film that is neither viscous nor liquid, and also means that it completes lubrication during tightening and loosening of screws on its own. A conventional manganese phosphate film or a copper galvanized film is a solid film. However, since lubrication is achieved by applying a grease compound, the conventional manganese phosphate film and the copper galvanized film are not included in the definition of a solid lubricating coating film.In this description, lubrication is achieved as a solid film, and an organic resin film is assumed to be the solid film. Therefore, in the following description, the solid film is also referred to as the binder resin. A conventional lubricant coating film used on a threaded joint for oil well tubing is described, for example, in Patent Bibliography documents 1 to 9. In the field of oil well pipe bolts, BN O boron nitride is exemplified 4 1810668 of 128 is widely cited in many documents in the patent literature as one of the candidates for a solid lubricant. For example, documents PTL 1 and PTL 2 exemplify BN as a solid lubricant present in a solid film of lubricating coating. Furthermore, an epoxy resin is exemplified in earlier documents in the patent literature. However, few documents in the patent literature clearly define an epoxy resin and specify its chemical composition. Additionally, many documents in the patent literature appear to specify the technology but fail to fully define it. The definition of epoxy resin is very broad. In general, epoxy resin is a generic term for a thermosetting resin formed by the crosslinking and bonding of a chemical substance containing an epoxy group as a prepolymer (precursor of the epoxy resin) and a curing agent. However, from an academic and commercial perspective, and in the description of patent bibliography documents, the expression epoxy resin can refer to a chemical substance itself containing an epoxy group from a prepolymer, or to an epoxy resin that can be generated by the copolymerization of the prepolymer and a curing agent. However, in most cases, it is used in a way that... 1810668 of 128 indistinctly. In documents from the earlier patent bibliography, the expression epoxy resin generally refers to the latter. In summary, the earlier documents in the patent bibliography only describe that epoxy resin is widely used (see documents PTL 3 to PTL 8). Note that, in the following description, when describing this disclosure, an epoxy resin agent as the starting material (prepolymer) for forming an epoxy resin film is referred to as a prepolymer or epoxy resin in the strict sense. Furthermore, an epoxy resin (film) finally obtained by polymerizing a prepolymer and a curing agent is referred to as an epoxy resin coating film for the sake of distinction. The following section describes documents PTL 3 to PTL 9. PTL 3 describes an invention for forming a solid lubricant coating film on a Cu-Sn-Zn galvanized base. PTL 3 employs a resin selected from one or two of an epoxy resin and a polyamide-imide resin as the binder resin for the solid lubricant coating film. Documents PTL 4 to PTL 6 exemplify an epoxy resin as a component of a 6 coating film 1810668 of 128 solid lubricant that has excellent heat resistance and excellent lubricity. Documents PTL 4 to PTL 6 do not clearly reveal up to what temperature the epoxy resin is heat resistant, and it is difficult to discern a characteristic of the epoxy resin used. PTL 7 clearly describes the formation of a two-liquid mixed-type epoxy on a Zr-based galvanizing base. However, the two-liquid mixed-type epoxy is not new, and as described above, epoxy resin is formed from an epoxy resin curing agent in a strict sense, like a prepolymer. The term "two-liquid mixed-type" simply refers to a type in which two liquids are directly mixed. Since even a single-liquid type contains a prepolymer and a curing agent, the two-liquid mixed-type itself is not novel. PTL 8 describes an invention in which an acrylic silicone resin is formed on a UV-curable resin. PTL 8 exemplifies an acrylic acid-modified epoxy resin as one of the candidates and describes an acrylic acid-modified epoxy resin in which a main chain structure of an epoxy resin is formed and a terminal of the main chain structure is acrylated. Document PTL 9 describes a film of 1810668 of 128 photocurable acrylic resin coating. The document PTL 9 describes a light-cured (meth)acrylate resin, specifies a film obtained by copolymerizing (meth)acrylate monomers based on a trigger as a photopolymerization initiator, and exemplifies an epoxy as well as a polyester, a polyether, and a polyurethane as the main chain structure forming an acrylate side chain among the candidates. Furthermore, although not a case study evaluating a solid film lubricant coating, NPL 1 from another publication describes, as a test method for tightening and loosening a screw using a vertical wrench and a short male member, a method for performing tightening and loosening under a constant 5 kN (510 kg) load on an upper end surface of the short male member. However, NPL 1 from another publication performs the evaluation using a conventional grease compound to determine whether a novel screw design is acceptable. List of References Patent Bibliography PTL 1: JPWO 2017-110686 A1 PTL 2: WO 2017-110685 A PTL 3: JPWO 2018-216497 A1 PTL 4: JP 2015-501906 A 8 1810668 8 of 128 PTL 5: JPWO 2015-198557 A1 PTL 6: JPWO 2017-110685 A1 PTL 7: JP 2017-71844 A PTL 8: JPWO 2013-183634 A1 PTL 9: JP 2011-12251 A Other bibliography NPL 1: Tsuru et al., Journal of Japan Petroleum Institute, Vol. 61, No. 6 (1996), pages 527-536. Summary description of the invention Technical problem The lubrication of a screw for oil well pipes, which is the subject of this description, is in a special sliding situation. This means that, at a given site (actual well), a male member with an actual length of approximately 8 m (plus or minus 15 m) is tightened and loosened on a female member positioned below it. At this point, even though the male member is tightened and loosened using a wrench to be lifted by a crane, the full load of the male member can be applied to the bolt of the female member. This means that lubrication is performed under a state of high applied load. At this time, the male member is not necessarily tightened and loosened in an ideal state. That is, during the tightening process, the screw of the male member is inserted into the screw of the female member or tightened. 1810668 of 128 in a slightly hand-tightened state. However, the male member is not positioned vertically and immobile with respect to the screw of the female member. Furthermore, the male member does not straighten when tilted obliquely, i.e., in the ascending state, without bending. That is, one side of the upper end (one side of the tip opposite the fitting side) of the male member bends slightly according to the elastic modulus (Young's modulus) of the material and the actual length of the male member, while a lower portion of the male member is constrained by the screw of the female member. In particular, in the case of a male member 8 m or longer, viewed from below, the male member appears to bend while being placed upright in the female member. In this state, the male member is tightened and loosened.Therefore, the female member screw and the male member screw are never tightened and loosened under a state where a load is applied uniformly and symmetrically to both. For this reason, tightening and loosening occur when the screw surfaces collide locally and forcefully. In other words, lubrication takes place under an unbalanced load. Furthermore, the specific area where the screw surfaces collide locally and forcefully varies depending on the specific load. 1810668 of 128 of the adjustment and loosening. In conventional lubrication technology using a grease compound, the compound shifts after tightening and loosening. For this reason, a lubricant (lubricating compound) works to ensure that the tightening and loosening converge in a favorable direction, even when there is a slight change in lubrication conditions. Therefore, in an evaluation test (also known as a laboratory test) of the tightening and loosening of a threaded joint, it is possible to assess the lubrication of a full-size male member by evaluating it using a short male member, without relying on the evaluation using the full-size male member. Meanwhile, according to a test by the inventor, in the lubrication technology of an oil well pipe screw that employs a solid lubricant coating film, the solid lubricant coating film inevitably scrapes off to some extent. It is necessary to devise a solution such that the screw hole does not become clogged with shavings from the solid lubricant coating film. At this time, a byproduct formed from the scraped solid lubricant coating film does not necessarily migrate during and after tightening and loosening. 1810668 of 128 The above is what happens in a real well, and it is a very different point between the case of lubrication using the solid lubricant coating film and the case of lubrication using the lubricating compound. When evaluating a solid lubricant coating film in a laboratory test, using a short male member as in the case of lubrication with the lubricating compound, it is not necessarily possible to simulate the influence of a large and unbalanced load for the reason mentioned above. In the evaluation using a male member shorter than the one used in an actual well situation, it was found that the solid lubricant coating film is less likely to be scraped, and it is not possible to create a situation that simulates sticking behavior in the actual well. As described above, in the conventional evaluation using a short male member, a byproduct formed by chips from the solid lubricant coating film causes obstruction and seizing, or the byproduct is pressed against a mating surface again. As a result, it is not possible to simulate, for example, a situation where an effect similar to that of a lubricant coating film is maintained. That is to say, in the conventional evaluation using simply a 12 1810668 of 128 short male member, the evaluation of the solid lubricant coating film is inevitably lax, and when a physical property parameter of the solid lubricant coating film is determined, a region that should be unacceptable is wrongly evaluated as a suitable range. For this reason, inventors have discovered that, in reality, an appropriate interval is often described in the description of the previous conventional literature based on the loose assessment mentioned above. Furthermore, the inventor discovered that it is necessary to specify a set of parameters related to a solid lubricant coating film by conducting an evaluation under conditions similar to those encountered when an oil well pipe screw is tightened and loosened in an actual well, i.e., under the assumption that tightening and loosening are performed under a heavy and unbalanced load. To this end, the inventor has found it necessary to establish each definition after ensuring lubricity and to clarify the meanings of the upper and lower limits of a parameter according to the conditions of use in the actual well. That is to say, the inventor of this document has found it important to specify the upper and lower limits of a parameter in the 13 1810668 of 128 evaluation of a situation according to the actual well. In the present document, as described above, in the evaluation of a lubrication behavior to be confirmed in the lubrication of a screw for oil well pipes, conventionally, the tightening and loosening behavior is often evaluated with a screw wrench using a short male member and the number of tightening and loosening times. At this point, when a grease compound is used as a lubricant, the compound also shifts with the tightening and loosening. For this reason, when evaluating lubrication, there is no particular problem whether the lubrication is evaluated with a horizontal or vertical tap wrench using a short tap, and it is possible to assess the lubrication behavior. That is to say, a conventional grease compound can be evaluated even by performing a laboratory test using a short tap, even on a thread with a specific design, regardless of whether a base coat such as a chemically converted or galvanized coating is acceptable or not, and the comparison and evaluation of the compound itself. Meanwhile, there is a problem in evaluating the lubrication of the solid lubricant coating film as described above. Specifically, in the evaluation using a laboratory test 14 1810668 of 128, using only a short male member, does not simulate real-world well behavior, and the lubrication assessment is very lax. For this reason, there is the problem that even if the assessment using a short male member is acceptable in conventional laboratory testing, it does not necessarily mean that the assessment will be acceptable when tightening and loosening in a real well. Furthermore, since the lubrication of oil well tube screws differs from other lubrication behaviors in some respects, there is a problem that a definition with evaluation based on other lubrication conditions cannot be applied. In general, regarding lubrication behavior between two objects rubbing against each other, a situation is assumed where one object is stationary and the other is moving. Lubrication is assumed to begin from a state where the moving object is in close contact with the stationary object. Even when both objects are moving, lubrication typically begins from a state where both objects are in contact with each other. Meanwhile, oil well pipe screw lubrication begins from a state in which a male member screw (male screw) taps against a female member screw (female screw) due to screw play in a 15 1810668 of 128 initial stage of adjustment. Therefore, the screws are not in stable contact with each other until they are engaged to a certain extent. That is, in the lubrication of oil well pipe screws, the cases where the screws are heavily impacted and those where they are barely impacted are unevenly distributed, and there is a significant concern that the lubricant coating film will be damaged when the screws collide heavily. Furthermore, in lubrication after the screws are engaged, they slip under the influence of the lubrication in place. In particular, in a situation where hammering occurs until the screws mesh together, the conventional method using a grease compound involves the compound moving along with the screw's adjustment. This occurs during an initial tightening stage and a final loosening stage as the screws hammer together. Therefore, the effect on hammering is minimal. However, with a solid lubricant coating film, the film is directly affected by the unbalanced load from hammering and is easily damaged. This differs from the conventional method using a 16 1810668 of 128 fatty compound. Furthermore, in an actual well, the full weight of a male member bolt applied to a female member bolt during tightening and loosening exerts a significant influence. Additionally, due to the hammering described above, the load is not applied uniformly, and the male member tends to rotate eccentrically until the bolts mesh. For this reason, the solid lubricant coating film must be capable of withstanding a large, unbalanced load. A film that completely washes off or is almost entirely destroyed and lost cannot withstand the heavy load. An actual well is often operated with an oil well tube approximately 12 to 16 meters long.For example, an oil well pipe that is approximately 12 m (40 ft) long and has an outside diameter of 9-5 / 8 inches weighs about one ton. On an offshore platform, three pre-connected male member bolts are often fitted and used. Therefore, when using an oil well pipe with an outside diameter of 9-5 / 8 inches, a critical situation arises where a load of approximately three tons is applied to one side of the female member. In the lubrication of the well pipe screw 17 1810668 of 128 petroleum, it is necessary to have a lubrication that can withstand such a large and unbalanced load. As a result of several studies, the inventor has discovered that the important thing is to devise a solid lubricant and a binding resin taking into account how to suppress damage to a solid lubricant coating film under a high load and in a situation where there is hammering until the screws mesh together. Meanwhile, in the previous literature, it is difficult to say that a solid lubricant coating film is designed based on that viewpoint. In the present document, the inventor has discovered that the above finding is unique to a solid film of lubricating coating. In conventional lubrication using a grease compound, the viscous liquid grease also moves with the tightening and loosening of the component. Therefore, much of the influence of heavy or unbalanced loads is mitigated. For this reason, lubrication performance can be readily assessed even when evaluated using a horizontal wrench with a short male member or a vertical wrench with a short male member, as referenced in the literature above. Meanwhile, in the case of a behavior of 1810668 of 128 Lubrication of an oil well pipe screw using a solid lubricant coating film as described herein, the solid lubricant coating film is damaged and peels off, or inevitably, the solid lubricant coating film gradually wears away and thins out by scraping even when tightening until the screws engage or tightening after the screws are meshed. The peeled chips do not necessarily move with the tightening and loosening, unlike the grease compound. It has been found that the influence of the release of a byproduct (chips) derived from the scraped solid lubricant coating film in a space between a male member screw and a female member screw greatly affects lubrication. That is, if the space is clogged with chips, these can directly cause seizing.Meanwhile, there is also a case where the chips are pressed by a large load to reconstitute a film, and the film adheres again to one of the screws to improve lubrication. The inventor has then discovered that, in the evaluation using a short male member in a laboratory test, it is not possible to simulate either a high load situation or an unbalanced load situation that is 19 1810668 of 128 produce in an actual well. That is, in the evaluation that uses only a short male member, the amount of formation of a byproduct derived from the solid lubricant coating film is small. For this reason, lubrication performance is often mistakenly judged as acceptable, and a solid lubricant coating film design is frequently found to be poor only when the solid lubricant coating film is applied in an actual well. Furthermore, in a laboratory test, it's impossible to simulate what actually happens in a well without intentionally creating a situation where hammering occurs until the bolts engage. Meanwhile, it's unrealistic to conduct a test every time in a real well or a simulated well (a test site where a tighten-and-loosen test is performed by vertically positioning a full-size male fitting) using a full-size male fitting. The cost of the experiment is enormous, which is far from practical. For example, the latter requires a rental cost of around ten million yen or more per day, and in a solid lubrication test, the maximum number of tighten-and-loosen cycles is estimated at 20 to 30, which incurs a huge expense. In the previous bibliography, most of the 1810668 out of 128 evaluations of a solid lubricant coating film do not take this into account. That is, the evaluation of screw lubrication is not described particularly clearly, and there are many cases of applying a horizontal tap wrench, which is often used in laboratory tests, and a vertical tap wrench that simply uses a short tap. In this conventional evaluation, since the previous influence of a large load and an unbalanced load is eliminated, most of the evaluation results are generally considered good. Therefore, specifying suitable upper and lower lubrication limits using a solid lubricant coating film in these evaluation methods does not constitute a suitable range in a practical sense.As described above, even the conditions selected in the evaluation of a short male member in the conventional laboratory test include a condition under which lubrication is not good in an actual well and the technology is not specified. In the present document, document NPL 1 from another bibliography describes that a load of 510 kg is applied continuously to an upper end of a male member at all times both when tightening the screw and when loosening it, although this is not an examination of the lubrication behavior of a 21 1810668 of 128 solid film lubricant coating. Applying a 510 kg load may be intended to apply a weight corresponding to a full-size male member with a size of 7. As described above, in evaluating a solid film lubricant coating, it is important to simulate a large and unbalanced load, which is what occurs in an actual well. This is because a secondary phenomenon caused by a byproduct of a solid film lubricant coating greatly affects lubrication. However, when a method described in document NPL 1 from another bibliography is applied to a laboratory test, two problems arise. First, in the actual well, a load is applied corresponding to one to three full-size male members connected in a real well, but the application of 510 kg of weight corresponds only to a specific case where the male members are lightweight. That is, a large load is not necessarily simulated depending on the size of the male member. Secondly, an unbalanced load cannot be simulated. As can be determined from Figure 5 and similar figures in NPL 1 of other literature, particularly in the case of a premium joint, since there is not a single rotation before the 22nd 1810668 of 128 adjustment, document NPL 1 is intended to test lubrication performed from a state in which an initial adjustment position (starting point of adjustment) when hand-tightening is in a state where the threads are engaged with each other. Furthermore, the following problem arises when loosening continues in a state where a weight load is applied even at the moment of loosening, although this is not easily encountered. This means that during loosening, the weight acts as a balancer, and the screw loosens directly from a tight position without hammering. Therefore, the male member does not oscillate, and the occurrence of seizing during loosening, which happens in a real well, cannot be properly simulated. For this reason, depending on the situation, a lubrication characteristic may be misinterpreted as good. Therefore, it has also been found that a condition parameter related to a solid lubricant coating film must demonstrate excellent lubrication characteristics by performing a simulation that considers a lubrication state where the screws are not sufficiently engaged and lubrication after the screws are sufficiently engaged.23 1810668 of 128 coupled together. In this document, as described above, and within the scope of this description, BN is widely exemplified in many patent literature documents as a candidate for a solid lubricant. For example, documents PTL 1 and PTL 2 exemplify BN as a solid lubricant present in a solid film of lubricating coating. However, it is not necessarily possible to maintain lubrication simply by defining BN in a broad sense, given that the lubricity required to support lubrication behavior in an actual well can not be guaranteed as described above. Furthermore, documents in the previous patent bibliography exemplify the use of an epoxy resin as a binder resin, but there are very few documents in the patent bibliography that can clearly define the binder resin according to the quality of the epoxy resin. Documents PTL 3 to PTL 8 refer to a mixture of a prepolymer and a curing agent as an epoxy resin, or refer to an epoxy resin coating film formed by the prepolymer and the curing agent as an epoxy resin, and simply exemplify epoxy resin as one of the candidate materials. 24 1810668 of 128 Furthermore, the definition of epoxy resin is broad and it is not clear what epoxy resin specifies. Here, an epoxy group is a three-membered ring containing an oxycyclopropane oxygen (oxirane), which undergoes a crosslinking reaction with a selected, appropriate curing agent to become a resin. This means the three-membered ring opens and polymerizes. In short, the epoxy group is not present in a state where it has been converted into an epoxy resin and exists in a final form of polyether (including RO-R'), polyester (including R-COO-R'), polyhydroxy ether (including the -OH group and the ether group), polyhydroxylamine (including the -OH group and the amine group), or similar. The characteristics of a film also supersede the characteristics of the epoxy resin in the strict sense and the characteristics of the curing agent. Therefore, even if the epoxy resin in a broad sense does not specify any technology, the characteristics of the epoxy resin coating film are also determined by a combination of an epoxy resin agent in the strict sense as a prepolymer and a curing agent. Even if only the epoxy resin agent is mentioned in the strict sense, the characteristics of the epoxy resin coating film are not specified. With reference to the 25 Based on 1810668 of the 128 documents in the prior patent bibliography, it might be interpreted that any epoxy group could be widely applied, but in reality, this is not necessarily the case. In most cases, the high lubricity intended in this description cannot be guaranteed. To achieve the desired outcome, it is necessary to select an epoxy resin coating film with excellent lubricity in its final form. Furthermore, in documents from prior patent bibliography, a statement that an epoxy resin (possibly meaning an epoxy resin coating film as a final film formed by an epoxy resin and a curing agent) is contained in an amount of 00% is also ambiguous. As described above, in a combination of an epoxy resin in the strict sense and a curing agent, when the epoxy resin is represented by A and the curing agent is represented by B, the polymerization is carried out as ABABA... It is a rough rule of thumb for mixing epoxy resin that the mixture is made by combining the equivalent of one epoxy group of the epoxy resin in the strict sense with the equivalent of one amine when the curing agent is an amine-based agent, or the equivalent of active hydrogen when the curing agent is another curing agent that includes an amine. Therefore, even a statement 26 The 1810668 of 128 of the weight occupied by the epoxy resin film expresses a numerical value that varies considerably depending on the selection of the prepolymer and the curing agent. Simply limiting the expression of the epoxy resin content to a quantity of 00% does not specify the epoxy resin and does not specify the technology. In other words, a simple expression for an epoxy resin describes the use of an epoxy resin agent as the starting material (prepolymer), and the resulting polymer has a completely different structure depending on the curing agent selected. Therefore, unless the physical properties of an epoxy resin as a fully cured object are specified, the physical properties of an agent containing an epoxy group of a prepolymer are specified, a curing agent is specified, or a range of parameters that secondarily defines them is clearly specified, the technology is not being specified. Document PTL 3 selects a resin chosen from one or two options: an epoxy resin and a polyamide-imide resin, such as one formed on a Cu-Sn-Zn galvanized base. It is unclear what the epoxy resin described here refers to. That is to say, it broadly includes an epoxy resin with low lubricity. Documents PTL 4 to PTL 7 merely exemplify 1810668 of 128 an epoxy resin for a solid film of lubricating coating, and it is also difficult to specify this epoxy resin. PTL 8 describes an invention in which a silicon acrylic resin is formed on a UV-curable resin. This exemplifies an acrylic acid-modified epoxy resin as a candidate, among organic and inorganic resins, for a binder in the UV-curable resin. Furthermore, a main chain structure of an epoxy resin is formed, and one end of the main chain structure is acrylated. PTL 8 merely exemplifies the acrylic acid-modified epoxy resin and does not specify other information such as a curing agent for the epoxy coating film or its characteristics. Meanwhile, PTL 9 describes a photocurable acrylic resin coating film. PTL 9 specifies a film obtained by copolymerizing a photocurable (meth)acrylate resin with a (meth)acrylate monomer group using a trigger as a photopolymerization initiator. PTL 9 exemplifies, as a candidate, an epoxy along with a polyester, a polyether, and a polyurethane as the main chain structure, which forms an acrylate side chain. This invention expresses an acrylate (corresponding to the prepolymer of the present description) and a polymer (corresponding to the curing agent of the present description) using a parts-per-hundred resin (PHR) system and can accurately express the ratio and weight of an epoxy resin when a main chain structure is formed from the epoxy resin.The description in document PTL 9 is clearer than the definitions in documents PTL 3 to PTL 7. However, since the present description does not concern a photopolymerization resin but a film formed by heating (curing), document PTL 9 differs technologically from the present description. The present invention has been made in view of the foregoing points, and an object of the present invention is to provide a solid lubricant coating film capable of imparting excellent corrosion resistance, as well as lubricity, to an oil well pipe screw, even when the solid lubricant coating film is adopted for lubrication. Solution to the problem Unlike a situation where a lubricating material was conventionally selected based on the 29 1810668 of 128 previous lax evaluation, the inventor of the present aims at an oil well pipe and a threaded union for oil well pipes, each with excellent lubrication and rust-prevention characteristics, and an agent for manufacturing oil well pipes and threaded unions for oil well pipes. The inventor of the present aims at a composition obtained by adding BN as a solid lubricating component in a suitable proportion to a binder resin containing primarily an epoxy resin and the appropriate addition of another additive thereto. These films are formed by specifying a parameter to be able to withstand severe lubrication conditions such as those encountered in the lubrication of an actual oil well pipe screw, to which a large and unbalanced load is applied, as described above. That is to say, one aspect of the present invention is an agent for forming a solid lubricant coating film on a threaded portion of an oil well pipe, wherein a solid lubricant is dispersed in a binder resin, the binder resin containing a prepolymer and a curing agent, wherein the prepolymer is formed from one or more epoxy resins, contains 70 parts by weight or more of the prepolymer with respect to 100 parts by weight of the binder resin, the 30 1810668 of 128 epoxy resin that constitutes the prepolymer has an epoxy equivalent of 100 or more and 500 or less, the solid lubricant contains boron nitride or BN in an amount of 80% by weight or more, the BN has an average particle size of 10 μm or less, and the total weight of the solid lubricant is 0.1 times or more and two times or less the total weight of the binder resin. Another aspect of the present invention is an oil well tube having a lubricant coating film that includes a solid lubricant coating film on a threaded portion, wherein the solid lubricant coating film is formed by dispersing a solid lubricant in a binder resin, the binder resin containing an epoxy resin cured with a curing agent, containing 70 parts by weight or more of the epoxy resin relative to 100 parts by weight of the binder resin, the epoxy resin having an epoxy equivalent of 100 or more and 500 or less, the solid lubricant containing boron nitride (BN) in an amount of 80% by weight or more, the BN having an average particle size of 10 μm or less, and the total weight of the solid lubricant being 0.1 times or more and two times or less than the total weight of the binder resin. Advantageous effects of the invention One aspect of the present invention exhaustively specifies the elements (property parameters 31 1810668 of 128 physical properties) of a binder resin (main component: epoxy resin) and a solid lubricant (main component: BN) forming a solid lubricant coating film with reference to evaluation by a newly designed laboratory test capable of reproducing behavior in an actual well. As a result, an aspect of the present invention can provide an agent capable of forming a solid lubricant coating film (lubricant coating film) capable of imparting lubricity equal to or greater than that of a conventionally used lubricating grease, and lubrication and corrosion resistance comparable to a storage oxidation-preventing grease or a petroleum oxidation-preventing material even when the solid lubricant coating film is used for lubrication. For example, one aspect of the present invention can provide a threaded connection for oil well tubing that has lubricity and corrosion resistance during tightening, considering a corresponding well condition that may occur in an actual well environment. Note that the corresponding well condition is a situation in which a weight is applied from a male member to a female member from 32 1810668 of 128 above, a situation in which a load is applied obliquely due to a deviation from the center of the axis, a situation in which a load is often applied locally rather than uniformly, or similar. Brief description of the drawings Figure 1 is a diagram illustrating an oil well pipe and a threaded union for oil well pipes. Figure 2A is a diagram of a fitting chart in an actual well, and Figure 2B is a diagram illustrating an initial set position at that time. Figure 3A is a diagram of a fit chart in a conventional laboratory test, and Figure 3B is a diagram illustrating an initial set position at that time. Figures 4A and 4B are schematic diagrams of a fitting chart, where Figure 4A illustrates a real well case and Figure 4B illustrates a conventional laboratory test case. Figure 5 is a diagram used to explain a new laboratory test (heavy weight key test). Figure 6 is a diagram illustrating an established example of a heavyweight in the new laboratory test (heavyweight key test). Figures 7A and 7B are diagrams that illustrate the 1810668 of 128 structure of a coating film. Description of the forms of implementation The following will describe one embodiment of the present invention with reference to the drawings. Conventionally, in order to lubricate and prevent oxidation during storage, and to achieve both objectives, lubrication for tightening and loosening and long-term outdoor storage (prevention of oxidation) was achieved using different types of grease compounds or the same type of grease compound. On the other hand, in a threaded structure of the present embodiment, an epoxy resin coating film, the parameters of which are appropriately specified, is used as a bonding resin for one or both parts where a metal on the male screw side and a metal on the female screw side of a screw material are in contact with each other or with a portion thereof. A solid lubricant coating film is adopted in which BN is dispersed as a solid lubricant, the parameters of which are appropriately specified. As a result, the present embodiment aims to improve lubrication and impart corrosion resistance. Furthermore, the object also serves as an agent for forming the solid lubricating coating film. Additionally, the object (34 1810668 34 of 128) also comprises a film structure suitable for lubricating an oil well pipe screw, including a lubricating coating film obtained by combining a coating film of the present embodiment with a base layer and a film hardening layer on the other side, which does not form. Moreover, the present embodiment can be applied to a range where the lubricating coating film can be widely used to enhance lubrication and prevent oxidation of a metallic material as another application. The inventor studied the problems described above. As a result, the above problems can be solved by mixing an agent, forming a solid lubricant coating film on an oil well pipe screw, a method for confirming the formation of the solid lubricant coating film, and the like. The solid lubricant coating film of the present embodiment is obtained by a study in which an epoxy resin cured with a curing agent is used as the main component of a binder resin and boron nitride or BN is used as the main component of a solid lubricant. Configuration 1810668 of 128 The present embodiment is an invention relating to a coating film structure formed on a fitting surface of a threaded portion of an oil well pipe within an oil well pipe and a threaded oil well pipe fitting used for real oil / gas, and a structure having the coating film structure as a lubricant coating film. The present embodiment is characterized by a lubricant coating film comprising a solid lubricant coating film formed on the threaded portion of the oil well pipe, and the threaded structure of the oil well pipe and the oil well pipe threaded fitting are not particularly restricted. For the oil well pipe thread structure and the oil well pipe threaded fitting, only a known or novel threaded structure is required.Oil well pipe and threaded union for oil well pipes. The oil well pipe includes, for example, a female member 2 as a coupling and a male member 1 as illustrated in Figure 1. As illustrated in Figure 1, the threaded union of the oil well pipe includes the female member 2 as a coupling having a female screw 2a and the 36 1810668 of 128 male member 1 having a male screw 1a. A lubricant coating film including a solid lubricant coating film is formed on a contact surface (fitting surface 10) of a threaded portion on at least one of the female member 2 and the male member 1. Agent The following will describe an agent for forming the solid lubricant coating film in the present embodiment. The agent of the present embodiment is formed by dispersing a solid lubricant in a binder resin as a matrix component. The agent contains a binding resin, a solid lubricant, and a solvent component. The binding resin contains a prepolymer and a curing agent. The prepolymer consists of one or more epoxy resins. The prepolymer is present in an amount of 70 parts by weight or more relative to 100 parts by weight of the binder resin. The epoxy resin that constitutes the prepolymer has an epoxy equivalent of 100 or more and 500 or less. The epoxy resin that constitutes the prepolymer preferably has a glass transition temperature Tg of 100 °C or higher. 1810668 of 128 The solid lubricant contains boron nitride (BN) at a concentration of 80% by weight or more. The BN has an average particle size of 10 μm or less. The total weight of the solid lubricant is 0.1 times or more and two times or less the total weight of the binder resin. The solvent component is preferably contained in an amount of 30 parts by weight or more and 80 parts by weight or less with respect to 100 parts by weight of the sum of the total weight of the solid lubricant and the total weight of the binder resin, excluding the curing agent. A curing accelerator may be contained in the agent in an amount of 0 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the total weight of the epoxy resin that constitutes the prepolymer. The curing agent is a curing agent for curing an epoxy resin and consists of an amine-based curing agent, an anhydride acid-based curing agent, a phenol-based curing agent, or a latent curing agent. Currently, the epoxy resin that constitutes the prepolymer preferably has more than two epoxy groups (polyfunctional epoxy resin). The epoxy resin that constitutes the prepolymer preferably has six or 38 1810668 of 128 fewer epoxy groups. The epoxy resin that constitutes the prepolymer preferably has four or fewer epoxy groups. The agent having the above composition preferably has a viscosity of 20 mPa.sec or more and 2,000 mPa.sec or less. The agent of the present embodiment is applied to a screw fitting surface and dries to form a solid lubricant coating film10A (see Figure 7A). Lubricant coating film including solid lubricant coating film 10A The solid lubricant coating film10A is formed by dispersing a solid lubricant in a binder resin as the matrix component. The binder resin contains a prepolymer and a curing agent, and the prepolymer polymerizes with the curing agent and cures. The prepolymer consists of one or more epoxy resins. The prepolymer is present in an amount of 70 parts by weight or more relative to 100 parts by weight of the binder resin. The epoxy resin that constitutes the prepolymer has an epoxy equivalent of 100 or more and 500 or less. The epoxy resin that constitutes the prepolymer preferably has a glass transition temperature Tg of 39 1810668 of 128 100 °C or higher. The solid lubricant contains boron nitride (BN) at a concentration of 80% by weight or more. The BN has an average particle size of 10 μm or less. The total weight of the solid lubricant is 0.1 times or more and two times or less the total weight of the binder resin. The curing agent is a curing agent for curing an epoxy resin and consists of an amine-based curing agent, an anhydride acid-based curing agent, a phenol-based curing agent, or a latent curing agent. Currently, the epoxy resin that constitutes the prepolymer preferably has more than two epoxy groups (polyfunctional epoxy resin). The epoxy resin that constitutes the prepolymer preferably has six or fewer epoxy groups. The epoxy resin that constitutes the prepolymer preferably has four or fewer epoxy groups. The 10A solid lubricant coating film of the present embodiment has a hardness of, for example, 3H or more. The 10A solid lubricant coating film has a thickness of, for example, 10 μm or more and 150 μm or less. The lubricant coating film of the 1810668 of 128 present embodiment may have a base layer 10B between a fitting surface of a threaded portion and the solid lubricant coating film 10A (see Figure 7B). The base layer 10B is formed, for example, by a chemically converted layer or a galvanized layer. The lubricant coating film described above forms on a mating surface of a threaded portion of at least one of the female and male members. Determination of each definition The inventor has found that the important thing to solve the above problems is to control the following four sections ((a) to (d)) and the matters related to them at appropriate intervals. (a) Design a suitable new laboratory test that simulates the tightening and loosening in an actual well, specifying the upper and lower limits of each parameter for a solid lubricant coating film through a method of the new laboratory test, and specifying a suitable interval thereof. (b) Specify an optimal BN range with reference to the assessment by laboratory testing in (a). (c) Specify an optimal range of a value of 1810668 of 128 physical properties of an epoxy resin using the definition in (b). (d) Specify further the appropriate intervals related to these. Here, the appropriate method for simulating tightening and loosening in a real well is a method for simulating the tightening behavior that occurs when a wellhead pipe screw is tightened in an actual well. Using this, the upper and lower limits of a parameter in the present embodiment are confirmed, and a suitable range is determined. The lubrication state of an oil well tubing screw is divided into two stages in both the laboratory test and an actual well. Stage 1 is the lubrication during tightening and loosening when the screws are not engaged, and Stage 2 is the lubrication during tightening and loosening when the screws are engaged. Stage 1 corresponds, for example, to region (x) in a torque diagram in Figures 4A and 4B. Stage 2 corresponds, for example, to regions (y) and (z) in Figures 4A and 4B. The first (stage 1) is eliminated if the screw is tightened to a point where the screws mesh together by hand or similar means at the time of starting to tighten the screw (example: Figures 3A and 3B). Without 42 1810668 of 128 However, in many actual wells, simply inserting a male member into a female member for tightening is defined as a starting position for tightening. Alternatively, from that point onward, tightening the screw by only rotating it several times to secure it so that no cross-threading occurs is defined as a starting position for tightening. That is, in many actual wells, it is common to begin tightening and loosening from a situation where the screws are not engaged (e.g., Figures 2A and 2B). Note that cross-threading refers to a situation where the screw is tightened with threads at different levels or slips back to the original thread positions in the process of tightening. In stage 1, a wrench tightens and loosens the screw at a high speed between 5 and 20 rpm. As the screw is tightened continuously, the screws begin to mesh together, and the process changes to stage 2. This change slightly increases the torque, and from then on, the tightening is performed slowly at a speed of between approximately 0.5 and 2.0 rpm. To loosen, the tightening procedure is reversed. These procedures are carried out similarly when a conventional grease compound is used as a lubricant or when a coating film of solid lubricant is formed, as in the present embodiment. As a condition for placing a screw in an initial position, certain behavior is important to create the tapping. As a condition for the established position, it is important that one to three or more threads are exposed with respect to a female member screw at the time of initially tightening a male member screw when considering the behavior of a joint. Figures 2A and 2B Figures 2A and 2B are examples simulating a real well as it is. Specifically, Figures 2A and 2B are fitting tables (pair turning diagrams) when a fitting test is performed using a male member of approximately 12 m (40 ft) in actual length as the male member and using a solid lubricant coating film for lubrication. The test conditions will be described in Figure 2A. As an example, a film obtained by dispersing MoS2 as a solid lubricant in a polyamideimide (PAI) binder resin is used as a solid lubricant coating film. Figures 2A and 2B are simulation examples of a situation that often occurs in a real oil / gas field. That is to say, this is an example in the 44 1810668 of 128 states that the adjustment begins from a situation where the screws are not sufficiently engaged, as illustrated in Figure 2B as the initial adjustment position at the start of the screw adjustment. That is, as illustrated in Figure 2B, this is an example where the adjustment begins from a state in which approximately half of the male member screws are exposed at the start of the initial adjustment. The state in which the screws are not engaged is not due to intentional failure to hand-tighten them. When attempting to insert the male member screw into a female member screw by hand-tightening, the male member screw inevitably stops halfway. This means that the screw cannot be tightened further by hand.A heavy, long male member is not exactly vertical relative to the female member screw, unlike in a theoretical case. When viewed from below, the male member is often slightly bent and cannot be tightened further by hand. The male member used is a JFELIONTM 9-5 / 8" 3.5" No. Q125 bolt that is approximately 12 meters (40 feet) long. Figure 2A is a diagram of when a joint is tightened while the male member is suspended from a crane along its entire length. 1810668 of 128 of a drilling rig. It can be seen that the example of the torque diagram in Figure 2A is a situation that often occurs in an actual well. What is notable in Figure 2A is a region prior to a point where the torque continuously increases (the number of rotations is from 0 to approximately 6.3 rotations, corresponding to stage 1). In this region, the torque should not, in principle, be sustained, but in reality, as illustrated in Figure 2A, it can be confirmed that a peaked torque tends to be sustained, often irregularly. This suggests that the male member screw is irregular and is locally in contact with the female member screw as it rotates. This is a situation that occurs in actual fitting. This means that the destruction or detachment of a solid lubricant coating film is inevitable to some extent, depending on the design or optimization of the solid lubricant coating film. What is notable here is that the graph in Figure 2A does not intentionally create the worst state as a condition, but is a torque-turn diagram for a very common sample with a solid film of lubricant coating. Figures 3A and 3B Figure 3A is a pair turning diagram when 1810668 of 128 uses the same solid lubricant coating film as in Figures 2A and 2B and the adjustment is made with a vertical threading wrench. In Figures 3A and 3B, a male member is adopted that has the same outside diameter, thickness, and screw type as in Figures 2A and 2B, but a short male member is adopted that has a length of about 1 meter. Figure 3A is a fitting chart (torque turning diagram) when the fitting starts from a state where the screws are sufficiently engaged. That is, Figure 3A is a fitting chart (torque turning diagram) when approximately one to three male member threads are exposed at the start of the initial fitting, as illustrated in Figure 3B. The condition in Figure 3A is also a condition that is often used at the time of adjustment in a conventional laboratory test, and is a case in which a screw is adjusted until the screws hook together by hand and then the adjustment test is performed. In Figure 3A, it is necessary to pay attention to a point where the unit of the horizontal geometric axis is different from that of Figures 2A and 2B. In Figure 3A, the adjustment with a wrench 1810668 of 128 starts from a state in which manual adjustment is made to a state in which the screws are coupled together and, therefore, no point-shaped torque is observed as seen in Figure 2A. That is, it has been discovered that the examination of a lubrication characteristic of the solid lubricant coating film in only stage 2 without going through stage 1 can be understood as corresponding to the conventional laboratory test. As can be seen in Figures 3A and 3B, in the conventional laboratory test, the destruction of the solid film of lubricating coating, which often occurs in stage 1, does not take place, and the tightening occurs from a state in which the screws are sufficiently engaged with each other, that is, from a region where the screw surfaces begin to make contact. Figures 4A and 4B Figures 4A and 4B illustrate Figures 2A and 3A in a state in which Figures 2A and 3A can be easily compared to each other. Figure 4A is the case of Figures 2A and 2B, and Figure 4B is the case of Figure 3. According to the inventor's study, considering use in an actual well, for an ideal solid lubricant coating film, the coating film 48 1810668 of 128 of the solid lubricant coating film is preferably not destroyed in region (x) in Figure 4A, and concerns about destruction and peeling are preferably minimized. Alternatively, a tip may be allowed to be in a slightly vertical position. Furthermore, it is preferable to design the solid lubricant coating film such that a byproduct derived from the destroyed or peeled solid lubricant coating film does not obstruct the screw hole during tightening and loosening, even in a situation where the solid lubricant coating film is damaged and, conversely, adheres well to the screws to aid lubrication. For this purpose, it is important to control the quality of the solid lubricant coating film so that it hardens to a predetermined hardness or higher. As a method for evaluating hardness, one can use pencil hardness, which is a hardness index based on scratching. However, when forming a lubricant coating film, it is preferable to suppress the viscosity of the coating agent to a degree low enough that the coating can be applied by spraying or brushing, and that the agent can be applied uniformly throughout the film thickness. Furthermore, during a heating stage (during a curing stage), the 1810668 of 128 constituent components of the solid lubricant coating film are preferably formed inside a single, smooth film with surface tension by a liquid-rubber behavior. Furthermore, in a laboratory test evaluation method of the present embodiment, it is preferable to perform the evaluation by means of a new laboratory test having the following conditions (1) to (6) in order to simulate fit and misfit behavior in an actual well. Note that an example of the actual laboratory test apparatus configuration will be described later. (1) A heavy weight having a weight corresponding to between 1 and 3 actual-sized male extremities is placed on top of a short male member. (2) As initial adjustment positions of the short male member screw and a female member screw, about half of the male member threads are fixed, e.g., half of the male member threads are exposed, i.e., the short male member screw is loosely fixed, and a fit and looseness test is initiated. (3) From state (2), the adjustment is initiated with a high-speed rotation of 15 rpm, and tightening continues until a torque of a predetermined value or more is detected. 1810668 of 128 (4) When the torque increases, the rotation is temporarily stopped and the adjustment is made by rotating at a low speed of 1 rpm (completing the adjustment). (5) The loosening is done in a reverse step. (6) When the screw is completely removed from the short male member, one surface of the male member thread and one surface of the female member screw (the air-blown portion is observed depending on the situation) to determine whether or not an abnormal event, such as seizing, has occurred. If there is no problem, step (2) and subsequent steps are repeated. If slight seizing occurs in a threaded part (seizing in a sealed part is unacceptable, regardless of the degree of seizing), the threaded portion is modified and, if necessary, a solid lubricant is applied to repair the threaded part, and step (2) and subsequent steps are repeated. In the present embodiment, a lubrication characteristic of the solid lubricant coating film was re-evaluated based on this evaluation method, and suitable conditions for the solid lubricant coating film were selected (see Examples). Here, it is acknowledged that the laboratory test The conventional lubrication characteristic described in 1810668 of 128 is lubrication after the screws are engaged (situations in region (y) and region (z) in Figures 4A and 4B), as determined from the results of numerous tightening and loosening tests (laboratory tests) in the literature above. The conventional laboratory test is considered to have superiority and inferiority characteristics based on lubrication after the screws are engaged, i.e., a state in which the solid lubricant coating film is satisfactory, and a state in region (x), i.e., a situation in which the torque spikes.That is to say, the conventional laboratory test appears to involve tightening and loosening the screws from a position where they were sufficiently tightened by hand to a point where they were engaged in the evaluation using a short male member and a horizontal or vertical wrench. In PTL documents that clearly describe the number of tightening and loosening cycles, it is stated that the number of cycles can be 10 for a small diameter screw size when tightening in an actual well. However, both in the evaluation with a... 1810668 of 128 short male member as in the evaluation in an actual well, if the initial fitting position (fitting start position) starts from a position where the screws are sufficiently engaged with each other, the number of times it is tightened and loosened appears to be a possible number. Meanwhile, in the literature above, it is sometimes described that the number of tightening and loosening cycles can be between 15 and 20 based on a solid lubricant coating film for a large diameter of 9-5 / 8 or 13-3 / 8. However, when tightening and loosening in an actual well—that is, when a full-size male member has its own weight and the tightening and loosening are performed from a state where the bolts are not engaged—it appears that this number is nearly impossible in a large diameter case using a solid lubricant coating film. It goes without saying that simulating a real-world tightening and loosening situation is important for evaluating the lubricity of the solid lubricant coating film. In a situation where hammering occurs until the screws engage, it is necessary to perform an evaluation based on a state in which the solid lubricant coating film is peeling or damaged. In the present embodiment, several definitions are made with reference to the results of a 53 1810668 of 128 new laboratory test that can be evaluated taking into account such conditions. The conditions for the solid lubricant coating film of the present embodiment are defined with reference to the results of the new laboratory test on the premise that the solid lubricant coating film is a solid lubricant coating film in which BN as the main component of a solid lubricant is dispersed in a binder resin containing an epoxy resin film as the main component. In addition, each definition will be described in detail. Basic composition of the solid lubricant coating film, film thickness, and film structure In the present embodiment, the solid lubricant coating film is formed by dispersing a solid lubricant containing primarily BN in an epoxy resin-cured coating film. In particular, a pencil hardness of 3H or higher is preferable. In the present embodiment, BN is selected as the main component of the solid lubricant to obtain a film capable of achieving high lubrication and maintaining that high lubrication even at high temperatures. That is to say, in 54 1810668 of 128 When tightening and loosening, a male member screw and a female member screw rub together to generate frictional heat. BN is selected to maintain sufficient lubrication even at this time. In the present embodiment, an epoxy resin coating film is selected as the binding resin. The epoxy resin coating film is selected because it is easy to handle and less expensive than other agents. Furthermore, the epoxy resin coating film is selected because it is a well-balanced material, and it facilitates obtaining the desired hard film of the present embodiment, or a film with excellent heat resistance, by selecting a suitable epoxy resin and curing agent.Furthermore, the epoxy resin coating film is selected because the epoxy resin coating film has many excellent advantages, for example, the epoxy resin coating film is excellent in adhesion / bonding, can be formed without a base layer (chemically conversion treated Mn phosphate, galvanized film or similar), and does not shrink significantly during curing. 1810668 of 128 Regarding the coating film thickness, a film thickness of at least 10 μm is required to maintain lubrication and corrosion resistance. The upper limit for film thickness is set at 150 μm, although it is difficult to state a definitive upper limit because the gap between the female and male threads varies depending on the type and design of the oil well pipe bolt. Here, since many oil well pipe bolts are designed so that the upper limit of the thread clearance is around 100 μm to 200 μm, the upper limit of the film thickness is specified at 150 μm or less. The film thickness is, most preferably, between 10 μm and 50 μm. There may be a clearance of between 100 μm and 200 μm between a thread and a fillet root of a male and female bolt, as described above. However, the clearance between an insert and a flank on a male and female bolt, and the clearance between a load and a flank, change between tightening and loosening. When the clearance narrows, the film is substantially in close contact. Therefore, the film thickness is, preferably, small, and the film thickness 56 1810668 of 128 is preferably between 10 μm and 50 μm. However, film thickness refers to the film thickness as it was formed before the initial tightening. During tightening and loosening, the bonding resin is actually scraped off slightly, and the film thickness applied at room temperature actually results in a thin film due to this compression. Therefore, even if there is a thickness equal to or greater than the assumed gap on a threaded surface, a problem such as seizing does not occur for this reason. Epoxy resin can be formed directly onto a threaded surface, or it can form a base layer between the threaded surface and the epoxy resin. Examples of base layers include a chemically converted layer with manganese phosphate and a metal-plated layer, including a copper-plated layer. Although there are varying opinions and it is difficult to say that it is theoretically determined, an OH group in epoxy resin can form a film that has strong hydrogen bonding or similar adhesion to a metallic surface. The aforementioned OH group is an OH group in the epoxy resin film, such as polyhydroxy ether or polyhydroxylamine. For this reason, even when there is no surface-treated base layer, or even when there is a surface-treated layer (the use of a 57 can be expected). 1810668 of 128 anchoring effect or similar in some cases), it is considered that there are few problems with adhesion. Solid lubricant The present embodiment relates to one in which a solid lubricant containing boron nitride (BN) as the main component is dispersed in a binder resin. Solid lubricant A range of BN as a solid lubricant has been identified that has a significant lubrication-enhancing effect using the aforementioned new laboratory test method. Specifically, by studying various lubricating coating films in which BN is dispersed in an epoxy resin as a binder, using the aforementioned new laboratory test method, the range of BN that has a significant lubrication-enhancing effect has been identified. Here, a highly lubricated state cannot necessarily be created using boron nitride or BN as a solid lubricant. Regarding BN, it has been found that when a BN-based component system is used that contains BN in an amount of 80% or more with respect to the total weight of the solid lubricant as the denominator, and the BN has an average particle size between 0.1 μm and 10 μm, a noticeable effect is obtained. 1810668 of 128 The particle size of the BN is preferably as small as possible. However, since the lower limit of the average particle size of commercially available BN is 0.1 μm, the lower limit of the BN is set at 0.1 μm. An upper limit was experimentally determined, and it was confirmed that excellent lubricity is exhibited up to 10 μm. In the case of a lubricant formed by overlapping sheets, or when the average particle size is greater than 10 μm, a strong crystalline structure on a two-dimensional surface, such as BN, achieves lubrication by forming a sheet-like structure. At this point, adjacent sheet structures extend and overlap each other. As a result, a white, ribbon-like byproduct is formed. Since this byproduct is thick, there is a high tendency for the screw clearance to become clogged with it, thus increasing the risk of seizing. Generally, the smaller the average particle size, the less overlap occurs, and the formation of the white, ribbon-like byproduct can be suppressed. Therefore, high lubrication is considered achievable. Based on this, they are defined as constituent elements of the present invention, containing BN 59 1810668 of 128 in an amount of 80% or more with respect to the total weight of the solid lubricant as the denominator, and the BN having an average particle size of 10 μm or less. The meanings of these definitions are as follows. A highly lubricated state cannot necessarily be created with boron nitride (BN) in a broad sense. This means that optimal and remarkably high lubricity can be expected when using BN within this range, so that the BN is dispersed in the epoxy resin as a binder resin in the present embodiment, in an oil well pipe screw operating environment, in order to achieve high lubricity. Here, the BN has a strong crystalline structure in a two-dimensional sheet surface direction, similar to MoS2 and graphite, and the two-dimensional sheet surfaces are connected by a weak intermolecular force in the geometric Z-axis direction. When a force is applied to the BN, its sheet surfaces slide past each other to achieve lubrication. In the present embodiment, the statement that the BN content is 80% or more means that BN is a major component of the solid lubricant. The BN content is specified as 80% or more, meaning that even if another solid lubricant is present in a proportion of 20% or less, there is no 60 1810668 of 128 bad influence on a BN-based design. In the present embodiment, the higher the BN content as a constituent of the solid lubricant, the better. Since lubricity can be impaired by the mixing of other components, the BN content is set at 80% or more as the acceptable range for BN as the main component. The BN content is preferably 90% or more. The smaller the average particle size of the BN, the better. Note that the average particle size is a parameter that represents a particle size within a 50% integrated range in a particle size distribution obtained using a laser diffraction / scattering method or similar. The upper limit for the average particle size of the BN is set at 10 μm because when the average particle size of the BN is greater than 10 μm, there is a significant concern that the binder resin film will be destroyed and detach completely due to the large particle size of the BN. That is, the BN that has detached from the solid lubricant coating film is pressed during tightening and loosening to form a byproduct. However, when each BN with a sheet-like structure is deformed to slide on a sheet surface, the BNs with similar sheet-like structures between 61 1810668 of 128 do overlap, and eventually, a strong, white ribbon-like byproduct is formed. Since this byproduct is thick, it cannot move after tightening and loosening, increasing the risk of seizing. Generally, the smaller the average particle size of the BN, the less overlap occurs, and the formation of the white ribbon-like byproduct can be suppressed. As a result, high lubrication is considered achievable. Currently, since the lower limit of the average particle size of commercially available BN is 0.1 μm, the lower limit of the BN is considered to be around 0.1 μm. However, the present embodiment also includes BN having an average particle size of 0.1 μm or less, obtained through technological development. Furthermore, industrial types of BN include flaked BN and granulated BN. In the present embodiment, any type can be used. The BN is preferably granulated. A solid lubricant other than BN may be blended in, provided its content is 20% or less, as described above. Any other type of solid lubricant may be used, and examples include polytetrafluoroethylene (PTFE: 62 1810668 of 128 Teflon (registered trademark), graphite, fluorographite, M0S2, WS2, melamine cyanurate (MCA), mica, and talc. An oil-based substance may be blended as a solid lubricant, provided its solid lubricant content is 20% or less. For example, carnauba wax, perfluoropolyether (PFPE) oil, chlorotrifluoroethylene (CTFE) oil (low chlorotrifluoroethylene polymer), or similar substances may be blended. The lubrication of the BN may be maintained or improved. Epoxy resin that constitutes a binding resin In the present embodiment, an epoxy resin film is selected as the binding resin. In the present embodiment, an epoxy resin is selected that contains an epoxy resin in an amount of 70 parts by weight or more relative to 100 parts by weight of a total amount of a resin other than the epoxy resin that constitutes the binder resin and the epoxy resin as a prepolymer. Furthermore, the epoxy resin is selected to have an epoxy equivalent of 100 or more and 500 or less. Furthermore, in the present embodiment, the solid lubricant coating film is preferably a hard film. To achieve this, a curing agent is selected and a design is implemented to obtain an epoxy resin coating film that 63 1810668 of 128 has a strong three-dimensional cross-linked structure. For example, an epoxy resin is selected as a prepolymer that has more than two epoxy groups (polyfunctional epoxy), along with a curing agent that has more than two functional groups, or an epoxy resin that has more than two epoxy groups and a curing agent that has more than two functional groups. This makes it possible to form a three-dimensional copolymerized film and confer heat resistance. The expression "heat resistance," as used herein, means that when even slight seizing occurs when tightening the screw, a portion where strong friction occurs can generate heat, and the epoxy resin is prevented from being destroyed by heat generation. The epoxy equivalent is selected to be in the range of 100 to 500 because the film hardens as the crosslinking density increases. This also means increasing the concentration of epoxy groups, which is done to suppress the epoxy equivalent to a low value, in other words. Here, when the epoxy equivalent exceeds 500, the film quality is inevitably soft. Furthermore, it is difficult to impart the heat resistance that can be exhibited during tightening and loosening. The lower limit value of the epoxy equivalent is set at 100 because the lower limit value is 64 1810668 of 128 specifies an approximate limiting value for a distributed epoxy resin. When an epoxy material having a lower epoxy equivalent is formed, the epoxy equivalent is not limited to 100, and in the present embodiment, the selection of an epoxy material having a lower epoxy equivalent is included. The term epoxy resin, as used herein, means an epoxy resin as a coating film obtained by the copolymerization of an epoxy resin (strictly speaking, as a prepolymer) with a curing agent. Epoxy resin is selected because it offers excellent advantages, such as superior adhesion, water / moisture resistance, and heat resistance, and it does not shrink significantly during curing. Furthermore, epoxy resin is chosen because it is a well-balanced material; for example, it is easy to work with and less expensive than other curing agents. Specifically, among the binder resins, the present embodiment aims to create a hard film, selects a suitable curing agent, and selects a hard epoxy resin coating film having a pencil hardness of 3H or higher. The binder resin is a matrix containing a BN 65-based solid lubricant. 1810668 of 128 and forms a major composition of the solid lubricant coating film together with BN. One of the reasons why a hard epoxy resin film is favorable for lubricity (tightening and loosening characteristics) is the one mentioned below. In the lubrication of an oil well pipe screw using a solid lubricant coating film, the hammering action until the screws mesh together tends to damage the solid lubricant coating film considerably. However, the solid lubricant coating film tends to resist damage. Even after the screws mesh, they are tightened while the weight of a typical oil well pipe screw, approximately 8 to 12 meters long, is applied. For this reason, a structure can inevitably develop where lubrication is maintained while the solid lubricant coating film is slightly scraped.Therefore, if the pencil hardness is not set to 3H or higher, the solid lubricant coating film is greatly damaged, and there is a real situation where the solid lubricant coating film can only withstand zero to several times tightening and loosening. Based on the above, in the present 1810668 of 128 embodiment, the epoxy resin in the strict sense is contained in an amount of 70 parts by weight or more in the resin-forming binder relative to 100 parts by weight of the sum of the epoxy resin group in the strict sense, excluding the weight of a curing agent component and a lubricating component as another component, thus making the epoxy resin a principal component. Furthermore, an epoxy resin having an epoxy equivalent of 100 or more and 500 or less is selected. This is to increase the number of crosslinking points (increase the crosslinking density) to form a strong coating film. Even if an epoxy resin, strictly speaking a prepolymer, has only two epoxy groups, a three-dimensional structure can form. However, a polyfunctional epoxy resin with more than two epoxy groups is preferable. Polyfunctional epoxy means that the number of epoxy groups in a molecule is, on average, greater than two. This means that the number of epoxy groups is higher than that of a normal epoxy resin containing only two epoxy groups. Since polyfunctional epoxy can crosslink three-dimensionally in a reaction with the curing agent, the film quality can be improved (pencil hardness can also be increased) because the crosslinked network... 1810668 of 128 is strengthened when it is (co)polymerized. At the same time, the multifunctional epoxy has a higher glass transition temperature (Tg) and therefore excellent heat resistance. Note that a multifunctional epoxy preferably has a Tg above 100 °C as a suitable range for excellent heat resistance. The number of epoxy groups in a molecule is preferably between 2 or more and 6 or fewer, and more ideally, between 2 or more and 4 or fewer. This is to suppress delamination and prevent complete destruction due to the hardening of the solid lubricant coating film during the initial tightening and final loosening stages. During the initial tightening and final loosening stages, the screws do not engage properly, resulting in hammering, and the solid lubricant coating film is easily destroyed.There is significant concern that an epoxy resin with more than six epoxy groups may cause steric hindrance in the reaction between the epoxy group and the curing agent. In this case, copolymerization between the epoxy resin and the curing agent may take too long, and a hard film may not necessarily be achieved. Therefore, an epoxy resin with six or fewer epoxy groups is used. Meanwhile, even when using a bifunctional epoxy resin and a 68-unit curing agent... 1810668 of 128 curing agents, which have more than two functional groups, form a three-dimensional network structure, thus improving film quality. When both the epoxy resin and the curing agent are multifunctional, a stronger three-dimensional network is formed, which is preferable. An epoxy equivalent of 100 or more and 500 or less is specified as a suitable range. The epoxy equivalent is a value obtained by dividing the molecular weight of an epoxy resin (strictly speaking, as a prepolymer) by the number of epoxy groups. The epoxy equivalent can be considered as a molecular weight bound and restricted at a crosslinking point. The epoxy equivalent is specified within the range above because the lower the epoxy equivalent, the greater the crosslinking density and the greater the hardness. The prepolymer is exemplified. Examples of a bifunctional epoxy resin as a prepolymer include a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, and a bisphenol C-type epoxy resin. Examples of a polyfunctional epoxy resin having more than two functional groups include a novolac phenol-type compound, a novolac cresol-type epoxy compound, an aliphatic epoxy compound, a glycidyl ester-type epoxy resin, a glycidyl amine-type epoxy resin, a polyfunctional phenol-type epoxy resin compound, and 69 1810668 of 128 groups derived from them. These can be used alone or in combination. In the present embodiment, the epoxy resin in the strict sense is contained in an amount of 70 parts by weight or more in the resin-forming binder relative to 100 parts by weight of the sum of the epoxy resin in the strict sense, excluding the weight of a curing agent component and a lubricant component as separate components. This makes the epoxy resin a principal component. Ideally, the multifunctional epoxy resin is contained in an amount of 70 parts by weight or more relative to 100 parts by weight of the total weight of the epoxy resin in the strict sense. The first expression stating that the epoxy resin is contained in an amount of 70 parts by weight or more refers to what follows. The present embodiment aims at a hard film having a pencil hardness of 3H or higher, as described above. However, when a hard film is selected with an epoxy resin, brittleness often occurs simultaneously. Therefore, the expression stating that the epoxy resin is contained in an amount of 70 parts by weight or more means that it may contain another resin binder component, provided that the content of the other resin binder component is less than 30 parts by weight. To obtain a hard film, it is preferable to reinforce a three-dimensional network structure. Therefore, the content of the multifunctional epoxy resin (having more than two epoxy groups) is specified as 70 parts by weight or more.A thermoplastic resin may be selected as another component of the binder resin on the condition that the thermoplastic resin content is less than 30 parts by weight to prevent the binder resin formed by the epoxy resin from becoming too hard and brittle. The epoxy resin coating film, as the final material formed by (co)polymerization between the prepolymer and the curing agent, is inevitably brittle when hardened. To avoid this brittleness, a suitable agent is prepared for a monopolymer epoxy resin. Alternatively, a resin obtained by introducing a strong structure, such as a benzene ring or a molecular chain, into the backbone of an epoxy resin can be used. In some cases, a flexible chain can be introduced by rubber modification, fluorene modification, urethane modification, or similar modifications to the epoxy resin itself. This aims to improve toughness by introducing a point of reduction of internal stress in the film. 1810668 of 128 epoxy resin coating. Alternatively, the adjustment can be made by introducing a thermoplastic polymer in an amount of less than 30 parts by weight. This is intended to improve toughness by a cavitation or similar effect through the introduction of a thermoplastic polymer into the epoxy resin coating film. The thermoplastic polymer as used herein is not particularly restricted. As a thermoplastic polymer, it is permitted to contain, for example, polyacetal (POM), polycarbonate (PC), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE) (Teflon (registered trademark)). Note that the weight of the epoxy resin mix is ​​expressed in parts by weight rather than weight percent or similar for the following reason. Basically, in each epoxy resin prepolymer, an active hydrogen reacts with an epoxy group. Note that when the curing agent is an amine, one active hydrogen corresponds to almost one amine equivalent. Therefore, the weight of the mix is ​​determined by the epoxy equivalent of each prepolymer and the active hydrogen equivalent of the curing agent. Thus, the number of combinations between the epoxy resin and the curing agent is infinite. On the other hand, the weight of the epoxy resin mix is ​​proportional to the amount of epoxy resin after curing. For this reason, 72 The mixing ratio in 1810668 of 128 is unclear unless the expression is made using the weight of the epoxy resin as a prepolymer. Therefore, the weight of the epoxy resin is defined using parts by weight. However, in the case of a latent curing agent, the curing agent itself is unnecessary in a true sense. For example, this is a case where the epoxy resin itself, as a prepolymer, self-polymerizes through a catalytic anionic polymerization reaction of the latent curing agent. Examples of latent curing agents include imidazole, a tertiary amine, dicyandiamide, and low-temperature, fast-curing polymercaptan. When these latent curing agents are used, polymerization does not necessarily occur in a 1:1 ratio. However, in this specification, the definition is made using the weight parts of the epoxy resin as a prepolymer as a parameter to specify the characteristics of the epoxy resin. Here, it is preferable to form a coating film by applying an agent with a brush or by mechanically applying an agent at room temperature. Therefore, the agent must be liquid within a room temperature range. Furthermore, for convenience, the agent is preferably a single-liquid type rather than a two-liquid type. Additionally, 73 1810668 of 128 agent is preferably treated with heat and therefore copolymerizes to form a film that does not solidify immediately after being applied to the surface of a screw. If the agent's viscosity is too low, it will drip down the thread immediately after being applied. With a female screw, there is a significant concern that the agent may pool and remain at the six o'clock position, increasing the film thickness only in that area. Similarly, with a male screw, drops of the agent may fall at the six o'clock position, making it difficult to achieve homogeneity before heat treatment. Conversely, if the agent's viscosity is too high, it cannot be applied with a brush. Furthermore, spray application is unsuitable due to clogging and other issues. Therefore, a preferred viscosity range for the agent is between 200 cps and 900 cps (0.2 Pa·s and 0.9 Pa·s).However, even when the viscosity of the agent itself is too high beyond this range, the present embodiment includes an agent with reduced viscosity achieved by adding a reactive diluent. Curing agent for epoxy resin. 1810668 of 128 In the present embodiment, the expression curing agent means an agent that contributes to a crosslinking reaction between the crosslinking groups of the epoxy resin in a strict sense as a prepolymer. The curing agent is not particularly restricted, and any curing agent generally known as an epoxy resin curing agent can be used. The curing agent is not specifically specified as long as the hard epoxy resin coating film described above, having a pencil hardness greater than 3H, is achieved through strict selection of the epoxy resin and the curing agent. Examples of curing agents include, as amine-based curing agents, an aliphatic amine, a polyether amine, an alicyclic amine, and an aromatic amine. An epoxy resin formed with these curing agents is polyhydroxyamine. Examples of an anhydride-based curing agent include dodecenylsuccinic anhydride, polyadipic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, and phthalic anhydride. An epoxy resin formed with these curing agents is polyester. Examples of phenol-based curing agents include dihydroxyphenyl-based curing agents, and an epoxy resin formed with these curing agents is polyhydroxy ether. 1810668 of 128 Examples of latent curing agents include an amine-based curing agent such as a tertiary amine or aromatic amine, imidazole, and a halogenated boron amine complex, and examples of an epoxy resin include polyether. The amount of curing agent, excluding latent curing agent, is based on mixing a quantity defined by the active hydrogen equivalent of each curing agent with the epoxy equivalent of the epoxy agent in the strict sense. Note that when the curing agent is an amine, the active hydrogen equivalent of each curing agent corresponds to approximately one amine equivalent. Meanwhile, since the amount of latent curing agent to be added changes with the reaction rate, it is only necessary to determine the appropriate mixing quantity each time. In the present embodiment, a hard coating film is formed with a pencil hardness of 3H or higher. Therefore, it is preferable to use a thermosetting curing agent rather than a room-temperature curing agent. With the first curing agent, the coating film has a low glass transition temperature (Tg) and a soft film quality. With the latter curing agent, the coating film has a high glass transition temperature (Tg) and, 76 1810668 of 128 often, is excellent in terms of heat resistance and mechanical strength. Curing accelerator for epoxy resin A curing accelerator can be used in a reaction between the epoxy resin in a strict sense and the curing agent. Although there is an exception: when the curing agent is an aromatic amine, a curing reaction occurs when the agent is heated. However, with many curing agents, the reaction does not occur even when the agent is heated. In this case, a curing accelerator can be used. When a curing agent is selected as an anhydrous acid-based curing agent, a phenol-based curing agent, or a dicyandiamide-based latent curing agent, in most cases curing cannot be performed unless a curing accelerator is used. Examples of curing accelerators include tertiary amines such as diazabicycloundecene (DBU) or diazabicyclononene (DBN), an imidazole-based agent, phosphine, and triphenylphosphine (TPP) such as a phosphonium salt. The amount of curing accelerator added is, for example, from 0.01 to 10 parts by weight to 100 parts by weight of the epoxy resin in the strict sense (the resin constituting 77 1810668 of 128 epoxy prepolymer). However, the additional amount needs to be adjusted according to the situation. The amount of addition is ideally 0.1 to 3 parts by weight. Other additives In the present embodiment, the coating film is formed by dispersing a solid lubricant containing primarily BN in a cured epoxy resin film. However, a hard film (with a pencil hardness of 3H or higher) is preferable. Therefore, a primary objective is to obtain a hard epoxy resin coating film. Additionally, fiberglass or carbon fiber may be added to further enhance the film's hardness. Furthermore, the resin composition of the present embodiment may also contain a surfactant, an emulsifier, a elasticity-reducing agent, a thinner, an antifoaming agent, an ion-capturing agent, and similar components. Method for analyzing the hardness of a film In the present embodiment, the pencil hardness of a hard film is evaluated. Specifically, the pencil hardness is measured using a method specified in JIS K 5600-5-4 (1999). The JIS standard clearly states that it is a translation of ISO / DIS 15184, Paints and varnishes: Determination of film hardness by the pencil test. However, the test method of 78 1810668 of 128 The hardness of the pencil itself is evaluated according to the definition in the JIS standard. The film hardness is evaluated using pencil hardness because this is an evaluation of scratching with a pencil, and it is a method for evaluating film hardness caused by scratching, which is similar to the behavior of a solid lubricant coating film peeling off a male screw and a female screw in an oil well pipe. The Rockwell, Vickers, Shore, and Knoop methods, which are forms of film hardness measurement caused by indentation and sometimes used on coating films or similar materials, are not suitable for a thin coating film and affect the base layer. Therefore, in the present embodiment, pencil hardness is used. Surface on which a solid film of lubricating coating is formed The solid lubricant coating film of the present embodiment is used while forming the coating film on one or both sides of the coupling (female screw side) and on one side of the male member (male screw side) in an oil well pipe screw. Alternatively, the solid lubricant coating film of the present embodiment is preferably used while the lubricant coating film 79 1810668 of 128 solid of the present embodiment is formed on one side of the coupling (female screw side) and on the side of the male member (male screw side), and a softer film that is of a different type than the coating film is formed on the other side. In the latter case, the pencil hardness of the different type of soft film formed on the side where the coating film of the present embodiment is not formed is, more preferably, 4B or less. Since the epoxy resin coating film of the present embodiment is a hard film having a pencil hardness of 3H or more, the film hardness of the different types of soft film produces a preferable lubrication characteristic by having a film structure with a different hardness. The first is a method of use that employs the lubricating characteristic of the solid lubricant coating film originally provided for in the present embodiment. The latter is a method for further improving the lubricating characteristic. The lubrication characteristic may be expected to be further improved by making the hardness of one of the films harder or softer than that of the film of the present embodiment and by making the films face each other instead of 80 1810668 of 128 to ensure the films have good lubrication characteristics relative to each other to achieve lubrication. In a situation (step 1) where a point-like torque is applied during tightening and loosening in a tapping situation until the screws mesh together as shown in Figures 2A and 2B, the soft coating film can be expected to deform to decrease the surface pressure. Furthermore, with the hard coating film of the present embodiment, which mainly contains BN and an epoxy resin coating film, high lubrication can be expected throughout the tightening and loosening region of the screws. Method for manufacturing a solid lubricating coating film A film can be formed by applying one agent at a time until the desired thickness is achieved, and forming a film by heating or similar means. Preferably, instead of performing the main heating many times using a film-forming method multiple times, it is preferable to perform a temporary heat treatment (temporary drying) one or more times at a temperature lower than the main heating temperature, and then perform the main heating to form a film. In this case, the thickness of the 81 1810668 of 128. When a solid lubricant coating film formed by an application is set at 50 μm or less, a temporary drying step is interspersed between applications. A coating film is then formed over the previously formed coating film and is temporarily dried. These steps are carried out in two or more stages, including the formation of the first film. In the formation of the final film, temporary drying is not performed, but a main drying step is. Examples of the main drying step include heating, infrared radiation, ultraviolet radiation, drying media such as hot air, leaving the film in the atmosphere, and natural drying. The final total film thickness of a coating film to be formed is preferably set between 10 μm and 150 μm. Temporary drying refers, for example, to drying in which only a portion (e.g., 30% to 70%) of a solvent is removed. In the present embodiment, a film is formed with an agent based on a solution obtained by dissolving a solid lubricant containing primarily BN and a binder resin containing primarily an epoxy resin in a solvent. The agent is preferably a highly viscous agent containing a large amount of film components relative to the solvent. In this case, when a film forms, due to the influence of the tension 82 1810668 of 128 surface along the structure of the oil well pipe screw, a liquid tends to be extracted so that it has a small thickness in a corner portion of a thread, and the liquid tends to accumulate in a corner portion at the bottom of the thread. Therefore, it is preferable to carry out the heating a plurality of times. However, when the main heating is performed multiple times, the adhesion between the films can be weak, and the films tend to peel away easily. Therefore, it is preferable to perform the temporary heating in a state where some of the solvent components have been removed, repeat the application and temporary heating again, form a film while performing the temporary heating until the required film thickness is achieved, and then perform the main heating. This is because it effectively ensures uniformity of film quality and thickness. Furthermore, applying the agent multiple times reduces the likelihood of a hole penetrating the entire film during film formation, improving corrosion resistance. This is also effective. Furthermore, it is preferable to carry out the main heating by means of a two-stage heat treatment 83 1810668 of 128 to strengthen the cross-linked structure of the epoxy resin. It can be expected that a complete cross-linked structure can be formed by performing a primary cure treatment at a Tg temperature or lower to gel the agent, and then performing a secondary cure at a Tg temperature or higher. Note that a detailed description will be provided of the solid lubricant containing BN as the main component, the binder resin containing an epoxy resin as the main component, and other additives related to the present embodiment, as well as the method for simulating actual well conditions as an evaluation method, and the appropriate intervals thereof. The present embodiment can be used not only for a solid lubricant coating film formed on a threaded connection for oil well tubing, but also for an agent for forming the coating film and lubricating something other than the oil well tubing screw. The description will then focus on a female member screw (female screw side) and a male member screw (male screw side).However, it is assumed to include a threaded and coupled (T&C) type joint and an integral type joint for oil well tubing. Test method to simulate real test conditions 1810668 of 128 wells (new laboratory test) In the present embodiment, as described with reference to Figures 2A to 4B, the phenomenon caused by the lubrication of the oil well pipe screw is considered in two stages: before the screws engage with each other (stage 1) and after the screws are sufficiently engaged (stage 2). Then, taking into account the tightening and loosening (lubrication) in the first stage (stage 1), the screw lubrication is thoroughly evaluated, including the lubrication in the second stage (stage 2). If this evaluation is not performed, although it is acceptable in a laboratory test, problems can often arise in an actual well. In a real well, a large and unbalanced load is applied before the bolts are engaged. Consequently, the solid lubricant coating film is damaged or peels off. In an extreme case, the film may peel off completely. Based on this, the upper and lower limits of a suitable range for a parameter of the present embodiment are selected. As described above, in the case of the solid film of lubricating coating, damage to the coating film cannot be avoided by adjusting or doing anything similar until the screws engage. 85 1810668 of 128 among themselves. Then, a byproduct is formed based on the detached film. If a screw clearance becomes clogged with this byproduct, seizing occurs. Therefore, if the lubrication evaluation is not performed under conditions that match an actual well, there is a concern that even a solid lubricant coating film that is actually at an unacceptable level may be mistakenly judged as acceptable. When the evaluation is based on such a lax assessment, limiting a parameter related to the solid lubricant coating film with upper and lower limits and selecting an appropriate range are meaningless. This means that it is impossible to accurately specify the solid lubricant coating film unless one considers whether a byproduct formed by damage to or detachment of the solid lubricant coating film—that is, a byproduct to be rebuilt—affects lubrication. In the present embodiment, the evaluation is performed by means of a new laboratory test taking these findings into account. Note that if you rely on evaluation with a horizontal wrench using a short male member or on evaluation with a vertical wrench using a short male member (evaluation by means of an 86 1810668 of 128 (conventional laboratory test), it is pointless to evaluate the solid film of lubricating coating. In documents from prior patent bibliography, it is sometimes described that the number of tightening and loosening cycles can be between 15 and 20, even for a large diameter size of 9-5 / 8 or 13-3 / 8 in a lubrication test based on a solid film of lubricating coating. That is to say, even with a solid film of lubricating coating, the result is no less than that of a grease compound, but the number of cycles is substantially impossible with a solid film of lubricating coating. With a solid film of lubricating coating, the solid film of lubricating coating, which primarily causes lubrication, inevitably gets scraped off.Meanwhile, in the case of grease, a surface is cleaned and the compound is reapplied each time it is tightened and loosened, thus supplying a heavy metal such as lead or zinc each time, which is the primary cause of lubrication. Therefore, in a large-diameter case with a solid lubricant coating film, a tightening and loosening rate of 15 to 20 times is practically impossible when tightening and loosening in a real well. Furthermore, regarding the lubrication of the solid lubricant coating film, the statement that the number of tightening and loosening cycles can be 15 to 20 is considered an 87. 1810668 of 128 case in which the lubrication of the screws is evaluated only in stage 2 after the screws are sufficiently engaged with each other without going through stage 1 in which the screws are not engaged with each other. That is, the evaluation is considered to be based on a horizontal or vertical force wrench using a short end, which is often seen in a conventional laboratory test. In the present embodiment, a test is carried out with a device configuration illustrated in Figure 5 based on the conditions of the previous new laboratory test. The new laboratory test is based on evaluation under conditions that can achieve a high load during tightening and an unbalanced load during tightening and loosening. In the new laboratory test, for example, in a step where a high load corresponding to a full-size male member is applied and the screws are tightened, tapping is considered until the screws are engaged. Additionally, in a screw loosening step, the tapping that occurs as the screws disengage is considered. In the new laboratory test, a vertical force wrench 4 is used. A short end 1 is adopted as the test end. However, it is possible 88 1810668 of 128 apply a load to an upper portion of the male member 1 by means of a heavy weight 3 and remove the load. The short male member 1 and the female member screw 2 are tightened by means of a threaded portion of the male member 1a and a threaded portion of the female member 2a. At this point, to simulate a situation where the threads do not engage, a temporary initial adjustment position is established so that half of the total number of threads on the male member 1a are exposed from the screw on the female member 2 (see Figure 2B). This is one of the causes of the rattling. The adjustment begins from this position. At the time of adjustment, the heavy weight 3 is attached to an upper end of the male member 1, which is an end opposite the adjusting screw of the female member 2 screw. The weight of Heavy Weight 3 is calculated based on a full-size male member with an outside diameter and wall thickness that corresponds to a load for one to three full-size male ends. For a male member sized 9-5 / 8" (53.5#), the weight of Heavy Weight 3 is approximately one tonne (2200 lb) of load for one male member, or approximately three tonnes (6600 lb) when the weight corresponds to three male ends. 1810668 out of 128 connected. As illustrated in Figure 6, the heavy weight 3 shown in Figure 5 includes a heavy weight body 3A and an insert rod 13. The insert rod 13 is welded to a lower surface of the heavy weight body 3A and is positioned symmetrically with respect to the geometric axis of the heavy weight 3. By inserting the insert rod 13 into the male member 1 in a loosely inserted state, the heavy weight is attached to the male member. Reference 1c indicates an inner diameter surface of the male member 1. In the insertion rod 13 and the male member 1, holes 1d and 13a are pre-formed, penetrating the male member 1 and the insertion rod 13 when the heavy weight 3 is attached as described above. Then, as illustrated in Figure 6, by inserting a penetrating rod 12 into holes 1d and 13a, the heavy weight 3 and the male member 1 are integrated. A swivel-type hook 11 is attached to an axial central position of a top portion of the heavy weight 3 by welding, and the heavy weight 3 is suspended from a ceiling suspension device 20 by means of a suspension chain 21. As a result, the magnitude of the load of the heavy weight on the male member can be adjusted by modifying the lifting level of the heavy weight with the suspension device 20. 1810668 of 128 During adjustment, the suspension chain 21 is loosened, a heavy load is applied to the female member screw, and the screws are tightened from 5 rpm to 20 rpm until the torque increases (stage 1). This simulates tapping. As the torque increases, the rotation speed is reduced from 0.5 rpm to 2 rpm, and the adjustment is made to the set position (stage 2). Meanwhile, when loosening (untightening), the suspension device 20 lifts the heavy weight 3, and the loosening is carried out in a state where the load of the heavy weight 3 is not applied. As for the rotation speed, when the torque increases, loosening starts at a rotation speed of 0.5 rpm to 2 rpm, and when the torque reaches about 1 / 10 of an adjustment torque value, loosening is carried out at a high rotation speed of 5 rpm to 20 rpm. Here, a condition closer to a real well environment is obtained when no load is applied by heavy weight 3 during loosening. This finding is based on the experimental fact that the evaluation of a lubrication characteristic is better when the load of heavy weight 3 is applied than when it is not. That is, as a result of observing the experiment, the inventor discovered that when loosening is performed with the heavy weight applied, heavy weight 91 1810668 of 128 acts as a balancer, and the male member loosens directly from the fitting completion position without tapping. Meanwhile, the inventor has discovered that when the heavy load is reduced—that is, when a test is performed by lifting a load to reduce the heavy load to zero—the test can be performed under conditions where tapping of the male member is severe, and the solid lubricant coating film is likely to be damaged in a situation where the load is reduced and the joint loosens, including a case where the load is not completely zero. In the new laboratory test under the above conditions, it is possible to simulate a situation in which a byproduct derived from a component of a solid lubricant coating film, released into a screw space due to unavoidable or similar shedding, does not move after tightening and loosening and obstructs a particular location, causing seizing, or a situation in which the coating film itself peels off completely. As a result, the upper and lower limits of a parameter related to the solid lubricant coating film can be specified as those that match the actual well conditions. After completing the loosening, the evaluation was performed by separating the male member screw and the 92 1810668 of 128 female member screw between each other, and removing fragments and the like derived from the solid lubricant coating film on the screw surfaces by air blowing, then checking the surfaces and continuing again with the fitting. The present embodiment specifies components and the like to achieve a lubrication characteristic that can withstand an environment that may be encountered in an actual well. Furthermore, the upper and lower limits are specified by performing confirmation under conditions that correspond to the tight and loose conditions in an actual well. The new laboratory test under the above conditions will henceforth also be referred to as the heavyweight key test. In the present embodiment, as described with reference to Figures 2A to 4B, it is important to divide a phenomenon occurring in the lubrication of an oil well tubing screw into two stages for consideration, and to evaluate the screw lubrication by taking into account the tightening and loosening (lubrication) in an initial stage. Failure to perform this evaluation, while correct in a laboratory test, can often lead to problems in an actual well. In an actual well, the tightening and loosening are primarily concentrated in the 93 1810668 of 128 Lubrication occurs in a state where tapping takes place before the bolts are engaged, and tightening and loosening are primarily focused on lubrication after the bolts are sufficiently engaged. In an actual well, the weight of a full-size male member, or the weight of three full-size male ends connected depending on the situation, is applied to a female bolt on a receiving side. Ideally, a male member is not tightened vertically in a straight line. In reality, a male member bolt bends in an elastic region, tends to become slightly buckled, and is necessarily tightened eccentrically by tapping in an initial tightening stage and a final loosening stage.In the above horizontal and vertical force tightening wrenches that use a short male member, the solid lubricant coating film must withstand a situation where the torque is not stable until the screws are engaged and sometimes increases the torque peak, as shown in the illustration with reference (x) in Figure 4A. Others. This description may also have the following configurations. (1) An agent for forming a solid lubricant coating film on a threaded portion of an oil well pipe, in which 1810668 of 128 disperses a solid lubricant in a binder resin, the binder resin containing a prepolymer and a curing agent, wherein the prepolymer is formed from one or more epoxy resins, contains 70 parts by weight or more of the prepolymer to 100 parts by weight of the binder resin, the epoxy resin constituting the prepolymer has an epoxy equivalent of 100 or more and 500 or less, the solid lubricant contains boron nitride or BN in an amount of 80% by weight or more, the BN has an average particle size of 10 μm or less, and the total weight of the solid lubricant is 0.1 times or more and two times or less the total weight of the binder resin. (2) The agent includes a solvent component in an amount of 30 parts by weight or more and 80 parts by weight or less with respect to 100 parts by weight of the sum of the total weight of the solid lubricant and the total weight of the binder resin excluding the curing agent. (3) The agent includes a curing accelerator in an amount of 0 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the total weight of the agent. (4) The epoxy resin that constitutes the prepolymer has more than two epoxy groups (polyfunctional epoxy resin). (5) The epoxy resin that constitutes the prepolymer has six or fewer epoxy groups. 1810668 of 128 (6) The epoxy resin that constitutes the prepolymer has four or fewer epoxy groups. (7) The curing agent is a curing agent for curing an epoxy resin and consists of an amine-based curing agent, an anhydrous acid-based curing agent, a phenol-based curing agent, or a latent curing agent. (8) The epoxy resin that constitutes the prepolymer has a glass transition temperature Tg of 100 °C or higher. (9) The agent has a viscosity of 20 mPa.sec or more and 2000 mPa.sec or less. (10) An oil well pipe having a lubricant coating film including a solid lubricant coating film over a threaded portion, wherein the solid lubricant coating film is formed by dispersing a solid lubricant in a binder resin, the binder resin containing an epoxy resin cured with a curing agent, containing 70 parts by weight or more of the epoxy resin to 100 parts by weight of the binder resin, the epoxy resin having an epoxy equivalent of 100 or more and 500 or less, the solid lubricant containing boron nitride or BN in an amount of 80% by weight or more, the BN having an average particle size of 10 μm or less, and the total weight of the solid lubricant being 0.1 times 96 1810668 of 128 or more and two times or less than the total weight of the binding resin. (11) Epoxy resin has more than two epoxy groups (polyfunctional epoxy resin). (12) Epoxy resin has six or fewer epoxy groups. (13) Epoxy resin has four or fewer epoxy groups. (14) The curing agent is a curing agent for curing an epoxy resin and consists of an amine-based curing agent, an anhydrous acid-based curing agent, a phenol-based curing agent, or a latent curing agent. (15) Epoxy resin has a glass transition temperature Tg of 100 °C or higher. (16) The solid lubricant coating film has a pencil hardness of 3H or more. (17) The solid lubricant coating film has a thickness of 10 μm or more and 150 μm or less. (18) The lubricant coating film is formed on a fitting surface of a threaded portion of at least one of the female member and the male member. (19) The lubricant coating film has a base layer between a fitting surface of the threaded portion and the solid lubricant coating film, and the base layer is formed by a chemically converted layer or a galvanized layer. 1810668 of 128 (20) A threaded union for oil well tubing connecting a female member having a female screw and a male member having a male screw, wherein at least one oil well tubing of the female member and the male member is comprised of oil well tubing having the lubricant coating film of the present description. Examples The following examples are based on the present embodiment. Acceptance criteria First, an acceptance criterion for lubrication behavior will be described based on the number of tightening and loosening cycles. Regarding casing diameter, those that could be tightened and loosened three or more times were considered acceptable, and those that could be tightened and loosened five times were considered better. Regarding pipe diameter, those that could be tightened and loosened five or more times were considered acceptable, and those that could be tightened and loosened ten or more times were considered better. Casing diameter is specified according to the definition in ISO 13679. As for the pipe, those that could be tightened and loosened five or more times were considered acceptable, which is a lower criterion. 1810668 of 128 to the definition of ISO 13679. It is clear that the M / B ratio tends to be worse than lubrication with a conventional grease compound due to the solid lubricant coating film. This is also being recognized in the oil and gas industry. As described above, the ISO 13679 standard definition can be a simple objective if a tighten-and-loosen test is performed using only a short male member from a state where the bolts are engaged. However, in the present embodiment, the evaluation was carried out using a heavy-weight wrench test (new laboratory test) to simulate a condition where a large, unbalanced load and hammering are applied, in which the threads do not engage, which is close to a condition that can actually occur in a well. In the following description, 9-5 / 853.5#, 95 / 843.5#, and 729# are used. In many cases, since a diameter is used to which the casing is applied, those that can be tightened and loosened three or more times are considered acceptable, and those that can be tightened and loosened five times are considered better, as described above. As a condition in which a load of three is applied 1810668 of 128 connected male ends, in a case study of 95 / 853.5#, a test was performed using a heavy weight of a three-ton load. In 9-5 / 843.5# and 729#, the study was performed with heavy weights of 2.5 tons and one ton, respectively. Regarding the initial adjustment position, the adjustment was made from a state where the screws were only tightened to a position where half the total number of threads on the male member were exposed from the screw on the female member, meaning the threads were not engaged. This adjustment was performed using the device illustrated in Figures 5 and 6. The test was conducted with a load applied during tightening and no load applied during loosening. If the test is performed under a load condition applied by a heavy weight at the time of loosening, when using a male member in which a short male member and a heavy weight are integrated, the short male member integrated with the heavy weight is lifted directly from a set position, unlike a full-size male member from an actual well. Since the heavy weight acts as a balancer, no knocking occurs. Since the full-size male member bends slightly due to its greater length, as the threads gradually move and do not engage with each other, knocking occurs. 1810668 100 of 128 a hammering sound occurs, and there is a strong tendency for the solid film of lubricating coating to be destroyed. Therefore, in the lubrication evaluation using a heavy-weight wrench, the test was performed without applying a load during loosening, and the hammering that occurs in a situation where the threads are not engaged was simulated. Furthermore, not applying a load does not necessarily mean the load is zero. The test was performed by lifting the heavy weight with an overhead crane or similar equipment so that no load was applied by the heavy weight. Note that the test to confirm the number of times the heavy-weight wrench tightens and loosens was performed two or more times.The number of times it was tightened and loosened in each test was compared and evaluated to see if it met the acceptance criteria, based on how many times the acceptance criteria were met relative to the number of tests, to determine whether the parameter was acceptable or not. Example 1 Example 1, based on the present embodiment, will now be described with reference to the Tables. In this example, primarily, a lubricant coating film is formed that includes a solid lubricant coating film on a 101 1810668 101 of 128 fitting surface 10 of a threaded union for oil well pipes, and it is evaluated whether the lubricant coating film, including the solid lubricant coating film, is acceptable or not. In this Example, a tightening and loosening test was performed under the conditions presented in Tables 1 to 4, and it was judged whether the lubricant coating film was acceptable or not. 102 1810668 102 of 128 Table 1 Steel Type DO (inch) Weight (LPF) Bolt Type Coating Film Forming Side Base Film and Base Treatment Epoxy Resin Chemical Agent Viscosity (mPa.sec at Room Temperature) % ​​by Weight of Solid Lubricant BN (relative to total weight of solid lubricant) Average Particle Size of BN (μ / m) Other Solid Lubricant Chemical Agent as Epoxy Resin Number of Epoxy Groups Epoxy Equivalent 1 Q125 9-5 / 8 53.5# JFELION™ CPLG MnPhos Bolt 200 100% 20* None Cresol / Novolac Type Epoxy Resin 6 200 Male Member Bolt - - - - - - - - 2 - 9-5 / 8 53.5# JFELION™ CPLG MnPhos Bolt 200 100% 20* None Cresol / Novolac Type Epoxy Resin 6 200 Male Member Bolt Sandblasted - ) - Metal soap Fluorine-based acrylate coating material - - 3 Q125 9-5 / 8 53,5# JFELION™ CPLG MnPhos 200 100% Screw 5 None Cresol / Novolac Epoxy Resin 6 200 Male Member Screw Sandblasted - - - Metal Soap Acrylate-Based Fluoride Coating Material - - 4 Q125 9-5 / 8 53.5# JFELION™ CPLG MnPhos 200 100% Screw 5 None Cresol / Novolac Epoxy Resin 6 200 Male Member Screw Sandblasted - - - Metal Soap Acrylate-Based Fluoride Coating Material - - 5 Q125 9-5 / 8 53.5# JFELION™ CPLG MnPhos 200 100% Screw 5 None Cresol / Novolac Epoxy Resin 6 200 Male Member Screw Sandblasted - - - Metal Soap Acrylate-Based Fluoride Coating Material Acrylate-based fluorine coating - - 6 Q125 9-5 / 8 53.5# JFELION™ CPLG MnPhos Screw - - - Metal soap Acrylate-based fluorine coating material - - Male member screw Sandblasted 200 100% 5 None Cresol / novolac type epoxy resin 6 200 7 C110 9-5 / 8 53,5# JFELION™ CPLG MnPhos Screw 2200* 100% 5 None Trisphenol Methane Epoxy Resin 3 165 Male Member Screw Sandblasted - - - Metal Soap Acrylate-Based Fluoride Coating Material - - 8 C110 9-5 / 8 53.5# JFELION™ CPLG MnPhos Screw 100% 10 None Trisphenol Methane Epoxy Resin 3 170 Male Member Screw Sandblasted - - - Aluminum Filings Aqueous Acrylate - - 9 C110 9-5 / 8 53.5# JFELION™ CPLG MnPhos Screw 180 100% 10 None Trisphenol Methane Epoxy Resin 3 170 Male Member Screw MnPhos 180 100% 10 None Epoxy Resin Triphenol Methane Type 3 170 10 C110 9-5 / 8 53.5# JFELION™ CPLG MnPhos Screw 180 100% 10 None Triphenol Methane Type 3 170 Epoxy Resin Male Member Screw Sandblasted - - - - - - -, 103 1810668 103 of 128 Table 2 Name of curing agent Functional group equivalent of curing agent Other additives Tg of epoxy resin film (°C) Parts by weight to 100 parts by weight of total weight of epoxy resin Curing aid (pbr) Curing aid Solvent Mixing ratio of solvent (parts by weight) to 100 parts by weight of solid lubricant + prepolymer Heating temperature Heating pattern Thickness of solid lubricant film (μm) Pencil hardness of solid lubricant film Number of times of durability / break Remarks 1 Phenol-based curing agent / novolac 195 None 200 2 Triphenylphosphine TPP Toluene / methyl ethyl ketone (MEK) / dimethyl cellosolve (DME) 70 160 °C x 2 h + 180 °C x 4 h 45 3H Horizontal wrench >5 times >5 times Comparative reference case - - - - - HFE - - - - 2 Phenol / novolac-based curing agent 195 None 200 2 Triphenylphosphine TPP Toluene / MEK / DME 50 160 °C x 2 h + 180 °C x 4 h 45 3H Weight key3-ton heavy weight wrench (Vertical screw wrench to which a weight corresponding to three vertically connected male members is applied) 2 times 1 time 3 times Comparative example - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B 3 Phenol / novolac-based curing agent 195 None 200 2 Triphenylphosphine TPP Toluene / MEK / DME 30 160 °C x 2 h + 180 °C x 4 h 45 3H 3-ton heavy weight wrench (Vertical screw wrench to which a weight corresponding to three vertically connected male members is applied) >5 times >5 times >5 times Example of the invention - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B 4 Phenol / novolac-based curing agent 195 None 200 2 Triphenylphosphine TPP Toluene / MEK / DME 30 160 °C x 2 h + 180 °C x 4 h 45 3H Simulated well test with one full-size male member (three 3-interval size male members are connected) >5 times >5 times >5 times Example of the invention - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B 5 AgentPhenol / novolac-based curing agent 195 None 200 2 Triphenylphosphine TPP Toluene / MEK / DME 30 160 °C x 2 h + 180 °C x 4 h 8* 3H 3-ton heavy weight wrench (Vertical screw wrench to which a weight corresponding to three vertically connected male members is applied) 3 times 1 time 1 time Comparative example - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B 6 - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B Single vertical wrench 3 times 4 times 4 times Example of the invention Phenol / novolac-based curing agent 195 None 200 2 Triphenylphosphine TPP Toluene / MEK / DME 30 160 °C x 2 h + 180 °C x 4 h 10 3H 104 1810668 104 of 128 Table 2 (continued) Name of curing agent Functional group equivalent of curing agent Other additives Tg of epoxy resin film (°C) Parts by weight to 100 parts by weight of total weight of epoxy resin Curing aid (pbr) Curing aid Solvent Mixing ratio of solvent (parts by weight) to 100 parts by weight of solid lubricant + prepolymer Heating temperature Heating pattern Thickness of solid lubricant film (μm) Pencil hardness of solid lubricant film Number of times lasting / breaking Remarks 7 40% modified alicyclic polyamine and 60% polyamidoamine 95 - 110 - - Example of two-liquid type epoxy resin side: none Curing agent side: MEK - Left in atmosphere and dried 20 3B* 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to is applied (three male members connected vertically) Solidifies quickly, in syrup formAqueous, and applied with difficulty 2 times 1 time 3 times Comparative example - - - - - HFE - Left in atmosphere and dried 30 6B 8 Diethylenetriamine-based curing agent 125 None 150 - - Propylene glycol monomethyl ether 80 Left in atmosphere for 5 days 55 3H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 8 times >10 times 10 times Example of the invention - - - - - Water - Air dried 10 ~ 15 4B 9 Diethylenetriamine-based curing agent 125 None 150 - - Propylene glycol monomethyl ether 60 Left in atmosphere for 5 days 55 3H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 4 times 3 times 3 times Example of the invention Diethylenetriamine-based curing agent 125 None 150 - - Propylene glycol monomethyl ether 60 Left in atmosphere for 5 days 55 3H 10 AgentDiethylenetriamine-based curing agent 125 None 150 - - Propylene glycol monomethyl ether 60 Left in atmosphere for 5 days 55 3H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 4 times 3 times 3 times Example of the invention - - - - - - - - - - 105 1810668 105 of 128 Table 3 Steel Type DO (inch) Weight (LPF) Bolt Type Coating Film Forming Side Base Film and Base Treatment Epoxy Resin Chemical Agent Viscosity (mPa.sec at Room Temperature) % ​​by Weight of Solid Lubricant BN (relative to Total Weight of Solid Lubricant) Average Particle Size of BN (μ / m) Other Solid Lubricant Chemical Agent as Epoxy Resin Number of Epoxy Groups Epoxy Equivalent 11 C110 9-5 / 8 53.5# JFELION™ Bolt CPLG MnPhos 800 100% 5 None Tetraquisphenol Ethane Type Epoxy Resin 4 165 Male Member Bolt Sandblasted - - - - - - - 12 C110 9-5 / 8 53.5# JFELION™ Bolt CPLG MnPhos 800 100% 5 None Tetraquisphenol Ethane Type Epoxy Resin 4 165 Male Member Bolt Sandblasting - - - - - - - 13 C110 9-5 / 8 53,5# JFELION™ CPLG MnPhos 750 Screw * * - Tetraquisphenol ethane type epoxy resin 4 165 Male member screw Sandblasted - - - Metal soap Acrylate-based fluorine coating material - - 14 C110 7 29 # JFELION™ CPLG MnPhos 250 Screw 85% 3 15% PTFE Glycidyl ester type epoxy resin 3 190 Male member screw Sandblasted - - - Metal soap Acrylate-based fluorine coating material - - 15 Q125 9-5 / 8 43.5# JFELION™ CPLG MnPhos 3500 Screw* (epoxy resin viscosity as prepolymer) 100% 5 None Polyglycerol polyglycidyl ether based resin and resin based Polyglycerol polyglycidyl ether are mixed in a 1:1 ratio 26 510* (epoxy resin) Male member screw Sandblasted - - - - - - - 16 Q125 9-5 / 8 43.5# JFELION™ CPLG MnPhos screw 25* 100% 5 None Cyclohexanedimethanol diglycidyl ether 2 135 Male member screw Sandblasted - - - Metal soap Acrylate-based fluorine coating material - -, 106 1810668 106 of 128 Table 4 Name of curing agent Functional group equivalent of curing agent Other additives Tg of epoxy resin film (°C) Parts by weight to 100 parts by weight of total weight of epoxy resin Curing aid (pbr) Curing aid Solvent Mixing ratio of solvent (parts by weight) to 100 parts by weight of solid lubricant + prepolymer Heating temperature Heating pattern Thickness of solid lubricant film (μm) Pencil hardness of solid lubricant film Number of times lasting / breaking Remarks 11 Phenol / novolac-based curing agent 200 None or 206 1 Triphenylphosphine TPP Ethylene glycol t-butyl ether 40 160 °C x 2 h + 180 °C x 6 h 30 6H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three is applied vertically connected male members) 7 times 8 times 6 times Example of the invention - - - - - - - - - - 12 Phenol / novolac based curing agent 200None 206 1 Triphenylphosphine TPP Ethylene glycol t-butyl ether 75 160 °C x 2 h + 180 °C x 6 h 30 6H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 9 times 6 times 7 times Example of the invention - - - - - - - - - - 13 Phenol / novolac-based curing agent 200 None 206 1 Triphenylphosphine TPP Ethylene glycol t-butyl ether 75 160 °C x 2 h + 180 °C x 6 h 45 6H 3-ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 2 times 1 time 2 times Comparative example - - - - - HFC - Left in atmosphere and dried 10 ~ 15 <6B 14 - - - 185 5 1,2,4-Triazole Dioxyalkylene ether 35 80 °C x 1 h + 180 °C x 1 h 50 4H 1 ton heavy weight wrench (Vertical screw-in wrench to which a weight corresponding to three vertically connected male members is applied) 3 times 4 times 4 times Example of the invention - - - - - HFE - SeIt was left in the atmosphere and dried for 10-15 minutes <6B 107 1810668 107 of 128 Table 4 (continued) Name of curing agent Functional group equivalent of curing agent Other additives Tg of epoxy resin film (°C) Parts by weight to 100 parts by weight of total weight of epoxy resin Curing aid (pbr) Curing aid Solvent Mixing ratio of solvent (parts by weight) to 100 parts by weight of solid lubricant + prepolymer Heating temperature Heating pattern Thickness of solid lubricant film (μm) Pencil hardness of solid lubricant film Number of times lasting / breaking Remarks 15 Phthalic anhydride 297 None 160 2 DMP-30: 2,4,6-tris(dimethylaminomethyl)phenol Example of two-liquid solvent type Epoxy resin solvent: diethyl acetamide Curing agent solvent: none Curing aid: none 40 165 °C x 1 h + 180 °C x 2 h In paste form, applied with difficulty Targeted at 40 μm 4H Heavyweight wrench of 2,5 tons (Vertical screw wrench to which a weight corresponding to three vertically connected male ends is applied) The chemical agent was in the form of a paste and was applied with difficulty, but two examples to which the chemical agent could be applied were tested. 3 times 3 times Example of the invention - - - - - - - - - - 16 Dicyandiamide 10 with respect to 100 of epoxy resin chemical agent None 95* 4 Imidazole (not used) The curing aid is mixed in when the epoxy resin is cured 60 120 °C 20π + 150 °Cx 10π It was applied smoothly with difficulty Dripping Intended for 50 μ / m 3H 2.5 tn heavy weight wrench (Vertical screw-in wrench to which a corresponding weight is applied to three vertically connected male ends) The chemical agent was too soft due to its viscosity similar to that of edible oil, it dried quickly,It was applied smoothly with difficulty and could not be applied to make it thick 2 times 1 time 3 times Comparative example - - - - - HFE - Left in atmosphere and dried 10 ~ 15 <6B, 108 1810668 108 of 128 In the Tables, numbers 1 through 4 are the results of a test performed using a steel grade: Q 125 high-strength carbon steel material, a screw size: 9-5 / 853.5# and a JFELIONTM screw. In items 1 to 4, a solid lubricant coating film was formed on a coupling-side bolt by forming an epoxy resin containing primarily BN. Additionally, items 1 to 4 are examples where one side of the male member was sandblasted and left as is, or a lubricating and anti-corrosive soft coating was formed on the side of the male member. A cresol / novolac-type epoxy resin with six epoxy groups and an epoxy equivalent of 200 was used as the epoxy resin. A phenol / novolac-based curing agent with a functional group equivalent to the curing agent (i.e., an active hydrogen equivalent of 195) was used as the curing agent. Triphenylphosphine (TPP) was used as the curing aid, and 2 parts by weight (2 pbr) of the curing aid were mixed with 100 parts by weight of the total weight of the epoxy resin and curing agent to continue curing. Heat treatment was performed at 160 °C for two hours followed by 180 °C for four hours. Note that the epoxy resin had a pencil hardness of 3H as its film hardness. Note that, in the Tables, the screw of 109 1810668 109 of 128 coupling is represented by a CPLG screw and the male member screw is represented by a male member screw. Number 1 is an example where the BN size of the solid lubricant is 20 μm, exceeding the specified size of 10 μm, and the film thickness is 45 μm. Number 1 is an example where a tighten-loosen test of an oil well tubing screw was performed using a horizontal threading wrench. Since the weight of the male member is not applied to the coupling and an axial adjustment is performed, Number 1 represents an ideal condition where the adjustment is made in a symmetrical position. Number 1 is an example where the tighten-loosen test could be performed without any particular problems. However, even though the BN was outside the norm, the required number of tighten-loosen cycles of five or more was achieved because the test evaluation was a more lenient condition compared to the tighten-loosen conditions in an actual well. Meanwhile, number 2 is a case in which an acrylate-based fluorine coating material was applied to one side of the male member screw under the same mating film conditions as in number 1. Number 2 is the result of the tighten-loosen test under a condition in which a 110 1810668 110 of 128 heavy load of three tons with a vertical screw wrench as illustrated in Figure 5, i.e., the condition of the new laboratory test. As described at the beginning of the Examples, tightening and loosening were performed by applying a load at the time of tightening and removing the load at the time of loosening (including loosening the load). Note that the three-ton load simulates three actual-length male ends connected. In case number 2, the number of tightening and loosening cycles was less than the required number. In a real well, the weight of a male member is applied to a coupling bolt. The male member is not positioned symmetrically and straight with respect to the coupling center, but rather in such a way that its geometric axis buckles. Furthermore, since there is play before the bolts mesh together, a large and unbalanced load is applied to the coupling bolt. Under such real-well-like conditions, when the average particle size of the solid lubricant exceeds the upper limit of 10 μm, the number of tightening and loosening cycles does not meet the standard. Number 3 is an example where the average particle size of BN in coating film 111 was changed 1810668 111 out of 128 solid lubricants on the coupling side compared to number 2. Specifically, number 3 is an example where the average particle size of BN is 5 μm within the standard range. Other parameters were also adjusted within the scope of this description. In number 3, the number of tightening and loosening cycles also meets the standard in a heavy-weight wrench test. It has been indicated that sufficient lubrication can be maintained even in an actual well. Case 4 is a case where the same conditions as Case 3 were used, except that the fit test was performed in a simulated well. Case 4 was designed to avoid impacting the side of a female member bolt when a male member bolt is inserted using an insertion guide with three connected, full-length male ends. Additionally, Case 4 was designed to prevent the male member bolt from oscillating more than necessary by using a compensator. This is the result of simulating a real-well situation. Case 4 exhibits good lubricity and had the same result as Case 3. This result indicates that the heavy-weight wrench test implementing the new laboratory test method can simulate the real-well situation. Number 5 is a case where the thickness of the 112 1810668 Number 112 of 128 film is 8 μm, which is less than the lower limit value of 10 μm, compared to numbers 3 and 4. Number 5 is a case where it was difficult to perform the adjustment and loosening and was considered unacceptable. Case 6 describes a situation where a film formed under the conditions of cases 1 through 5, not on the coupling bolt side but on the short male member side, with a film thickness of 10 μm. A simply vertical wrench was used, and structurally, no heavy weight was applied to the top of the coupling. It has been found that even when the coating film ratio between the coupling bolt and the male member bolt is reversed, a sufficient number of tightening and loosening cycles are ensured within the parameters of this description. In numbers 3 and 6, it is clear that good lubrication behavior is exhibited in the case where a BN-based epoxy resin coating film is formed on the coupling side and a soft coating material is applied on the male member side and, conversely, in the case where a BN-based epoxy resin coating film is formed on the male member side and a soft coating material is applied on the coupling side. Number 7 is a case in which a test was performed 113 1810668 113 of 128 with a steel grade: carbon steel, strain-resistant material C 110, a bolt size: 95 / 853.5#, and a JFELION™ bolt. A solid lubricant coating film was formed on a mating-side bolt by forming an epoxy resin containing primarily BN. Number 7 is an example where the side of a male member was sandblasted, and a soft, lubricating, and anti-corrosive paint formed on the sandblasted surface. Only this example of the mating-side bolt solid lubricant coating film is of the mixed, two-liquid type. A bisphenol A-type epoxy resin having four epoxy groups and an epoxy equivalent of 220 was used as the epoxy resin. A modified alicyclic polyamine and a polyamidoamine, which are curing agents, were dissolved in a solvent at a weight ratio of 4:6.The functional group equivalent of the curing agent as a whole, i.e., the active hydrogen equivalent, was 95. Therefore, the mixture was prepared in such a way that the reaction occurred while the bisphenol A epoxy resin had an epoxy equivalent of 185. This is a soft case where the film hardness is 3B, which is below the lower limit of the standard. Furthermore, due to the two-liquid composition, as the mixture progressed, it tended to solidify rapidly, taking on the form of an aqueous syrup and having a specific gravity of 114. 1810668 114 out of 128 aimed for a film thickness of 50 μm. However, it was difficult to say whether the film was homogeneous. This is a case (Comparative Example) where the number of adjustments and loosenings was not optimal. Numbers 8 through 10 are cases where a test was performed with a steel grade of carbon steel, strain-resistant material C 110, a bolt size of 9-5 / 853.5#, and a JFELIONTM bolt. A solid lubricant coating film was formed on a mating-side bolt by forming an epoxy resin containing primarily BN. Numbers 8 through 10 are examples where the side of a male member was sandblasted, and a soft, lubricating, and anti-corrosive paint formed on the sandblasted surface. A trisphenol methane-type epoxy resin with three epoxy groups and an epoxy equivalent of 185 was used as the epoxy resin. In numbers 8 through 10, a diethylenetriamine-based curing agent with one functional group equivalent (i.e., an active hydrogen equivalent of 125) was used as the curing agent. Curing was performed without a lubricating auxiliary, and the glass transition temperature (Tg) was [missing value]. 150 °C. Numbers 8 to 10 are examples where the film thickness was 55 μm and the pencil hardness was 3H. Number 8 is a case where an epoxy resin coating film formed on the screw side of 115 1810668 115 of 128 coupling and an anti-corrosive paint and soft lubricant were applied to the side of the male member, and the number of times of tightening and loosening was equal to or greater than the specified number of times. Number 9 is a case in which an epoxy resin coating film formed not only on the mating screw side but also on the male member screw side, and this case is also a case in which the number of tightening and loosening times was equal to or greater than the specified number of times. When comparing numbers 8 and 9, number 8 is better in terms of the number of tightening and loosening cycles. Lubrication is considered better when one screw has a hard epoxy resin coating film of 3H or higher containing BN, as specified in the invention, and the other screw has a soft coating film. Number 10 is a case where the side of a male member had no film and was only sandblasted. It is clear that the BN as a solid lubricant is contained within a range specified by the present embodiment, and the epoxy resin coating film has excellent lubricating characteristics. Numbers 11 to 13 are cases where a test was performed with a steel rating: carbon steel, 116 1810668 116 of 128, C 110 strain-resistant material, a bolt size of 9-5 / 853.5#, and a JFELION™ bolt. A solid lubricant coating film was formed on a mating-side bolt by creating an epoxy resin, changing the condition of the BN solid lubricant. Numbers 11 through 13 are examples where one side of the male member was sandblasted, and a soft, lubricating, and anti-corrosive paint formed on the sandblasted surface. A tetrakisphenol ethane-type epoxy resin with four epoxy groups and an epoxy equivalent of 165 was used as the epoxy resin. A phenol / novolac-based curing agent with a functional group equivalent (i.e., an active hydrogen equivalent) of 206 was used as the curing agent. This is one instance where triphenylphosphine (TPP) was used as a curing aid. This is a case where an epoxy resin formed on a coupling-side screw when the condition of the BN solid lubricant changed. Numbers 11 and 12 are examples where only one side of the male member was sandblasted. Number 13 is a case where an acrylate-based coating material F containing a metallic soap was applied. One difference between numbers 11 and 12 is the film thickness and the solvent mixing ratio, but both provide good lubrication. Number 13 is a case where BN was not added, and 117 1810668 117 of 128 is an example where the number of tightening and loosening cycles does not meet the acceptance criterion because it did not contain a solid lubricant. Number 14 is a case where a test was performed with the following steel grade: carbon steel, strain-resistant material C 110, bolt size: 729#, and a JFELION™ bolt. A solid lubricant coating film was formed on a mating-side bolt by creating an epoxy resin in a condition where the BN solid lubricant was present at 85% and PTFE as another solid lubricant was present at 15%. Number 14 is an example where the side of a male member was sandblasted, and a soft, lubricating, and anti-corrosive paint formed on the sandblasted surface. A glycidyl ester-type epoxy resin with three epoxy groups and an epoxy equivalent of 190 was used as the epoxy resin.This is an example of a self-curing epoxy resin coating film, in which 5 parts by weight of 1,2,4-triazole were added to 100 parts by weight of the total weight of the solid lubricant and the epoxy resin as a prepolymer to form a self-curing epoxy catalyst. In section 14, the lubrication can be considered acceptable in a coating film formed within a specified mixing parameters. 118 1810668 118 of 128 of the standard in this description. Numbers 15 and 16 are cases where the agent viscosity is outside a suitable range. Numbers 15 and 16 are cases where a test was performed with the following steel grade: carbon steel, strain-resistant material C 110, bolt size: 95 / 843.5#, and a JFELION™ bolt. An epoxy resin coating film containing BN was formed on one mating side. In number 15, one side of a male member was sandblasted and left as is. In number 16, one side of the male member was sandblasted, and an acrylate-based fluorine resin was applied to that side. In case number 15, the epoxy resin used was a mixture of a polyglycerol polyglycidyl ether-based resin and a polyglycerol polyglycidyl ether-based resin in a 1:1 ratio. Phthalic anhydride was used as the curing agent. DMP30, i.e., 2,4,6-tris(dimethylaminomethyl)phenol, was added as a curing aid at a ratio of 5 parts by weight to 100 parts by weight of the sum of the total weight of the solid lubricant and the total weight of the epoxy resin. In this case, the viscosity of the epoxy resin is 3500 mPa·s, which is significantly higher than the standard upper limit. Because the viscosity is too high, it is difficult to apply properly and consistently. 119 1810668 119 of 128 homogeneously applied the epoxy resin in paste form. However, the number of adjustments and loosenings was three times for each of the two examples in which the epoxy resin could be applied. Therefore, this is an example that is considered an example of the present invention. Case 16 involved the use of cyclohexanedimethanol diglycidyl ether as the epoxy resin, dicyandiamide as the curing agent, and imidazole as a curing aid. The epoxy resin had a viscosity of 25 mPa·s, significantly lower than the standard lower limit. In case 16, the epoxy resin had a viscosity similar to cooking oil, and it tended to pool at the six o'clock position even when applied. Even when attempts were made to apply the resin while rotating the tube, it pooled at the six o'clock position before heating, resulting in a thin film of only 25 μm that was not homogeneous. Therefore, the lubrication was inadequate.Furthermore, this is a case where the Tg of the epoxy resin film is also outside the appropriate range. Therefore, the tightening and loosening test was performed three times, but in sample number 16, the results were only obtained twice. 120 1810668 120 out of 128 once and three times, which can hardly be described as excellent. Number 16 corresponds to the Comparative Example. Example 2 Example 2 is the evaluation of corrosion resistance by means of a salt spray test. Among the cases illustrated in Example 1, numbers 3, 8, 11 and 14 were taken under screw conditions for carbon steel-based oil well pipes, and a salt water spray was performed on them. As a material, a coupling sample was recently formed for this saltwater spray test. The test was carried out using a thin sheet of general normal mild steel / cold rolled sheet (SPCC) that had a thickness of 0.8 mtm as a Comparative Example (Condition A). In the oil well tubing screw material, both ends of a coupling screw were tightened and loosened once with a shield. Samples left as is (numbers 3-2, 8-2, 11-2, and 14-2) and samples with the shield replaced and tightened (corresponding to the second tightening: numbers 3-3, 8-3, 11-3, and 14-3) were then sprayed with salt water. A corrosion test was then performed under conditions where the samples were observed side by side. 121 1810668 121 of 128 the other in a state where the samples were not in a vertical position. A specimen with only one thread was used as the male member screw, and the threaded side was tightened and loosened once with a shield. An imide tape was glued to an outer portion where the shield was not replaced to prevent water from entering the tube. The detailed conditions are as follows. The conditions for the solid lubricating coating films of numbers 3-2 and 3-3, 8-2 and 8-3, 11-2 and 11-3, and 14-2 and 14-3 correspond to the conditions of numbers 3, 8, 11, and 14 of Example 1, respectively. Saltwater spray conditions The conditions for salt water spraying are as follows. Spraying conditions: JIS K 5600-7-1 Saltwater concentration: 5 ± 0.5% by weight Temperature: 35 °C Humidity: between 98% and 99% Spray quantity: 1-2 ml / h / 80 cm2pH: between 6.5 and 7.2 Time: 24 hours The importance of this test method is as follows. An oil well pipe screw is sent after one end of it has been fitted with a 122 1810668 122 of 128 protective and is often stored in a tank near a well as is. Therefore, a state in which salt water is sprayed onto a bolt is an environment similar to actual operating conditions. The condition of not having the protective film in place means a more severe condition when the film is removed. The case of the SPCC thin film is a case where tightening and loosening are not performed with a protective film, in which the corrosion resistance of the film itself is observed in the bolt form. The results are presented in Table 5. 123 1810668 123 of 128 Table 5 No. Steel Type DO Weight Screw Type Lubricant Coating Solid Film Condition Treatment Before Saltwater Spray Sample Condition in Saltwater Spray Corrosion Result Remarks A SPCC 75 mm X 150 mm X 0.8 mm (thin steel sheet) Solid lubricant coating film on the mating screw film side of Example 1- No. 3 None (Entire back surface: imide tape) (With imide tape 10 mm from the end surface on the evaluation side) Set obliquely (Comb-shaped jig assembly made of vinyl chloride) No corrosion Comparative reference example 3-2 Q125 9-5 / 8 53,5# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 3 The durability / break test was carried out with the shield only once. The shield was reattached to the sample and the sample was placed horizontally (meaning the sample was not held vertically). No corrosion. Example of the invention 3-3 Q125 9-5 / 8 53.5# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 3 The durability / break test was carried out with the shield only once. The sample was placed horizontally in a saltwater sprayer (meaning the sample was not held vertically). No corrosion. Example of the invention 8-2 C110 9-5 / 8 53.5# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 8 The durability / break was carried out with a shield only once. The shield was reattached to the sample and the sample was placed horizontally (meaning the sample was not made to be held vertically). No corrosion. Example of the invention 8-3 C110 9-5 / 8 53.5# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 8 The durability / break was carried out with a shield only once. The shield was reattached to the sample and the sample was placed horizontally (meaning the sample was not made to be held vertically). No corrosion. Example of the invention 11-2 C110 9-5 / 8 53.5# CPLG JFELION™ Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 11 The durability / break was carried out with the shield only once. The shield was attached to the specimen again and the specimen was placed horizontally (meaning the specimen was not made to stand vertically). No corrosion. Example of the invention 11-3 C110 9-5 / 8 53,5# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 11 The durability / break was carried out with a shield only once The shield was attached to the sample and the sample was placed horizontally (meaning the sample was not made to be held vertically) No corrosion Example of the invention 14-2 C110 7 29# JFELION™ CPLG Screw Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 14 The durability / break was carried out with a shield only once The shield was attached to the sample and the sample was placed horizontally (meaning the sample was not made to be held vertically) No corrosion Example of the invention, 124 1810668 124 of 128 14-3 C110 7 29 # Screw CPLG JFELIONTM Solid lubricant coating film on the film side of the coupling screw of Example 1- No. 14 The durability / break was carried out with a shield only once The shield was attached to the sample and the sample was placed horizontally (meaning the sample was not made to be held vertically) No corrosion Example of the invention 125 1810668 125 of 128 As can be seen in Table 5, none of the numbers 3-2, 3-3, 8-2, 8-3, 11-2, 11-3, 14-2 and 14-3, including number A as a Comparative Example, have been found to corrode by salt water spray and have sufficient corrosion resistance. It is estimated that this is because these samples have a hard film quality of 3H, and because these samples are not inevitably damaged even when these samples are tightened and loosened with a protector, since BN itself is water-repellent and does not absorb water. In this case, the entire content of Japanese patent application No. 2021-91463 (filed on May 31, 2021), the priority of which is claimed in this application, forms part of the present description by reference. The description herein is made with reference to a limited number of embodiments, but the scope of the rights is not limited to them, and modifications to each embodiment based on the above description are obvious to those skilled in the art. List of references male test member 1a male screw 1c inner diameter surface 1d through hole 127 1810668 126 of 128 female member (coupling) 2a female screw weight heavy thread wrench 10A solid lubricant coating film 10B base layer hook attachment (swivel type) penetrating rod insertion rod lifting device (crane) chain (sling) 128 1810668 127 of 128 G. BREUER - 30525624826 Digitally signed by PORTALTRAM ITES - INPI Date: 2022.05.27 10:01:30 -03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 1810668 128 of 128

Claims

1. An agent for forming a solid lubricant coating film on a threaded portion of an oil well pipe, characterized in that a solid lubricant is dispersed in a binder resin, the binder resin contains a prepolymer and a curing agent, the prepolymer is formed from one or more epoxy resins, and contains 70 parts by weight or more of the prepolymer to 100 parts by weight of the binder resin, the epoxy resin constituting the prepolymer has an epoxy equivalent of 100 or more and 500 or less, the solid lubricant contains boron nitride or BN in an amount of 80% by weight or more, and the BN has an average particle size of 10 µm or less, the total weight of the solid lubricant is 0.1 times or more and two times or less the total weight of the binder resin, and the agent has a viscosity of 20 mPa.s or more and 2000 mPa.s or less. 15 more demands follow