JP2005290112A - Torque coefficient stabilizing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a torque coefficient stabilizing agent which is applied on a material member having a screwed part such as a fastened bolt to reduce an ambient temperature dependence of the axial force of the screwed part at the time of fastening. <P>SOLUTION: The torque coefficient stabilizing agent is composed of an aqueous dispersion containing 0.5-20 wt.% graphite and 5-30 wt.% wax. The material member for screwing having the screwed part and at least a part of the surface of which is covered with a covering material containing a mixture of graphite and wax is presented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a torque coefficient stabilizer that is used to reduce the dependency of the axial force of a screwed portion such as a bolt that has been fastened on the ambient temperature during fastening.

  The variation in the axial force of the screwed part such as a bolt that has been tightened is related to the strength of the structure such as a bridge or a steel tower, and thus safety, so this axial force is constant over the screwed part of a large number of bolts. It is desirable that However, even when fastened with a constant torque, the axial force often varies due to the ambient temperature dependence during fastening.

  For this reason, it is known in the art to apply a lubricating oil such as machine oil or a metal soap to a screwing member such as a bolt or a nut before fastening.

  Alternatively, it is disclosed that a film-forming mixture mainly composed of a fatty acid amine salt, a fatty acid, a fatty acid glycerin ester, or the like is applied to a screw member, particularly a friction surface, and then fastened. (For example, refer to Patent Document 1.)

  Furthermore, it is also disclosed that the screw member is covered with a lubricant containing graphite, an ethylene vinyl acetate copolymer and sodium stearate before being fastened. (For example, see Patent Document 2.)

  It is also disclosed that at least a part of a member having a threaded portion is coated with a composition comprising graphite powder, an epoxy resin and a curing agent to stabilize the torque at the time of tightening. (For example, refer to Patent Document 3.)

  Furthermore, a composition for coating a screw member containing 40 to 200 parts by weight of an epoxy resin and an appropriate amount of an organic solvent as a diluent is attached to at least a part of the member having a screw part with respect to 100 parts by weight of graphite powder. It is also disclosed to stabilize the torque during tightening. (For example, see Patent Document 4)

  However, fatty acids and fats and oils are easily oxidized when left in contact with air for a long time, and a film-forming mixture containing them as a main composition is likely to be deteriorated with time. In particular, it is not easy to prevent deterioration during storage in a state where the screw member is applied.

  In addition, an ethylene vinyl acetate copolymer or a composition mainly composed of an epoxy resin is applied to a threaded member or a threaded portion to form a film, and is applied to the threaded member. There is a problem that if the film is stored for a long time, the film is hardened and easily peeled off.

Even when the epoxy resin is used without containing a curing agent, when it is stored for a long time in the state where it is applied to the screwing member, the applied resin will not be exposed to light or mixed impurities. There is a possibility that the film may be hardened and peeled easily due to the influence. In addition, the temperature dependence of the hardness and viscosity of the epoxy resin may affect the axial force.
JP 52-39057 A (Claims) Japanese Patent Publication No. 55-32758 (Claims) JP-A-8-28535 (Claims) JP 2000-120638 A (Claims)

  An object of the present invention is applied to a member in order to reduce the dependency of the axial force of the screwed portion on the ambient temperature at the time of fastening of a member having a screwed portion such as a bolt. It is to provide a torque coefficient stabilizer.

  The gist of the present invention is that it is a water-based dispersion liquid containing a graphite and a wax, and these are torque coefficient stabilizers dispersed in water.

  The wax content may be 5 to 30% by weight.

  The graphite content may be 0.5 to 20% by weight.

  The graphite content may be 0.5 to 10% by weight.

  Further, the gist of the present invention is a member having a screwing portion, and a screwing member in which at least a part of the surface is covered with a coating containing a mixture of graphite and wax. is there.

  Further, the gist of the present invention is that the member having a screwing portion is a nut, and the screwing member has at least a seating surface covered with the covering.

Furthermore, the gist of the present invention is that
Preparing a screwing member having the torque coefficient stabilizer and a screwing part;
Attaching the torque coefficient stabilizer to at least a part of the surface of the screwing member;
Drying the screwing member to which the torque coefficient stabilizer is adhered;
It is in the fastening method of the screwing member including the process of fastening the dried screwing member.

In the fastening method of the screwing member, the screwing member may be a nut,
The step of attaching the torque coefficient stabilizer may be a step of attaching the torque coefficient stabilizer to at least the bearing surface of the nut.

  According to the present invention, it is possible to reduce the dependency of the axial force of the screwed portion of the member having a screwed portion such as a bolt, which is fastened, on the ambient temperature during fastening.

  The torque coefficient stabilizer of the present invention can maintain the effect of stabilizing the torque coefficient with little decrease even when stored for a long time in a state where it is applied to a member having a threaded portion such as a bolt or nut. .

  By using the torque coefficient stabilizer of the present invention, it is possible to eliminate coating unevenness and paint peeling troubles caused by the lubricating oil that spills out from the portion that rubs against the body member after fastening.

  When the torque coefficient stabilizer of the present invention is wetted, the frictional force between the members increases and the axial force decreases, so there is little risk of occurrence of abnormalities such as bolt elongation and breakage.

  The torque coefficient stabilizer of the present invention is an aqueous dispersion containing graphite and wax, and these are graphite / wax dispersions dispersed in water. This liquid can be obtained by mixing wax and water, dispersing the wax in the water to obtain a wax dispersion, and further adding graphite and stirring.

  The wax dispersion is obtained by stirring a mixed liquid of wax and water at a temperature not lower than the melting point of the wax. Alternatively, it can be obtained by stirring a mixed solution of wax and water with a stirring device having a high-speed rotating blade. Alternatively, the mixed liquid may be spray-pulverized at a high pressure. You may emulsify with a high-pressure homogenizer. The mixed liquid of wax and water may contain a surfactant such as alkylphenol. The surfactant can promote atomization by stirring the wax. Further, the surfactant can contribute to the stable presence of the dispersed wax fine particles and graphite fine particles without associating in water. The mixture of wax and graphite previously mixed with water may be stirred to disperse the wax and graphite in water.

  The content of wax in the torque coefficient stabilizer of the present invention is preferably 5 to 30% by weight. More preferably, it is 5 to 15% by weight. The graphite content is preferably 0.5 to 20% by weight because the torque is stable. It is more preferable that the graphite content is 0.5 to 10% by weight because the dirt during use is not noticeable. In order to stabilize the torque, the graphite is preferably a graphite powder having a cleavage property and having a diameter of 0.3 to 30 μm. The surfactant is preferably mixed in an amount of 5 to 30% by weight based on the amount of wax.

  The torque coefficient stabilizer of the present invention is used by being applied to, or dipped in, or sprayed onto a fastening member such as a bolt or nut having a threaded portion. Specifically, when the main body member is fastened and combined with the fastening member, the torque coefficient stabilizer of the present invention is attached to the fastening member and dried to form a film of a mixture of graphite and wax on the surface of the fastening member. . Next, the fastening member is fastened together with the main body member. In this case, the torque coefficient stabilizer is attached to at least one member of the fastening member including the male screw and the female screw. Further, the torque coefficient stabilizer does not necessarily have to be attached to the screw portion, but it is necessary that the member having male screws or the member having screws be attached to a portion that will rub against the body member at the time of fastening. For example, a nut needs to be attached to the seating surface. Ordinary lubricating oil or rust preventive oil may be adhered to the male screw portion in order to adjust the level of axial force or to prevent rust.

  Thus, the fastening member fastened using the torque coefficient stabilizer of the present invention has very little dependence on the ambient temperature at the time of fastening. For example, the difference between the axial force when fastened at an ambient temperature of 0 ° C. and the axial force when fastened with the same torque at an ambient temperature of 60 ° C. is 15% or less.

  In the present invention, fastening members such as bolts and nuts may be previously taken out by immersing them in the torque coefficient stabilizer of the present invention, dried or stored as they are, and may be transported to a construction site for use as necessary. . Alternatively, the fastening member may be taken out by being immersed in the torque coefficient stabilizer of the present invention at a construction site and dried by hot air or the like.

  The fastening member that has been tightened by applying an oil-based lubricant such as a normal rust preventive oil squeezes out from the part that rubs against the body member after fastening, and the fastening member and the body member It becomes attached to the exposed surface and soils the exposed surface. For this reason, when painting is performed after fastening, the portion to which the oil adheres becomes uneven coating. In addition, the pre-painted main body member may be damaged due to the oil squeezed out of the paint and may peel off. The fastening member fastened using the torque coefficient stabilizer of the present invention does not squeeze out a liquid substance such as oil from the portion that frictions with the main body member after fastening, and the fastening member and the main body member after fastening. The exposed surface is not contaminated. Therefore, troubles such as uneven coating and peeling of the coating do not occur.

  In addition, a fastening member that is tightened by applying a conventional oil-based lubricant increases the axial force when the lubricant gets wet, increasing the risk of abnormalities such as bolt elongation and breakage. . On the other hand, in the present invention, when the torque coefficient stabilizer becomes wet, the frictional force between the members increases and the axial force decreases, so that there is little risk of occurrence of abnormality such as bolt elongation and breakage.

  As the wax used in the present invention, any one of plant wax, animal wax, mineral wax, petroleum wax and synthetic wax, which are natural waxes, can be used.

  Examples of natural waxes include plant-based waxes such as candelilla wax, carnauba wax, and weiss oil wax. Examples of animal waxes include shellac wax. Examples of mineral waxes include montan wax and derivatives thereof, ozokerite ceresin. It is done. In addition, modified waxes such as derivatives having a carboxyl group or the like added thereto are also included. Examples of petroleum waxes include paraffin wax, microcristan wax, and petrolatum wax. Examples of the synthetic wax include modified waxes such as polyethylene wax, polypropylene wax, derivatives having a carboxyl group added thereto, and oxides thereof. Also, esterification of various hydrogenated waxes, various aliphatic amides, aliphatic ketones, mono-, di-, tri- and poly-alcohols with various natural or synthetic fatty acids, resin acids and polybasic acids Things can be used. Further, there are copolymer waxes with ethylene and propylene, and ethylene copolymer waxes. This system can be used in various ways including terpolymer systems by changing the copolymerization partner.

  As the surfactant used in the present invention, carboxylate type, sulfate type, sulfonate type, phosphate ester type, fatty acid ester type, alkanolamide type anionic surfactant, fatty acid amine salt type, Cationic surfactants such as quaternary ammonium salt types, amphoteric surfactant types, and nonionic surfactants such as polyoxyethylene alkyl ether type and polyoxyethylene polyoxypropylene ether type, amino ether type , Ether ester type, and the like. Furthermore, polymer surfactants and reactive surfactants can be selected and used in combination.

[Examples 1 to 4, Comparative Examples 1 and 2]
Graphite: A scaly graphite powder (manufactured by Nippon Graphite Industries Co., Ltd.), a commercially available wax dispersion for stabilizing the torque coefficient, and water were mixed and stirred with a stirrer having a stirring blade to obtain a graphite / wax dispersion.

  Change the composition ratio of graphite and wax as shown in Table 1 and use a structural torcia-type high-strength bolt (M22) and hexagon nut as a fastening member. did. High strength bolts and washers were treated with commercially available rust preventive oil. Table 1 also shows the appearance of the graphite / wax dispersion. The measurement result of the torque coefficient value is shown in FIG.

  When the graphite content is 0, the torque coefficient value is close to the upper limit standard of JIS B 1186 A type at 0 ° C, and close to the lower limit standard at 60 ° C. That is, the torque coefficient value changes from a value close to the upper limit standard to a value close to the lower limit standard.

  In the wax dispersion to which graphite is added, the torque coefficient value is lower than that when the temperature coefficient is entirely low, the torque coefficient value is less than 0, and the temperature value from 0 ° C. to 60 ° C. The degree to which the torque coefficient value changes is smaller than when the graphite content is zero. That is, the gradient of the temperature-torque coefficient value change is smaller than when the graphite content is zero.

  On the other hand, when the graphite content exceeds 10%, the appearance becomes black, and there is no problem in performance, but apparent stains are observed during handling. If the graphite content exceeds 20%, the apparent stains during handling are significant.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

It is a graph which shows the temperature dependence of the torque coefficient value by the graphite concentration in the Example of this invention, and a comparative example.

Claims (8)

A torque coefficient stabilizer comprising an aqueous dispersion containing graphite and wax. 2. The torque coefficient stabilizer according to claim 1, wherein the content ratio of the wax is 5 to 30% by weight. The torque coefficient stabilizer according to claim 1 or 2, wherein a content ratio of the graphite is 0.5 to 20% by weight. The torque coefficient stabilizer according to claim 1 or 2, wherein a content ratio of the graphite is 0.5 to 10% by weight. A member having a screwing portion, wherein at least a part of the surface is covered with a covering containing a mixture of graphite and wax. The member for screwing according to claim 5, wherein the member having a screwing portion is a nut, and at least a seating surface is covered with the covering. Preparing a screwing member having a torque coefficient stabilizer according to any one of claims 1 to 5 and a screwing part;
Attaching the torque coefficient stabilizer to at least a part of the surface of the screwing member;
Drying the screwing member to which the torque coefficient stabilizer is adhered;
A method for fastening a screwing member including a step of fastening the dried screwing member. The screwing member is a nut;
The method for fastening a screwing member according to claim 7, wherein the step of attaching the torque coefficient stabilizer is a step of attaching the torque coefficient stabilizer to at least a seating surface of the nut.

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